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Document and Entity Information	9 Months Ended
Sep. 30, 2013
Document and Entity Information
Entity Registrant Name	Ophthotech Corp.
Entity Central Index Key	0001410939
Document Type	S-1
Document Period End Date	Sep. 30, 2013
Amendment Flag	false
Entity Filer Category	Non-accelerated Filer

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 4,304	$ 6,396
Prepaid expenses and other current assets	44	65
Other receivables		1,036
Other Assets	331
Security deposits	158
Total current assets	4,837	7,497
Property and equipment, net	42	73
Other long-term assets		158
Total assets	4,879	7,728
Current liabilities:
Notes payable	11,040
Accrued clinical drug supplies and trial costs	1,013	1,497
Accounts payable and accrued expenses	1,391	1,626
Warrant Liability	966	193
Deferred Rent		22
Total current liabilities	14,410	3,338
Royalty purchase liability	0
Total liabilities	14,410	3,338
Commitments and contingencies
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable	113,939	106,877
Stockholders' equity (deficit)
Common stock-December 31, 2012-$0.001 par value, $0.001 par value, 155,864,851 shares authorized, 1,469,798 shares issued and outstanding; December 31, 2011-155,544,651 shares authorized, 1,451,294 shares issued and outstanding	1	1
Deficit accumulated during development stage	(126,471)	(105,488)
Total stockholders' equity deficit	(123,470)	(102,487)
Total liabilities and stockholders' equity deficit	4,879	7,728
Series A
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable	69,471	65,327
Series A-1
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable	8,460	7,981
Series B
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable	35,456	33,057
Series B-1
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable	552	512
Junior Series A Convertible Preferred Stock
Stockholders' equity (deficit)
Preferred Stock	3,000	3,000
Total stockholders' equity deficit	$ 3,000	$ 3,000

Balance Sheets (Parenthetical) $ in Thousands	Dec. 31, 2012 USD ($) $ / shares shares
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001
Common stock, shares authorized	155,864,851
Common stock, shares issued	1,469,798
Common stock, shares outstanding	1,469,798
Series A
Preferred Stock, Convertible and Redeemable, par value (in dollars per share) \| $ / shares	$ 0.001
Preferred Stock, Convertible and Redeemable, shares authorized	73,094,000
Preferred Stock, Convertible and Redeemable, shares issued	51,790,000
Preferred Stock, Convertible and Redeemable, shares outstanding	51,790,000
Preferred Stock, Convertible and Redeemable, aggregate liquidation preference \| $	$ 70,564
Series A-1
Preferred Stock, Convertible and Redeemable, par value (in dollars per share) \| $ / shares	$ 0.001
Preferred Stock, Convertible and Redeemable, shares authorized	18,480,000
Preferred Stock, Convertible and Redeemable, shares issued	6,000,000
Preferred Stock, Convertible and Redeemable, shares outstanding	6,000,000
Preferred Stock, Convertible and Redeemable, aggregate liquidation preference \| $	$ 8,460
Series B
Preferred Stock, Convertible and Redeemable, par value (in dollars per share) \| $ / shares	$ 0.001
Preferred Stock, Convertible and Redeemable, shares authorized	42,320,200
Preferred Stock, Convertible and Redeemable, shares issued	30,000,000
Preferred Stock, Convertible and Redeemable, shares outstanding	30,000,000
Preferred Stock, Convertible and Redeemable, aggregate liquidation preference \| $	$ 35,868
Series B-1
Preferred Stock, Convertible and Redeemable, par value (in dollars per share) \| $ / shares	$ 0.001
Preferred Stock, Convertible and Redeemable, shares authorized	700,000
Preferred Stock, Convertible and Redeemable, shares issued	500,000
Preferred Stock, Convertible and Redeemable, shares outstanding	500,000
Preferred Stock, Convertible and Redeemable, aggregate liquidation preference \| $	$ 552
Junior Series A Convertible Preferred Stock
Preferred stock, par value (in dollars per share) \| $ / shares	$ 0.001
Preferred stock, shares authorized	3,000,000
Preferred stock, shares issued	3,000,000
Preferred stock, shares outstanding	3,000,000

Statements of Operations shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2012 USD ($) $ / shares shares
Costs and expenses:
Research and development	$ 6,792
General and administrative	6,889
Total costs and expenses	13,681
Loss from operations	(13,681)
Interest (expense) income	(507)
Other loss	(374)
Net loss before income tax benefit	(14,562)
Net loss	(14,562)
Add: accretion of preferred stock dividends	(7,063)
Net loss attributable to common stockholders	$ (21,625)
Net loss attributable to common stockholders per share -Basic and diluted (in dollars per share) \| $ / shares	$ (14.89)
Weighted average common shares outstanding:
Basic and diluted (in shares) \| shares	1,452
Unaudited basic and diluted proforma net loss attributable to common stockholders per share (in dollars per share) \| $ / shares	$ 0.65
Unaudited basic and diluted proforma weighted average shares outstanding (in shares) \| shares	22,491

Statements of Changes in Stockholders' Deficit - USD ($) $ in Thousands	Total	Junior Series A Convertible Preferred Stock	Common stock	Additional paid-in Capital	Deficit Accumulated During the Development Stage
Balance at Dec. 31, 2007	$ (12,008)	$ 3,000	$ 1		$ (15,009)
Balance (in shares) at Dec. 31, 2007		3,000,000	932,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock	11			$ 11
Issuance of common stock (in shares)			97,000
Share-based compensation	14			14
Preferred Stock dividends	(2,597)			(25)	(2,572)
Net loss	(20,556)				(20,556)
Balance at Dec. 31, 2008	(35,136)	$ 3,000	$ 1		(38,137)
Balance (in shares) at Dec. 31, 2008		3,000,000	1,029,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock	13			13
Issuance of common stock (in shares)			107,000
Share-based compensation	58			58
Preferred Stock dividends	(4,188)			(71)	(4,117)
Net loss	(13,514)				(13,514)
Balance at Dec. 31, 2009	(52,767)	$ 3,000	$ 1		(55,768)
Balance (in shares) at Dec. 31, 2009		3,000,000	1,136,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock	39			39
Issuance of common stock (in shares)			290,000
Share-based compensation	231			231
Preferred Stock dividends	(5,823)			(270)	(5,553)
Net loss	(18,948)				(18,948)
Balance at Dec. 31, 2010	(77,268)	$ 3,000	$ 1		(80,269)
Balance (in shares) at Dec. 31, 2010		3,000,000	1,426,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock	4			4
Issuance of common stock (in shares)			25,000
Share-based compensation	248			248
Preferred Stock dividends	(6,838)			(252)	(6,586)
Net loss	(18,633)				(18,633)
Balance at Dec. 31, 2011	(102,487)		$ 1		(105,488)
Balance (in shares) at Dec. 31, 2011		3,000,000	1,451,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock	2			2
Issuance of common stock (in shares)			19,000
Share-based compensation	640			640
Preferred Stock dividends	(7,063)			$ (642)	(6,421)
Net loss	(14,562)				(14,562)
Balance at Dec. 31, 2012	$ (123,470)		$ 1		$ (126,471)
Balance (in shares) at Dec. 31, 2012		3,000,000	1,470,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock (in shares)	8,740,000
Net loss	$ (30,757)
Balance at Sep. 30, 2013	$ 188,801

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

+ Details

Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended		12 Months Ended		72 Months Ended	81 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Sep. 30, 2013
Operating Activities
Net loss	$ (30,757)	$ (10,731)	$ (14,562)	$ (18,633)	$ (100,630)	$ (131,387)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	14	24	31	32	154	169
Amortization of debt issuance costs	88	24	47		47	135
Accretion of debt discount	87	30	59		59	146
Non-cash change in fair value of warrant liability	1,231	332	366	7	382	1,612
Non-cash change in fair value of investor rights liability					(683)	(683)
Share-based compensation	1,607	283	640	248	1,190	2,797
Series A-1, Series B-1 and Junior Preferred Stock issued for acquired technology and licenses				500	9,500
Accrued interest expense converted to Series A Preferred Stock					2	2
Changes in operating assets and liabilities:
Prepaid expense and other current assets	(2,052)	27	21	135	(56)	(2,107)
Other receivables		1,036	1,036	(738)
Security deposits	(11)			(1)	(158)	(170)
Accrued clinical drug supplies and trial costs	2,464	(1,039)	(484)	(822)	1,013	3,477
Accounts payable and accrued expenses	3,040	787	(236)	173	1,391	4,431
Deferred rent		(22)	(22)	(24)
Net cash used in operating activities	(23,198)	(9,249)	(13,104)	(19,123)	(87,789)	(110,987)
Investing Activities
Purchase of marketable securities					(4,238)	(4,238)
Maturities of marketable securities				3,400	4,250	4,250
Purchase of property and equipment	(5)			(4)	(196)	(201)
Net cash provided by (used in) investing activities	(5)			3,396	(184)	(189)
Financing Activities
Payment of debt issuance costs	(43)	(263)	(377)		(377)	(421)
Proceeds from issuance of common stock		2	2	4	124	124
Proceeds from issuance of notes payable, net			11,387		11,596	210
Proceeds from issuance of preferred stock, net	49,699			14,990	80,934	130,632
Net cash provided by financing activities	254,978	7,199	11,012	14,994	92,277	347,255
Net change in cash and cash equivalents	231,775	(2,050)	(2,092)	(733)	4,304	236,079
Cash and cash equivalents
Beginning of period	4,304	6,396	6,396	7,129
End of period	236,079	4,346	4,304	6,396	4,304	236,079
Supplemental disclosures of cash flow information
Accreted dividends on Series A, Series A-1, Series B and Series B-1 Preferred Stock	$ 5,891	$ 5,288	$ 7,063	$ 6,838	27,155	33,046
Notes payable and accrued interest converted to Series A Preferred Stock					$ 212	$ 212

Business	9 Months Ended	12 Months Ended
Business	Sep. 30, 2013	Dec. 31, 2012
Business
Business	1. Business Description of Business and Organization Ophthotech Corporation (the "Company" or "Ophthotech") was incorporated on January 5, 2007, in Delaware. The Company is a biopharmaceutical company specializing in the development of novel therapeutics to treat diseases of the eye with a focus on developing therapeutics for age-related macular degeneration, or AMD. The Company's operations since inception have been limited to organizing and staffing the Company, acquiring rights to product candidates, business planning, raising capital and developing its product candidates. Accordingly, the Company is considered to be in the development stage as defined by Financial Accounting Standards Board Accounting Standards Codification ("ASC") 915, Development Stage Entities. The Company operates in one business segment. Capitalized terms not otherwise defined herein are defined in their respective agreements. Liquidity Since the Company's inception, it has incurred significant operating losses. The Company reported a net loss of $30.8 million for the nine months ended September 30, 2013 and $10.7 million for the nine months ended September 30, 2012. As of September 30, 2013, the Company had a deficit accumulated during the development stage of $162.7 million. To date, the Company has not generated any revenues and has financed its operations primarily through private placements of its preferred stock, venture debt borrowings, its royalty purchase and sale agreement with Novo A/S and its initial public offering ("IPO"), which closed on September 30, 2013. The Company issued and sold an aggregate of 8,740,000 shares of common stock in its IPO at a public offering price of $22.00 per share, including 1,140,000 shares pursuant to the exercise by the underwriters of an over-allotment option. The Company received net proceeds from the IPO of $175.6 million, after deducting underwriting discounts and commissions and other offering expenses. The Company has devoted substantially all of its financial resources and efforts to research and development and expects to continue to incur significant expenses and increasing operating losses over the next several years. The Company's net losses may fluctuate significantly from quarter to quarter and year to year. To fully execute its business plan, the Company will need to complete certain research and development activities and clinical trials. Further, the Company's product candidates will require regulatory approval prior to commercialization. These activities may span many years and require substantial expenditures to complete and may ultimately be unsuccessful. Any delays in completing these activities could adversely impact the Company. The Company plans to meet its capital requirements primarily through a combination of equity and debt financings, collaborations, strategic alliances and marketing distribution or licensing arrangements and in the longer term, revenue from potential product sales. There can be no assurance that such funds will be available, or if available, on terms favorable to the Company. The Company faces the normal risks associated with a development stage company, including but not limited to the risk that the Company's research and development activities will not be successfully completed, that adequate patent protection for the Company's technology will not be obtained, that any products developed will not obtain necessary government regulatory approval and that any approved products will not be commercially viable. In addition, the Company operates in an environment of rapid change in technology, substantial competition from pharmaceutical and biotechnology companies and is dependent upon the services of its employees and its consultants. The Company's capital requirements will depend on many factors, including the success of its development and commercialization of its product candidates and whether it pursues the development of additional product candidates. Even if the Company succeeds in developing and commercializing one or more of its product candidates, it may never achieve sufficient sales revenue to achieve or maintain profitability.	1. Business Description of Business and Organization Ophthotech Corporation (the "Company" or "Ophthotech") was incorporated on January 5, 2007, in Delaware. The Company is a biopharmaceutical company specializing in the development of novel therapeutics to treat diseases of the eye with a focus on developing therapeutics for age-related macular degeneration, or AMD. The Company's operations since inception have been limited to organizing and staffing the Company, acquiring rights to product candidates, business planning, raising capital and developing its product candidates. Accordingly, the Company is considered to be in the development stage as defined by Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 915, Development Stage Entities. The Company operates in one business segment. Capitalized terms not otherwise defined herein are defined in their respective agreements. Liquidity The Company expects to continue to incur substantial losses over the next several years during its development phase. To fully execute its business plan, the Company will need to complete certain research and development activities and clinical trials. Further, the Company's product candidates will require regulatory approval prior to commercialization. These activities may span many years and require substantial expenditures to complete and may ultimately be unsuccessful. Any delays in completing these activities could adversely impact the Company. The Company plans to meet its capital requirements primarily through a combination of equity and debt financings, collaborations, strategic alliances and marketing distribution or licensing arrangements and in the longer term, revenue from product sales. There can be no assurance that such funds will be available, or if available, on terms favorable to the Company. The Company faces the normal risks associated with a development stage company, including but not limited to the risk that the Company's research and development activities will not be successfully completed, that adequate patent protection for the Company's technology will not be obtained, that any products developed will not obtain necessary government regulatory approval and that any approved products will not be commercially viable. In addition, the Company operates in an environment of rapid change in technology, substantial competition from pharmaceutical and biotechnology companies and is dependent upon the services of its employees and its consultants. Since inception, the Company has primarily relied upon private placements of its preferred stock and venture debt borrowings to fund operations. However, the Company's capital requirements will depend on many factors, including the success of its development and commercialization of the Company's product candidates and whether it pursues the development of additional product candidates. Even if the Company succeeds in developing and commercializing one or more of its product candidates, it may never achieve sufficient sales revenue to achieve or maintain profitability.

Significant Accounting Policies

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Significant Accounting Policies

Significant Accounting Policies

2. Summary of Significant Accounting Policies

The Company's complete listing of significant accounting policies are described in Note 2 of the notes to the audited financial statements as of December 31, 2012, included in this prospectus.

Basis of Presentation

The accompanying unaudited financial information as of September 30, 2013, for the nine months ended September 30, 2013 and 2012, and for the period from January 5, 2007 (Inception) to September 30, 2013 has been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles have been condensed or omitted pursuant to such rules and regulations. The December 31, 2012 balance sheet was derived from the Company's audited financial statements. These interim financial statements should be read in conjunction with the 2012 audited annual financial statements and notes thereto in the final prospectus dated September 25, 2013 related to the Company's initial public offering.

In the opinion of management, the unaudited financial information as of September 30, 2013, for the nine months ended September 30, 2013 and 2012, and for the period from January 5, 2007 (Inception) to September 30, 2013, reflects all adjustments, which are normal recurring adjustments, necessary to present a fair statement of financial position, results or operations and cash flows. The results of operations for the nine months ended September 30, 2013 and 2012, are not necessarily indicative of the operating results for the full fiscal year or any future period.

Use of Estimates

The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company's Balance Sheets and the amount of expenses reported for each of the periods presented are affected by estimates and assumptions, which are used for, but not limited to, accounting for share-based compensation and accounting for research and development costs. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. The carrying amounts reported in the Balance Sheets for cash and cash equivalents are valued at cost, which approximates their fair value.

Concentration of Credit Risk

The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash and cash equivalents. The Company maintains its cash in bank accounts, which, at times, exceed federally insured limits. The Company also maintains cash equivalents in money market funds that invest primarily in U.S. Treasury securities. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on its cash and cash equivalents.

Foreign Currency Translation

The Company maintains a bank account in a foreign currency. The Company considers the U.S. dollar to be its functional currency. Expenses are translated at the exchange rate on the date the expense is incurred. The effect of exchange rate fluctuations on translating foreign currency assets and liabilities into U.S. dollars is included in the Statements of Operations. Foreign exchange transaction gains and losses are included in the results of operations and are not material in the Company's financial statements.

Financial Instruments

The carrying amounts of the Company's financial instruments, which include cash and cash equivalents, accounts payable and accrued expenses approximate their respective fair value due to their short maturities.

Property and Equipment

Property and equipment, which consist mainly of computers and other equipment, are carried at cost less accumulated depreciation. Depreciation is computed over the estimated useful lives of the respective assets, generally five to seven years, using the straight-line method.

Research and Development

Research and development expenses consist of costs associated with the development and clinical testing of Fovista, an anti-PDGF aptamer the Company is developing for use in combination with anti-VEGF drugs for treatment of wet age-related macular degeneration, or wet AMD, and the Company's other product candidates. Research and development expenses consist of:

•

external research and development expenses incurred under arrangements with third parties, such as contract research organizations, ("CROs") and other vendors, contract manufacturing organizations and consultants; and

•

employee-related expenses, including salaries, benefits, travel and share-based compensation expense.

Research and development costs also include costs of acquired product licenses and related technology rights where there is no alternative future use, prototypes used in research and development, consultant fees and amounts paid to collaborative partners.

All research and development costs are charged to operations as incurred in accordance with ASC 730 Research and Development. The Company accounts for non-refundable advance payments for goods and services that will be used in future research and development activities as expenses when the service has been performed or when the goods have been received, rather than when the payment is made.

The Company anticipates that its research and development expenses will increase substantially as compared to prior periods in connection with initiating and conducting its pivotal Phase 3 clinical program for Fovista and if such trials are successful, seeking marketing approval for Fovista.

The Company does not currently utilize a formal time allocation system to capture expenses on a project-by-project basis because it records expenses by functional department. Accordingly, the Company does not allocate expenses to individual projects or product candidates, although it does allocate some portion of its research and development expenses by functional area and by compound.

Income Taxes

The Company utilizes the liability method of accounting for deferred income taxes, as set forth in ASC 740-10, Income Taxes-Overall. Under this method, deferred tax liabilities and assets are recognized for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. A valuation allowance is established against net deferred tax assets because, based on the weight of available evidence, it is more likely than not that some or all of the net deferred tax assets will not be realized. The Company maintains a full valuation allowance on its deferred tax assets. Accordingly, the Company has not recorded a benefit or provision for income taxes other than for the sale of a portion of its unused New Jersey State operating loss carryforwards through a program sponsored by the State of New Jersey and the New Jersey Economic Development Authority in 2011. The Company's U.S. federal net operating losses have occurred since inception and as such, tax years subject to potential tax examination could apply from that date because carrying-back net operating loss opens the relevant year to audit.

Share-Based Compensation

The Company follows the provisions of the ASC 718, Compensation—Stock Compensation which requires the measurement and recognition of compensation expense for all share-based payment awards made to employees and non-employee directors, including employee stock options. Share-based compensation expense is based on the grant date fair value estimated in accordance with the provisions of ASC 718 and is generally recognized as an expense over the requisite service period.

For stock options granted as consideration for services rendered by non-employees, the Company recognizes expense in accordance with the requirements of ASC 505-50, Equity Based Payments to Non-Employees. Non-employee option grants that do not vest immediately upon grant are recorded as an expense over the vesting period of the underlying stock options. At the end of each financial reporting period prior to vesting, the value of these options, as calculated using the Black-Scholes option-pricing model, will be re-measured using the fair value of the Company's common stock and the non-cash expense recognized during the period will be adjusted accordingly. Since the fair value of options granted to non-employees is subject to change in the future, the amount of the future expense will include fair value re-measurements until the stock options are fully vested.

Prior to the Company's initial public offering, the Company determined the estimated fair value of the common stock based on a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector and the prices at which the Company sold shares of its common stock.

Due to the lack of trading history, the Company's computation of stock-price volatility is based on the volatility rates of comparable publicly held companies over a period equal to the expected term of the options granted by the Company. The Company's computation of expected term was determined using the "simplified" method which is the midpoint between the vesting date and the end of the contractual term. The Company believes that it does not have sufficient reliable exercise data in order to justify the use of a method other than the "simplified" method of estimating the expected exercise term of employee stock option grants. The Company has paid no dividends to stockholders. The risk-free interest rate is based on the zero-coupon U.S. Treasury yield at the date of grant for a term equivalent to the expected term of the option.

