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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Oct. 31, 2018
Document And Entity Information
Entity Registrant Name	Ophthotech Corp.
Entity Central Index Key	0001410939
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Smaller Reporting Company	false
Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		41,266,671
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3

Unaudited Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 135,208	$ 166,972
Prepaid expenses and other current assets	2,055	3,146
Income tax receivable	0	1,387
Total current assets	137,263	171,505
Property and equipment, net	379	518
Deferred tax assets	3,296	3,529
Other assets	19	24
Total assets	140,957	175,576
Current liabilities
Accrued research and development expenses	5,916	4,984
Accounts payable and accrued expenses	4,614	7,551
Total current liabilities	10,530	12,535
Royalty purchase liability	125,000	125,000
Total liabilities	135,530	137,535
Stockholders' equity
Preferred stock—$0.001 par value, 5,000,000 shares authorized, no shares issued or outstanding	0	0
Common stock—$0.001 par value, 200,000,000 shares authorized, 36,217,920 and 36,110,298 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	36	36
Additional paid-in capital	531,172	522,759
Accumulated deficit	(525,781)	(484,754)
Total stockholders' equity	5,427	38,041
Total liabilities and stockholders' equity	$ 140,957	$ 175,576

Unaudited Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	36,217,920	36,110,298
Common stock, shares outstanding (in shares)	36,217,920	36,110,298

Unaudited Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Collaboration revenue	$ 0	$ 206,654	$ 0	$ 209,977
Operating expenses:
Research and development	9,407	10,707	25,609	58,343
General and administrative	5,968	7,059	17,945	28,770
Total operating expenses	15,375	17,766	43,554	87,113
Income (loss) from operations	(15,375)	188,888	(43,554)	122,864
Interest income	637	391	1,711	1,113
Other expense	(1)	(12)	(17)	(34)
Income (loss) before income tax provision (benefit)	(14,739)	189,267	(41,860)	123,943
Income tax provision (benefit)	6	194	(833)	196
Net income (loss)	$ (14,745)	$ 189,073	$ (41,027)	$ 123,747
Net income (loss) per common share:
Net income (loss) per common share, basic (in dollars per share)	$ (0.41)	$ 5.26	$ (1.13)	$ 3.45
Net income (loss) per common share, diluted (in dollars per share)	$ (0.41)	$ 5.25	$ (1.13)	$ 3.44
Weighted average common shares outstanding:
Weighted average common shares outstanding, basic (in shares)	36,202	35,971	36,181	35,878
Weighted average common shares outstanding, diluted (in shares)	36,202	36,047	36,181	35,984

Unaudited Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (14,745)	$ 189,073	$ (41,027)	$ 123,747
Other comprehensive loss:
Unrealized gain on available for sale securities, net of tax	0	186	0	212
Other comprehensive income	0	186	0	212
Comprehensive income (loss)	$ (14,745)	$ 189,259	$ (41,027)	$ 123,959

- Definition

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

+ References + Details

Unaudited Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Unaudited Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Operating Activities
Net loss	$ (41,027)	$ 123,747
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	139	1,979
Amortization of premium and discounts on investment securities	0	140
Deferred income taxes	233	163
Share-based compensation	8,348	14,463
Changes in operating assets and liabilities:
Due from Novartis Pharma AG	0	3,531
Income tax receivable	1,387	(52)
Prepaid expense and other current assets	1,091	1,694
Accrued interest receivable	0	465
Other assets	5	435
Accrued research and development expenses	932	(41,028)
Accounts payable and accrued expenses	(2,937)	(4,137)
Deferred revenue	0	(209,976)
Net cash used in operating activities	(31,829)	(108,576)
Investing Activities
Purchase of marketable securities	0	(12,014)
Maturities of marketable securities	0	166,806
Net cash provided by investing activities	0	154,792
Financing Activities
Proceeds from employee stock plan purchases and stock option exercises	65	71
Net cash provided by financing activities	65	71
Net change in cash and cash equivalents	(31,764)	46,287
Cash and cash equivalents
Beginning of period	166,972	133,930
End of period	135,208	180,217
Supplemental disclosure of cash paid
Income tax refunds received	2,467	0
Supplemental disclosures of non-cash information related to investing activities
Unrealized gain on available for sale securities, net of tax	$ 0	$ 212

Business	9 Months Ended
Business	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business	Business Description of Business and Organization Ophthotech Corporation (the “Company” or “Ophthotech”) was incorporated on January 5, 2007, in Delaware. The Company is a science-driven biopharmaceutical company specializing in the development of novel therapies to treat ophthalmic diseases, with a focus on age-related and orphan retinal diseases. The Company is seeking to leverage its development platform, clinical experience and retina expertise to develop both therapeutics and gene therapies in these disease areas. The Company is developing Zimura® (avacincaptad pegol), its complement C5 inhibitor, for the treatment of multiple age-related retinal diseases: geographic atrophy ("GA"), a late-stage form of dry age-related macular degeneration ("AMD") characterized by retinal cell death and degeneration of tissue in the central portion of the retina, referred to as the macula; wet AMD, an advanced form of AMD characterized by the growth of abnormal new blood vessels under and into the retina; and idiopathic polypoidal choroidal vasculopathy ("IPCV"), an age-related retinal disease involving the choroidal vasculature characterized by the presence of polypoidal lesions and which leads to vision loss. The Company is also developing Zimura for autosomal recessive Stargardt disease, or STGD1, an orphan inherited retinal disease that also may result in loss of central and peripheral vision. In October 2018, the Company acquired Inception 4, Inc. ("Inception 4"), a privately held biopharmaceutical company that owns rights to certain inhibitors of the High temperature requirement A serine peptidase 1 protein ("HtrA1"), which the Company expects to develop for the treatment of GA, and potentially other age-related retinal diseases. The Company is also developing a novel preclinical adeno-associated virus ("AAV") gene therapy product candidate for the treatment of rhodopsin-mediated autosomal dominant retinitis pigmentosa ("RHO-adRP"), an orphan monogenic disease that is characterized by progressive and severe loss of vision leading to blindness. Additionally, the Company has an ongoing gene therapy research collaboration with the University of Massachusetts Medical School to develop new AAV gene therapy product candidates and technologies for ophthalmic gene therapy applications. Furthermore, in October 2018, the Company entered into an exclusive option agreement with the University of Pennsylvania ("Penn") and the University of Florida Research Foundation ("UFRF") and a related sponsored research agreement with Penn, for rights to negotiate to acquire an exclusive global license to develop and commercialize novel AAV gene therapy product candidates for the treatment of Best vitelliform macular dystrophy disease ("Best disease"), an orphan inherited retinal disease characterized by egg yolk-like macular lesions that, over time, lead to atrophy and loss of central vision. As the Company continues to evaluate opportunities to potentially obtain rights to additional therapeutic and gene therapy product candidates, the Company expects to take a more targeted approach to these business development efforts in light of the status of its ongoing Zimura development programs, its expanded pipeline and its available capital resources. The Company intends to continue to focus on opportunities that present a compelling scientific rationale, have the potential to address an unmet medical need, present a meaningful commercial opportunity and where the Company can leverage its development platform, clinical experience and retina expertise.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies,” in the notes to the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 filed with the Securities and Exchange Commission ("SEC") on March 5, 2018.

Basis of Presentation

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

Segment and geographic information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating and reporting segment.

Use of Estimates

The preparation of financial statements and related disclosures in conformity with GAAP 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 research and development costs, revenue recognition, accounting for share-based compensation and accounting for income taxes. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of 90 days 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.

As of September 30, 2018, the Company had cash and cash equivalents of approximately $135.2 million.

Available for Sale Securities

The Company considers securities with original maturities of greater than 90 days when purchased to be available for sale securities. Available for sale securities with original maturities of greater than one year are recorded as non-current assets. Available for sale securities are recorded at fair value and unrealized gains and losses are recorded within accumulated other comprehensive loss. The estimated fair value of the available for sale securities is determined based on quoted market prices or rates for similar instruments. In addition, the cost of debt securities in this category is adjusted for amortization of premium and accretion of discount to maturity. The Company evaluates securities with unrealized losses to determine whether such losses, if any, are other than temporary. The Company did not hold any available for sale securities at September 30, 2018 or December 31, 2017.

Revenue Recognition

Collaboration Revenue

Prior to 2018, the Company's revenue resulted from payments received under its May 2014 licensing and commercialization agreement (the “Novartis Agreement”) with Novartis Pharma AG ("Novartis"), as modified by the July 2017 letter agreement entered into by the Company and Novartis in relation to the Novartis Agreement (the "Letter Agreement"). See "Note 5—Licensing and Commercialization Agreements" below for a description of these agreements. The Company used the relative selling price method to allocate arrangement consideration to the Company’s performance obligations under the Novartis Agreement. The Company completed the deliverables under the Novartis Agreement and the Letter Agreement during the third quarter of 2017.

As the Company has no products approved for sale, the Company does not expect to receive any revenue from product candidates that it develops until it obtains regulatory approval and commercializes such products, or until the Company potentially enters into agreements with third parties for the development and commercialization of product candidates. If the Company's development efforts for any of its product candidates result in regulatory approval or the Company enters into collaboration agreements with third parties, the Company may generate revenue from product sales or from such third parties.

In the future, the Company will evaluate revenue contracts and arrangements, if any, following the provisions of the Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, Revenue from Contracts with Customers (Topic 606).

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, the balances of which generally exceed federally insured limits. The Company maintains its cash equivalents in investments in money market funds and, at times, in U.S. Treasury securities and investment-grade corporate debt securities with original maturities of 90 days or less.

The Company's available for sale securities are also invested in U.S. Treasury securities and investment-grade corporate debt securities. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents and available for sale securities.

Concentration of Suppliers

The Company currently relies exclusively upon a single third-party manufacturer to provide supplies of the drug substance for Zimura on a purchase order basis. The Company also engages a single third-party manufacturer to provide fill/finish services for clinical supplies of Zimura. In addition, the Company currently relies upon a single third-party supplier to supply it with the polyethylene glycol ("PEG") reagent used to manufacture Zimura on a purchase order basis. Furthermore, the Company and its contract manufacturers currently rely upon sole-source suppliers of certain raw materials and other specialized components of production used in the manufacture and fill/finish of Zimura. The Company is in the process of establishing manufacturing capabilities with a single third-party contract manufacturer for its RHO-adRP gene therapy product candidate and expects to rely on sole-source suppliers for certain starting materials to be used in the manufacture of such product candidate. If the Company’s third-party manufacturers or fill/finish service providers should become unavailable to the Company for any reason, including as a result of capacity constraints, financial difficulties or insolvency, the Company believes that there are a limited number of potential replacement manufacturers, and the Company likely would incur added costs and delays in identifying or qualifying such replacements.

Foreign Currency Translation

The Company considers the U.S. dollar to be its functional currency. Expenses denominated in foreign currencies 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

Cash equivalents and available for sale securities are reflected in the accompanying financial statements at fair value. The carrying amount of accounts payable and accrued expenses, including accrued research and development expenses, approximates fair value due to the short-term nature of those instruments.

Property and Equipment

Property and equipment, which consists mainly of manufacturing and clinical equipment, furniture and fixtures, computers, software, other office equipment, and leasehold improvements, are carried at cost less accumulated depreciation. Depreciation is computed over the estimated useful lives of the respective assets, generally three to ten years, using the straight-line method. Amortization of leasehold improvements is recorded over the shorter of the lease term or estimated useful life of the related asset.

Research and Development

The Company's Research and development expenses primarily consist of costs associated with the manufacturing, development and clinical testing of Zimura and, historically, Fovista, as well as costs associated with the preclinical development of other product candidates, formulations and technologies, including costs associated with the Company's RHO-adRP gene therapy product candidate, including related sponsored research with the University of Pennsylvania, and costs associated with the Company's ongoing gene therapy research collaboration with the University of Massachusetts Medical School ("UMMS"). Research and development expenses consist of:


•	external research and development expenses incurred under arrangements with third parties, such as academic research collaborators, contract research organizations ("CROs") and other vendors and contract manufacturing organizations ("CMOs") for the production of drug substance and drug product; and


•	employee-related expenses for employees dedicated to research and development activities, including salaries, benefits and share-based compensation expense.

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

All research and development expenses 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.

Income Taxes

The Company utilizes the liability method of accounting for deferred income taxes, as set forth in ASC 740, Income Taxes. 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 when, 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.

Share-Based Compensation

The Company follows the provisions of 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, restricted stock units (“RSUs”) and options granted to employees to purchase shares under the 2016 Employee Stock Purchase Plan (the “ESPP”). 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, net of estimated forfeitures. For grants containing performance-based vesting provisions, expense is recognized over the estimated achievement period.

Stock Options

The Company estimates the fair value of stock options granted to employees and non-employee directors on the date of grant using the Black-Scholes option-pricing model. 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 is 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 utilizes a dividend yield of zero based on the fact that the Company has never paid cash dividends to stockholders and has no current intentions to pay cash dividends. 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.

For stock options and RSUs granted as consideration for services rendered by consultants, the Company recognizes expense in accordance with the requirements of ASC 505-50, Equity Based Payments to Non-Employees. Consultant stock option grants 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 consultants 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.

The weighted-average assumptions used to estimate grant date fair value of stock options using the Black-Scholes option pricing model were as follows for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Expected common stock price volatility	84%	82%	83%	81%
Risk-free interest rate	2.80%-2.90%	1.95%-2.06%	2.39%-2.90%	1.82%-2.38%
Expected term of options (years)	6.1	6.1	5.8	6.1
Expected dividend yield	—	—	—	—

RSUs

The Company estimates the fair value of RSUs granted to employees using the closing market price of the Company's common stock on the date of grant.

ESPP

In April 2016, the board of directors adopted the ESPP pursuant to which the Company may sell up to an aggregate of 1,000,000 shares of common stock. The ESPP was approved by the Company’s stockholders in June 2016. The ESPP is considered compensatory and the fair value of the discount and look back provision are estimated using the Black-Scholes option-pricing model and recognized over the six month withholding period prior to purchase.

Share-based compensation expense includes expenses related to stock options and RSUs granted to employees, non-employee directors and consultants, as well as options granted to employees to purchase shares under the ESPP, all of which have been reported in the Company’s Statements of Operations as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	1,171	$	1,840	$	3,717	$	8,887
General and administrative	1,433		1,571		4,631		5,576
Total	$	2,604	$	3,411	$	8,348	$	14,463

Recently Adopted Accounting Pronouncements

In May 2014, the FASB issued Accounting Standards Codification 606, Revenue from Contracts with Customers (“ASC 606”). ASC 606 outlines a new, single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. This new revenue recognition model provides a five-step analysis in determining when and how revenue is recognized. The new model requires revenue recognition to depict the transfer of promised goods or services to customers in an amount that reflects the consideration a company expects to receive in exchange for those goods or services. On January 1, 2018, the Company adopted this guidance using the modified retrospective approach. Due to the termination of the Novartis Agreement and the Company's current lack of other revenue sources, the Company's financial statements were not impacted by adoption of this standard. The future impact of ASC 606 will be dependent on the nature of the Company’s future revenue contracts and arrangements, if any.

In August 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which clarifies the presentation of certain specific cash flow issues in the Statement of Cash Flows. For public companies, the amendments are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods and early adoption is permitted. During the three months ended March 31, 2018, the Company adopted this guidance. The adoption did not have a material impact on the Company's financial statements.

In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, in an effort to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments of this ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. This new guidance was applicable for the acquisition of Inception 4 and will be applicable for any other acquisitions by the Company on or after January 1, 2018.

Recent Accounting Pronouncements

In February 2016, the FASB issued ASU No. 2016-2, Leases (Topic 842). Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases) at the commencement date: (1) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and (2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. Under the new guidance, lessor accounting is largely unchanged. Certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. The new lease guidance simplified the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees will no longer be provided with a source of off-balance sheet financing. Publicly-traded business entities should apply the amendments in ASU 2016-2 for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years (i.e., January 1, 2019, for a calendar year entity). Early application is permitted for all publicly-traded business entities and all nonpublicly-traded business entities upon issuance. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. Lessees and lessors may not apply a full retrospective transition approach. The Company is currently assessing the impact that adopting this new accounting guidance will have on its financial statements and footnote disclosures.

In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting, which supersedes ASC 505-50 and expands the scope of ASC 718 to include all share-based payments arrangements related to the acquisition of goods and services from both employees and nonemployees. For public companies, the amendments are effective for annual reporting periods beginning after December 15, 2018, including interim periods within those annual periods. Early adoption is permitted, but no earlier than a company's adoption date of ASC 606. The Company is currently assessing the impact that adopting this new accounting guidance will have on its financial statements and footnote disclosures.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), which modifies the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement, including, among other changes, the consideration of costs and benefits when evaluating disclosure requirements. For public companies, the amendments are effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual periods. Early adoption is permitted. The Company is currently assessing the impact that adopting this new accounting guidance will have on its financial statements and footnote disclosures.

In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). This guidance is effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the potential effects of this guidance on its consolidated financial statements.

Other recent authoritative guidance issued by the FASB (including technical corrections to the ASC), the American Institute of Certified Public Accountants, and the Securities Exchange Commission during the three months ended September 30, 2018, did not, or are not expected to, have a material effect on the Company’s consolidated financial statements.