Share-based compensation expense includes stock options granted to employees and non-employees and has been reported in the Company's statements of operations as follows:

	Nine months ended September 30,

	2013		2012
Research and development	$	1,052	$	182
General and administrative		555		101

Total	$	1,607	$	283

The Company had no shares of unvested restricted common stock granted to employees at September 30, 2013 or at December 31, 2012, respectively.

Reclassification

Certain amounts in prior periods have been reclassified to conform to the current year presentation. Such reclassifications did not have a material effect on the Company's financial condition or results of operations as previously reported.

JOBS Act

As an "emerging growth company" under the Jumpstart Our Business Startups Act of 2012, the Company can take advantage of an extended transition period for complying with new or revised accounting standards. This allows an emerging growth company to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. The Company has elected to delay the adoption of such new or revised accounting standards. As a result of this election, the Company's financial statements may not be comparable to the financial statements of other public companies.

2. Significant Accounting Policies

Basis of Presentation

The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States and include all adjustments necessary for the fair presentation of the Company's financial position for the periods presented.

Unaudited Pro Forma Information

Unaudited pro forma net loss per share is computed using the weighted-average number of common shares outstanding and gives effect to the automatic conversion of all outstanding shares of the Company's preferred stock, into an aggregate of 21,038,477 shares of the Company's common stock, as if they had occurred during the year ended December 31, 2012, and the completion of the Company's initial public offering that occurred on September 30, 2013.

Use of Estimates

The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company's Balance Sheets and the amount of expenses reported for each of the periods presented are affected by estimates and assumptions, which are used for, but not limited to, the accounting for stock-based compensation and investor rights liabilities, for income taxes and accounting for research and development costs. Actual results could differ from those estimates.

Cash and Cash Equivalents

Concentration of Credit Risk

The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash. The Company maintains its cash in bank accounts, which, at times, exceed federally insured limits. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on cash.

Foreign Currency Translation

The Company maintains a bank account in a foreign currency. The Company considers the United States dollar to be the functional currency. Expenses are translated at the exchange rate on the date the expense is incurred. The effect of exchange rate fluctuations on translating foreign currency assets and liabilities into United States dollars is included in the Statements of Operations. Foreign exchange transaction gains and losses are included in the results of operations and are not material in the Company's financial statements.

Financial Instruments

The carrying amounts of the Company's financial instruments, which include cash and cash equivalents, other receivables, accounts payable and accrued expenses, and warrants, approximate their fair value due to their short maturities. The carrying amounts of warrants approximate their fair value based upon option pricing models.

Property and Equipment

Research and Development

All research and development costs are expensed as incurred. Research and development costs include costs of acquired product license and related technology rights where there is no alternative future use, prototypes used in research and development, consultant fees and amounts paid to collaborative partners. All research and development costs are charged to operations as incurred in accordance with ASC 730, Research and Development.

Income Taxes

The Company utilizes the liability method of accounting for deferred income taxes, as set forth in ASC 740-10, Income Taxes-Overall. Under this method, deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. A valuation allowance is established against deferred tax assets because the Company's management believes it cannot at this time conclude that it is more likely than not that some or all of the deferred tax assets will not be realized. The Company maintains a full valuation allowance on its deferred tax assets. Accordingly, the Company has not recorded a benefit or provision for income taxes other than for the sale of a portion of its unused New Jersey State operating loss carryforwards through a program sponsored by the State of New Jersey and the New Jersey Economic Development Authority in 2011. Since its inception, the Company has incurred losses for U.S. Federal income tax purposes, and is subject to potential tax examination from the date these losses are utilized in future tax returns.

Share-Based Compensation

At December 31, 2012 and 2011, the Company had one share-based employee compensation plan, which is described more fully in Note 12.

The Company grants stock options for a fixed number of shares to employees and non-employees with an exercise price equal to the fair value of the share at the grant date.

The Company accounts for share-based compensation in accordance with ASC 718, Compensation—Stock Compensation. The Company selected the Black-Scholes option pricing model as the most appropriate model for determining the estimated fair value for share-based awards. The fair value is then amortized on a straight-line basis over the requisite service periods of the awards, which is generally the vesting period. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs. Expected volatility was calculated based on the weighted-average of historical information of similar public entities. The Company will continue to use a weighted-average approach using other similar public entity volatility information until historical volatility of the Company is relevant to measure expected volatility for future option grants.

The average expected life was determined according to the Securities and Exchange Commission ("SEC") shortcut approach as described in Staff Accounting Bulletin ("SAB") No. 110, which is the mid-point between the vesting date and the end of the contractual term.

The risk-free interest rate is based on U.S. Treasury zero-coupon bonds with a remaining term equal to the expected life assumed at the date of grant. Forfeitures are estimated based on voluntary termination behavior, as well as historical analysis of actual option forfeitures. The weighted-average assumptions used in the Black-Scholes option pricing model are as follows:

	Year Ended December 31,

	2012	2011
Expected common stock price volatility	81%	79%
Risk-free interest rate	0.94% - 1.77%	1.72% - 2.38%
Expected term of options (years)	6.6	6.7
Expected annual dividend per share	$—	$—

Recent Accounting Pronouncements

In May 2011, the Financial Accounting Standards Board issued guidance that changed the requirement for presenting "Comprehensive Income" in the financial statements. The update requires an entity to present the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. The currently available option to disclose the components of other comprehensive income within the statement of stockholders' equity will no longer be available. The update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2011, and should be applied retrospectively. The Company did not incur any components of comprehensive income for the periods presented and therefore did not include a statement of comprehensive income in the financial statements.

In February 2013, the FASB issued Accounting Standards Update ("ASU") 2013-02, Comprehensive Income: Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income ("ASU 2013-02"). ASU 2013-02 requires an entity to present the effect of certain significant reclassifications out of accumulated other comprehensive income on the respective line items in net income. The amendments in the ASU do not change the items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income. ASU 2013-02 is effective prospectively for fiscal years beginning after December 15, 2012. As the ASU requires additional presentation only, there will be no impact to the Company's results of operations or financial position.

Financing Activities	12 Months Ended
Financing Activities	Dec. 31, 2012
Financing Activities
Financing Activities	5. Financing Activities On June 18, 2007, the Company issued promissory notes (the "Notes") totaling $0.2 million to certain investors. The Notes carried an interest rate of 8% per annum. The Notes and related accrued interest expense were converted into Series A Preferred Stock in conjunction with the Initial Closing under the Series A Agreement described below. On August 9, 2007, the Company entered into a Series A Preferred Stock Purchase Agreement (the "Series A Agreement") with the holders of the Notes and another investor (the "Series A Investors") which provided for the sale and issuance of the Company's Series A Preferred Stock at a price of $1.00 per share in the following tranches: (a) 9,253,101 shares at closing (the "Initial Closing"), (b) 9,217,243 shares provided that the License Agreement described in Note 6 remained in effect within 10 days of the date of the Series A Agreement (the "First Milestone Event") and (c) 17,319,656 shares upon initiation of a Phase 1b study with respect to any of the assets acquired or licensed under the Product and Technology Agreements entered into by the Company in 2007 described in Note 6. As of December 31, 2007, the Company and the Series A Investors had completed the Initial Closing and the First Milestone Event Closing. On April 14, 2008, the Series A Agreement was amended and established the following tranches for the sale and issuance of Series A Preferred Stock to each of the Series A Investors at $1.00 per share: (a) 6,000,000 shares provided the Collaborative License Agreement referred to above remains in effect on or before April 15, 2008 (the "Second Milestone Event"), (b) 13,000,000 shares upon initiation of a Phase 1b study with respect to any one of the assets (each such asset a "Milestone Asset") identified in the amendment to the Series A Agreement (the "Third Milestone Event"), (c) 4,319,656 shares upon initiation of a Phase 1b study with respect to a Milestone Asset other than the Milestone Asset relating to the Third Milestone Event (the "Fourth Milestone Event"), and (d) 7,000,000 shares upon initiation of a Phase 1b study with respect to a Milestone Asset other than the Milestone Asset relating to the Third Milestone Event or the Fourth Milestone Event (the "Fifth Milestone Event"). In connection with the issuance of the Notes in June 2007, the Company issued 210,000 warrants to purchase Series A Preferred Stock with an exercise price of $0.01 per share. The warrants expire on June 18, 2017. The warrants provide for proportionate adjustments to be made to the number of shares purchasable and the exercise price payable under the warrants in the event of certain changes to the underlying Series A Preferred Stock, including for subdivisions, combinations and stock dividends. The Series A warrants are accounted for as a liability and are marked to market using a hybrid method of an option pricing model and a probability-weighted return methodology. The change in fair value of the Series A warrant liability is recorded within other loss. As of December 31, 2012 and 2011, the value of the Series A warrant liability was $0.5 million and $0.2 million, respectively, as reflected in the accompanying Balance Sheets and the change in the fair value of $0.3 million for the year ended December 31, 2012, was recorded in the Statements of Operations. The Company and the Series A Investors closed the Second Milestone Event on April 14, 2008, and closed the Third Milestone Event on September 19, 2008, issuing 6,000,000 and 13,000,000 shares of Series A Preferred Stock, respectively. ASC 480, Distinguishing Liabilities from Equity, concluded that these rights for shares in redeemable instruments represent free-standing financial instruments and should be accounted for as liabilities under ASC 480. In accordance with ASC 480, the Company adjusts the carrying value of such rights to their estimated fair value at each reporting date. Pursuant to ASC 480, increases or decreases in the fair value of such rights are recorded in the Statements of Operations. The estimated fair value was determined using a valuation model which considers the probability of achieving a milestone, if any, the Company's cost of capital, the estimated period the rights will be outstanding, consideration received for the instrument with the rights, the number of shares to be issued to satisfy the rights and at what price and any changes in the fair value of the underlying instrument to the rights. The recorded liability was fulfilled in May 2009 upon the exercise of the remaining rights by investors. Since such time, there have not been, and there continue not to be, any rights outstanding. Upon the closing of an initial public offering in which all of the outstanding shares of the Company's Series A Preferred Stock and Series B Preferred Stock convert into Common Stock, the Company expects to reclassify the warrant liability to additional paid-in capital as a result of the outstanding warrants to purchase shares of Series A Preferred Stock and Series B Preferred Stock becoming, in accordance with their terms, warrants to purchase shares of Common Stock, at a weighted average exercise price of $5.47 per share. On September 19, 2008, the Company met the Third Milestone and issued 13,000,000 shares of Series A Preferred Stock at $1.00 per share, resulting in net proceeds to the Company of $13.0 million. As a result of the exercise of certain investor rights, the related liability amounting to $0.3 million was extinguished and recorded as an increase in Preferred Stock. On May 6, 2009, the Company met the Fourth Milestone and the Fifth Milestone and issued 11,319,656 shares of Series A Preferred Stock at $1.00 per share, resulting in net proceeds to the Company of $11.3 million. As a result of the exercise of certain investor rights, the related liability amounting to $0.3 million was extinguished and recorded as an increase in Preferred Stock. On October 14, 2009, the Series A Agreement was amended to allow for the sale and issuance of up to 3,000,000 additional shares of Series A Preferred Stock at an additional closing. Consequently, on October 14, 2009, the Company issued 3,000,000 shares of Series A Preferred Stock to existing Series A stockholders at a price per share of $1.00. In connection with the Product and Technology Agreements entered into by the Company (see Note 6), the Company issued on August 9, 2007, 2,000,000 shares of Series A-1 Preferred Stock and 3,000,000 shares of Junior Series A Preferred Stock, with each class of Preferred Stock being recorded at a fair market value of $1.00 per share based on the cash price paid by the Series A Investors for similar shares on the same date. In connection with a license agreement entered into by the Company on January 4, 2008 (see Note 6), the Company issued 4,000,000 shares of Series A-1 Preferred Stock. The Series A-1 Preferred Stock was valued at $1.00 per share. Accordingly, the Company charged $4.0 million to research and development expense during the year ended December 31, 2008. On December 11, 2009, the Company entered into a Series B Preferred Stock Purchase Agreement (the "Series B Agreement") with the Series A Investors and another investor (the "Series B Investors") which provided for the sale and issuance of the Company's Series B Preferred Stock at a price of $1.00 per share in the following tranches: (a) 15,000,000 shares at closing (the "Initial B Closing") and (b) up to an additional 15,000,000 shares based on the satisfaction of the Second Closing Conditions, as defined in the Series B Agreement. On March 1, 2011, the Company met the Second Closing Conditions, as defined in the Series B Agreement, and issued 15,000,000 shares of Series B Preferred Stock at $1.00 per share to the existing holders of Series B Preferred Stock. On June 20, 2012 and December 24, 2012, the Company issued secured promissory notes (the "2012 Notes") in the amount of $7.5 million and $4.0 million, respectively, to the same Lender. The 2012 Notes bear interest on the outstanding principal amount thereof from the Closing Date until paid in full at a rate per annum equal to the sum of (i) the greater of (A) the LIBOR Rate in effect for the applicable Interest Period and (B) 3.0%, plus (ii) the LIBOR Rate Margin adjusted on the first day of each Interest Period and fixed for the duration of each such Interest Period. In conjunction with the secured promissory note issued on June 20, 2012, the Lender received warrants to purchase 225,000 shares of Series B Preferred Stock with an exercise price of $1.00 per share. The warrants expire on June 20, 2022. In conjunction with the secured promissory note issued on December 24, 2012, the Lender received warrants to purchase 95,200 shares of Series B Preferred Stock with an exercise price of $2.50 per share. The warrants expire on December 24, 2022. The warrants provide for proportionate adjustments to be made to the number of shares purchasable and the exercise price payable under the warrants in the event of certain changes to the underlying Series B Preferred Stock, including for subdivisions, combinations and stock dividends. The Series B warrants are accounted for as a liability and are marked to market using a hybrid method of an option pricing model and a probability-weighted return methodology. The change in fair value of the Series B warrant liability is recorded within other loss. As of December 31, 2012, the value of the Series B warrant liability was $0.4 million as reflected in the accompanying Balance Sheet and the change in the fair value of $36 thousand for the year ended December 31, 2012 was recorded in the Statement of Operations.

Product and Technology Agreements	12 Months Ended
Product and Technology Agreements	Dec. 31, 2012
Product and Technology Agreements
Product and Technology Agreements	6. Product and Technology Agreements Transferred Technology and Assumed Agreements Under an agreement dated July 27, 2007, the Company assumed the rights and obligations related to certain patents and know-how (the "Transferred Technology") and under certain agreements (the "Assumed Agreements") owned and/or controlled by OSI (Eyetech), Inc. (the "Transferor") for use in the Company's activities in the research, development and commercial production of a product as defined in the agreement (the "Divestiture Agreement"). In consideration for the Transferred Technology and the Assumed Agreements, the Company made an upfront payment of $4.0 million to the Transferor. In addition, on August 9, 2007, the Company issued to the Transferor 3,000,000 shares of Junior Series A Preferred Stock which was valued at $1.00 per share based upon the Original Issue Price. The Divestiture Agreement also entitles the Transferor to significant payments from the Company upon achievement of certain milestones, and to royalties on the Company's net sales of Products, as defined, and on terms set forth in the Divestiture Agreement. The Divestiture Agreement may be terminated by either party in the event of the other party's insolvency or material breach (following a specified cure period). Unless terminated earlier by the Company or the Transferor, the Divestiture Agreement will remain in effect until the Company no longer has any financial obligations to the Transferor, after which the rights granted to the Company under the Divestiture Agreement will become perpetual and fully paid-up. If the Company fails to satisfy its diligence obligations under the Divestiture Agreement, the Transferor may terminate the Divestiture Agreement as to particular countries with respect to which such failure has occurred, and upon such termination the Company will be obligated to transfer to the Transferor specified rights and licenses related to the product covered by the Divestiture Agreement and other related assets, and if the Company is then manufacturing such product or products, at the time of such termination, the Company may be obligated to provide transitional supply of the covered products to the Transferor, for the applicable countries. The Assumed Agreements include a license, manufacturing and supply agreement (the "Supply Agreement") with Nektar Therapeutics, AL (the "Supplier") for a reagent linked with the active ingredient in the Company's lead product candidate. Prior to the Company's assumption of the Supply Agreement in 2007, the Transferor paid the Supplier approximately $0.3 million under the Supply Agreement. The Company has paid the Supplier an aggregate of approximately $0.8 million under the Supply Agreement, which was charged to research and development expense during the year ended December 31, 2010. Under the Supply Agreement, the Company is obligated to make certain milestone payments to the Supplier, as well as tiered royalties based on certain percentages of net sales as well as certain other payments and revenue it may receive if it licenses certain product rights to a third party. See "Note 11—Commitments and Contingencies" below. The Supply Agreement, unless earlier terminated by either party, will expire upon the expiration of the Company's obligation to pay royalties to the Supplier on net sales of licensed products. The Supply Agreement may be terminated by either party in the event of the other party's material breach (following a specified cure period). The Company may terminate the Supply Agreement, without cause, effective at the end of a specified period following written notice to the Supplier, in which event the Company will be obligated to pay the Supplier specified termination fees and reimburse the Supplier for certain costs. License Agreements The Assumed Agreements also included an agreement with Archemix Corp. (the "Licensor") for the Company's acquisition of an exclusive royalty-bearing license over certain patent rights and technology owned and/or controlled by the Licensor (the "PDGF License") for use in the Company's activities in the research, development and commercial production of pharmaceutical products related to anti-PDGF aptamers (the "PDGF Licensed Products") as contemplated in the agreement (the "PDGF Agreement"). In addition, on July 31, 2007, the Company also entered into an agreement with the Licensor for the Company's acquisition of an exclusive royalty-bearing license over certain patent rights and technology owned and/or controlled by the Licensor (the "C5 License" and together with the PDGF License, the "Licenses") for use in the Company's activities in the research, development and commercial production of pharmaceutical products related to Zimura (the "C5 Licensed Product") as contemplated in the agreement (the "C5 License Agreement" and together with the PDGF License Agreement, the "License Agreements"). In consideration of the Licenses, the Company paid the Licensor aggregate upfront fees of $1.0 million and, on August 9, 2007, issued to the Licensor an aggregate of 2,000,000 shares of Series A-1 Preferred Stock which was valued at $1.00 per share based on the cash price paid by the Series A Investors for similar shares on the same date. The Licensor is also entitled to certain regulatory milestone payments and sales milestone payments under the License Agreements. The upfront fees totaling $5.0 million and the value of the Junior Series A Preferred Stock and Series A-1 Preferred Stock issued totaling $5.0 million to the Transferor and the Licensor, under the Divestiture Agreement and the License Agreement, respectively, were charged to research and development expense during the year ended December 31, 2007. On January 4, 2008, the Company entered into an agreement with certain collaborative partners whereby the Company acquired an exclusive license to develop, market and promote products containing or comprising certain material upon which the collaborative partners have sole and exclusive worldwide rights to develop, market and sell. Upon the execution of the license agreement, the Company issued 4,000,000 shares of Series A-1 Preferred Stock to such partners. The Series A-1 Preferred Stock was valued at $1.00 per share based upon the Original Issue Price. Accordingly, the Company charged research and development expense for $4.0 million. Under the license agreement, the corroborative partners are entitled to certain development and sales milestone payments plus royalties on net sales. On May 3, 2012, the Company terminated such agreement. On September 12, 2011, the License Agreements, were amended to cover expanded licenses for all indications outside of the ophthalmic field (as defined in the amended license agreements (the "Amended License Agreements")). Upon the execution of the Amended License Agreements, the Company issued 500,000 shares of Series B-1 Preferred Stock to the Licensor. The Series B-1 Preferred Stock was valued at $1.00 per share based upon the Original Issue Price, which was still deemed to be fair value as of the date of this transaction. Accordingly, the Company charged research and development expense for $0.5 million. Unless earlier terminated, the amended PDGF Agreement will expire upon the later of 10 years after the first commercial sale in any country of the last PDGF Licensed Product and the expiration of the last-to-expire valid claim of the PDGF licensed patents that covers a PDGF Licensed Product. Unless earlier terminated, the amended C5 Agreement will expire upon the later of 12 years after the first commercial sale in any country of the last C5 Licensed Product, the expiration of the last-to-expire valid claim of the C5 licensed patents, and the date on which no further payments of sublicensing income, if any, are to be received by the Company. Either of the Amended License Agreements may be terminated by either party in the event of the other party's material breach (following a specified cure period). The Licensor may also terminate each of the Amended License Agreements, or may convert the Company's exclusive licenses to non-exclusive licenses, if the Company challenges or assists a third party in challenging the validity or enforceability of any of the patents licensed under the applicable Amended License Agreement. The Company may terminate each of the Amended License Agreements at any time and for any or no reason effective at the end of a specified period following written notice to the Licensor.