Net Loss Per Common Share

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Net Loss Per Common Share

Basic and diluted net loss per common share is determined by dividing net loss by the weighted average common shares outstanding during the period. For the periods where there is a net loss, shares underlying stock options and RSUs have been excluded from the calculation of diluted net loss per common share because the effect of including such shares would be anti-dilutive. Therefore, the weighted average common shares used to calculate both basic and diluted net loss per common share would be the same. The following table sets forth the computation of basic and diluted net loss per common share for the periods indicated:



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018			2017		2018			2017
Basic and diluted net income (loss) per common share calculation:
Net income (loss)	$	(14,745	)	$	189,073	$	(41,027	)	$	123,747
Weighted average common shares outstanding - basic	36,202			35,971		36,181			35,878
Plus: net effect of dilutive stock options and unvested restricted stock units	—			76		—			106
Weighted average common shares outstanding - dilutive	36,202			36,047		36,181			35,984
Net income (loss) per share of common stock - basic	$	(0.41	)	$	5.26	$	(1.13	)	$	3.45
Net income (loss) per share of common stock - diluted	$	(0.41	)	$	5.25	$	(1.13	)	$	3.44

The following potentially dilutive securities have been excluded from the computations of diluted weighted average common shares outstanding for the periods presented, as the effect of including such shares would be anti-dilutive:



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Stock options outstanding	4,855	3,640	4,855	3,813
Restricted stock units	184	269	184	332
Total	5,039	3,909	5,039	4,145

Cash, Cash Equivalents and Available for Sale Securities	9 Months Ended
	Sep. 30, 2018
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash, Cash Equivalents and Available for Sale Securities	Cash, Cash Equivalents and Available for Sale Securities The Company considers all highly liquid investments purchased with original maturities of 90 days or less at the date of purchase to be cash equivalents. As of September 30, 2018 and December 31, 2017, the Company had cash and cash equivalents of approximately $135.2 million and $167.0 million, respectively. Cash and cash equivalents included cash of $4.1 million at September 30, 2018 and $9.5 million at December 31, 2017. Cash and cash equivalents at September 30, 2018 included $131.1 million of investments in money market funds and certain investment-grade corporate debt securities with original maturities of 90 days or less. Cash and cash equivalents at December 31, 2017, included $157.4 million of investments in money market funds. The Company considers securities with original maturities of greater than 90 days at the date of purchase to be available for sale securities. The Company held no available for sale securities at September 30, 2018 or at December 31, 2017, respectively. During the year ended December 31, 2017, the Company's investments matured and were reinvested in money market funds. The Company believes that its existing cash and cash equivalents as of September 30, 2018, together with the approximately $6.1 million of cash acquired in October 2018 through its acquisition of Inception 4, will be sufficient to fund its operations and capital expenditure requirements as currently planned for at least the next 12 months.

Licensing and Commercialization Agreements

9 Months Ended

Sep. 30, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Licensing and Commercialization Agreements

Gene Therapy Agreements with the University of Florida and the University of Pennsylvania

On June 6, 2018, the Company entered into an exclusive global license agreement (the "RHO-adRP License Agreement") with the University of Florida Research Foundation ("UFRF") and the University of Pennsylvania ("Penn," and together with UFRF, the "Licensors"). Under the agreement, the Company was granted a worldwide, exclusive license under specified patent rights and a worldwide, non-exclusive license under specified know-how, including specified preclinical data, to manufacture, develop and commercialize certain adeno-associated virus, or AAV, gene therapy products for the treatment of rhodopsin-mediated diseases. Included in the RHO-adRP License Agreement are patent rights covering a novel AAV gene therapy product candidate intended to treat rhodopsin-mediated autosomal dominant retinitis pigmentosa (the "RHO-adRP Licensed Product").

During June 2018, the Company paid a $0.5 million upfront license issuance fee in connection with entry into the agreement, which was recorded as a research and development expense, as well as accrued patent prosecution expenses of approximately $30 thousand, which was recorded as general and administrative expense. Under the agreement, the Company agreed to pay an annual license maintenance fee in the low double-digit thousands of dollars, which will be payable on an annual basis until the first commercial sale of a licensed product. In addition, the Company has agreed to reimburse UFRF for the costs and expenses of patent prosecution and maintenance related to the licensed patent rights.

The Company has further agreed to pay UFRF, on behalf of both Licensors, up to an aggregate of $23.5 million if the Company achieves specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product and up to an aggregate of an additional $70.0 million if the Company achieves specified commercial sales milestones with respect to a licensed product.

The Company is also obligated to pay UFRF, on behalf of both Licensors, royalties at a low single-digit percentage of net sales of licensed products. Such royalties are subject to customary deductions, credits, and reductions for lack of patent coverage and loss of regulatory exclusivity. Beginning on the earlier of (i) the calendar year following the first commercial sale of a licensed product and (ii) the first business day of 2031, the Company is also obligated to pay certain minimum royalties, not to exceed an amount in the low hundreds of thousands of dollars on an annual basis, which minimum royalties are creditable against the Company's royalty obligation with respect to net sales of licensed products due in the year the minimum royalty is paid. In addition, if the Company or its affiliate sublicenses any of the licensed patent rights to a third party, the Company will be obligated to pay UFRF, on behalf of both Licensors, a low double-digit percentage of the consideration received in exchange for such sublicense. If the Company receives a rare pediatric disease priority review voucher from the U.S. Food and Drug Administration in connection with obtaining marketing approval for a licensed product and the Company subsequently uses such priority review voucher in connection with a different product candidate or sells such priority review voucher, the Company will be obligated to make certain payments to UFRF, on behalf of both Licensors.

Unless earlier terminated by the Company, the RHO-adRP License Agreement will expire upon the expiration of the Company’s obligation to pay royalties to UFRF on net sales of licensed products. The Company may terminate the agreement at any time for any reason upon prior written notice. Penn or UFRF may terminate the RHO-adRP License Agreement in the event of certain breaches by the Company or in the event of certain insolvency events regarding the Company.

In addition to the exclusive license agreement, the Company and Penn also agreed to a Master-Sponsored Research Agreement (the "MSA"), facilitated by the Penn Center for Innovation. Under the MSA, the Company and Penn plan to conduct preclinical studies for the RHO-adRP Licensed Product, as well as a natural history study for RHO-adRP patients.

Prior Licensing and Commercialization Agreement with Novartis Pharma AG

Prior to 2018, the Company's revenue resulted from payments received under the Novartis Agreement, as modified by the July 2017 letter agreement entered into by the Company and Novartis. These two agreements are described below. The Company used the relative selling price method to allocate arrangement consideration to the Company’s performance obligations under the Novartis Agreement. The Company completed the deliverables under the Novartis Agreement and the Letter Agreement during the third quarter of 2017.

Below is a summary of the components of the Company's collaboration revenue for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
License revenue	$	—	$	152,912	$	—	$	152,912
Research and development activity revenue	—		52,864		—		56,180
Drug substance transfer revenue	—		754		—		754
Joint operating committee revenue	—		124		—		131
Total collaboration revenue	$	—	$	206,654	$	—	$	209,977

In May 2014, the Company entered into the Novartis Agreement. Under the Novartis Agreement, the Company granted Novartis exclusive rights under specified patent rights, know-how and trademarks controlled by the Company to manufacture, from bulk drug substance supplied by the Company, standalone Fovista products and products combining Fovista with an anti-VEGF agent to which Novartis has rights in a co-formulated product, for the treatment, prevention, cure or control of any human disease, disorder or condition of the eye, and to develop and commercialize those licensed products in all countries outside of the United States (the “Novartis Territory”). The Company agreed to use commercially reasonable efforts to complete its ongoing pivotal Phase 3 clinical program for Fovista and Novartis agreed to use commercially reasonable efforts to develop a standalone Fovista product and a co-formulated product containing Fovista and an anti-VEGF agent to which Novartis has rights, as well as a pre-filled syringe presentation of such products and to use commercially reasonable efforts, subject to obtaining marketing approval, to commercialize licensed products in the Novartis Territory in accordance with agreed development and marketing plans.

In July 2017, the Company and Novartis entered into the Letter Agreement to streamline the process and timeline for evaluating data from the OPH1004 trial once it became available. On October 23, 2017, following the failure of the Phase 3 Fovista program and pursuant to the terms of the Letter Agreement, Novartis elected to terminate the Novartis Agreement with immediate effect.

In May 2014, Novartis paid the Company a $200.0 million upfront payment. In each of September 2014 and March 2015, the Company achieved a $50.0 million enrollment-based milestone, and in June 2016, the Company achieved a $30.0 million enrollment-based milestone, for an aggregate total of $130.0 million in enrollment-based milestones under the Novartis Agreement. The Company used the relative selling price method to allocate these payments to contract deliverables based on its performance obligations under the Novartis Agreement.

Activities under the Novartis Agreement were evaluated under ASC 605-25, Revenue Recognition—Multiple Element Arrangements (“ASC 605-25”) (as amended by ASU 2009-13, Revenue Recognition (“ASU 2009-13”)), the relevant codification applicable at the time, to determine if they represented a multiple element revenue arrangement. The Novartis Agreement included the following deliverables: (1) an exclusive license to commercialize Fovista outside the United States (the “License Deliverable”); (2) the performance obligation to conduct research and development activities related to the Phase 3 Fovista clinical trials and certain Phase 2 trials for Fovista (the “R&D Activity Deliverable”); (3) the performance obligation to supply drug substance to Novartis for development and manufacturing purposes (the “Manufacturing Deliverable”) and (4) the Company’s obligation to participate on the joint operating committee established under the terms of the Novartis Agreement and related subcommittees (the “Joint Operating Committee Deliverable”). The Company’s obligation to provide access to clinical and regulatory information as part of the License Deliverable included the obligation to provide access to all clinical data, regulatory filings, safety data and manufacturing data to Novartis which was necessary for the commercialization of Fovista in the Novartis Territory. The R&D Activity Deliverable included the right and responsibility for the Company to conduct the Phase 3 Fovista clinical program and other Phase 2 studies of Fovista which were necessary or desirable for regulatory approval or commercialization of Fovista. The Manufacturing Deliverable included the obligation for the Company to supply drug substance to Novartis for clinical purposes, for which Novartis agreed to pay the Company’s manufacturing costs. The Joint Operating Committee Deliverable included the obligation to participate in the Joint Operating Committee and related subcommittees at least through the first anniversary of regulatory approval in the European Union. All of these deliverables were deemed to have stand-alone value and to meet the criteria to be accounted for as separate units of accounting under ASC 605-25. Factors considered in this determination included, among other things, the subject of the licenses and the research and development and commercial capabilities of Novartis. Accordingly, each unit was accounted for separately.

The Novartis Agreement included a termination right for the Company in the event that specified governmental actions prevented the parties from materially progressing the development or commercialization of licensed products. If the Company elected to exercise this termination option, it would have been required to pay a substantial termination fee equivalent to the entire upfront payment amount. The Company concluded that this termination provision constituted a contingent event that was unknown at the inception of the agreement. As such, the Company recorded the $200.0 million upfront payment in deferred revenue, long-term until such time that the contingency related to this termination provision was resolved. In July 2017, the contingency was resolved when the Company permanently waived this termination right as part of the Letter Agreement.

The Letter Agreement also provided Novartis with a shorter notice period in the event Novartis determined to terminate the Novartis Agreement in certain circumstances. In addition, the Letter Agreement provided Novartis with a fully paid-up, royalty free license to use data from the Lucentis monotherapy arms of the Company's Phase 2b OPH1001 trial and Phase 3 OPH1002 and OPH1003 trials in the Novartis Territory in connection with the development, manufacturing and commercialization of Novartis-controlled anti-VEGF products. The Lucentis study data license continues until the fifth anniversary of the Letter Agreement.

The Company evaluated the Letter Agreement under ASC 605-25, the relevant codification applicable at the time, and determined that the Letter Agreement does not create any new deliverables. The Company is treating the Fovista license granted at the inception of the Novartis Agreement and the Lucentis study data license granted under the Letter Agreement as one collective technology license (the "Licenses") delivered at the inception of the Novartis Agreement. In addition, as the waiver of its right to terminate the Novartis Agreement as a result of specified governmental actions resolved the Company’s contingency with respect to such termination right and the associated termination fee, the Company allocated the entire previously deferred amount, $200.0 million, to the deliverables that were determined based on the relative selling price at contract inception. Upon entry into the Letter Agreement in July 2017, the Company immediately recognized as revenue $189.8 million of the upfront payment allocated to contract deliverables completed during prior periods. Upon termination of the OPH1004 trial in August 2017, the Company recognized the remaining $16.9 million of collaboration revenue, attributable to the R&D Deliverable, previously deferred under the Novartis Agreement. In total, during the third quarter of 2017, the Company recognized $206.7 million in previously deferred collaboration revenue in connection with the Novartis Agreement. The recognition of this revenue during the third quarter of 2017 did not impact the Company's cash balance.

The Company's collaboration revenue for the three and nine months ended September 30, 2017 related to the research and development activities performed by the Company during the period under the Novartis Agreement. All activities under the Novartis Agreement were completed during the third quarter of 2017 prior to the adoption of ASC 606.

Financing Agreement with Novo A/S	9 Months Ended
Financing Agreement with Novo A/S	Sep. 30, 2018
Related Party Transactions [Abstract]
Financing Agreement with Novo A/S	Financing Agreement with Novo A/S In May 2013, the Company entered into a Purchase and Sale Agreement with Novo A/S, which is referred to as the Novo Agreement, pursuant to which the Company obtained financing from Novo A/S in three tranches in an amount equal to $125.0 million in return for the sale to Novo A/S of aggregate royalties of worldwide sales of (a) Fovista, (b) Fovista-Related Products, and (c) Other Products (each as defined in the Novo Agreement), calculated as mid-single digit percentages of net sales. The Novo Agreement provided 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 would acquire rights to a low single digit percentage of net sales. In each of May 2013, January 2014 and November 2014, the Company received cash payments of $41.7 million, or $125.0 million in the aggregate, and Novo A/S received, in the aggregate, a right to receive royalties on net sales of Fovista at a mid-single digit percentage. The royalty payment period covered by the Novo Agreement would begin on commercial launch and end, 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. The Company's obligations under the Novo Agreement were secured by a lien on certain of the Company's intellectual property and other rights related to Fovista, Fovista-Related Products and Other Products. Under the terms of the Novo Agreement, the Company was not required to reimburse or otherwise compensate Novo A/S through any means other than the agreed royalty entitlement. In addition, the Company did not, under the terms of the Novo Agreement, have the right or obligation to prepay Novo A/S in connection with a change of control of the Company or otherwise. The $125.0 million in aggregate proceeds from the three financing tranches under the Novo Agreement represented the full funding available under the Novo Agreement, and was recorded as a liability on the Company's Balance Sheet as of September 30, 2018, in accordance with ASC 730, Research and Development. 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 Novo Agreement as an implicit obligation to repay the funds advanced by Novo A/S. If the Company were to make royalty payments under the Novo Agreement, it would reduce the liability balance at such time. 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. The Novo 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.

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, the U.S. Tax Cuts and Jobs Act (“TCJA”) was enacted reducing the corporate tax rate from 35% to 21% effective for tax years beginning on or after January 1, 2018. ASC 740, Income Taxes, requires the effects of changes in tax laws to be recognized in the period in which the legislation is enacted. However, due to the complexity and significance of TCJA's provisions, the SEC staff issued Staff Accounting Bulletin 118, which allows companies to record the tax effects of the TCJA on a provisional basis based on a reasonable estimate, and then, if necessary, subsequently adjust such amounts during a limited measurement period as more information becomes available. The measurement period ends when a company has obtained, prepared, and analyzed the information necessary to finalize its accounting, but cannot extend beyond one year from enactment of the TCJA. Under the TCJA, the Corporate Alternative Minimum Tax ("AMT") was repealed. The Company's previously recorded AMT credits of approximately $3.5 million are now refundable over a four-year period beginning in 2018, and the previously recorded valuation allowance for these AMT credits was reversed during the fourth quarter of 2017. During the nine months ended September 30, 2018, the Company reduced its estimate of refundable AMT credits to approximately $3.3 million to reflect the impact of sequestration as required by the Balanced Budget and Emergency Deficit Control Act of 1985, as amended. As a result of the TCJA’s reduction in the corporate tax rate from 35% to 21% the value of the Company’s deferred tax assets, and related valuation allowance, were reduced by a provisional amount of approximately $54.6 million during the year ended December 31, 2017. The Company does not have any offshore earnings from which to record the mandatory transition tax enacted under the TCJA. Given the significant complexity of the TCJA, anticipated guidance from the US Treasury and the Internal Revenue Service about implementing the TCJA, and the potential for additional guidance from the SEC or the FASB related to the TCJA, the deferred taxes provisional amounts may be adjusted during the measurement period. These provisional amounts were based on the Company’s present interpretations of the TCJA and current available information, including assumptions and expectations about future events, such as its projected financial performance, and are subject to further refinement as additional information becomes available (including potential new interpretative guidance) and further analyses are completed. For the three and nine months ended September 30, 2018, the Company recorded a de minimis provision for income taxes and $0.8 million benefit for income taxes, respectively. The benefit for income taxes recorded during the nine months ended September 30, 2018 includes the settlement of a local tax audit recorded by the Company during the three months ended June 30, 2018 offset partially by the provision for income taxes recorded by the Company during the three months ended March 31, 2018 to reflect the impact of sequestration on the Company's estimate of refundable AMT credits. For the three and nine months ended September 30, 2017, the Company recorded a provision for income taxes of $0.2 million primarily due to discrete income tax items associated with changes in the fair value of the Company's available for sale marketable securities which are reflected in other comprehensive income (loss). The Company will continue to evaluate its ability to realize its deferred tax assets on a quarterly basis and will adjust such amounts in light of changing facts and circumstances including, but not limited to, future projections of taxable income, tax legislation, rulings by relevant tax authorities, the progress of ongoing tax audits and the regulatory approval of products currently under development. Any additional changes to the valuation allowance recorded on deferred tax assets in the future would impact the Company’s income taxes.

Fair Value Measurements

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

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 Company reviews investments on a periodic basis for other than temporary impairments. This review is subjective as it requires management to evaluate whether an event or change in circumstances has occurred in the period that may have a significant adverse effect on the fair value of the investment. The Company uses the market approach to measure fair value for its financial assets. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets. The Company classifies its investment-grade corporate debt securities within the fair value hierarchy as Level 2 assets, as it primarily utilizes quoted market prices or rates for similar instruments to value these securities.

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. The Company's Level 1 assets consist of investments in money market funds and U.S. Treasury securities.


•	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. The Company's Level 2 assets may consist of investments in investment-grade corporate debt securities.


•	Level 3—inputs to the valuation methodology are unobservable and significant to the fair value measurement of the asset or liability. The Company does not hold any assets that are measured using Level 3 inputs.