Capital Structure	12 Months Ended
Capital Structure	Dec. 31, 2012
Capital Structure
Capital Structure	7. Capital Structure Authorized Capital Stock In connection with the issuance of the notes on June 20, 2012, the Company amended its certificate of incorporation to increase the authorized shares of capital stock to the following: 155,769,651 shares of common stock and 73,094,000 shares of Series A Preferred Stock, 18,480,000 shares of Series A-1 Preferred Stock, 3,000,000 shares of Junior Series A Preferred Stock, 42,225,000 shares of Series B Preferred Stock, and 700,000 shares of Series B-1 Preferred Stock, each with a par value of $0.001 per share. In connection with the issuance of the notes on December 24, 2012, the Company amended its certificate of incorporation to increase the authorized shares of capital stock to the following: 155,864,851 shares of common stock and 73,094,000 shares of Series A Preferred Stock, 18,480,000 shares of Series A-1 Preferred Stock, 3,000,000 shares of Junior Series A Preferred Stock, 42,320,200 shares of Series B Preferred Stock, and 700,000 shares of Series B-1 Preferred Stock, each with a par value of $0.001 per share. Such authorized amounts remained the same at December 31, 2012. Common Stock The Company's common stock has a par value of $0.001 per share. The voting, dividend and liquidation rights of the holders of the common stock are subject to and qualified by the rights, powers and preferences of the holders of the Preferred Stock. Each holder of common stock is entitled to vote on all matters and is entitled to one vote for each share held. *Restricted Stock* Of the 1,469,798 shares of common stock issued and outstanding at December 31, 2012, 677,964 shares were issued to officers of the Company. Such shares of stock are subject to restrictions on transfer and a risk of forfeiture as set forth in the respective restricted stock agreements between the Company and the owners of such shares. At December 31, 2012, all shares were 100% vested and no longer subject to forfeiture. Preferred Stock *Voting Rights* Each holder of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock is entitled to vote on all matters and is entitled to one vote equal to the number of shares of common stock into which such shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock could be converted. Except as provided by law or by the other provisions of the Certificate of Incorporation, holders of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock vote together with the holders of common stock as a single class. The Junior Series A Preferred Stock is non-voting and is not entitled to receive notice of, or vote at, any meetings of the stockholders of the Company. *Dividend Rights* The holders of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock, in preference to the holders of common stock, are entitled to receive dividends as described below. Such dividends accrue from day to day, whether or not declared and are cumulative. The dividends are payable only when, as and if declared by the Board of Directors. No dividends were declared for the years ended December 31, 2012 and 2011, or for the period from January 5, 2007 (inception) to December 31, 2012. For any shares of Series A Preferred Stock and Series A-1 Preferred Stock outstanding as of the Series B Original Issue Date (as defined in the Series B Purchase Agreement), during the period from and after the issuance of each such share through but excluding the Series B Original Issue Date, cash dividends accrued with respect to such shares at a rate of $0.08 per share. From and after the Series B Original Issue Date, cash dividends continue to accrue with respect shares of Series A Preferred Stock and Series A-1 Preferred Stock that were outstanding as of the Series B Original Issue Date at a rate of $0.04 per share per annum. For any shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock or Series B-1 Preferred Stock issued on or after the Series B Original Issue Date, during the period from and after the issuance of each such share, cash dividends accrue with respect to each outstanding share at a rate of $0.04 per share per annum. For all outstanding shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock, during the period from and after the later of the Series B Original Issue Date or the issuance of each such share, stock dividends accrue with respect to each outstanding share at a rate of 0.04 of a share per annum. The dividend rights of the holders of Junior Series A Preferred Stock are subject to and qualified by the rights, powers and preferences of the holders of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock. *Liquidation Preference of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock* The liquidation rights of the holders of Junior Series A Preferred Stock are subject to and qualified by the rights, powers and preferences of the holders of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock. Upon the liquidation of the Company, before any distribution shall be made to the holders of the Junior Series A Preferred Stock or common stock, the holders of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock, are entitled to be paid out of the assets of the Company, for each outstanding share and for each share accrued as stock dividends an amount equal to the original issue price of one dollar (the "Series A Original Issue Price", the "Series A-1 Original Issue Price", the "Series B Original Issue Price", or the "Series B-1 Original Issue Price", as applicable) plus any accrued cash dividends unpaid, whether or not declared, together with any other dividends declared but unpaid (the "Series A Preferential Payment Amount", the "Series A-1 Preferential Payment Amount", the "Series B Preferential Payment Amount", or the "Series B-1 Preferential Payment Amount", as applicable). The holders of the Junior Series A Preferred Stock then outstanding are then entitled to be paid out of the assets of the Company, before any distribution to the holders of the Company's common stock, an amount equal to the original issue price of one dollar plus any dividends declared but unpaid (the "Junior Series A Preferred Stockholders Preferential Payment Amount"). After the payment of the Series A, Series A-1, Series B, Series B-1 and Junior Series A Preferential Payment Amounts, the remaining assets shall be distributed pro rata based on the number of shares to the holders of the Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock (after giving effect to the payment of any accrued stock dividends to the holders of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock) and common stock as if the Series A Preferred Stock, the Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock had been converted to common stock immediately prior to such dissolution, liquidation or winding up of the Company (as-if-converted basis), provided however that (i) if the Series A Preferential Payment Amount per share plus the payment received after the pro rata distribution or Series A-1 Preferential Payment Amount per share plus the payment received after the pro rata distribution, as the case may be, exceeds two times the Series A Original Issue Price or the Series A-1 Original Issue Price, as applicable (the "Series A Maximum Participation Amount"), the amount such holder of the Series A Preferred Stock or Series A-1 Preferred Stock shall receive shall be the greater of (a) the Series A Maximum Participation Amount or (b) the amount such holder of Series A Preferred Stock and Series A-1 Preferred Stock would receive on an as-if-converted basis, (ii) if the Series B Preferential Payment Amount per share plus the payment received after the pro rata distribution, exceeds 2.65 times the Series B Original Issue Price (the "Series B Maximum Participation Amount"), the amount such holder of the Series B Preferred Stock and Series B-1 Preferred Stock shall receive shall be the greater of (a) the Series B Maximum Participation Amount or (b) the amount such holder of Series B Preferred Stock and Series B-1 Preferred Stock would receive on an as-if-converted basis. Under the Company's certificate of incorporation, any merger, acquisition or consolidation involving the Company, or the sale, lease, transfer, exclusive license or other disposition in a single transaction or series of related transactions of all or substantially all of the assets of the Company that would have resulted in a change in control of the Company, shall be considered a liquidation event ("Deemed Liquidation Event"), unless the holders of at least a majority of the outstanding shares of Series A Preferred Stock and holders of at least 60% of the outstanding shares of Series B Preferred Stock elect otherwise. Because in a Deemed Liquidation Event, the holders of shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock retain their preferential rights as described above, the Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock have been presented outside of stockholders' deficit in the accompanying Balance Sheets. In a Deemed Liquidation Event, the Junior Series A Preferred Stockholder is treated the same as common stock. *Optional Conversion* Subject to and in compliance with the provisions of the Certificate of Incorporation, each share of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock and Series B-1 Preferred Stock, and Junior Series A Preferred Stock are convertible, at the option of the holder thereof, at any time and from time to time, and without the payment of additional consideration by the holder thereof, into such number of fully paid and nonassessable shares of common stock as is determined by dividing the Series A, Series A-1, Series B and Series B-1 Original Issue Price by the Series A, Series A-1, Series B and Series B-1 Conversion Price in effect at the time of conversion. The Series A, Series A-1, Series B and Series B-1 Conversion Price is initially equal to $1.00. Such respective initial conversion prices, and the rate at which shares of respective classes of Preferred Stock may be converted into shares of common stock, are subject to adjustment as provided in the Certificate of Incorporation. Immediately prior to an optional conversion, all accrued stock dividends, accrued but unpaid, whether or not declared, shall be deemed issued in respect of the shares of preferred stock. *Adjustment for Stock Splits and Combinations* If the Company shall effect a stock split or combination with respect to the common stock, the Series A Conversion Price, Series A-1 Conversion Price, Series B Conversion Price and Series B-1 Conversion Price shall be proportionately adjusted so that the number of shares of common stock issuable on conversion of each outstanding share of the relevant series is increased or decreased in proportion to the corresponding increase or decrease in the aggregate number of shares of common stock outstanding as a result of the stock split or combination, as applicable. Any such adjustment becomes effective at the close of business on the date the stock split or combination becomes effective. *Mandatory Conversion* All outstanding shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock and Junior Series A Preferred Stock are subject to automatic conversion into shares of common stock, at the then effective applicable conversion rate, upon the closing of an underwritten public offering of shares of common stock to the public at a specified minimum price per share (subject to adjustment as a result of any stock dividend, stock split, combination or similar recapitalization of the common stock), resulting in at least $40.0 million of proceeds, net of underwriting discount and commissions, to the Company. In addition, (a) all outstanding shares of Series A Preferred Stock and Series A-1 Preferred Stock are subject to conversion into shares of common stock, at the then effective applicable conversion rate at such date and time, or upon the occurrence of such event as may be, specified by vote or written consent of the holders of at least majority of the then outstanding shares of Series A Preferred Stock and (b) all outstanding shares of Series B Preferred Stock and Series B-1 Preferred Stock are subject to conversion into shares of common stock, at the then effective applicable conversion rate at such date and time, or upon the occurrence of such event as may be, specified by vote or written consent of the holders of at least 60% of the then outstanding shares of Series B Preferred Stock. Immediately prior to a mandatory conversion, all accrued stock dividends, accrued but unpaid, whether or not declared, shall be deemed issued in respect to the shares of preferred stock. In the event that any holder of shares of Series A Preferred Stock or Series B Preferred Stock does not participate in a qualified financing (defined as any transaction involving the issuance or sale of additional shares of common stock after the Series B Original Issue Date that would result in the reduction of the Series B Conversion Price pursuant to the terms of the Certificate of Incorporation or any bridge financing, unless the holders of at least a majority of the Series A Preferred Stock and at least 60% of the Series B Preferred Stock elect that such transaction not be treated as a qualified financing) by purchasing, in the aggregate, such holder's pro rata amount, then each share of Series A Preferred Stock and Series B Preferred Stock held by such holder shall automatically, and without any further action on the part of such holder, be converted into one share of common stock.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph d
-Article 4

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Income Taxes

12 Months Ended

Dec. 31, 2012

Income Taxes

Income Taxes

8. Income Taxes

The Company utilizes the liability method of accounting for deferred income taxes. Under this method, deferred tax liabilities and assets are recognized for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. A valuation allowance is established against deferred tax assets because, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company's policy is to record interest and penalties on uncertain tax positions as income tax expense. As of December 31, 2012, the Company does not believe any material uncertain tax positions are present. Accordingly, interest and penalties have not been accrued due to an uncertain tax position and the fact the Company has reported tax losses since inception.

Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. A reconciliation of the statutory U.S. federal rate to the Company's effective tax rate is as follows:

	For the years ended December 31,

	2012			2011
Percent of pre-tax income:
U.S. federal statutory income tax rate		35.0	%		35.0	%
State taxes, net of federal benefit		0.0	%		3.4	%
Permanent items		(1.0	)%		(0.6	)%
Research and development credit		1.0	%		0.7	%
Change in valuation allowance		(35.0	)%		(33.3	)%

Effective income tax rate		0.0	%		5.2	%

Significant components of the Company's deferred tax assets/liabilities for 2012 and 2011 consist of the following:

	December 31,

	2012			2011
Deferred tax assets/liabilities
Federal net operating loss carryforwards	$	29,464		$	24,325
State and local net operating loss carryforwards		4,825			3,487
License and technology payments		5,566			6,099
Share-based compensation		476			220
Depreciation		(11	)		(27	)
Federal research and development credit carryforwards		1,562			1,417
State research and development credit carryforwards		781			708

Deferred income tax assets		42,663			36,229
Valuation allowance		(42,663	)		(36,229	)

Net deferred tax assets (liabilities)		—			—

In assessing the reliability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the temporary differences representing net future deductible amounts become deductible. Due to the Company's history of losses, and lack of other positive evidence, the Company has determined that it is more likely than not that its deferred tax assets will not be realized, and therefore, the deferred tax assets are fully offset by a valuation allowance at December 31, 2012 and 2011.

The following table summarizes carryforwards of net operating losses and tax credits as of December 31, 2012:

	Amount

Federal net operating losses	$	84,200	2032
Research and development credits	$	1,600	2032

The federal, state, and local net operating loss carryforwards will start to expire in 2027.

For the year ended December 31, 2011, the Company sold a portion of its unused New Jersey State operating loss carryforwards through a program sponsored by the State of New Jersey and the New Jersey Economic Development Authority. On January 24, 2012, the Company received cash proceeds of $1.0 million, net of fees of $34 thousand, resulting in the recognition of a tax benefit for the year ended December 31, 2011. Such amount is reflected in other receivables in the accompanying Balance Sheet as of December 31, 2011. The Company did not participate in the program during 2012.

Utilization of the net operating losses and general business tax credits carryforwards may be subject to a substantial limitation under Sections 382 and 383 of the Internal Revenue Code of 1986 due to changes in ownership of the Company that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating losses and general business tax credits carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50 percentage points over a three-year period.

The Company believes that it had undergone at least one ownership change during 2007, but has not completed a study to determine the impact of the ownership change on its ability to utilize the aforementioned carryforwards. The amount of net operating losses and credits incurred during the year of ownership change amounted to $4.5 million and $0.1 million, respectively. As such, the net operating losses and credits at the time of the ownership change would have been no greater than $4.5 million and $0.1 million, respectively. Accordingly, the Company's ability to utilize its carryforwards may be limited. Additionally, U.S. tax laws limit the time during which these carryforwards may be applied against future taxes. Therefore, the Company may not be able to take full advantage of these carryforwards for federal or state income tax purposes. No other ownership changes have been identified in any years subsequent to 2007.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2012

Commitments and Contingencies

Commitments and Contingencies

11. Commitments and Contingencies

From time to time, the Company may be subject to claims or liabilities that arise in the ordinary course of its business activities.

The following table summarizes the Company's contractual obligations as of December 31, 2012:

	Payments Due by Period

	Total		Less than 1 year		1 - 3 years		3 - 5 years		More than 5 years
	($ in thousands)
Operating Leases(1)	$	90	$	90	$	—	$	—	$	—
Debt Obligations(2)		11,500		2,889		8,611		—		—

Total(3)	$	11,590	$	2,979	$	8,611	$	—	$	—

(1): Operating lease obligations reflect our obligation to make payments in connection with the lease for the Company's office space.
(2): Debt obligations reflect the Company's obligation to make monthly principal payments under the loan and security agreement for its venture facility that the Company entered into in June 2012 and amended in December 2012 and in March 2013.
(3): This table does not include (a) any milestone payments which may become payable to third parties under license agreements as the timing and likelihood of such payments are not known with certainty, (b) any royalty payments to third parties as the amounts, timing and likelihood of such payments are not known and (c) contracts that are entered into in the ordinary course of business which are not material in the aggregate in any period presented above.

Under various agreements, the Company will be required to pay royalties and make milestone payments. These agreements include the following:

•

Under an acquisition agreement with OSI (Eyetech), Inc. for rights to particular anti-PDGF aptamers, including Fovista, the Company is obligated to pay to OSI Pharmaceuticals one-time payments of $12.0 million in the aggregate upon marketing approval in the United States and the European Union, of a covered anti-PDGF product. The Company is also obligated to pay to OSI Pharmaceuticals a royalty at a low single-digit percentage of net sales of any covered anti-PDGF product it successfully commercializes.

•

Under a license agreement with Archemix Corp., or Archemix, with respect to pharmaceutical products comprised of or derived from anti-PDGF aptamers, the Company is obligated to make payments to Archemix of up to an aggregate of $16.5 million in additional payments if it achieves specified clinical and regulatory milestones with respect to Fovista, including a payment of $2.5 million that will be triggered by the initiation of its planned Phase 3 clinical program of Fovista. In addition, the Company is obligated to make payments to Archemix up to an aggregate of $3.0 million if it achieves specified commercial milestones with respect to Fovista and, for each other anti-PDGF aptamer product that it may develop under the agreement, up to an aggregate of approximately $18.8 million if it achieves specified clinical and regulatory milestones and up to an aggregate of $3.0 million if it achieves specified commercial milestones. From inception through December 31, 2012, the Company has made approximately $2.3 million in payments resulting from this agreement.

•

Under a license agreement with Archemix with respect to pharmaceutical products derived from anti-C5 aptamers, for each anti-C5 aptamer product that the Company may develop under the agreement, including Zimura, it is obligated to make payments to Archemix of up to an aggregate of $57.5 million if it achieves specified development, clinical and regulatory milestones and, as to all anti-C5 products under the agreement collectively, up to an aggregate of $22.5 million if it achieves specified commercial milestones. From inception through December 31, 2012, the Company has made $2.0 million in payments resulting from this agreement.

•

Under a license, manufacturing and supply agreement with Nektar Therapeutics, or Nektar, for specified pegylation reagents used to manufacture Fovista, the Company is obligated to pay Nektar up to an aggregate of $5.5 million in additional payments if it achieves specified clinical and regulatory milestones, including a payment of $1.0 million that will be triggered by the initiation of its planned Phase 3 clinical program of Fovista. In addition, the Company is obligated to pay Nektar an additional payment of $3.0 million if it achieves a specified commercial sale milestone. The Company is obligated to pay Nektar tiered royalties at low to mid single-digit percentages of net sales of any licensed product it successfully commercializes, with the royalty percentage determined by its level of licensed product sales, the extent of patent coverage for the licensed product and whether it has granted a third party commercialization rights to the licensed product. The Company has agreed to pay Nektar a low double-digit percentage of any upfront payment it receives in connection with granting any third party commercialization rights to a licensed product, less certain milestone events the Company has previously paid to Nektar, and a higher double-digit percentage of other specified amounts it receives in connection with any such commercialization agreement, subject to agreed minimum and maximum amounts. From inception through December 31, 2012, the Company has made approximately $0.8 million in payments resulting from this agreement.

We also have employment agreements with certain employees which require the funding of a specific level of payments, if certain events, such as a change in control or termination without cause, occur.

In addition, in the course of normal business operations, we have agreements with contract service providers to assist in the performance of our research and development and manufacturing activities. We can elect to discontinue the work under these agreements at any time. We could also enter into additional collaborative research, contract research, manufacturing, and supplier agreements in the future, which may require upfront payments and even long-term commitments of cash.

Stock Option and Compensation Plans

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Stock Option and Compensation Plans

Stock Option and Compensation Plans

7. Stock Option and Compensation Plans

The Company adopted its 2007 Stock Incentive Plan (the "2007 Plan") for employees and consultants for the purpose of advancing the interests of the Company stockholders by enhancing its ability to attract, retain and motivate persons who are expected to make important contributions to the Company. The 2007 Plan provided for the granting of stock option awards, restricted stock awards, and other stock-based and cash-based awards. Following the effectiveness of the 2013 Stock Incentive Plan described below in connection with the closing of the Company's initial public offering, the Company is no longer granting additional awards under the 2007 Plan.

During the nine months ended September, 30, 2013, the Company's Board of Directors and stockholders increased the number of shares authorized under the 2007 Plan by 1,878,343 shares. The Company's board of directors also adopted and the Company's stockholders also approved the 2013 stock incentive plan (the "2013 Plan"), which became effective immediately prior to the closing of the Company's initial public offering. The 2013 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other stock-based awards. Upon effectiveness of the 2013 Plan, the number of shares of the Company's common stock that were reserved for issuance under the 2013 Plan was the sum of (1) such number of shares (up to approximately 3,359,641 shares) as is equal to the sum of 739,317 shares (the number of shares of the common stock then available for issuance under the 2007 Plan), and such number of shares of the Company's common stock that are subject to outstanding awards under the 2007 Plan that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right plus (2) an annual increase, to be added the first day of each fiscal year, beginning with the fiscal year ending December 31, 2014 and continuing until, and including, the fiscal year ending December 31, 2023, equal to the lowest of 2,542,372 shares of the Company's common stock, 4% of the number of shares of the Company's common stock outstanding on the first day of the fiscal year and an amount determined by our board of directors. The Company's employees, officers, directors, consultants and advisors are eligible to receive awards under the 2013 Plan. However, incentive stock options may only be granted to employees of the Company.