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, 2018:



	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*	$	111,986	$	—	$	—
Investments in investment-grade corporate debt securities*	$	—	$	19,169	$	—



	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*	$	162,457	$	—	$	—


*	Investments in money market funds and investment-grade corporate debt securities with maturities less than 90 days are reflected in cash and cash equivalents in the accompanying Balance Sheets.

No transfer of assets between Level 1 and Level 2 of the fair value measurement hierarchy occurred during the three and nine months ended September 30, 2018.

The Company's available for sale securities are reported at fair value on the Company's Balance Sheets. The Company held no available for sale securities at September 30, 2018 or at December 31, 2017. Unrealized gains (losses) are reported within accumulated other comprehensive loss in the statements of comprehensive loss. The cost of securities sold and any realized gains/losses from the sale of available for sale securities are based on the specific identification method. The changes in accumulated other comprehensive loss associated with the unrealized loss on available for sale securities for the three and nine months ended September 30, 2018 and September 30, 2017 were as follows:



	Three months ended September 30,					Nine months ended September 30,
	2018		2017			2018		2017
Beginning balance	$	—	$	(186	)	$	—	$	(212	)
Current period changes in fair value before reclassifications, net of tax	—		186			—		212
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	—		—			—		—
Total other comprehensive income (loss)	—		186			—		212
Ending balance	$	—	$	—		$	—	$	—

Stock Option and Compensation Plans

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock Option and Compensation Plans

The Company adopted its 2007 Stock Incentive Plan (the "2007 Plan") for employees, non-employee directors and consultants for the purpose of advancing the interests of the Company's 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, RSUs, 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.

In August 2013, the Company's board of directors adopted and the Company's stockholders approved the 2013 stock incentive plan (the "2013 Plan"), which became effective immediately prior to the closing of the Company's initial public offering. In June 2015, the Company’s board of directors adopted a first amendment to the 2013 Plan. The 2013 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, RSUs, restricted stock awards and other stock-based awards. Upon the 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 business 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 its 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.

Annual increases under the evergreen provisions of the 2013 Plan have resulted in the addition of an aggregate of approximately 6,898,000 additional shares to the 2013 Plan, including for 2018, an increase of approximately 1,444,000 shares, or 4% of the total number of shares of the Company's common stock outstanding as of January 1, 2018. As of September 30, 2018, the Company had approximately 2,386,868 shares available for grant under the 2013 Plan.

In April 2016, the board of directors adopted the ESPP pursuant to which the Company may sell up to an aggregate of 1,000,000 shares of common stock. The ESPP was approved by the Company’s stockholders in June 2016. The ESPP allows eligible employees to purchase common stock at a price per share equal to 85% of the lower of the fair market value of the common stock at the beginning or end of each six-month offering period during the term of the ESPP. The first offering period began in September 2016.

A summary of the stock option activity, weighted average exercise prices, options outstanding and exercisable as of September 30, 2018 is as follows (in thousands except weighted average exercise price):



	Number of Shares Underlying Options		Weighted Average Exercise Price
Outstanding, December 31, 2017	5,284		$	19.58
Granted	226		$	2.65
Forfeited	(655	)	$	37.12
Outstanding, September 30, 2018	4,855		$	16.42



Options exercisable at September 30, 2018	2,177
Weighted average grant date fair value (per share) of options granted during the period	$	1.88

As of September 30, 2018, there were outstanding, net of estimated forfeitures, options to purchase approximately 4,558,000 shares, which options had vested or are expected to vest. The weighted-average exercise price of these options was $17.06 per share; the weighted-average remaining contractual life of these options was 7.6 years; and the aggregate intrinsic value of these options was de minimis. A summary of the stock options outstanding and exercisable as of September 30, 2018 is as follows (in thousands except exercise prices and weighted average exercise price):



			Options Outstanding			Options Exercisable
Range of Exercise Prices	Total Shares Underlying Options Outstanding		Weighted Average Remaining Life (Years)	Weighted Average Exercise Price		Number of Shares for which Options are Exercisable		Weighted Average Exercise Price
$0.12-$10.03	3,176		8.7	$	3.61	673		$	4.99
$10.04-$20.00	133		4.8	$	13.68	133		$	13.68
$20.01-$30.00	114		5.1	$	24.69	114		$	24.69
$30.01-$40.00	681		4.7	$	33.12	680		$	33.12
$40.01-$55.00	514		6.8	$	46.54	401		$	46.34
$55.01-$73.22	237		7.3	$	72.32	176		$	72.01
	4,855		7.7	$	16.42	2,177		$	28.37

Aggregate Intrinsic Value	$	44				$	44

Cash proceeds from, and the aggregate intrinsic value of, stock options exercised during the three months ended September 30, 2018 and 2017, respectively, were as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Cash proceeds from options exercised	$	—	$	—	$	—	$	33
Aggregate intrinsic value of options exercised	$	—	$	—	$	—	$	43

In connection with stock option awards granted to employees, the Company recognized approximately $1.8 million and $2.3 million in share-based compensation expense during the three months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. In connection with stock option awards granted to employees, the Company recognized approximately $5.7 million and $10.3 million in share-based compensation expense during the nine months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. As of September 30, 2018, there were approximately $9.5 million of unrecognized compensation costs, net of estimated forfeitures, related to stock option awards granted to employees, which are expected to be recognized over a remaining weighted average period of 2.0 years.

In connection with stock option awards granted to consultants, the Company recognized a de minimis amount of share-based compensation expense and approximately $0.1 million in share-based compensation expense during the three months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. In connection with stock option awards granted to consultants, the Company recognized approximately $0.1 million and $0.3 million in share-based compensation expense during the nine months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. As of September 30, 2018, there were approximately $0.1 million of unrecognized compensation costs, net of estimated forfeitures, related to stock option awards granted to consultants, which are expected to be recognized over a remaining weighted average period of 1.5 years.

The following table presents a summary of the Company's outstanding RSU awards granted as of September 30, 2018 (in thousands except weighted average grant-date fair value):



	Restricted Stock Units		Weighted Average Grant-Date Fair Value
Outstanding, December 31, 2017	327		$	51.08
Vested	(75	)	$	47.52
Forfeited	(68	)	$	45.73
Outstanding, September 30, 2018	184		$	54.22

As of September 30, 2018, there were approximately 98,000 RSUs outstanding, net of estimated forfeitures, that are expected to vest. The weighted-average fair value of these RSUs was $51.37 per share; and the aggregate intrinsic value of these RSUs was approximately $0.2 million.

In connection with RSUs granted to employees, the Company recognized approximately $0.8 million and $0.9 million in share-based compensation expense during the three months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. In connection with RSUs granted to employees, the Company recognized approximately $2.5 million and $3.4 million in share-based compensation expense during the nine months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. As of September 30, 2018, there was approximately $3.2 million of unrecognized compensation costs, net of estimated forfeitures, related to RSUs granted to employees, which are expected to be recognized over a remaining weighted average period of 1.3 years. The total grant date fair value of the RSUs that vested during the three months ended September 30, 2018 was $0.6 million.

In connection with RSUs granted to consultants, the Company recognized a de minimis amount and $0.1 million of share-based compensation expense during the three months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. In connection with RSUs granted to consultants, the Company recognized a de minimis amount of share-based compensation expense and approximately $0.3 million in share-based compensation expense during the nine months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. As of September 30, 2018, there were a de minimis amount of unrecognized compensation costs, net of estimated forfeitures, related to RSUs granted to consultants, which are expected to be recognized over a remaining weighted average period of 1.1 years.

In connection with the ESPP made available to employees, the Company recognized a de minimis amount of share-based compensation expense during the three and nine months ended September 30, 2018 and 2017, respectively, net of expected forfeitures. As of September 30, 2018, there was a de minimis amount of unrecognized compensation costs, net of estimated forfeitures, related to the ESPP, which are expected to be recognized over 0.5 years. There were 19,184 and 31,413 shares of common stock issued under the ESPP during the three and nine months ended September 30, 2018. Cash proceeds from ESPP purchases were $38 thousand and $65 thousand during the three and nine months ended September 30, 2018. There were 11,612 and 16,358 shares of common stock issued under the ESPP during the three and nine months ended September 30, 2017. Cash proceeds from ESPP purchases were $25 thousand and $38 thousand during the three and nine months ended September 30, 2017. As of September 30, 2018, there were 952,229 shares available for future purchases under the ESPP.