As of September 30, 2013, the Company had approximately 2,620,000 stock options outstanding under the 2007 Plan and approximately 739,000 shares available for grant under the 2013 Plan.

The Company recognized share-based compensation of approximately $1.6 million for the nine months ended September 30, 2013 and approximately $0.3 million during the nine months ended September 30, 2012. As of September 30, 2013, there was approximately $11.6 million of total unrecognized share-based compensation expense that is expected to be recognized over a weighted average period of approximately 3.4 years.

The intrinsic value of the Company's approximately 1,091,000 vested options as of September 30, 2013 was $30.8 million, based on a per share price of $29.71, the closing price of the Company's stock at September 30, 2013, and a weighted average exercise price of $1.36 per share. The intrinsic value of the Company's approximately 1,529,000 unvested options as of September 30, 2013 was $30.5 million, based on a per share price of $29.71, the closing price of the Company's stock at September 30, 2013, and a weighted average exercise price of $9.76 per share.

12. Stock Option and Compensation Plans

The Company adopted its 2007 Stock Incentive Plan (the "Plan") for employees and consultants for the purpose of advancing the interests of the Company stockholders by enhancing its ability to attract, retain and motivate persons who are expected to make important contributions to the Company.

The following table sets forth the activity under the Company's Option Plan:

				Options Outstanding

	Shares Available for Grant			Number of Shares			Weighted- Average Exercise Price		Weighted- Average Fair Value Per Share
	(shares in thousands)
Balance, December 31, 2010		260			953
Increase to Option pool		—			—
Options granted		(184	)		184		$	1.65	$	1.18
Options exercised		—			(24	)	$	0.17	$	0.12
Options forfeited		—			—

Balance, December 31, 2011		76			1,113
Increase to Option pool		314			—
Options granted		(250	)		250		$	3.12	$	1.65
Options exercised		—			(18	)	$	0.12	$	1.59
Options forfeited		1			(1	)

Balance, December 31, 2012		141			1,344		$	1.65	$	1.30

The aggregate intrinsic value of options outstanding as of December 31, 2012 was $11.3 million. The aggregate intrinsic value is calculated as the difference between the Company's estimated stock price of $10.03 on December 31, 2012, and the exercise price of the option, multiplied by the number of options.

In determining this exercise price, the Company considered input from management and the valuation of the common stock. The Company determined the value of common stock based on the probability weighted expected return method, or PWERM, described in the AICPA Practice Aid. The Company considered but did not use the market approach because the early stage of its development and the absence of clinical trial data from the lead candidate made comparisons to public companies difficult. Similarly, the Company did not use the income approach because of the uncertain outcomes of the ongoing and future clinical trials. Under a PWERM analysis, the value of a company's common stock is estimated based upon an analysis of current and future enterprise values, assuming three possible liquidity scenarios: an initial public offering ("IPO"), a recapitalization of the company and a sale of the company. After considering the various potential liquidity scenarios and the likely timing, the Company used a pre-money enterprise value assigned to each scenario based on recent trends in capital markets. To determine the price per share of the common stock, the Company divided the resulting enterprise value for each liquidity scenario by the number of common shares that would be outstanding under each scenario. The common stock price for each scenario was then assigned a probability based on management's estimates.

Employees Options

Employee options outstanding at December 31, 2012 and 2011, had a weighted average remaining contractual life of approximately 7.8 and 8.3 years, respectively. As of December 31, 2012, the number of vested and non-vested shares granted was 1,158,456 and 465,700, respectively, at a weighted average exercise price of $1.36 per share. As of December 31, 2011, the number of vested and non-vested shares granted was 949,259 and 519,976, respectively, at a weighted average exercise price of $1.18 per share.

In general, the options vest at 25% of the original number of shares after one year of service with the Company. Thereafter, the remaining 75% vest at 2.08% per month over the next three years. Only vested options can be exercised and can be exercised up to ten years from the grant date. Upon change in control of the Company, all unvested options vest immediately. Vested options can be exercised up to ten years from the grant date.

For the years ended December 31, 2012 and 2011, the Company incurred share-based compensation expense in the amounts of $0.5 million and $0.2 million, respectively. For the period from January 5, 2007 (inception) to December 31, 2012, share-based compensation expense was $0.9 million. As of December 31, 2012, there was $0.6 million of total unrecognized share-based compensation. Such costs are expected to be recognized over a weighted average period of approximately 2.7 years.

On December 30, 2012, the Board of Directors modified the vesting terms related to an employee's unvested shares so that all unvested shares immediately vested as of the employee's death on October 29, 2012. As a result of the modification, the Company recorded an additional $0.3 million in share-based compensation expense.

Non-employee Options

Non-employee options outstanding at December 31, 2012 and 2011 had a weighted average remaining contractual life of approximately 6.9 and 7.0 years, respectively. As of December 31, 2012, the number of vested and non-vested shares granted was 183,808 and 55,304, respectively, at a weighted average exercise price of $0.59 per share. As of December 31, 2011, the number of vested and non-vested shares granted was 161,082 and 31,963, respectively, at a weighted average exercise price of $0.41 per share.

For the years ended December 31, 2012 and 2011, the Company granted a total of 41,946 and 3,812 stock options, respectively, to its Consultants. In general, the grants vest ratably over a three-year period and have a life of 10 years. Stock options issued to nonemployees uses the fair value method of accounting as prescribed under ASC 505, Equity-Based Payments to Non-Employees, and are periodically revalued as the options vest and are recognized as expense over the related service period.

For the years ended December 31, 2012 and 2011, the Company incurred share-based compensation expense in the amount of $0.1 million for each respective year. As of December 31, 2012, there was $0.4 million of total unrecognized share-based compensation, respectively. Such costs are expected to be recognized over a weighted average period of approximately 3.0 years.

Fair Value Measurements

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Fair Value Measurements

Fair Value Measurements

5. Fair Value Measurements

ASC 820, Fair Value Measurements and Disclosures, defines fair value as the price that would be received to sell an asset, or paid to transfer a liability, in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. The fair value standard also establishes a three-level hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value.

The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels are defined as follows:

•

Level 1—inputs to the valuation methodology are quoted prices (unadjusted) for an identical asset or liability in an active market.

•

Level 2—inputs to the valuation methodology include quoted prices for a similar asset or liability in an active market or model-derived valuations in which all significant inputs are observable for substantially the full term of the asset or liability.

•

Level 3—inputs to the valuation methodology are unobservable and significant to the fair value measurement of the asset or liability.

The following table presents, for each of the fair value hierarchy levels required under ASC 820, the Company's assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2013:

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in U.S. Treasury money market funds*	$	234,843	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	—
Series B Warrant Liability	$	—	$	—	$	—

*: Investments in U.S. Treasury money market funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money market funds*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liability	$	—	$	—	$	443

*: Investments in money markets funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Level 3 Valuation

The warrant liability was recorded in its own line item on the Company's Balance Sheets. The warrant liability was marked-to-market each reporting period with the change in fair value recorded to other loss in the Statement of Operations. The fair value of the warrant liability was estimated using a hybrid method between a probability-weighted expected return method, or PWERM, model and an option pricing model, which includes variables such as the expected volatility based on guideline public companies, the preferred stock value, and the estimated time to a liquidity event.

The significant assumptions used in preparing the option pricing model for valuing the Company's warrants for the Series A preferred shares as of December 31, 2012, include (i) volatility (47.2% - 85.3%), (ii) risk free interest rate (0.05% - 0.62%), (iii) strike price ($0.01), (iv) fair value of Series A preferred shares ($1.22 - $4.34), (v) expected life (0.25 years to 4.5 years) and (vi) expected outcome probability weighting of three outcome scenarios: merger (65%); dissolution (20%) and an initial public offering (15%).

The significant assumptions used in preparing the option pricing model for valuing the Company's warrants for the Series B preferred shares as of December 31, 2012, include (i) volatility (47.2% - 80.1%), (ii) risk free interest rate (0.05% - 1.68%), (iii) strike prices ($1.00 - $2.50), (iv) fair value of Series B preferred shares ($1.18 - $4.22), (v) expected life (0.25 years to 9.5 years) and (vi) expected outcome probability weighting of three outcome scenarios: merger (65%); dissolution (20%) and an initial public offering (15%).

The table presented below is a summary of changes in the fair value of the Company's Level 3 valuation for the Series A and Series B warrant liabilities for the period ended September 30, 2013:

	Level 3

	Series A Warrant Liability			Series B Warrant Liability
Balance at December 31, 2012		523			443
Warrants issued in connection with venture debt facility		—			32
Change in fair value of warrant liability		379			852
Conversion of warrant liability to equity		(902	)		(1,327	)

Balance at September 30, 2013	$	—		$	—

Upon completion of the Company's IPO on September 30, 2013, the underlying preferred stock was converted to common stock and the preferred stock warrants became exercisable for common stock. The fair value of the warrant liability was re-measured immediately prior to the completion of the Company's IPO, and the fair value of the warrant liability at that time was reclassified to additional paid-in capital. Based on the initial public offering price of $22.00 per share, the fair value of the warrant liability that was reclassified to additional paid-in capital was $2.2 million. The Company recorded a related charge of approximately $1.0 million and $1.2 million as other loss in its results of operations for the three and nine months ended September 30, 2013, respectively.

14. Fair Value Measurements

The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels are defined as follows:

•

Level 1—inputs to the valuation methodology are quoted prices (unadjusted) for an identical asset or liability in an active market.

•

Level 2—inputs to the valuation methodology include quoted prices for a similar asset or liability in an active market or model-derived valuations in which all significant inputs are observable for substantially the full term of the asset or liability.

•

Level 3—inputs to the valuation methodology are unobservable and significant to the fair value measurement of the asset or liability.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liabilty	$	—	$	—	$	443

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	4,874	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	193

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Level 3 Valuation

The warrant liability is recorded in its own line item on the Company's Balance Sheets. The warrant liability is marked-to-market each reporting period with the change in fair value recorded to other loss in the Statement of Operations until the warrants are exercised, expire or other facts and circumstances lead the warrant liability to be reclassified as an equity instrument.

The fair value of the warrant liability is estimated using a hybrid method that integrates a scenario based PWERM model and an option pricing model. The three scenarios used for the PWERM model include dissolution, acquisition and an initial public offering. The variables used in the models include the expected volatility based on similar public companies, the preferred stock value, risk free interest rates and the estimated time to a liquidity event. The range of risk free interest rates and volatility included in each model are predicated on the length of time to reach the expected outcome employed in each scenario. The range of fair value used in each model relates to the enterprise value calculated for each of the expected outcome scenarios. For example, the enterprise value for a dissolution scenario is significantly less than the enterprise value for an initial public offering.

The significant assumptions used in preparing the option pricing model for valuing the Company's warrants for the Series A preferred shares as of December 31, 2011, include (i) volatility (64.7%), (ii) risk free interest rate (0.06% - 0.12%), (iii) strike price ($.01), (iv) fair value of Series A preferred shares ($0.18 - $1.51), (v) expected life (0.5 years to 1.0 years) and (vi) expected outcome probability weighting of three outcome scenarios: merger (50%); technology sale (20%) and dissolution (30%).

The table presented below is a summary of changes in the fair value of the Company's Level 3 valuation for the Series A and Series B warrant liabilities for periods ending December 31, 2012 and 2011:

	Level 3

	Series A Warrant Liability		Series B Warrant Liability
Balance at December 31, 2010	$	186	$	—
Change in fair value of warrant liability		7		—

Balance at December 31, 2011		193		—
Warrants issued in connection with venture debt facility		—		407
Change in fair value of warrant liability		330		36

Balance at December 31, 2012	$	523	$	443

No other changes in valuation techniques or inputs occurred during the year ended December 31, 2012. No transfer of assets between Level 1 and Level 2 of the fair value hierarchy occurred during the year ended December 31, 2012.

Subsequent Events	9 Months Ended	12 Months Ended
Subsequent Events	Sep. 30, 2013	Dec. 31, 2012
Subsequent Events
Subsequent Events	10. Subsequent Events On January 23, 2014, in connection with its royalty agreement with Novo A/S, the Company received approximately $41.7 million in exchange for a low single-digit royalty interest in future potential worldwide sales of Fovista. The receipt of this second financing tranche under the royalty agreement was triggered as a result of the Company reaching an initial enrollment milestone of a specified number of patients in its Phase 3 clinical program for Fovista. The closing of a third potential financing tranche of approximately $41.7 million is subject to the further enrollment milestone of a specified number of patients in the Company's Phase 3 clinical program for Fovista, and the Company satisfying additional closing conditions and other obligations.	17. Subsequent Events On March 15, 2013, the Company issued a secured promissory note in the amount of $1.5 million (the "2013 Note") to the holder of the 2012 Notes. The 2013 Note carries interest at a rate per annum equal to the sum of (i) the greater of (A) the LIBOR Rate in effect for the applicable Interest Period and (B) 3.0%, plus (ii) the LIBOR Rate Margin adjusted on the first day of each Interest Period and fixed for the duration of each such Interest Period. In conjunction with the issuance of the 2013 Note, the Lender received warrants to purchase 35,700 shares of Series B Preferred Stock with an exercise price of $2.50 per share. The warrants expire on March 15, 2023 and provide for proportionate adjustments to be made to the number of shares purchasable and the exercise price payable under the warrants in the event of certain changes to the underlying Series B Preferred Stock, including for subdivisions, combinations and stock dividends. On April 25, 2013, the Company amended its certificate of incorporation to increase the authorized shares of capital stock to the following: 187,918,509 shares of common stock and 73,094,000 shares of Series A Preferred Stock, 18,480,000 shares of Series A-1 Preferred Stock, 3,000,000 shares of Junior Series A Preferred Stock, 42,391,600 shares of Series B Preferred Stock, 700,000 shares of Series B-1 Preferred Stock, and 28,000,000 shares of Series C Preferred Stock, each with a par value of $0.001 per share. On May 23, 2013, the Company entered into a Purchase and Sale Agreement (the "Purchase and Sale Agreement") with Novo A/S, providing for the Company to sell, and Novo A/S to purchase, the right, title, and interest in a portion of the revenues from the sale of (a) Fovista, (b) Fovista-Related Products, and (c) Other Products (as defined in the Purchase and Sale Agreement), calculated as low to mid single-digit percentages of net sales. The Purchase and Sale Agreement provides for up to three separate purchases for a purchase price of $41.7 million each, at a first, second and third closing, for an aggregate purchase price of $125.0 million. In each purchase, Novo A/S acquires rights to a low single-digit percentage of net sales. Following the purchase of all royalty interests under the Purchase and Sale Agreement, Novo A/S will have a right to receive royalties on net sales at a mid-single digit percentage. On May 23, 2013, the Company received cash proceeds of $41.7 million for the royalty entitlement related to the first closing on the date of the Purchase and Sale Agreement. Receipt of cash proceeds for the second and third purchases is contingent upon certain triggers and conditions detailed in the Purchase and Sale Agreement, none of which occurred prior to the Company's initial public offering. The royalty payment period covered by the Purchase and Sale Agreement begins on commercial launch and ends, on a product by product and country by country basis, on the latest to occur of (i) the 12th anniversary of the commercial launch, (ii) the expiration of certain patent rights and (iii) the expiration of the regulatory exclusivity for each product in each country. Under the terms of the Purchase and Sale Agreement, the Company is not required to reimburse or otherwise compensate Novo A/S through any means other than the agreed royalty entitlement. In addition, the Company does not, under the terms of the Purchase and Sale Agreement, have the right or obligation to prepay Novo A/S in connection with a change of control of the Company or otherwise. The Purchase and Sale Agreement requires the establishment of a Joint Oversight Committee in the event that Novo A/S does not continue to have a representative on the Company's board of directors. The Joint Oversight Committee would have responsibilities that include "discussion and review" of all matters related to Fovista research, development, regulatory approval and commercialization, but there is no provision either implicit or explicit that gives the Joint Oversight Committee or its members decision-making authority. On May 23, 2013, the Company entered into a Series C Preferred Stock Purchase Agreement (the "Series C Agreement") with certain of its existing investors for the sale and issuance of an aggregate of 20,000,000 shares of the Company's Series C Preferred Stock at a price of $2.50 per share. In connection with entering into the Series C Agreement, the Company issued 6,666,667 shares of Series C Preferred Stock at $2.50 per share in a closing that occurred on May 23, 2013, simultaneous with entry into the Series C Agreement. In connection with entering into the Series C Agreement, the minimum public offering price per share in an underwritten public offering of common stock required for the automatic conversion of outstanding shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock and Junior Series A Preferred Stock was adjusted to $14.75 per share (subject to further adjustment as a result of any stock dividend, stock split, combination or similar recapitalization of the common stock). On May 23, 2013, the Company repaid the outstanding principal, interest and related prepayment fees on the 2012 Notes and 2013 Note. The Company has determined that in accordance with ASC 470-20-20, at the time of the initial closing under the Series C Agreement on May 23, 2013, there was a firm commitment from the Series C Preferred Stock investors with respect to the significant terms of the financing, including the quantity of shares to be issued, the fixed price of the shares and the timing of the transaction. In addition, the Company has concluded that the Series C Agreement and the Company's certificate of incorporation includes a disincentive feature for non-performance that was sufficiently large enough to make investor performance at subsequent closings probable. As such, the Company's measurement of any beneficial conversion feature occurred at the time of the initial closing. Based on a $10.03 per share valuation of the Company's common stock as of the date of the initial closing of the sale of the Series C Preferred Stock, as well as the fact that the Series C Preferred Stock include a common stock conversion price of $14.75 per share (implying a one-to-one conversion into shares of common stock), the Company determined that there was no beneficial conversion feature associated with the issuance of its Series C Preferred Stock. The Company filed a registration statement on Form S-1 with the SEC relating to the initial public offering of its common stock. In connection with the Company's initial public offering: (i) The Company effected a one-for-5.9000 reverse stock split of its common stock on September 9, 2013. All share and per share amounts related to common stock, options and warrants included in these financial statements and notes to financial statements have been restated to reflect the reverse stock split. The conversion ratios of the Company's preferred stock have also been adjusted to reflect the reverse stock split. (ii) The Company's board of directors adopted and the Company's stockholders approved the 2013 stock incentive plan ("2013 Plan"), which became effective immediately prior to the closing of the Company's initial public offering. The 2013 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other stock-based awards. The Company's employees, officers, directors, consultants and advisors are eligible to receive awards under the 2013 Plan.

Significant Accounting Policies (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Significant Accounting Policies

Basis of Presentation

Basis of Presentation

Unaudited Pro Forma Information

Unaudited Pro Forma Information

Use of Estimates

Use of Estimates

The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company's Balance Sheets and the amount of expenses reported for each of the periods presented are affected by estimates and assumptions, which are used for, but not limited to, the accounting for stock-based compensation and investor rights liabilities, for income taxes and accounting for research and development costs. Actual results could differ from those estimates.

Cash and Cash Equivalents

Cash and Cash Equivalents

Concentration of Credit Risk

Concentration of Credit Risk

Foreign Currency Translation

Foreign Currency Translation

Financial Instruments

Financial Instruments

Property and Equipment

Property and Equipment

Research and Development

Research and Development

•

external research and development expenses incurred under arrangements with third parties, such as contract research organizations, ("CROs") and other vendors, contract manufacturing organizations and consultants; and

•

employee-related expenses, including salaries, benefits, travel and share-based compensation expense.

Research and Development

Income Taxes

Income Taxes

Share-Based Compensation

Share-Based Compensation

Share-based compensation expense includes stock options granted to employees and non-employees and has been reported in the Company's statements of operations as follows:

	Nine months ended September 30,

	2013		2012
Research and development	$	1,052	$	182
General and administrative		555		101

Total	$	1,607	$	283

The Company had no shares of unvested restricted common stock granted to employees at September 30, 2013 or at December 31, 2012, respectively.

Share-Based Compensation

At December 31, 2012 and 2011, the Company had one share-based employee compensation plan, which is described more fully in Note 12.

The Company grants stock options for a fixed number of shares to employees and non-employees with an exercise price equal to the fair value of the share at the grant date.