Property and Equipment

9 Months Ended

Sep. 30, 2018

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment as of September 30, 2018 and December 31, 2017 were as follows:



	Useful Life (Years)	September 30, 2018			December 31, 2017
Manufacturing and clinical equipment	7 - 10	$	412		$	412
Computer, software and other office equipment	5	933			933
		1,345			1,345
Accumulated depreciation		(966		)	(827		)
Property and equipment, net		$	379		$	518

For the three and nine months ended September 30, 2018, depreciation expense was $45 thousand and $139 thousand, respectively. For the three and nine months ended September 30, 2017, depreciation expense was $0.6 million and $2.0 million, respectively.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Archemix Corp. The Company is party to an agreement with Archemix Corp., or Archemix, under which the Company in-licensed rights in certain patents, patent applications and other intellectual property related to Zimura and pursuant to which the Company may be required to pay sublicense fees and make milestone payments. Under the license agreement, for each anti‑C5 aptamer product that the Company may develop under the agreement, including Zimura, the Company is obligated to make payments to Archemix of up to an aggregate of $57.5 million if the Company achieves specified development, clinical and regulatory milestones, with $30.5 million of such payments relating to a first indication, $24.5 million of such payments relating to second and third indications and $2.5 million of such payments relating to sustained delivery applications. Under the license agreement, the Company is also obligated to make additional payments to Archemix of up to an aggregate of $22.5 million if the Company achieves specified commercial milestones based on net product sales of all anti‑C5 products licensed under the agreement. The Company is also obligated to pay Archemix a double‑digit percentage of specified non‑royalty payments the Company may receive from any sublicensee of its rights under the C5 agreement. The Company is not obligated to pay Archemix a running royalty based on net product sales in connection with the C5 agreement. University of Florida and the University of Pennsylvania Under the RHO-adRP License Agreement with the Company is obligated to make payments to UFRF, on behalf of both Licensors, of up to an aggregate of $23.5 million if the Company achieves specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product and up to an aggregate of an additional $70.0 million if the Company achieves specified commercial sales milestones with respect to a licensed product. The Company is also obligated to pay UFRF, on behalf of both Licensors, a low single-digit percentage of net sales of licensed products. The Company is also obligated to pay UFRF, on behalf of both Licensors, a double-digit percentage of specified non-royalty payments the Company may receive from any sublicensee of the licensed patent rights to a third party. Further, if the Company receives a rare pediatric disease priority review voucher from the FDA in connection with obtaining marketing approval for a licensed product and the Company subsequently uses such priority review voucher in connection with a different product candidate, the Company will be obligated to pay UFRF, on behalf of both Licensors, aggregate payments in the low double-digit millions of dollars based on certain approval and commercial sales milestones with respect to such other product. In addition, if the Company sells such a priority review voucher to a third party, the Company will be obligated to pay UFRF, on behalf of both Licensors, a low double-digit percentage of any consideration received from such third party in connection with such sale. Employment Contracts The Company also has letter agreements with certain employees that require the funding of a specific level of payments, if certain events, such as a termination of employment in connection with a change in control or termination of employment by the employee for good reason or by the Company without cause, occur. Contract Service Providers In addition, in the course of normal business operations, the Company has agreements with contract service providers to assist in the performance of the Company’s research and development and manufacturing activities. Expenditures to CROs, CMOs and academic research institutions represent significant costs in clinical development. Subject to required notice periods and the Company’s obligations under binding purchase orders, the Company can elect to discontinue the work under these agreements at any time. Legal Proceedings On January 11, 2017, a putative class action lawsuit was filed against the Company and certain of its current and former executive officers in the United States District Court for the Southern District of New York, captioned Frank Micholle v. Ophthotech Corporation, et al., No. 1:17-cv-00210. On March 9, 2017, a related putative class action lawsuit was filed against the Company and the same group of its current and former executive officers in the United States District Court for the Southern District of New York, captioned Wasson v. Ophthotech Corporation, et al., No. 1:17-cv-01758. These cases were consolidated on March 13, 2018. On June 4, 2018, lead plaintiff filed a consolidated amended complaint (the “CAC”). The CAC purports to be brought on behalf of shareholders who purchased the Company’s common stock between March 2, 2015 and December 12, 2016. The CAC generally alleges that the Company and certain of its officers violated Sections 10(b) and/or 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder by making allegedly false and/or misleading statements concerning the results of the Company’s Phase 2b trial and the prospects of the Company’s Phase 3 trials for Fovista in combination with anti-VEGF agents for the treatment of wet AMD. The CAC seeks unspecified damages, attorneys’ fees, and other costs. The Company and individual defendants filed a motion to dismiss the CAC on July 27, 2018. Plaintiff filed its opposition to the defendants’ motion to dismiss on October 12, 2018, and the defendants’ reply is due on November 19, 2018. On February 7, 2018, a shareholder derivative action was filed against the members of the Company’s Board of Directors in the New York Supreme Court Commercial Division, captioned Cano v. Guyer, et al., No. 650601/2018. The complaint alleges that the defendants breached their fiduciary duties to the Company by adopting a compensation plan that overcompensates the non-employee members of the Board relative to boards of companies of comparable market capitalization and size. The complaint also alleges that the defendants were unjustly enriched as a result of the alleged conduct. The complaint purports to seek unspecified damages, on behalf of the Company, attorneys’ fees, and other costs, as well as an order directing the Company to reform and improve its corporate governance and internal procedures to comply with applicable laws. The Company filed a motion to dismiss this case on May 14, 2018. On June 4, 2018, plaintiff filed an amended complaint. The Company filed a renewed motion to dismiss this case on June 25, 2018. On July 25, 2018, September 28, 2018 and October 9, 2018, the parties filed stipulations adjourning the deadline for plaintiff to file an opposition to the Company’s motion to dismiss while the parties engage in settlement negotiations. The parties are required to provide the court with a status report on or before November 5, 2018. On August 31, 2018, a shareholder derivative action was filed against current and former members of the Company's Board of Directors and certain current and former officers of the Company in the United States District Court for the Southern District of New York, captioned Luis Pacheco v. David R. Guyer, et al., Case No. 1:18-cv-07999. The complaint, which is based substantially on the facts alleged in the CAC, alleges that the defendants breached their fiduciary duties to the Company and wasted the Company's corporate assets by failing to oversee the Company's business, and also alleges that the defendants were unjustly enriched as a result of the alleged conduct, including through receipt of bonuses, stock options and similar compensation from the Company, and through sales of the Company's stock between March 2, 2015 and December 12, 2016. The complaint purports to seek unspecified damages on the Company's behalf, attorneys’ fees, and other costs, as well as an order directing the Company to reform and improve its corporate governance and internal procedures to comply with applicable laws, including submitting certain proposed amendments to the Company's corporate charter, bylaws and corporate governance policies for vote by the Company's stockholders. The Company denies any allegations of wrongdoing and intends to vigorously defend against these lawsuits. The Company is unable, however, to predict the outcome of these matters at this time. Moreover, any conclusion of these matters in a manner adverse to the Company and for which it incurs substantial costs or damages not covered by the Company's directors’ and officers’ liability insurance would have a material adverse effect on its financial condition and business. In addition, the litigation could adversely impact the Company's reputation and divert management’s attention and resources from other priorities, including the execution of business plans and strategies that are important to the Company's ability to grow its business, any of which could have a material adverse effect on the Company's business.

Restructuring Activities

9 Months Ended

Sep. 30, 2018

Restructuring and Related Activities [Abstract]

Restructuring Activities

In December 2016, the Company announced its intention to implement a reduction in personnel to focus on an updated business plan. In January 2017, the Board of Directors approved a plan to implement a reduction in personnel involving approximately 80% of the Company’s workforce based on the number of employees at the time the plan was approved. The reduction in personnel was substantially completed during 2017 with a limited number of departing employees scheduled to receive severance payments during 2018.

In January 2017, the Company issued a notice of termination under the Lease Agreement, dated as of September 30, 2007, between the Company and One Penn Plaza LLC, as previously supplemented and amended (as so supplemented and amended, the “Lease”) for office space at One Penn Plaza in New York, New York. The termination of the Lease triggered an early termination payment by the Company of approximately $0.9 million. On November 1, 2017, the Company and One Penn Plaza LLC executed a further amendment to the Lease extending the term of the Lease to the end of 2018, and on June 29, 2018, the Company and One Penn Plaza LLC executed a further amendment to the Lease extending the term of the Lease to June 2020. Payments under the further lease amendments do not constitute restructuring charges.

On January 26, 2017, the Company issued a notice of termination under the Sublease Agreement between the Company and Otsuka America Pharmaceutical, Inc. (the “Sublease”) for office space at One University Square, Princeton, New Jersey. The termination of the Sublease triggered an early termination payment by the Company of approximately $1.2 million and became effective February 2018, through which time the Company was responsible for paying continuing rental fees, as well as taxes, operating expenses and utility and other charges related to the subleased premises.

On January 26, 2017, the Company issued a notice of termination under its Office Lease Agreement between the Company and PSN Partners, L.P. (the "Office Lease") for office space in Palmer Square in Princeton, New Jersey. The termination of the Office Lease did not trigger any early termination payment.

In connection with the Company's restructuring activities, the Company recognized severance, stock compensation, other employee costs and lease termination costs, all of which have been reported in the Company’s Statements of Operations, as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	—	$	951	$	—	$	6,834
General and administrative	—		392		—		5,041
Total	$	—	$	1,343	$	—	$	11,875

As of September 30, 2018, the Company's accrual balance for severance and benefit costs was $0.2 million which was recorded in "Accounts payable and accrued expenses" in the Company's Balance Sheet. The severance and other employee cost accruals as of September 30, 2018 are expected to be paid through to December of 2018.