	Year Ended December 31,

	2012	2011
Expected common stock price volatility	81%	79%
Risk-free interest rate	0.94% - 1.77%	1.72% - 2.38%
Expected term of options (years)	6.6	6.7
Expected annual dividend per share	$—	$—

Recent Accounting Pronouncements

JOBS Act

Recent Accounting Pronouncements

Fair Value Measurements (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Fair Value Measurements

Schedule of the Company's assets and liabilities that are measured at fair value on recurring basis

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in U.S. Treasury money market funds*	$	234,843	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	—
Series B Warrant Liability	$	—	$	—	$	—

*: Investments in U.S. Treasury money market funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money market funds*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liability	$	—	$	—	$	443

*: Investments in money markets funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liabilty	$	—	$	—	$	443

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	4,874	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	193

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Summary of changes in fair value of the Company's Level 3 valuation for the Series A and Series B warrant liabilities

	Level 3

	Series A Warrant Liability			Series B Warrant Liability
Balance at December 31, 2012		523			443
Warrants issued in connection with venture debt facility		—			32
Change in fair value of warrant liability		379			852
Conversion of warrant liability to equity		(902	)		(1,327	)

Balance at September 30, 2013	$	—		$	—

	Level 3

	Series A Warrant Liability		Series B Warrant Liability
Balance at December 31, 2010	$	186	$	—
Change in fair value of warrant liability		7		—

Balance at December 31, 2011		193		—
Warrants issued in connection with venture debt facility		—		407
Change in fair value of warrant liability		330		36

Balance at December 31, 2012	$	523	$	443

Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended											9 Months Ended		12 Months Ended						72 Months Ended	81 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2012	Sep. 30, 2013
Basic and diluted net loss per common share calculation:
Net loss												$ (30,757)	$ (10,731)	$ (14,562)	$ (18,633)	$ (18,948)	$ (13,514)	$ (20,556)	$ (14,417)	$ (100,630)	$ (131,387)
Accretion of preferred stock dividends												(5,891)	(5,288)	(7,063)	(6,838)					(27,155)	(33,046)
Net loss attributable to common stockholders	$ (18,424)	$ (11,863)	$ (6,361)	$ (5,606)	$ (5,928)	$ (5,326)	$ (4,765)	$ (6,052)	$ (6,765)	$ (6,441)	$ (6,213)	$ (36,648)	$ (16,019)	$ (21,625)	$ (25,471)					$ (127,785)	$ (164,433)
Weighted average common shares outstanding												1,579	1,447	1,452	1,394
Net loss per share of common stock - basic and diluted (in dollars per share)	$ (10.26)	$ (8.07)	$ (4.33)	$ (3.82)	$ (4.07)	$ (3.68)	$ (3.31)	$ (4.27)	$ (4.81)	$ (4.65)	$ (4.56)	$ (23.21)	$ (11.07)	$ (14.89)	$ (18.27)
Anti-dilutive securities
Total (in shares)												2,721	17,892	18,102	17,233
Redeemable convertible preferred stock
Anti-dilutive securities
Total (in shares)													16,513	16,663	16,064
Unvested restricted stock
Anti-dilutive securities
Total (in shares)															18
Options outstanding
Anti-dilutive securities
Total (in shares)												2,620	1,301	1,344	1,113
Warrants
Anti-dilutive securities
Total (in shares)												101	78	95	38

Financing Activities (Details) $ in Thousands								3 Months Ended											9 Months Ended		12 Months Ended				72 Months Ended	81 Months Ended
Financing Activities (Details) $ in Thousands	Mar. 01, 2011 $ / shares shares	Oct. 14, 2009 $ / shares shares	May 06, 2009 USD ($) $ / shares shares	Sep. 19, 2008 USD ($) $ / shares shares	Apr. 14, 2008 $ / shares shares	Jan. 04, 2008 $ / shares shares	Aug. 09, 2007 $ / shares shares	Sep. 30, 2013 USD ($)	Jun. 30, 2013 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2012 USD ($) $ / shares	Sep. 30, 2012 USD ($)	Jun. 30, 2012 USD ($)	Mar. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Sep. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Mar. 31, 2011 USD ($)	Sep. 30, 2013 USD ($) shares	Sep. 30, 2012 USD ($)	Dec. 31, 2012 USD ($) $ / shares	Dec. 31, 2011 USD ($)	Dec. 31, 2008 USD ($)	Aug. 09, 2008	Dec. 31, 2012 USD ($) $ / shares	Sep. 30, 2013 USD ($)	Dec. 24, 2012 USD ($) $ / shares shares	Jun. 20, 2012 USD ($) $ / shares shares	Dec. 11, 2009 $ / shares shares	Jun. 18, 2007 USD ($) $ / shares shares
Financing activities
Warrant Liability \| $											$ 966				$ 193						$ 966	$ 193			$ 966
Shares issued																			8,740,000
Proceeds from issuance of shares \| $																			$ 49,699			14,990			80,934	$ 130,632
Research and development expense \| $								$ 11,101	$ 4,345	$ 2,390	1,998	$ 1,595	$ 1,578	$ 1,621	3,422	$ 3,627	$ 3,316	$ 3,531	$ 17,836	$ 4,794	6,792	13,896			74,891	$ 92,727
Series A Warrant
Financing activities
Warrant Liability \| $											500				$ 200						500	200			500
Change in fair value of warrant liability \| $																					(330)	$ (7)
Series B Warrant
Financing activities
Warrant Liability \| $											$ 400										400				$ 400
Change in fair value of warrant liability \| $																					$ (36)
Common stock \| Series A Warrant
Financing activities
Weighted Average Exercise Price to Purchase Common Stock Upon Closing of an IPO \| $ / shares											$ 5.47										$ 5.47				$ 5.47
Common stock \| Series B Warrant
Financing activities
Weighted Average Exercise Price to Purchase Common Stock Upon Closing of an IPO \| $ / shares											5.47										5.47				5.47
Series A Preferred Stock
Financing activities
Share price (in dollars per share) \| $ / shares											1										1				1
Series A Preferred Stock \| Series A Warrant
Financing activities
Warrants issued (in shares)																														210,000
Exercise price of warrants (in dollars per share) \| $ / shares																														0.01
Series A-1 Preferred Stock
Financing activities
Share price (in dollars per share) \| $ / shares											1										1				1
Series A-1 Preferred Stock \| License Agreements
Financing activities
Share price (in dollars per share) \| $ / shares						$ 1.00	$ 1.00
Shares issued						4,000,000	2,000,000
Research and development expense \| $																							$ 4,000
Junior Series A Preferred Stock
Financing activities
Share price (in dollars per share) \| $ / shares											1										1				1
Junior Series A Preferred Stock \| Divestiture Agreement
Financing activities
Share price (in dollars per share) \| $ / shares							$ 1.00
Shares issued							3,000,000
Series B Preferred Stock
Financing activities
Share price (in dollars per share) \| $ / shares											$ 1										$ 1				$ 1
Series B Preferred Stock \| Series B Warrant
Financing activities
Warrants issued (in shares)																											95,200	225,000
Exercise price of warrants (in dollars per share) \| $ / shares																											2.50	1.00
Series A Investors \| Series A Preferred Stock
Financing activities
Share price (in dollars per share) \| $ / shares					$ 1.00		$ 1.00
Series A Investors \| Series A Preferred Stock \| Initial Closing
Financing activities
Shares available for sale and issuance under agreement							9,253,101
Series A Investors \| Series A Preferred Stock \| First Milestone Event
Financing activities
Shares available for sale and issuance under agreement							9,217,243
Period up to which the License Agreement is to be kept in effect																								10 days
Series A Investors \| Series A Preferred Stock \| Initiation of Phase 1b study of assets acquired or licensed
Financing activities
Shares available for sale and issuance under agreement							17,319,656
Series A Investors \| Series A Preferred Stock \| Second Milestone Event
Financing activities
Shares available for sale and issuance under agreement					6,000,000
Shares issued					6,000,000
Series A Investors \| Series A Preferred Stock \| Third Milestone Event
Financing activities
Share price (in dollars per share) \| $ / shares				$ 1.00
Shares available for sale and issuance under agreement					13,000,000
Shares issued				13,000,000
Proceeds from issuance of shares \| $				$ 13,000
Extinguishment of liability due to exercise of investor rights \| $				$ 300
Series A Investors \| Series A Preferred Stock \| Fourth and Fifth Milestone Event
Financing activities
Share price (in dollars per share) \| $ / shares			$ 1.00
Shares issued			11,319,656
Proceeds from issuance of shares \| $			$ 11,300
Extinguishment of liability due to exercise of investor rights \| $			$ 300
Series A Investors \| Series A Preferred Stock \| Fourth Milestone Event
Financing activities
Shares available for sale and issuance under agreement					4,319,656
Series A Investors \| Series A Preferred Stock \| Fifth Milestone Event
Financing activities
Shares available for sale and issuance under agreement					7,000,000
Series A Investors \| Series A Preferred Stock \| Additional closing
Financing activities
Share price (in dollars per share) \| $ / shares		$ 1.00
Shares available for sale and issuance under agreement					3,000,000
Shares issued		3,000,000
Series B Investors \| Series B Preferred Stock
Financing activities
Share price (in dollars per share) \| $ / shares																													$ 1.00
Series B Investors \| Series B Preferred Stock \| Initial Closing
Financing activities
Shares available for sale and issuance under agreement																													15,000,000
Series B Investors \| Series B Preferred Stock \| Second Closing
Financing activities
Share price (in dollars per share) \| $ / shares	$ 1.00
Shares available for sale and issuance under agreement																													15,000,000
Shares issued	15,000,000
Notes
Financing activities
Secured promissory notes issued \| $										$ 1,500	$ 4,000		$ 7,500								$ 4,000				$ 4,000		$ 4,000	$ 7,500		$ 200
Interest rate (as a percent)								3.00%			3.00%								3.00%		3.00%				3.00%	3.00%				8.00%
Basis of interest rate																			LIBOR		LIBOR

Product and Technology Agreements (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended											9 Months Ended		12 Months Ended					72 Months Ended	81 Months Ended
	Sep. 12, 2011	Jan. 04, 2008	Jul. 27, 2007	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2012	Sep. 30, 2013	Aug. 09, 2007
Product and Technology Agreements
Research and development expense related to upfront fees																	$ 5,000
Research and development expense related to issuance of preferred stock																	5,000
Research and development expense				$ 11,101	$ 4,345	$ 2,390	$ 1,998	$ 1,595	$ 1,578	$ 1,621	$ 3,422	$ 3,627	$ 3,316	$ 3,531	$ 17,836	$ 4,794	$ 6,792	$ 13,896				$ 74,891	$ 92,727
Junior Series A Preferred Stock
Product and Technology Agreements
Preferred stock issued (in shares)							3,000,000				3,000,000						3,000,000	3,000,000				3,000,000
Share price (in dollars per share)							$ 1										$ 1					$ 1
Series A-1 Preferred Stock
Product and Technology Agreements
Share price (in dollars per share)							$ 1										$ 1					$ 1
Shares issued							6,000,000				6,000,000						6,000,000	6,000,000				6,000,000
Series B-1 Preferred Stock
Product and Technology Agreements
Share price (in dollars per share)							$ 1										$ 1					$ 1
Shares issued							500,000				500,000						500,000	500,000				500,000
Divestiture Agreement \| Junior Series A Preferred Stock
Product and Technology Agreements
Preferred stock issued (in shares)																								3,000,000
Share price (in dollars per share)																								$ 1.00
Divestiture Agreement \| Transferor
Product and Technology Agreements
Upfront payment			$ 4,000
Divestiture Agreement \| Transferor \| Junior Series A Preferred Stock
Product and Technology Agreements
Share price (in dollars per share)																								1.00
Supply Agreement \| Supplier
Product and Technology Agreements
Aggregate payment by supplier																					$ 300
Aggregate payment																			$ 800
License Agreements \| Series A-1 Preferred Stock
Product and Technology Agreements
Share price (in dollars per share)		$ 1.00																						1.00
Research and development expense																				$ 4,000
License Agreements \| PDGF Licensed Products
Product and Technology Agreements
Expiration period of agreements																	10 years
License Agreements \| C5 Licensed Product
Product and Technology Agreements
Expiration period of agreements																	12 years
License Agreements \| Licensor
Product and Technology Agreements
Upfront payment																	$ 1,000
License Agreements \| Licensor \| Series A-1 Preferred Stock
Product and Technology Agreements
Share price (in dollars per share)		$ 1.00																						$ 1.00
Shares issued		4,000,000																						2,000,000
Research and development expense		$ 4,000
License Agreements \| Licensor \| Series B-1 Preferred Stock
Product and Technology Agreements
Share price (in dollars per share)	$ 1.00
Shares issued	500,000
Research and development expense	$ 500

Capital Structure (Details) $ / shares in Units, $ in Millions	12 Months Ended		72 Months Ended
	Dec. 31, 2012 USD ($) item $ / shares shares	Dec. 31, 2011 $ / shares shares	Dec. 31, 2012 item $ / shares shares	Sep. 30, 2013 $ / shares shares	Aug. 31, 2013 shares	Dec. 24, 2012 $ / shares shares	Jun. 20, 2012 $ / shares shares
Capital structure
Authorized shares of common stock \| shares	155,864,851	155,544,651	155,864,851	200,000,000	200,000,000	155,864,851	155,769,651
Authorized shares of preferred stock \| shares					5,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001	$ 0.001		$ 0.001	$ 0.001
Common stock, votes per share held \| item	1		1
Common stock, shares issued \| shares	1,469,798	1,451,294	1,469,798	31,250,817
Common stock, shares outstanding \| shares	1,469,798	1,451,294	1,469,798	31,250,817
Vesting percentage of restricted stock	100.00%
Minimum proceeds of an underwritten public offering, net of underwriting discount and commissions to trigger automatic conversion of preferred stock into shares of common stock \| $	$ 40.0
Officers
Capital structure
Common stock, shares issued \| shares	677,964		677,964
Convertible and redeemable preferred stock
Capital structure
Dividend declared (in dollars per share)	$ 0.00	$ 0.00	$ 0.00
Series A Preferred Stock
Capital structure
Authorized shares of preferred stock \| shares	73,094,000	73,094,000	73,094,000			73,094,000	73,094,000
Preferred stock, votes per share of common stock into which it could be converted \| item	1		1
Cash dividend accrual rate before Series B Original Issue Date (in dollars per share)	$ 0.08
Cash dividend annual accrual rate for shares outstanding as of the Series B Original Issue Date after that date (in dollars per share)	0.04
Cash dividend annual accrual rate for shares issued on or after Series B Original Issue Date (in dollars per share)	$ 0.04
Stock dividend annual accrual rate per share after Series B Original Issue Date	0.04
Original Issue Price (in dollars per share)	$ 1		$ 1
Multiplier used to determine liquidation preference of preferred stock	2
Conversion Price (in dollar per share)	$ 1.00		$ 1.00
Number of shares of common stock issued on conversion of each share of preferred stock \| shares	1		1
Series A-1 Preferred Stock
Capital structure
Authorized shares of preferred stock \| shares	18,480,000	18,480,000	18,480,000			18,480,000	18,480,000
Preferred stock, votes per share of common stock into which it could be converted \| item	1		1
Cash dividend accrual rate before Series B Original Issue Date (in dollars per share)	$ 0.08
Cash dividend annual accrual rate for shares outstanding as of the Series B Original Issue Date after that date (in dollars per share)	0.04
Cash dividend annual accrual rate for shares issued on or after Series B Original Issue Date (in dollars per share)	$ 0.04
Stock dividend annual accrual rate per share after Series B Original Issue Date	0.04
Original Issue Price (in dollars per share)	$ 1		$ 1
Multiplier used to determine liquidation preference of preferred stock	2
Conversion Price (in dollar per share)	$ 1.00		$ 1.00
Series B Preferred Stock
Capital structure
Authorized shares of preferred stock \| shares	42,320,200	42,000,000	42,320,200			42,320,200	42,225,000
Preferred stock, votes per share of common stock into which it could be converted \| item	1		1
Cash dividend annual accrual rate for shares issued on or after Series B Original Issue Date (in dollars per share)	$ 0.04
Stock dividend annual accrual rate per share after Series B Original Issue Date	0.04
Original Issue Price (in dollars per share)	$ 1		$ 1
Multiplier used to determine liquidation preference of preferred stock	2.65
Minimum percentage of outstanding shares of preferred stock that must elect in favor to prevent consideration of a change in control of the entity as a deemed liquidation event	60.00%
Conversion Price (in dollar per share)	$ 1.00		$ 1.00
Minimum percentage of outstanding shares of preferred stock that must agree by vote or written consent for mandatory conversion	60.00%
Minimum percentage of outstanding shares of preferred stock that must elect in favor to prevent treatment of a transaction involving the issuance or sale of additional shares of common stock as a qualified financing	60.00%
Number of shares of common stock issued on conversion of each share of preferred stock \| shares	1		1
Series B-1 Preferred Stock
Capital structure
Authorized shares of preferred stock \| shares	700,000	700,000	700,000			700,000	700,000
Preferred stock, votes per share of common stock into which it could be converted \| item	1		1
Cash dividend annual accrual rate for shares issued on or after Series B Original Issue Date (in dollars per share)	$ 0.04
Stock dividend annual accrual rate per share after Series B Original Issue Date	0.04
Original Issue Price (in dollars per share)	$ 1		$ 1
Conversion Price (in dollar per share)	$ 1.00		$ 1.00
Junior Series A Preferred Stock
Capital structure
Authorized shares of preferred stock \| shares	3,000,000	3,000,000	3,000,000			3,000,000	3,000,000
Original Issue Price (in dollars per share)	$ 1		$ 1

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2012	Dec. 31, 2011
Percent of pre-tax income:
U.S. federal statutory income tax rate (as a percent)	35.00%	35.00%
State taxes, net of federal benefit (as a percent)	0.00%	3.40%
Permanent items (as a percent)	(1.00%)	(0.60%)
Research and development credit (as a percent)	1.00%	0.70%
Change in valuation allowance (as a percent)	(35.00%)	(33.30%)
Effective income tax rate (as a percent)	0.00%	5.20%
Deferred tax assets/liabilities
Federal net operating loss carryforwards	$ 29,464	$ 24,325
State and local net operating loss carryforwards	4,825	3,487
License and technology payments	5,566	6,099
Share-based compensation	476	220
Depreciation	(11)	(27)
Federal research and development credit carryforwards	1,562	1,417
State research and development credit carryforwards	781	708
Other	0
Deferred income tax assets	42,663	36,229
Valuation allowance	(42,663)	$ (36,229)
Net deferred tax assets (liabilities)	$ 0

Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2012 USD ($)
Operating Leases, Payments Due by Period
Total	$ 90
Less than 1 year	90
Debt Obligations, Payments Due by Period
Total	11,500
Less than 1 year	2,889
1-3 years	8,611
Contractual obligations, Payments Due by Period
Total	11,590
Less than 1 year	2,979
1-3 years	8,611
Acquisition agreement \| OSI Pharmaceuticals \| Anti-PDGF aptamers
Commitments and contingencies
Amount of obligation to make one-time payments	12,000
License agreement \| Archemix \| Anti-PDGF aptamers
Commitments and contingencies
Cumulative payments	2,300
License agreement \| Archemix \| Fovista \| Achievement of specified clinical and regulatory milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	16,500
License agreement \| Archemix \| Fovista \| Initiation of planned Phase 3 clinical program of Fovista
Commitments and contingencies
Amount to be paid on achievement of milestone	2,500
License agreement \| Archemix \| Fovista \| Achievement of specified commercial milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	3,000
License agreement \| Archemix \| Other anti-PDGF aptamer \| Achievement of specified clinical and regulatory milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	18,800
License agreement \| Archemix \| Other anti-PDGF aptamer \| Achievement of specified commercial milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	3,000
License agreement \| Archemix \| Anti-C5 aptamers
Commitments and contingencies
Cumulative payments	2,000
License agreement \| Archemix \| Anti-C5 aptamers \| Achievement of specified commercial milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	22,500
License agreement \| Archemix \| Anti-C5 aptamers \| Achievement of specified development, clinical and regulatory milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	57,500
License, manufacturing and supply agreement \| Nektar
Commitments and contingencies
Cumulative payments	800
License, manufacturing and supply agreement \| Nektar \| Achievement of specified clinical and regulatory milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	5,500
License, manufacturing and supply agreement \| Nektar \| Initiation of planned Phase 3 clinical program of Fovista
Commitments and contingencies
Amount to be paid on achievement of milestone	1,000
License, manufacturing and supply agreement \| Nektar \| Achievement of specified commercial sale milestone
Commitments and contingencies
Amount to be paid on achievement of milestone	$ 3,000

Stock Option and Compensation Plans (Details) - Stock option $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2013 $ / shares shares	Dec. 31, 2012 USD ($) item $ / shares shares	Dec. 31, 2011 $ / shares shares
Shares Available for Grant
Balance at the beginning of the period (in shares)	141	76	260
Increase to Option pool (in shares)		314
Options granted (in shares)		(250)	(184)
Options forfeited (in shares)		1
Balance at the end of the period (in shares)		141	76
Number of Shares
Balance at the beginning of the period (in shares)	1,344	1,113	953
Options granted (in shares)		250	184
Options exercised (in shares)		(18)	(24)
Options forfeited (in shares)		(1)
Balance at the end of the period (in shares)		1,344	1,113
Weighted - Average Exercise Price
Balance at the beginning of the period (in dollars per share) \| $ / shares	$ 1.65
Options granted (in dollars per share) \| $ / shares		$ 3.12	$ 1.65
Options exercised (in dollars per share) \| $ / shares		0.12	0.17
Balance at the end of the period (in dollars per share) \| $ / shares		1.65
Weighted - Average Fair Value Per Share
Balance at the beginning of the period (in dollars per share) \| $ / shares	1.30
Options granted (in dollars per share) \| $ / shares		1.65	1.18
Options exercised (in dollars per share) \| $ / shares		1.59	$ 0.12
Balance at the end of the period (in dollars per share) \| $ / shares		$ 1.30
Additional disclosures
Aggregate intrinsic value of options outstanding \| $		$ 11.3
Estimated stock price (in dollars per share) \| $ / shares	$ 29.71	$ 10.03
Number of possible liquidity scenarios considered in determining value of common stock \| item		3

Stock Option and Compensation Plans (Details 2) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended		72 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Stock Option and Compensation Plans
Vesting percentage			100.00%
Share-based compensation expense	$ 1,607	$ 283
Employees Options
Stock Option and Compensation Plans
Weighted average remaining contractual life			7 years 9 months 18 days	8 years 3 months 18 days
Number of vested shares granted			1,158,456	949,259
Number of non-vested shares granted			465,700	519,976
Weighted average exercise price (in dollars per share)			$ 1.36	$ 1.18
Share-based compensation expense			$ 500	$ 200	$ 900
Unrecognized share-based compensation costs			$ 600		600
Expected weighted average period to recognize share-based compensation costs			2 years 8 months 12 days
Additional share-based compensation expense recorded as a result of modification			$ 300
Employees Options \| Maximum
Stock Option and Compensation Plans
Expiration period			10 years
Employees Options \| Vesting of share-based compensation awards after one year of service
Stock Option and Compensation Plans
Vesting percentage			25.00%
Vesting period			1 year
Employees Options \| Vesting of share-based compensation awards over the next three years
Stock Option and Compensation Plans
Vesting percentage			75.00%
Vesting period			3 years
Vesting percentage per month			2.08%
Non-employee Options
Stock Option and Compensation Plans
Weighted average remaining contractual life			6 years 10 months 24 days	7 years
Number of vested shares granted			161,082	183,808
Number of non-vested shares granted			31,963	55,304
Weighted average exercise price (in dollars per share)			$ 0.41	$ 0.59
Share-based compensation expense			$ 100	$ 100
Unrecognized share-based compensation costs			$ 400		$ 400
Expected weighted average period to recognize share-based compensation costs			3 years
Non-employee Options \| Consultants
Stock Option and Compensation Plans
Vesting period			3 years
Expiration period			10 years
Options granted (in shares)			41,946	3,812

Fair Value Measurements (Details 2)	12 Months Ended
Fair Value Measurements (Details 2)	Dec. 31, 2012 item $ / shares	Dec. 31, 2011 item $ / shares
Series A Preferred Stock
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 1
Series B preferred shares
Level 3 Valuation
Fair value of shares (in dollars per share)	1
Level 3 \| Series A Warrant
Level 3 Valuation
Volatility (as a percent)		64.70%
Strike price (in dollars per share)	$ 0.01	$ 0.01
Number of scenarios for expected outcome probability weight \| item	3	3
Expected outcome probability rate of merger (as a percent)	65.00%	50.00%
Expected outcome probability rate of technology sale (as a percent)		20.00%
Expected outcome probability rate of dissolution (as a percent)	20.00%	30.00%
Expected outcome probability rate of initial public offering (as a percent)	15.00%
Level 3 \| Series A Warrant \| Minimum
Level 3 Valuation
Volatility (as a percent)	47.20%
Risk free interest rate (as a percent)	0.05%	0.06%
Expected life	3 months	6 months
Level 3 \| Series A Warrant \| Maximum
Level 3 Valuation
Volatility (as a percent)	85.30%
Risk free interest rate (as a percent)	0.62%	0.12%
Expected life	4 years 6 months	1 year
Level 3 \| Series A Warrant \| Series A Preferred Stock \| Minimum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 1.22	$ 0.18
Level 3 \| Series A Warrant \| Series A Preferred Stock \| Maximum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 4.34	$ 1.51
Level 3 \| Series B Warrant
Level 3 Valuation
Number of scenarios for expected outcome probability weight \| item	3
Expected outcome probability rate of merger (as a percent)	65.00%
Expected outcome probability rate of dissolution (as a percent)	20.00%
Expected outcome probability rate of initial public offering (as a percent)	15.00%
Level 3 \| Series B Warrant \| Minimum
Level 3 Valuation
Volatility (as a percent)	47.20%
Risk free interest rate (as a percent)	0.05%
Strike price (in dollars per share)	$ 1.00
Expected life	3 months
Level 3 \| Series B Warrant \| Maximum
Level 3 Valuation
Volatility (as a percent)	80.10%
Risk free interest rate (as a percent)	1.68%
Strike price (in dollars per share)	$ 2.50
Expected life	9 years 6 months
Level 3 \| Series B Warrant \| Series B preferred shares \| Minimum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 1.18
Level 3 \| Series B Warrant \| Series B preferred shares \| Maximum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 4.22

Subsequent Events (Details)				1 Months Ended	9 Months Ended	12 Months Ended	81 Months Ended
Subsequent Events (Details)	Sep. 09, 2013	May 23, 2013 USD ($) item $ / shares shares	Mar. 15, 2013 USD ($) $ / shares shares	May 31, 2013 USD ($) item $ / shares shares	Sep. 30, 2013 USD ($) $ / shares shares	Dec. 31, 2012 USD ($) $ / shares shares	Sep. 30, 2013 USD ($) $ / shares shares	Aug. 31, 2013 shares	Aug. 07, 2013 $ / shares shares	Apr. 25, 2013 $ / shares shares	Mar. 31, 2013 USD ($)	Dec. 24, 2012 USD ($) $ / shares shares	Jun. 30, 2012 USD ($)	Jun. 20, 2012 USD ($) $ / shares shares	Dec. 31, 2011 $ / shares shares	Jun. 18, 2007 USD ($)
Subsequent events
Authorized shares of common stock \| shares					200,000,000	155,864,851	200,000,000	200,000,000				155,864,851		155,769,651	155,544,651
Authorized shares of preferred stock \| shares								5,000,000
Par value of common stock (in dollars per share)					$ 0.001	$ 0.001	$ 0.001					$ 0.001		$ 0.001	$ 0.001
Royalty entitlement purchase price \| $					$ 41,667,000	$ 0	$ 41,667,000
Proceeds from royalty purchase agreement \| $					$ 41,667,000		$ 41,667,000
Reverse stock split conversion ratio	5.9
Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products
Subsequent events
Royalty entitlement purchase price \| $				$ 41,700,000
Aggregate royalty entitlements \| $				125,000,000
Proceeds from royalty purchase agreement \| $				$ 41,700,000
Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products \| Maximum
Subsequent events
Number of purchases \| item				3
Common stock \| Series C Agreement
Subsequent events
Share price at fair value (in dollars per share)		$ 10.03
Conversion ratio (per share of common stock) \| shares		1
Series A Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares						73,094,000						73,094,000		73,094,000	73,094,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)						$ 0.001						$ 0.001		$ 0.001	$ 0.001
Share price (in dollars per share)						$ 1
Shares issued \| shares						51,790,000									51,790,000
Series A-1 Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares						18,480,000						18,480,000		18,480,000	18,480,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)						$ 0.001						$ 0.001		$ 0.001	$ 0.001
Share price (in dollars per share)						$ 1
Shares issued \| shares						6,000,000									6,000,000
Junior Series A Preferred Stock
Subsequent events
Authorized shares of preferred stock \| shares						3,000,000						3,000,000		3,000,000	3,000,000
Par value of Preferred stock (in dollars per share)						$ 0.001						$ 0.001		$ 0.001	$ 0.001
Share price (in dollars per share)						$ 1
Series B Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares						42,320,200						42,320,200		42,225,000	42,000,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)						$ 0.001						$ 0.001		$ 0.001	$ 0.001
Share price (in dollars per share)						$ 1
Shares issued \| shares						30,000,000									30,000,000
Series B-1 Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares						700,000						700,000		700,000	700,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)						$ 0.001						$ 0.001		$ 0.001	$ 0.001
Share price (in dollars per share)						$ 1
Shares issued \| shares						500,000									500,000
Series C Preferred Stock \| Series C Agreement
Subsequent events
Shares available for sale and issuance under agreement \| shares				20,000,000
Share price (in dollars per share)				$ 2.50					$ 2.50
Shares issued \| shares				6,666,667					13,333,333
Share price at fair value (in dollars per share)		$ 2.50
Common stock conversion price (in dollars per share)		$ 14.75
Beneficial conversion feature \| $		$ 0
2013 Note
Subsequent events
Secured promissory notes issued \| $						$ 4,000,000					$ 1,500,000	$ 4,000,000	$ 7,500,000	$ 7,500,000		$ 200,000
Fixed interest rate (as a percent)					3.00%	3.00%	3.00%									8.00%
Basis of interest rate					LIBOR	LIBOR
Subsequent event
Subsequent events
Authorized shares of common stock \| shares										187,918,509
Par value of common stock (in dollars per share)										$ 0.001
Reverse stock split conversion ratio	5.9000
Subsequent event \| Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products
Subsequent events
Royalty entitlement purchase price \| $		41,700,000
Aggregate royalty entitlements \| $		125,000,000
Proceeds from royalty purchase agreement \| $		$ 41,700,000
Subsequent event \| Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products \| Maximum
Subsequent events
Number of purchases \| item		3
Subsequent event \| Common stock \| Series C Agreement
Subsequent events
Share price at fair value (in dollars per share)		$ 10.03
Conversion ratio (per share of common stock) \| shares		1
Subsequent event \| Common stock \| Minimum \| Initial Public Offering
Subsequent events
Share price (in dollars per share)		$ 14.75
Subsequent event \| Series A Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares										73,094,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)										$ 0.001
Subsequent event \| Series A-1 Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares										18,480,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)										$ 0.001
Subsequent event \| Junior Series A Preferred Stock
Subsequent events
Authorized shares of preferred stock \| shares										3,000,000
Par value of Preferred stock (in dollars per share)										$ 0.001
Subsequent event \| Series B Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares										42,391,600
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)										$ 0.001
Subsequent event \| Series B-1 Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares										700,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)										$ 0.001
Subsequent event \| Series C Preferred Stock
Subsequent events
Authorized shares of Preferred Stock, Convertible and Redeemable \| shares										28,000,000
Par value of Preferred Stock, Convertible and Redeemable (in dollars per share)										$ 0.001
Subsequent event \| Series C Preferred Stock \| Series C Agreement
Subsequent events
Shares available for sale and issuance under agreement \| shares		20,000,000
Share price (in dollars per share)		$ 2.50
Shares issued \| shares		6,666,667
Share price at fair value (in dollars per share)		$ 2.50
Common stock conversion price (in dollars per share)		$ 14.75
Beneficial conversion feature \| $		$ 0
Subsequent event \| 2013 Note
Subsequent events
Secured promissory notes issued \| $			$ 1,500,000
Fixed interest rate (as a percent)			3.00%
Basis of interest rate			LIBOR
Subsequent event \| 2013 Note \| Warrants
Subsequent events
Warrants issued (in shares) \| shares			35,700
Exercise price of warrants (in dollars per share)			2.50

Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 236,079	$ 4,304	$ 6,396
Prepaid expenses and other current assets	2,096	44	65
Other Assets		331
Security deposits	158	158
Total current assets	238,333	4,837	7,497
Property and equipment, net	32	42	73
Other long-term assets	11		158
Total assets	238,376	4,879	7,728
Current liabilities:
Accrued clinical drug supplies and trial costs	3,477	1,013	1,497
Accounts payable and accrued expenses	4,431	1,391	1,626
Notes payable		11,040
Warrant Liability		966	193
Total current liabilities	7,908	14,410	3,338
Royalty purchase liability	41,667	0
Total liabilities	49,575	14,410	3,338
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable		113,939	106,877
Stockholders' equity (deficit)
Common stock - $0.001 par value, 200,000,000 shares authorized, 31,250,817 shares issued and outstanding at September 30, 2013; 155,864,851 shares authorized, 1,469,798 shares issued and outstanding at December 31, 2012	31	1	1
Additional paid-in capital	351,431
Deficit accumulated during development stage		(126,471)	(105,488)
Total stockholders' equity deficit	188,801	(123,470)	(102,487)
Total liabilities and stockholders' equity deficit	238,376	4,879	7,728
Series A
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable		69,471	65,327
Series A-1
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable		8,460	7,981
Series B
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable		35,456	33,057
Series B-1
Preferred Stock, Convertible and Redeemable:
Total Preferred Stock, Convertible and Redeemable		552	512
Junior Series A Convertible Preferred Stock
Stockholders' equity (deficit)
Preferred Stock		3,000	3,000
Total stockholders' equity deficit		$ 3,000	$ 3,000
Preferred stock
Stockholders' equity (deficit)
Preferred Stock

Balance Sheets (Parenthetical)	Sep. 30, 2013 $ / shares shares
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001
Common stock, shares authorized	200,000,000
Common stock, shares issued	31,250,817
Common stock, shares outstanding	31,250,817
Preferred Stock
Preferred stock, par value (in dollars per share) \| $ / shares	$ 0.001
Preferred stock, shares authorized	5,000,000
Preferred stock, shares issued	0
Preferred stock, shares outstanding	0

Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended	72 Months Ended	81 Months Ended
	Dec. 31, 2011	Dec. 31, 2012	Sep. 30, 2013
Costs and expenses:
Research and development	$ 13,896	$ 74,891	$ 92,727
General and administrative	5,738	27,349	36,494
Total costs and expenses	19,634	102,240	129,221
Loss from operations	(19,634)	(102,240)	(129,221)
Interest expense	2	(510)	(1,964)
Interest and other income		481	481
Loss on extinguishment of debt			(1,091)
Other loss	(30)	(371)	(1,602)
Change in fair value related to investor rights liability		683	683
Net loss before income tax benefit	(19,662)	(101,957)	(132,714)
Income tax benefit	1,029	1,327	1,327
Net loss	(18,633)	(100,630)	(131,387)
Add: accretion of preferred stock dividends	(6,838)	(27,155)	(33,046)
Net loss attributable to common stockholders	$ (25,471)	$ (127,785)	$ (164,433)
Net loss attributable to common stockholders per share -Basic and diluted (in dollars per share)	$ (18.27)
Weighted average common shares outstanding:
Basic and diluted (in shares)	1,394

Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended		81 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Operating Activities
Net loss	$ (30,757)	$ (10,731)	$ (131,387)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	14	24	169
Amortization of debt issuance costs	88	24	135
Accretion of debt discount	87	30	146
Non-cash change in fair value of warrant liability	1,231	332	1,612
Non-cash change in fair value of investor rights liability			(683)
Loss on extinguishment of debt	1,091		1,091
Share-based compensation	1,607	283	2,797
Accrued interest expense converted to Series A Preferred Stock			2
Changes in operating assets and liabilities:
Prepaid expense and other current assets	(2,052)	27	(2,107)
Other receivables		1,036
Security deposits	(11)		(170)
Accrued clinical drug supplies and trial costs	2,464	(1,039)	3,477
Accounts payable and accrued expenses	3,040	787	4,431
Deferred rent		(22)
Net cash used in operating activities	(23,198)	(9,249)	(110,987)
Investing Activities
Purchase of marketable securities			(4,238)
Maturities of marketable securities			4,250
Purchase of property, equipment	(5)		(201)
Net cash provided by (used in) investing activities	(5)		(189)
Financing Activities
Payment of debt issuance costs	(43)	(263)	(421)
Proceeds from issuance of common stock		2	124
Proceeds from initial public offering, net	175,555		175,555
Proceeds from issuance of notes payable, net			210
(Repayment of) proceeds from issuance of venture debt facility, net	(11,900)	7,460	(512)
Proceeds from issuance of preferred stock, net	49,699		130,632
Proceeds from royalty purchase agreement	41,667		41,667
Net cash provided by financing activities	254,978	7,199	347,255
Net change in cash and cash equivalents	231,775	(2,050)	236,079
Cash and cash equivalents
Beginning of period	4,304	6,396
End of period	236,079	4,346	236,079
Supplemental disclosures of cash flow information
Conversion of preferred stock to common stock upon completion of IPO	174,310		174,310
Accreted dividends on Series A, Series A-1, Series of B, B-1 and Series C Preferred Stock	$ 5,891	$ 5,288	33,046
Notes payable and accrued interest converted to Series A Preferred Stock			212
Series A-1, Series B-1 and Junior Series A Convertible Preferred Stock
Adjustments to reconcile net loss to net cash used in operating activities:
Preferred Stock issued for acquired technology and licenses			$ 9,500

Business	9 Months Ended	12 Months Ended
Business	Sep. 30, 2013	Dec. 31, 2012
Business
Business	1. Business Description of Business and Organization Ophthotech Corporation (the "Company" or "Ophthotech") was incorporated on January 5, 2007, in Delaware. The Company is a biopharmaceutical company specializing in the development of novel therapeutics to treat diseases of the eye with a focus on developing therapeutics for age-related macular degeneration, or AMD. The Company's operations since inception have been limited to organizing and staffing the Company, acquiring rights to product candidates, business planning, raising capital and developing its product candidates. Accordingly, the Company is considered to be in the development stage as defined by Financial Accounting Standards Board Accounting Standards Codification ("ASC") 915, Development Stage Entities. The Company operates in one business segment. Capitalized terms not otherwise defined herein are defined in their respective agreements. Liquidity Since the Company's inception, it has incurred significant operating losses. The Company reported a net loss of $30.8 million for the nine months ended September 30, 2013 and $10.7 million for the nine months ended September 30, 2012. As of September 30, 2013, the Company had a deficit accumulated during the development stage of $162.7 million. To date, the Company has not generated any revenues and has financed its operations primarily through private placements of its preferred stock, venture debt borrowings, its royalty purchase and sale agreement with Novo A/S and its initial public offering ("IPO"), which closed on September 30, 2013. The Company issued and sold an aggregate of 8,740,000 shares of common stock in its IPO at a public offering price of $22.00 per share, including 1,140,000 shares pursuant to the exercise by the underwriters of an over-allotment option. The Company received net proceeds from the IPO of $175.6 million, after deducting underwriting discounts and commissions and other offering expenses. The Company has devoted substantially all of its financial resources and efforts to research and development and expects to continue to incur significant expenses and increasing operating losses over the next several years. The Company's net losses may fluctuate significantly from quarter to quarter and year to year. To fully execute its business plan, the Company will need to complete certain research and development activities and clinical trials. Further, the Company's product candidates will require regulatory approval prior to commercialization. These activities may span many years and require substantial expenditures to complete and may ultimately be unsuccessful. Any delays in completing these activities could adversely impact the Company. The Company plans to meet its capital requirements primarily through a combination of equity and debt financings, collaborations, strategic alliances and marketing distribution or licensing arrangements and in the longer term, revenue from potential product sales. There can be no assurance that such funds will be available, or if available, on terms favorable to the Company. The Company faces the normal risks associated with a development stage company, including but not limited to the risk that the Company's research and development activities will not be successfully completed, that adequate patent protection for the Company's technology will not be obtained, that any products developed will not obtain necessary government regulatory approval and that any approved products will not be commercially viable. In addition, the Company operates in an environment of rapid change in technology, substantial competition from pharmaceutical and biotechnology companies and is dependent upon the services of its employees and its consultants. The Company's capital requirements will depend on many factors, including the success of its development and commercialization of its product candidates and whether it pursues the development of additional product candidates. Even if the Company succeeds in developing and commercializing one or more of its product candidates, it may never achieve sufficient sales revenue to achieve or maintain profitability.	1. Business Description of Business and Organization Ophthotech Corporation (the "Company" or "Ophthotech") was incorporated on January 5, 2007, in Delaware. The Company is a biopharmaceutical company specializing in the development of novel therapeutics to treat diseases of the eye with a focus on developing therapeutics for age-related macular degeneration, or AMD. The Company's operations since inception have been limited to organizing and staffing the Company, acquiring rights to product candidates, business planning, raising capital and developing its product candidates. Accordingly, the Company is considered to be in the development stage as defined by Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 915, Development Stage Entities. The Company operates in one business segment. Capitalized terms not otherwise defined herein are defined in their respective agreements. Liquidity The Company expects to continue to incur substantial losses over the next several years during its development phase. To fully execute its business plan, the Company will need to complete certain research and development activities and clinical trials. Further, the Company's product candidates will require regulatory approval prior to commercialization. These activities may span many years and require substantial expenditures to complete and may ultimately be unsuccessful. Any delays in completing these activities could adversely impact the Company. The Company plans to meet its capital requirements primarily through a combination of equity and debt financings, collaborations, strategic alliances and marketing distribution or licensing arrangements and in the longer term, revenue from product sales. There can be no assurance that such funds will be available, or if available, on terms favorable to the Company. The Company faces the normal risks associated with a development stage company, including but not limited to the risk that the Company's research and development activities will not be successfully completed, that adequate patent protection for the Company's technology will not be obtained, that any products developed will not obtain necessary government regulatory approval and that any approved products will not be commercially viable. In addition, the Company operates in an environment of rapid change in technology, substantial competition from pharmaceutical and biotechnology companies and is dependent upon the services of its employees and its consultants. Since inception, the Company has primarily relied upon private placements of its preferred stock and venture debt borrowings to fund operations. However, the Company's capital requirements will depend on many factors, including the success of its development and commercialization of the Company's product candidates and whether it pursues the development of additional product candidates. Even if the Company succeeds in developing and commercializing one or more of its product candidates, it may never achieve sufficient sales revenue to achieve or maintain profitability.

Summary of Significant Accounting Policies

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

The Company's complete listing of significant accounting policies are described in Note 2 of the notes to the audited financial statements as of December 31, 2012, included in this prospectus.

Basis of Presentation

Use of Estimates

Cash and Cash Equivalents

Concentration of Credit Risk

Foreign Currency Translation

Financial Instruments

Property and Equipment

Research and Development

•

external research and development expenses incurred under arrangements with third parties, such as contract research organizations, ("CROs") and other vendors, contract manufacturing organizations and consultants; and

•

employee-related expenses, including salaries, benefits, travel and share-based compensation expense.

Income Taxes

Share-Based Compensation

Share-based compensation expense includes stock options granted to employees and non-employees and has been reported in the Company's statements of operations as follows:

	Nine months ended September 30,

	2013		2012
Research and development	$	1,052	$	182
General and administrative		555		101

Total	$	1,607	$	283

The Company had no shares of unvested restricted common stock granted to employees at September 30, 2013 or at December 31, 2012, respectively.

Reclassification

JOBS Act

2. Significant Accounting Policies

Basis of Presentation

Unaudited Pro Forma Information

Use of Estimates

The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company's Balance Sheets and the amount of expenses reported for each of the periods presented are affected by estimates and assumptions, which are used for, but not limited to, the accounting for stock-based compensation and investor rights liabilities, for income taxes and accounting for research and development costs. Actual results could differ from those estimates.

Cash and Cash Equivalents

Concentration of Credit Risk

Foreign Currency Translation

Financial Instruments

Property and Equipment

Research and Development

Income Taxes

Share-Based Compensation

At December 31, 2012 and 2011, the Company had one share-based employee compensation plan, which is described more fully in Note 12.

The Company grants stock options for a fixed number of shares to employees and non-employees with an exercise price equal to the fair value of the share at the grant date.

	Year Ended December 31,

	2012	2011
Expected common stock price volatility	81%	79%
Risk-free interest rate	0.94% - 1.77%	1.72% - 2.38%
Expected term of options (years)	6.6	6.7
Expected annual dividend per share	$—	$—

Recent Accounting Pronouncements

Fair Value Measurements

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Fair Value Measurements

Fair Value Measurements

5. Fair Value Measurements

The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels are defined as follows:

•

Level 1—inputs to the valuation methodology are quoted prices (unadjusted) for an identical asset or liability in an active market.

•

Level 2—inputs to the valuation methodology include quoted prices for a similar asset or liability in an active market or model-derived valuations in which all significant inputs are observable for substantially the full term of the asset or liability.

•

Level 3—inputs to the valuation methodology are unobservable and significant to the fair value measurement of the asset or liability.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in U.S. Treasury money market funds*	$	234,843	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	—
Series B Warrant Liability	$	—	$	—	$	—

*: Investments in U.S. Treasury money market funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money market funds*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liability	$	—	$	—	$	443

*: Investments in money markets funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Level 3 Valuation

The table presented below is a summary of changes in the fair value of the Company's Level 3 valuation for the Series A and Series B warrant liabilities for the period ended September 30, 2013:

	Level 3

	Series A Warrant Liability			Series B Warrant Liability
Balance at December 31, 2012		523			443
Warrants issued in connection with venture debt facility		—			32
Change in fair value of warrant liability		379			852
Conversion of warrant liability to equity		(902	)		(1,327	)

Balance at September 30, 2013	$	—		$	—

14. Fair Value Measurements

The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels are defined as follows:

•

Level 1—inputs to the valuation methodology are quoted prices (unadjusted) for an identical asset or liability in an active market.

•

Level 2—inputs to the valuation methodology include quoted prices for a similar asset or liability in an active market or model-derived valuations in which all significant inputs are observable for substantially the full term of the asset or liability.

•

Level 3—inputs to the valuation methodology are unobservable and significant to the fair value measurement of the asset or liability.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liabilty	$	—	$	—	$	443

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	4,874	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	193

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Level 3 Valuation

The table presented below is a summary of changes in the fair value of the Company's Level 3 valuation for the Series A and Series B warrant liabilities for periods ending December 31, 2012 and 2011:

	Level 3

	Series A Warrant Liability		Series B Warrant Liability
Balance at December 31, 2010	$	186	$	—
Change in fair value of warrant liability		7		—

Balance at December 31, 2011		193		—
Warrants issued in connection with venture debt facility		—		407
Change in fair value of warrant liability		330		36

Balance at December 31, 2012	$	523	$	443

Stock Option and Compensation Plans

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Stock Option and Compensation Plans

Stock Option and Compensation Plans

7. Stock Option and Compensation Plans

As of September 30, 2013, the Company had approximately 2,620,000 stock options outstanding under the 2007 Plan and approximately 739,000 shares available for grant under the 2013 Plan.

12. Stock Option and Compensation Plans

The following table sets forth the activity under the Company's Option Plan:

				Options Outstanding

	Shares Available for Grant			Number of Shares			Weighted- Average Exercise Price		Weighted- Average Fair Value Per Share
	(shares in thousands)
Balance, December 31, 2010		260			953
Increase to Option pool		—			—
Options granted		(184	)		184		$	1.65	$	1.18
Options exercised		—			(24	)	$	0.17	$	0.12
Options forfeited		—			—

Balance, December 31, 2011		76			1,113
Increase to Option pool		314			—
Options granted		(250	)		250		$	3.12	$	1.65
Options exercised		—			(18	)	$	0.12	$	1.59
Options forfeited		1			(1	)

Balance, December 31, 2012		141			1,344		$	1.65	$	1.30

Employees Options

Non-employee Options

Royalty Agreement and Series C Agreement	9 Months Ended
Royalty Agreement and Series C Agreement	Sep. 30, 2013
Royalty Agreement and Series C Agreement
Royalty Agreement and Series C Agreement	8. Royalty Agreement and Series C Agreement In May 2013, the Company entered into a Purchase and Sale Agreement (the "Purchase and Sale Agreement") with Novo A/S, providing for the Company to sell, and Novo A/S to purchase, the right, title, and interest in a portion of the revenues from the sale of (a) Fovista, (b) Fovista-Related Products, and (c) Other Products (as defined in the Purchase and Sale Agreement), calculated as low to mid-single digit percentages of net sales. The Purchase and Sale Agreement provides for up to three separate purchases for a purchase price of $41.7 million each, at a first, second and third closing, for an aggregate purchase price of $125.0 million. In each purchase, Novo A/S acquires rights to a low single digit percentage of net sales. If all royalty interests under the Purchase and Sale Agreement are purchased, Novo A/S will have a right to receive royalties on net sales at a mid-single digit percentage. In May 2013, the Company received cash proceeds of $41.7 million for the royalty entitlement related to the first closing on the date of the Purchase and Sale Agreement. Receipt of cash proceeds for the second and third purchases is contingent upon certain triggers and conditions detailed in the Purchase and Sale Agreement, none of which have occurred prior to this filing. The royalty payment period covered by the Purchase and Sale Agreement begins on commercial launch and ends, on a product-by-product and country-by-country basis, on the latest to occur of (i) the 12th anniversary of the commercial launch, (ii) the expiration of certain patent rights and (iii) the expiration of the regulatory exclusivity for each product in each country. Under the terms of the Purchase and Sale Agreement, the Company is not required to reimburse or otherwise compensate Novo A/S through any means other than the agreed royalty entitlement. In addition, the Company does not, under the terms of the Purchase and Sale Agreement, have the right or obligation to prepay Novo A/S in connection with a change of control of the Company or otherwise. The proceeds from the first financing tranche under the Purchase and Sale Agreement were recorded as a liability on the Company's Balance Sheet as of September 30, 2013, in accordance with ASC 730. Because there is a significant related party relationship between the Company and Novo A/S, the Company is treating its obligation to make royalty payments under the Purchase and Sale Agreement as an implicit obligation to repay the funds advanced by Novo A/S. As the Company makes royalty payments in accordance with the Purchase and Sale Agreement, it will reduce the liability balance. At the time that such royalty payments become probable and estimable, and if such amounts exceed the liability balance, the Company will impute interest accordingly on a prospective basis based on such estimates, which would result in a corresponding increase in the liability balance. The Purchase and Sale Agreement requires the establishment of a Joint Oversight Committee in the event that Novo A/S does not continue to have a representative on the Company's board of directors. The Joint Oversight Committee would have responsibilities that include "discussion and review" of all matters related to Fovista research, development, regulatory approval and commercialization, but there is no provision either implicit or explicit that gives the Joint Oversight Committee or its members decision-making authority. Also in May 2013, the Company entered into a Series C Preferred Stock Purchase Agreement (the "Series C Agreement") with certain of its existing investors for the sale and issuance, upon the satisfaction of certain conditions, of an aggregate of 20,000,000 shares of the Company's Series C Preferred Stock at a price of $2.50 ($14.75 on a post-reverse stock split basis) per share. The Company issued 6,666,667 shares of Series C Preferred Stock at $2.50 ($14.75 on a post-reverse stock split basis) per share in a closing that occurred in May 2013, simultaneous with entry into the Series C Agreement. In August 2013, the Company amended the Series C Agreement to provide for the acceleration of the sale and issuance of the remaining 13,333,333 shares issuable thereunder, the purchase and sale of which closed on August 7, 2013 at $2.50 ($14.75 on a post-reverse stock split basis) per share for aggregate proceeds of $33.3 million. There are no further rights or obligations for the issuance of Series C Preferred Stock under the Series C Agreement. As the Series C Agreement was entered into in conjunction with the Purchase and Sale Agreement, the Company's management considered whether the consideration received for the issuance of Series C Preferred Stock or the consideration received for the sale of the royalty entitlement at the first closing under the Purchase and Sale Agreement should be allocated in the Company's financial statements in a manner different than the prices stated in the respective agreements. The Company's management, with the assistance of an outside valuation specialist, determined that the $2.50 ($14.75 on a post-reverse stock split basis) per share price approximated the fair value of a share of Series C Preferred Stock, and therefore concluded that the consideration received under the agreements should be allocated in accordance with the terms of the respective agreements. In connection with entering into the Series C Agreement, the minimum public offering price per share in an underwritten public offering of common stock required for the automatic conversion of outstanding shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock and Junior Series A Preferred Stock pursuant to the Company's certificate of incorporation was adjusted to $14.75 per share (subject to further adjustment as a result of any stock dividend, stock split, combination or similar recapitalization of the common stock). The Company has determined that in accordance with ASC 470-20-20, at the time of the initial closing under the Series C Agreement on May 23, 2013, there was a firm commitment from the Series C Preferred Stock investors with respect to the significant terms of the financing, including the quantity of shares to be issued, the fixed price of the shares and the timing of the transaction. In addition, the Company has concluded that the Series C Agreement and the Company's certificate of incorporation includes a disincentive feature for non-performance that was sufficiently large enough to make investor performance at subsequent closings probable. As such, the Company's measurement of any beneficial conversion feature occurred at the time of the initial closing. Based on a $10.03 per share valuation of the Company's common stock as of the date of the initial closing of the sale of the Series C Preferred Stock, as well as the fact that the Series C Preferred Stock featured a common stock conversion price of $14.75 per share (implying a one-to-one conversion into shares of common stock), the Company determined that there was no beneficial conversion feature associated with the issuance of its Series C Preferred Stock. The proceeds received from Novo A/S under the Purchase and Sale Agreement will be reported as revenue for income tax purposes. Notwithstanding the Company's receipt of $41.7 million in proceeds under the Purchase and Sale Agreement in May 2013, the Company has forecasted a tax loss for the 2013 tax year. Based upon the Company's cumulative history of losses and expected future losses, the Company recorded a full valuation allowance against all net federal and state deferred tax assets.

Subsequent Events	9 Months Ended	12 Months Ended
Subsequent Events	Sep. 30, 2013	Dec. 31, 2012
Subsequent Events
Subsequent Events	10. Subsequent Events On January 23, 2014, in connection with its royalty agreement with Novo A/S, the Company received approximately $41.7 million in exchange for a low single-digit royalty interest in future potential worldwide sales of Fovista. The receipt of this second financing tranche under the royalty agreement was triggered as a result of the Company reaching an initial enrollment milestone of a specified number of patients in its Phase 3 clinical program for Fovista. The closing of a third potential financing tranche of approximately $41.7 million is subject to the further enrollment milestone of a specified number of patients in the Company's Phase 3 clinical program for Fovista, and the Company satisfying additional closing conditions and other obligations.	17. Subsequent Events On March 15, 2013, the Company issued a secured promissory note in the amount of $1.5 million (the "2013 Note") to the holder of the 2012 Notes. The 2013 Note carries interest at a rate per annum equal to the sum of (i) the greater of (A) the LIBOR Rate in effect for the applicable Interest Period and (B) 3.0%, plus (ii) the LIBOR Rate Margin adjusted on the first day of each Interest Period and fixed for the duration of each such Interest Period. In conjunction with the issuance of the 2013 Note, the Lender received warrants to purchase 35,700 shares of Series B Preferred Stock with an exercise price of $2.50 per share. The warrants expire on March 15, 2023 and provide for proportionate adjustments to be made to the number of shares purchasable and the exercise price payable under the warrants in the event of certain changes to the underlying Series B Preferred Stock, including for subdivisions, combinations and stock dividends. On April 25, 2013, the Company amended its certificate of incorporation to increase the authorized shares of capital stock to the following: 187,918,509 shares of common stock and 73,094,000 shares of Series A Preferred Stock, 18,480,000 shares of Series A-1 Preferred Stock, 3,000,000 shares of Junior Series A Preferred Stock, 42,391,600 shares of Series B Preferred Stock, 700,000 shares of Series B-1 Preferred Stock, and 28,000,000 shares of Series C Preferred Stock, each with a par value of $0.001 per share. On May 23, 2013, the Company entered into a Purchase and Sale Agreement (the "Purchase and Sale Agreement") with Novo A/S, providing for the Company to sell, and Novo A/S to purchase, the right, title, and interest in a portion of the revenues from the sale of (a) Fovista, (b) Fovista-Related Products, and (c) Other Products (as defined in the Purchase and Sale Agreement), calculated as low to mid single-digit percentages of net sales. The Purchase and Sale Agreement provides for up to three separate purchases for a purchase price of $41.7 million each, at a first, second and third closing, for an aggregate purchase price of $125.0 million. In each purchase, Novo A/S acquires rights to a low single-digit percentage of net sales. Following the purchase of all royalty interests under the Purchase and Sale Agreement, Novo A/S will have a right to receive royalties on net sales at a mid-single digit percentage. On May 23, 2013, the Company received cash proceeds of $41.7 million for the royalty entitlement related to the first closing on the date of the Purchase and Sale Agreement. Receipt of cash proceeds for the second and third purchases is contingent upon certain triggers and conditions detailed in the Purchase and Sale Agreement, none of which occurred prior to the Company's initial public offering. The royalty payment period covered by the Purchase and Sale Agreement begins on commercial launch and ends, on a product by product and country by country basis, on the latest to occur of (i) the 12th anniversary of the commercial launch, (ii) the expiration of certain patent rights and (iii) the expiration of the regulatory exclusivity for each product in each country. Under the terms of the Purchase and Sale Agreement, the Company is not required to reimburse or otherwise compensate Novo A/S through any means other than the agreed royalty entitlement. In addition, the Company does not, under the terms of the Purchase and Sale Agreement, have the right or obligation to prepay Novo A/S in connection with a change of control of the Company or otherwise. The Purchase and Sale Agreement requires the establishment of a Joint Oversight Committee in the event that Novo A/S does not continue to have a representative on the Company's board of directors. The Joint Oversight Committee would have responsibilities that include "discussion and review" of all matters related to Fovista research, development, regulatory approval and commercialization, but there is no provision either implicit or explicit that gives the Joint Oversight Committee or its members decision-making authority. On May 23, 2013, the Company entered into a Series C Preferred Stock Purchase Agreement (the "Series C Agreement") with certain of its existing investors for the sale and issuance of an aggregate of 20,000,000 shares of the Company's Series C Preferred Stock at a price of $2.50 per share. In connection with entering into the Series C Agreement, the Company issued 6,666,667 shares of Series C Preferred Stock at $2.50 per share in a closing that occurred on May 23, 2013, simultaneous with entry into the Series C Agreement. In connection with entering into the Series C Agreement, the minimum public offering price per share in an underwritten public offering of common stock required for the automatic conversion of outstanding shares of Series A Preferred Stock, Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock and Junior Series A Preferred Stock was adjusted to $14.75 per share (subject to further adjustment as a result of any stock dividend, stock split, combination or similar recapitalization of the common stock). On May 23, 2013, the Company repaid the outstanding principal, interest and related prepayment fees on the 2012 Notes and 2013 Note. The Company has determined that in accordance with ASC 470-20-20, at the time of the initial closing under the Series C Agreement on May 23, 2013, there was a firm commitment from the Series C Preferred Stock investors with respect to the significant terms of the financing, including the quantity of shares to be issued, the fixed price of the shares and the timing of the transaction. In addition, the Company has concluded that the Series C Agreement and the Company's certificate of incorporation includes a disincentive feature for non-performance that was sufficiently large enough to make investor performance at subsequent closings probable. As such, the Company's measurement of any beneficial conversion feature occurred at the time of the initial closing. Based on a $10.03 per share valuation of the Company's common stock as of the date of the initial closing of the sale of the Series C Preferred Stock, as well as the fact that the Series C Preferred Stock include a common stock conversion price of $14.75 per share (implying a one-to-one conversion into shares of common stock), the Company determined that there was no beneficial conversion feature associated with the issuance of its Series C Preferred Stock. The Company filed a registration statement on Form S-1 with the SEC relating to the initial public offering of its common stock. In connection with the Company's initial public offering: (i) The Company effected a one-for-5.9000 reverse stock split of its common stock on September 9, 2013. All share and per share amounts related to common stock, options and warrants included in these financial statements and notes to financial statements have been restated to reflect the reverse stock split. The conversion ratios of the Company's preferred stock have also been adjusted to reflect the reverse stock split. (ii) The Company's board of directors adopted and the Company's stockholders approved the 2013 stock incentive plan ("2013 Plan"), which became effective immediately prior to the closing of the Company's initial public offering. The 2013 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other stock-based awards. The Company's employees, officers, directors, consultants and advisors are eligible to receive awards under the 2013 Plan.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Significant Accounting Policies

Basis of Presentation

Basis of Presentation

Use of Estimates

Use of Estimates

The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company's Balance Sheets and the amount of expenses reported for each of the periods presented are affected by estimates and assumptions, which are used for, but not limited to, the accounting for stock-based compensation and investor rights liabilities, for income taxes and accounting for research and development costs. Actual results could differ from those estimates.

Cash and Cash Equivalents

Cash and Cash Equivalents

Concentration of Credit Risk

Concentration of Credit Risk

Foreign Currency Translation

Foreign Currency Translation

Financial Instruments

Financial Instruments

Property and Equipment

Property and Equipment

Research and Development

Research and Development

•

external research and development expenses incurred under arrangements with third parties, such as contract research organizations, ("CROs") and other vendors, contract manufacturing organizations and consultants; and

•

employee-related expenses, including salaries, benefits, travel and share-based compensation expense.

Research and Development

Income Taxes

Income Taxes

Share-Based Compensation

Share-Based Compensation

Share-based compensation expense includes stock options granted to employees and non-employees and has been reported in the Company's statements of operations as follows:

	Nine months ended September 30,

	2013		2012
Research and development	$	1,052	$	182
General and administrative		555		101

Total	$	1,607	$	283

The Company had no shares of unvested restricted common stock granted to employees at September 30, 2013 or at December 31, 2012, respectively.

Share-Based Compensation

At December 31, 2012 and 2011, the Company had one share-based employee compensation plan, which is described more fully in Note 12.

The Company grants stock options for a fixed number of shares to employees and non-employees with an exercise price equal to the fair value of the share at the grant date.

	Year Ended December 31,

	2012	2011
Expected common stock price volatility	81%	79%
Risk-free interest rate	0.94% - 1.77%	1.72% - 2.38%
Expected term of options (years)	6.6	6.7
Expected annual dividend per share	$—	$—

Reclassification

Reclassification

Certain amounts in prior periods have been reclassified to conform to the current year presentation. Such reclassifications did not have a material effect on the Company’s financial condition or results of operations as previously reported.

JOBS Act

JOBS Act

Recent Accounting Pronouncements

Fair Value Measurements (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Fair Value Measurements

Schedule of the Company's assets and liabilities that are measured at fair value on recurring basis

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in U.S. Treasury money market funds*	$	234,843	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	—
Series B Warrant Liability	$	—	$	—	$	—

*: Investments in U.S. Treasury money market funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money market funds*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liability	$	—	$	—	$	443

*: Investments in money markets funds are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	524	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	523
Series B Warrant Liabilty	$	—	$	—	$	443

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

	Fair Value Measurement Using

	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money markets*	$	4,874	$	—	$	—
Liabilities
Series A Warrant Liability	$	—	$	—	$	193

*: Investments in money markets are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Summary of changes in fair value of the Company's Level 3 valuation for the Series A and Series B warrant liabilities

	Level 3

	Series A Warrant Liability			Series B Warrant Liability
Balance at December 31, 2012		523			443
Warrants issued in connection with venture debt facility		—			32
Change in fair value of warrant liability		379			852
Conversion of warrant liability to equity		(902	)		(1,327	)

Balance at September 30, 2013	$	—		$	—

	Level 3

	Series A Warrant Liability		Series B Warrant Liability
Balance at December 31, 2010	$	186	$	—
Change in fair value of warrant liability		7		—

Balance at December 31, 2011		193		—
Warrants issued in connection with venture debt facility		—		407
Change in fair value of warrant liability		330		36

Balance at December 31, 2012	$	523	$	443

Business (Details) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended						72 Months Ended	81 Months Ended
Business (Details) $ / shares in Units, $ in Thousands	Sep. 30, 2013 USD ($) item $ / shares shares	Sep. 30, 2012 USD ($)	Dec. 31, 2012 USD ($) item	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)	Dec. 31, 2007 USD ($)	Dec. 31, 2012 USD ($)	Sep. 30, 2013 USD ($)
Business
Number of business segments \| item	1		1
Net loss	$ 30,757	$ 10,731	$ 14,562	$ 18,633	$ 18,948	$ 13,514	$ 20,556	$ 14,417	$ 100,630	$ 131,387
Accumulated deficit during the development stage			$ 126,471	$ 105,488					$ 126,471
Common stock issued and sold in IPO (in shares) \| shares	8,740,000
Public offering price (in dollars per share) \| $ / shares	$ 22.00
Shares issued on exercise of over-allotment option by underwriters \| shares	1,140,000
Net proceeds from IPO after deducting underwriting discounts and commissions and other offering expenses	$ 175,555									$ 175,555

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Capitalization (Details) $ / shares in Units, $ in Thousands			9 Months Ended	12 Months Ended	81 Months Ended
	Sep. 30, 2013 USD ($) $ / shares shares	Sep. 09, 2013	Sep. 30, 2013 USD ($) $ / shares shares	Dec. 31, 2012 shares	Sep. 30, 2013 USD ($) shares	Aug. 31, 2013 shares	Dec. 24, 2012 shares	Jun. 20, 2012 shares	Dec. 31, 2011 shares
Capitalization
Reverse stock split conversion ratio		5.9
Capital structure
Price of common stock issued in initial public offering (in dollars per share) \| $ / shares			$ 22.00
Net proceeds from issuance of shares of common stock after deducting underwriters' commissions and other offering expenses (in dollars) \| $			$ 175,555		$ 175,555
Authorized shares of common stock	200,000,000		200,000,000	155,864,851	200,000,000	200,000,000	155,864,851	155,769,651	155,544,651
Authorized shares of preferred stock						5,000,000
Common stock
Capital structure
Number of shares registered in initial public offering	8,740,000
Price of common stock issued in initial public offering (in dollars per share) \| $ / shares	$ 22.00
Net proceeds from issuance of shares of common stock after deducting underwriters' commissions and other offering expenses (in dollars) \| $	$ 175,600
Shares issued on automatic conversion of redeemable convertible preferred stock	21,038,477			21,038,477

Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended											9 Months Ended		12 Months Ended						72 Months Ended	81 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2012	Sep. 30, 2013
Basic and diluted net loss per common share calculation:
Net loss												$ (30,757)	$ (10,731)	$ (14,562)	$ (18,633)	$ (18,948)	$ (13,514)	$ (20,556)	$ (14,417)	$ (100,630)	$ (131,387)
Accretion of preferred stock dividends												(5,891)	(5,288)	(7,063)	(6,838)					(27,155)	(33,046)
Net loss attributable to common stockholders	$ (18,424)	$ (11,863)	$ (6,361)	$ (5,606)	$ (5,928)	$ (5,326)	$ (4,765)	$ (6,052)	$ (6,765)	$ (6,441)	$ (6,213)	$ (36,648)	$ (16,019)	$ (21,625)	$ (25,471)					$ (127,785)	$ (164,433)
Weighted average common shares outstanding												1,579	1,447	1,452	1,394
Net loss per share of common stock - basic and diluted (in dollars per share)	$ (10.26)	$ (8.07)	$ (4.33)	$ (3.82)	$ (4.07)	$ (3.68)	$ (3.31)	$ (4.27)	$ (4.81)	$ (4.65)	$ (4.56)	$ (23.21)	$ (11.07)	$ (14.89)	$ (18.27)
Anti-dilutive securities
Total (in shares)												2,721	17,892	18,102	17,233
Redeemable convertible preferred stock
Anti-dilutive securities
Total (in shares)													16,513	16,663	16,064
Stock options
Anti-dilutive securities
Total (in shares)												2,620	1,301	1,344	1,113
Warrants
Anti-dilutive securities
Total (in shares)												101	78	95	38

Fair Value Measurements (Details 2)	12 Months Ended
Fair Value Measurements (Details 2)	Dec. 31, 2012 item $ / shares	Dec. 31, 2011 item $ / shares
Series A Preferred Stock
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 1
Series B preferred shares
Level 3 Valuation
Fair value of shares (in dollars per share)	1
Level 3 \| Series A Warrant
Level 3 Valuation
Volatility (as a percent)		64.70%
Strike price (in dollars per share)	$ 0.01	$ 0.01
Number of scenarios for expected outcome probability weight \| item	3	3
Expected outcome probability rate of merger (as a percent)	65.00%	50.00%
Expected outcome probability rate of dissolution (as a percent)	20.00%	30.00%
Expected outcome probability rate of initial public offering (as a percent)	15.00%
Level 3 \| Series A Warrant \| Minimum
Level 3 Valuation
Volatility (as a percent)	47.20%
Risk free interest rate (as a percent)	0.05%	0.06%
Expected life	3 months	6 months
Level 3 \| Series A Warrant \| Maximum
Level 3 Valuation
Volatility (as a percent)	85.30%
Risk free interest rate (as a percent)	0.62%	0.12%
Expected life	4 years 6 months	1 year
Level 3 \| Series A Warrant \| Series A Preferred Stock \| Minimum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 1.22	$ 0.18
Level 3 \| Series A Warrant \| Series A Preferred Stock \| Maximum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 4.34	$ 1.51
Level 3 \| Series B Warrant
Level 3 Valuation
Number of scenarios for expected outcome probability weight \| item	3
Expected outcome probability rate of merger (as a percent)	65.00%
Expected outcome probability rate of dissolution (as a percent)	20.00%
Expected outcome probability rate of initial public offering (as a percent)	15.00%
Level 3 \| Series B Warrant \| Minimum
Level 3 Valuation
Volatility (as a percent)	47.20%
Risk free interest rate (as a percent)	0.05%
Strike price (in dollars per share)	$ 1.00
Expected life	3 months
Level 3 \| Series B Warrant \| Maximum
Level 3 Valuation
Volatility (as a percent)	80.10%
Risk free interest rate (as a percent)	1.68%
Strike price (in dollars per share)	$ 2.50
Expected life	9 years 6 months
Level 3 \| Series B Warrant \| Series B preferred shares \| Minimum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 1.18
Level 3 \| Series B Warrant \| Series B preferred shares \| Maximum
Level 3 Valuation
Fair value of shares (in dollars per share)	$ 4.22

Stock Option and Compensation Plans (Details) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2013 USD ($) item $ / shares shares	Sep. 30, 2012 USD ($)	Dec. 31, 2012 item $ / shares shares	Dec. 31, 2011 item shares	Dec. 31, 2010 shares
Stock Option and Compensation Plans
Number of option plans \| item	2		1	1
Share-based compensation expense \| $	$ 1,607	$ 283
2007 Plan
Stock Option and Compensation Plans
Increase in number of shares authorized under the Plan	1,878,343
Number of shares of common stock available for issuance under the Plan	739,317
Awards outstanding (in shares)	2,620,000
2013 Plan
Stock Option and Compensation Plans
Number of shares of common stock available for issuance under the Plan	739,000
Annual increase in shares reserved for issuance under the Plan	2,542,372
Annual increase in shares reserved for issuance under the Plan (as a percent)	4.00%
2013 Plan \| Maximum
Stock Option and Compensation Plans
Number of shares reserved for issuance under the Plan	3,359,641
Stock option
Stock Option and Compensation Plans
Number of shares of common stock available for issuance under the Plan			141,000	76,000	260,000
Awards outstanding (in shares)			1,344,000	1,113,000	953,000
Share-based compensation expense \| $	$ 1,600	$ 300
Unrecognized share-based compensation costs \| $	$ 11,600
Expected weighted average period to recognize share-based compensation costs	3 years 4 months 24 days
Additional disclosure of vested and non-vested options
Outstanding vested options (in shares)	1,091,000
Intrinsic value of outstanding vested options \| $	$ 30,800
Estimated stock price (in dollars per share) \| $ / shares	$ 29.71		$ 10.03
Weighted average exercise price of vested stock options (in dollars per share) \| $ / shares	$ 1.36
Outstanding unvested options (in shares)	1,529,000
Intrinsic value of outstanding unvested options \| $	$ 30,500
Weighted average exercise price of unvested stock options (in dollars per share) \| $ / shares	$ 9.76

Royalty Agreement and Series C Agreement (Details 2) - USD ($)		1 Months Ended	9 Months Ended	12 Months Ended	72 Months Ended	81 Months Ended
	May 23, 2013	Aug. 31, 2013	Sep. 30, 2013	Dec. 31, 2011	Dec. 31, 2012	Sep. 30, 2013	Aug. 07, 2013	May 31, 2013
Series C Preferred Stock Purchase Agreement
Aggregate proceeds			$ 49,699,000	$ 14,990,000	$ 80,934,000	$ 130,632,000
Series C Agreement \| Series C Preferred Stock
Series C Preferred Stock Purchase Agreement
Shares available for sale and issuance under agreement								20,000,000
Share price (in dollars per share)							$ 2.50	$ 2.50
Share price on a post-reverse stock split basis (in dollars per share)							$ 14.75	$ 14.75
Shares issued							13,333,333	6,666,667
Share price at fair value (in dollars per share)	$ 2.50
Common stock conversion price (in dollars per share)	$ 14.75
Beneficial conversion feature	$ 0
Aggregate proceeds		$ 33,300,000
Series C Agreement \| Common stock
Series C Preferred Stock Purchase Agreement
Share price at fair value (in dollars per share)	$ 10.03
Conversion ratio (per share of common stock)	1
Initial Public Offering \| Common stock \| Conversion Terms \| Minimum
Series C Preferred Stock Purchase Agreement
Share price (in dollars per share)	$ 14.75

Label	Element	Value
Dividends, Preferred Stock	us-gaap_DividendsPreferredStock	$ 646,000
Preferred Stock Issued During Period Value New Issues	opht_PreferredStockIssuedDuringPeriodValueNewIssues	3,000,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	55,000
Common Stock [Member]
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 1,000
Stock Issued During Period, Shares, New Issues	us-gaap_StockIssuedDuringPeriodSharesNewIssues	932,000
Additional Paid-in Capital [Member]
Dividends, Preferred Stock	us-gaap_DividendsPreferredStock	$ 54,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	54,000
Accumulated Deficit during Development Stage [Member]
Dividends, Preferred Stock	us-gaap_DividendsPreferredStock	592,000
Net Income (Loss) Attributable to Parent	us-gaap_NetIncomeLoss	$ (14,417,000)
Junior Series A Convertible Preferred Stock [Member]
Preferred Stock Issued During Period Shares New Issues	opht_PreferredStockIssuedDuringPeriodSharesNewIssues	3,000,000
Preferred Stock Issued During Period Value New Issues	opht_PreferredStockIssuedDuringPeriodValueNewIssues	$ 3,000,000

Security Deposits	12 Months Ended
Security Deposits	Dec. 31, 2012
Security Deposits
Security Deposits	10. Security Deposits Security deposits consist of amounts required to secure the Company's performance of its obligations under the operating leases for its New Jersey and New York offices. As of December 31, 2012, such amount was approximately $0.2 million and reflected in the Balance Sheet as Security Deposits. As of December 31, 2011, such amount was approximately $0.2 million and reflected in the Balance Sheet as Other long-term assets.

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2012
Employee Benefit Plan
Employee Benefit Plan	13. Employee Benefit Plan Through a professional employer organization, the Company maintains a defined contribution 401(k) plan available to employees. Employee contributions are voluntary and are determined on an individual basis, limited by the maximum amounts allowable under federal tax regulations. The Company does not match any of the employee contributions.

Notes Payable	9 Months Ended	12 Months Ended
Notes Payable	Sep. 30, 2013	Dec. 31, 2012
Notes Payable
Notes Payable	6. Notes Payable In June 2012, December 2012 and March 2013, the Company issued secured promissory notes (the "Notes") in the amount of $7.5 million and $4.0 million and $1.5 million, respectively, to the same lender. The Notes bore interest on the outstanding principal amount thereof from the Closing Date until paid in full at a rate per annum equal to the sum of (i) the greater of (A) the LIBOR Rate in effect for the applicable Interest Period and (B) 3.0%, plus (ii) the LIBOR Rate Margin adjusted on the first day of each Interest Period and fixed for the duration of each such Interest Period. As of December 31, 2012, the Company classified the debt with the lender as a current liability since the Company intended to pay down the balance in its entirety within twelve months. The Company repaid in full the outstanding principal, interest and related prepayment fees in May 2013. The repayment of the Notes resulted in a loss on extinguishment of debt in the amount of $1.1 million for the nine months ended September 30, 2013. In addition, the Company made payments of $0.8 million which, in accordance with the Notes, were required upon the earlier of the maturity date or the prepayment date of the Notes. These payments were recorded as interest expense for the nine months ended September 30, 2013.	15. Notes Payable On June 20, 2012, and December 24, 2012, the Company issued secured promissory notes (the "2012 Notes") in the amount of $7.5 million and $4.0 million, respectively, to the same Lender. The 2012 Notes bear interest on the outstanding principal amount thereof from the Closing Date until paid in full at a rate per annum equal to the sum of (i) the greater of (A) the LIBOR Rate in effect for the applicable Interest Period and (B) 3.0%, plus (ii) the LIBOR Rate Margin adjusted on the first day of each Interest Period and fixed for the duration of each such Interest Period.

Property and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended		72 Months Ended	81 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Sep. 30, 2013
Property and equipment
Property, plant and equipment, gross			$ 197	$ 197	$ 197
Accumulated depreciation and amortization			(155)	(124)	(155)
Property, plant and equipment, net	$ 32		42	73	42	$ 32
Depreciation expense	$ 14	$ 24	$ 31	32	154	$ 169
Computer and other equipment
Property and equipment
Useful Life			5 years
Property, plant and equipment, gross			$ 80	80	80
Furniture and fixtures
Property and equipment
Useful Life			7 years
Property, plant and equipment, gross			$ 117	$ 117	$ 117

Income Taxes (Details 2) $ in Thousands		12 Months Ended	72 Months Ended
Income Taxes (Details 2) $ in Thousands	Jan. 24, 2012 USD ($)	Dec. 31, 2007 USD ($) item	Dec. 31, 2012 USD ($) item
Ownership change
Number of ownership changes undergone \| item			0
Amount of net operating losses incurred		$ 4,500
Amount of credits incurred		$ 100
Minimum
Ownership change
Number of ownership changes undergone \| item		1
Maximum
Ownership change
Amount of net operating losses incurred		$ 4,500
Amount of credits incurred		$ 100
Research and development
Carryforwards of tax credits
Credits			$ 1,600
Federal
Carryforwards of net operating losses
Net operating losses			$ 84,200
New Jersey State
Carryforwards of net operating losses
Cash proceeds received from sale of unused operating loss carryforwards	$ 1,000
Fee expense on sale of unused operating loss carryforwards	$ 34

Business (Details) - item	9 Months Ended	12 Months Ended
Business (Details) - item	Sep. 30, 2013	Dec. 31, 2012
Business
Number of business segments	1	1

Significant Accounting Policies (Details) - shares		12 Months Ended
Significant Accounting Policies (Details) - shares	Sep. 30, 2013	Dec. 31, 2012
Common stock
Unaudited pro forma information
Shares issued on automatic conversion of redeemable convertible preferred stock	21,038,477	21,038,477

Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2012	Dec. 31, 2011
Future minimum rental commitments under noncancelable operating leases
2013	$ 90
Total	90
Rent expense	$ 400	$ 400
Deferred rent liability		$ 22

Security Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011
Security Deposits
Security deposits required to secure the Company's performance of its obligations under the operating leases	$ 158	$ 158
Security deposits required to secure the Company's performance of its obligations under the operating leases	$ 11		$ 158

Notes Payable (Details) - Notes - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Notes Payable (Details) - Notes - USD ($) $ in Millions	Sep. 30, 2013	Dec. 31, 2012	Mar. 31, 2013	Dec. 24, 2012	Jun. 30, 2012	Jun. 20, 2012	Jun. 18, 2007
Notes payable
Secured promissory notes issued		$ 4.0	$ 1.5	$ 4.0	$ 7.5	$ 7.5	$ 0.2
Fixed interest rate (as a percent)	3.00%	3.00%					8.00%
Basis of interest rate	LIBOR	LIBOR

Summary of Significant Accounting Policies (Details 3) - shares	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Restricted common stock \| Unvested
Other information
Shares of unvested restricted common stock granted to employees	0	0

Notes Payable (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended	81 Months Ended
Notes Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Mar. 31, 2013	Dec. 24, 2012	Jun. 30, 2012	Jun. 20, 2012	Jun. 18, 2007
Notes payable
Loss on extinguishment of debt	$ 1,091		$ 1,091
Notes
Notes payable
Secured promissory notes issued		$ 4,000		$ 1,500	$ 4,000	$ 7,500	$ 7,500	$ 200
Fixed interest rate (as a percent)	3.00%	3.00%	3.00%					8.00%
Basis of interest rate	LIBOR	LIBOR
Period to pay debt	12 months
Loss on extinguishment of debt	$ 1,100
Payment of debt recorded as interest expense	$ 800

Royalty Agreement and Series C Agreement (Details) $ in Thousands	1 Months Ended	9 Months Ended	81 Months Ended
	May 31, 2013 USD ($) item	Sep. 30, 2013 USD ($)	Sep. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)
Royalty agreement
Royalty entitlement purchase price		$ 41,667	$ 41,667	$ 0
Proceeds from royalty purchase agreement		$ 41,667	$ 41,667
Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products
Royalty agreement
Royalty entitlement purchase price	$ 41,700
Aggregate royalty entitlements	125,000
Proceeds from royalty purchase agreement	$ 41,700
Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products \| Maximum
Royalty agreement
Number of purchases \| item	3

Subsequent Events (Details) - USD ($) $ in Thousands		1 Months Ended	9 Months Ended	81 Months Ended
Subsequent Events (Details) - USD ($) $ in Thousands	May 23, 2013	May 31, 2013	Sep. 30, 2013	Sep. 30, 2013
Subsequent events
Proceeds from royalty purchase agreement			$ 41,667	$ 41,667
Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products
Subsequent events
Proceeds from royalty purchase agreement		$ 41,700
Subsequent event \| Novo A/S \| Purchase and Sale Agreement \| Fovista, Fovista-Related Products, and Other Products
Subsequent events
Proceeds from royalty purchase agreement	$ 41,700