The following is a reconciliation of the severance-related accrual activity for the nine months ended September 30, 2018:



	Accrued Severance and Other Employee Costs
Beginning Balance	$	2,529
Accrued restructuring expenses	—
Payments	(2,306		)
Ending Balance	$	223

Subsequent Event	9 Months Ended
Subsequent Event	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Event Inception 4 Merger Agreement On October 30, 2018, the Company acquired Inception 4, a privately held biopharmaceutical company that owns rights to certain small molecule inhibitors of HtrA1, which the Company expects to develop for the treatment of GA, and potentially other age-related retinal diseases. Pursuant to the terms of the acquisition agreement for Inception 4 (the "Inception 4 Merger Agreement"), as upfront consideration, the Company agreed to issue approximately 5.2 million shares of the Company’s common stock to the former equityholders of Inception 4, which shares were valued at approximately $11.8 million based on the acquisition date closing price of the Company’s common stock of $2.26. Additionally, subject to the terms and conditions of the Inception 4 Merger Agreement, the former equityholders of Inception 4 will be entitled to receive contingent payments up to an aggregate of $105.0 million from the Company for the achievement of specified clinical and regulatory milestones in certain AMD indications for any product candidates from Inception 4's HtrA1 inhibitor program. As a result of the closing of the acquisition, the Company acquired approximately $6.1 million of cash from Inception 4. The Company is currently evaluating the initial accounting for this acquisition. Best Option Agreement and Sponsored Research Agreement On October 30, 2018, the Company entered into an exclusive option agreement with Penn and UFRF for rights to obtain an exclusive global license to develop and commercialize novel preclinical AAV gene therapy product candidates for the treatment of Best disease. The Company also entered into a sponsored research agreement with Penn to conduct certain preclinical and natural history studies in Best disease. The scope of each research project under the sponsored research agreement and certain associated terms, including financial terms, will be specified in a statement of work for each project.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Basis of Presentation

Segment and geographic information

Use of Estimates

Cash and Cash Equivalents

Available for Sale Securities

Revenue Recognition

Collaboration Revenue

Concentration of Credit Risk

Concentration of Suppliers

Foreign Currency Translation

Financial Instruments

Property and Equipment

Research and Development


•	external research and development expenses incurred under arrangements with third parties, such as academic research collaborators, contract research organizations ("CROs") and other vendors and contract manufacturing organizations ("CMOs") for the production of drug substance and drug product; and


•	employee-related expenses for employees dedicated to research and development activities, including salaries, benefits and share-based compensation expense.

Income Taxes

Share-Based Compensation

Stock Options



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Expected common stock price volatility	84%	82%	83%	81%
Risk-free interest rate	2.80%-2.90%	1.95%-2.06%	2.39%-2.90%	1.82%-2.38%
Expected term of options (years)	6.1	6.1	5.8	6.1
Expected dividend yield	—	—	—	—

RSUs

The Company estimates the fair value of RSUs granted to employees using the closing market price of the Company's common stock on the date of grant.

ESPP



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	1,171	$	1,840	$	3,717	$	8,887
General and administrative	1,433		1,571		4,631		5,576
Total	$	2,604	$	3,411	$	8,348	$	14,463

Recently Adopted and Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Recent Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Schedule of weighted-average assumptions used to estimate grant date fair value of stock options



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Expected common stock price volatility	84%	82%	83%	81%
Risk-free interest rate	2.80%-2.90%	1.95%-2.06%	2.39%-2.90%	1.82%-2.38%
Expected term of options (years)	6.1	6.1	5.8	6.1
Expected dividend yield	—	—	—	—

Schedule of share-based compensation expense



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	1,171	$	1,840	$	3,717	$	8,887
General and administrative	1,433		1,571		4,631		5,576
Total	$	2,604	$	3,411	$	8,348	$	14,463

Net Loss Per Common Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Schedule of computation of basic and diluted net income (loss) per common share

The following table sets forth the computation of basic and diluted net loss per common share for the periods indicated:



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018			2017		2018			2017
Basic and diluted net income (loss) per common share calculation:
Net income (loss)	$	(14,745	)	$	189,073	$	(41,027	)	$	123,747
Weighted average common shares outstanding - basic	36,202			35,971		36,181			35,878
Plus: net effect of dilutive stock options and unvested restricted stock units	—			76		—			106
Weighted average common shares outstanding - dilutive	36,202			36,047		36,181			35,984
Net income (loss) per share of common stock - basic	$	(0.41	)	$	5.26	$	(1.13	)	$	3.45
Net income (loss) per share of common stock - diluted	$	(0.41	)	$	5.25	$	(1.13	)	$	3.44

Schedule of potentially dilutive securities that have been excluded from the computations of diluted weighted average common shares outstanding



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Stock options outstanding	4,855	3,640	4,855	3,813
Restricted stock units	184	269	184	332
Total	5,039	3,909	5,039	4,145

Licensing and Commercialization Agreements (Tables)

9 Months Ended

Sep. 30, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of collaboration revenue components

Below is a summary of the components of the Company's collaboration revenue for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
License revenue	$	—	$	152,912	$	—	$	152,912
Research and development activity revenue	—		52,864		—		56,180
Drug substance transfer revenue	—		754		—		754
Joint operating committee revenue	—		124		—		131
Total collaboration revenue	$	—	$	206,654	$	—	$	209,977

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of assets and liabilities that are measured at fair value on a 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 money market funds*	$	111,986	$	—	$	—
Investments in investment-grade corporate debt securities*	$	—	$	19,169	$	—



	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*	$	162,457	$	—	$	—


*	Investments in money market funds and investment-grade corporate debt securities with maturities less than 90 days are reflected in cash and cash equivalents in the accompanying Balance Sheets.

Schedule of changes in accumulated other comprehensive income (loss) associated with the unrealized loss on available for sale securities

The changes in accumulated other comprehensive loss associated with the unrealized loss on available for sale securities for the three and nine months ended September 30, 2018 and September 30, 2017 were as follows:



	Three months ended September 30,					Nine months ended September 30,
	2018		2017			2018		2017
Beginning balance	$	—	$	(186	)	$	—	$	(212	)
Current period changes in fair value before reclassifications, net of tax	—		186			—		212
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	—		—			—		—
Total other comprehensive income (loss)	—		186			—		212
Ending balance	$	—	$	—		$	—	$	—

Stock Option and Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of the stock option activity including weighted average exercise prices, options outstanding and exercisable



	Number of Shares Underlying Options		Weighted Average Exercise Price
Outstanding, December 31, 2017	5,284		$	19.58
Granted	226		$	2.65
Forfeited	(655	)	$	37.12
Outstanding, September 30, 2018	4,855		$	16.42



Options exercisable at September 30, 2018	2,177
Weighted average grant date fair value (per share) of options granted during the period	$	1.88

Summary of the stock options outstanding and exercisable

A summary of the stock options outstanding and exercisable as of September 30, 2018 is as follows (in thousands except exercise prices and weighted average exercise price):



			Options Outstanding			Options Exercisable
Range of Exercise Prices	Total Shares Underlying Options Outstanding		Weighted Average Remaining Life (Years)	Weighted Average Exercise Price		Number of Shares for which Options are Exercisable		Weighted Average Exercise Price
$0.12-$10.03	3,176		8.7	$	3.61	673		$	4.99
$10.04-$20.00	133		4.8	$	13.68	133		$	13.68
$20.01-$30.00	114		5.1	$	24.69	114		$	24.69
$30.01-$40.00	681		4.7	$	33.12	680		$	33.12
$40.01-$55.00	514		6.8	$	46.54	401		$	46.34
$55.01-$73.22	237		7.3	$	72.32	176		$	72.01
	4,855		7.7	$	16.42	2,177		$	28.37

Aggregate Intrinsic Value	$	44				$	44

Schedule of cash proceeds from, and the aggregate intrinsic value of, stock options exercised

Cash proceeds from, and the aggregate intrinsic value of, stock options exercised during the three months ended September 30, 2018 and 2017, respectively, were as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Cash proceeds from options exercised	$	—	$	—	$	—	$	33
Aggregate intrinsic value of options exercised	$	—	$	—	$	—	$	43

Summary of the Company's outstanding shares of RSU awards

The following table presents a summary of the Company's outstanding RSU awards granted as of September 30, 2018 (in thousands except weighted average grant-date fair value):



	Restricted Stock Units		Weighted Average Grant-Date Fair Value
Outstanding, December 31, 2017	327		$	51.08
Vested	(75	)	$	47.52
Forfeited	(68	)	$	45.73
Outstanding, September 30, 2018	184		$	54.22

Property and Equipment (Tables)

9 Months Ended

Sep. 30, 2018

Property, Plant and Equipment [Abstract]

Schedule of property and equipment

Property and equipment as of September 30, 2018 and December 31, 2017 were as follows:



	Useful Life (Years)	September 30, 2018			December 31, 2017
Manufacturing and clinical equipment	7 - 10	$	412		$	412
Computer, software and other office equipment	5	933			933
		1,345			1,345
Accumulated depreciation		(966		)	(827		)
Property and equipment, net		$	379		$	518

Restructuring Activities (Tables)

9 Months Ended

Sep. 30, 2018

Restructuring and Related Activities [Abstract]

Schedule of severance costs



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	—	$	951	$	—	$	6,834
General and administrative	—		392		—		5,041
Total	$	—	$	1,343	$	—	$	11,875

The following is a reconciliation of the severance-related accrual activity for the nine months ended September 30, 2018:



	Accrued Severance and Other Employee Costs
Beginning Balance	$	2,529
Accrued restructuring expenses	—
Payments	(2,306		)
Ending Balance	$	223

Summary of Significant Accounting Policies - Segment and Geographic Information (Details)	9 Months Ended
	Sep. 30, 2018 segment
Accounting Policies [Abstract]
Number of operating segments	1
Number of reporting segments	1

Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 135,208	$ 166,972	$ 180,217	$ 133,930

Summary of Significant Accounting Policies - Property and Equipment (Details)	9 Months Ended
	Sep. 30, 2018
Minimum
Property and equipment
Estimated useful lives	3 years
Maximum
Property and equipment
Estimated useful lives	10 years

Summary of Significant Accounting Policies - Share-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Apr. 30, 2016
Share-Based Compensation
Expected dividend yield			0.00%
Share-based compensation expense	$ 2,604	$ 3,411	$ 8,348	$ 14,463
Research and development
Share-Based Compensation
Share-based compensation expense	1,171	1,840	3,717	8,887
General and administrative
Share-Based Compensation
Share-based compensation expense	$ 1,433	$ 1,571	$ 4,631	$ 5,576
ESPP \| Maximum
Share-Based Compensation
Number of shares reserved for issuance under the Plan (in shares)					1,000,000

Summary of Significant Accounting Policies - Schedule of Weighted-Average Assumptions (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield			0.00%
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected common stock price volatility	84.00%	82.00%	83.00%	81.00%
Risk-free interest rate, minimum	2.80%	1.95%	2.39%	1.82%
Risk-free interest rate, maximum	2.90%	2.06%	2.90%	2.38%
Expected term of options (years)	6 years 1 month 6 days	6 years 1 month 6 days	5 years 9 months 18 days	6 years 1 month 6 days
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Basic and diluted net income (loss) per common share calculation:
Net income (loss)	$ (14,745)	$ 189,073	$ (41,027)	$ 123,747
Weighted average common shares outstanding, basic (in shares)	36,202	35,971	36,181	35,878
Plus: net effect of dilutive stock options and unvested restricted stock units (in shares)	0	76	0	106
Weighted average common shares outstanding, diluted (in shares)	36,202	36,047	36,181	35,984
Net income (loss) per share of common stock - basic (in dollars per share)	$ (0.41)	$ 5.26	$ (1.13)	$ 3.45
Net income (loss) per share of common stock - diluted (in dollars per share)	$ (0.41)	$ 5.25	$ (1.13)	$ 3.44
Anti-dilutive securities
Total (in shares)	5,039	3,909	5,039	4,145
Stock options outstanding
Anti-dilutive securities
Total (in shares)	4,855	3,640	4,855	3,813
Restricted stock units
Anti-dilutive securities
Total (in shares)	184	269	184	332

Cash, Cash Equivalents and Available for Sale Securities (Details) - USD ($)	Oct. 30, 2018	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash and cash equivalents		$ 135,208,000	$ 166,972,000	$ 180,217,000	$ 133,930,000
Cash		4,100,000	9,500,000
Investments in money market funds, U.S. Treasury securities and certain short-term investment-grade corporate debt securities with original maturities of 90 days or less		131,100,000	157,400,000
Available for sale securities with maturities of greater than 90 days		$ 0	$ 0
Inception 4 \| Subsequent Event
Subsequent Event [Line Items]
Cash acquired through acquisition	$ 6,100,000

Licensing and Commercialization Agreements - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended							3 Months Ended		9 Months Ended		22 Months Ended
	Jun. 30, 2018	Aug. 31, 2017	Jul. 31, 2017	Jun. 30, 2016	Mar. 31, 2015	Sep. 30, 2014	May 31, 2014	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront fees received		$ 16,900
Total collaboration revenue								$ 0	$ 206,654	$ 0	$ 209,977
Novartis Pharma AG \| Licensing and Commercialization Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront fees received			$ 189,800				$ 200,000
Achievement of specified patient enrollment milestones \| Novartis Pharma AG \| Licensing and Commercialization Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Patient enrollment-based milestone revenue achieved				$ 30,000	$ 50,000	$ 50,000						$ 130,000
Research and development \| University of Florida Research Foundation (UFRF) \| RHO-adRP License Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
License fees paid	$ 500
Research and development \| Specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product \| University of Florida Research Foundation (UFRF) \| RHO-adRP License Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
License fees paid	23,500
Research and development \| Specified commercial sales milestones with respect to a licensed product \| University of Florida Research Foundation (UFRF) \| RHO-adRP License Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
License fees paid	70,000
General and administrative \| University of Florida Research Foundation (UFRF) \| RHO-adRP License Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
License fees paid	$ 30

Licensing and Commercialization Agreements - Summary of Collaboration Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	$ 0	$ 206,654	$ 0	$ 209,977
License revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	0	152,912	0	152,912
Research and development activity revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	0	52,864	0	56,180
Drug substance transfer revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	0	754	0	754
Joint operating committee revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	$ 0	$ 124	$ 0	$ 131

Financing Agreement with Novo A/S (Details)	1 Months Ended			19 Months Ended
Financing Agreement with Novo A/S (Details)	Nov. 30, 2014 USD ($)	Jan. 31, 2014 USD ($)	May 31, 2013 USD ($) tranche purchase	Nov. 30, 2014 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty purchase liability					$ 125,000,000	$ 125,000,000
Novo A/S \| Novo Agreement \| Fovista, Fovista-Related Products, and Other Products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Number of tranches in financing (in tranche) \| tranche			3
Aggregate royalty rights			$ 125,000,000.0
Number of separate purchases provided for in financing agreement \| purchase			3
Proceeds from royalty purchase agreement	$ 41,700,000	$ 41,700,000	$ 41,700,000	$ 125,000,000
Royalty purchase liability			$ 125,000,000

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Previously recorded Alternative Minimum Tax		$ 3,500		$ 3,300
Decrease in deferred tax asset as a result of the Tax Cuts and Jobs Act of 2017						$ 54,600
Income tax benefit	$ 6		$ 194	$ (833)	$ 196

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Fair Value Measurements
Investments in investment-grade corporate debt securities	$ 0	$ 0
Transfer of assets from Level 1 to Level 2 of the fair value measurement hierarchy	0
Recurring basis \| Quoted prices in active markets for identical assets (Level 1) \| Money market funds
Fair Value Measurements
Investments in money market funds	111,986,000	162,457,000
Recurring basis \| Quoted prices in active markets for identical assets (Level 1) \| Corporate debt securities
Fair Value Measurements
Investments in investment-grade corporate debt securities	0
Recurring basis \| Significant other observable inputs (Level 2) \| Money market funds
Fair Value Measurements
Investments in money market funds	0	0
Recurring basis \| Significant other observable inputs (Level 2) \| Corporate debt securities
Fair Value Measurements
Investments in investment-grade corporate debt securities	19,169,000
Recurring basis \| Significant unobservable inputs (Level 3) \| Money market funds
Fair Value Measurements
Investments in money market funds	0	$ 0
Recurring basis \| Significant unobservable inputs (Level 3) \| Corporate debt securities
Fair Value Measurements
Investments in investment-grade corporate debt securities	$ 0

Fair Value Measurements - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period			$ 38,041
Current period changes in fair value before reclassifications, net of tax	$ 0	$ 186	0	$ 212
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	0	0	0
Other comprehensive income	0	186	0	212
Balance at end of period	5,427		5,427
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	0	(186)	0	(212)
Balance at end of period	$ 0	$ 0	$ 0	$ 0

Stock Option and Compensation Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2018	Apr. 30, 2016	Aug. 31, 2013	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Stock Option and Compensation Plans
Options outstanding (in shares)				4,558,000		4,558,000
Weighted-average exercise price of options (in dollars per share)				$ 17.06		$ 17.06
Weighted-average remaining contractual life of options						7 years 7 months 6 days
Aggregate intrinsic value of options outstanding				$ 0		$ 0
Share-based compensation expense				$ 2,604	$ 3,411	$ 8,348	$ 14,463
ESPP
Stock Option and Compensation Plans
Number of shares of common stock available for issuance under the Plan (in shares)				952,229		952,229
Purchase price of common stock as percentage of fair market value		85.00%
Expected weighted average period to recognize share-based compensation costs						6 months
Common stock issued (in shares)				19,184	11,612	31,413	16,358
Proceeds from stock plans				$ 38	$ 25	$ 65	$ 38
Restricted stock units
Stock Option and Compensation Plans
RSUs expected to vest (in shares)				98,000		98,000
Weighted-average fair value of RSUs expected to vest (in dollars per share)				$ 51.37		$ 51.37
Aggregate intrinsic value of RSUs expected to vest				$ 200		$ 200
Total fair value vested				600
Employees \| ESPP
Stock Option and Compensation Plans
Share-based compensation expense				0	0	0	0
Unrecognized compensation costs, net of estimated forfeitures				0		0
Employees \| Stock options
Stock Option and Compensation Plans
Share-based compensation expense				1,800	2,300	5,700	10,300
Unrecognized share-based compensation costs for option awards, net of estimated forfeitures				9,500		$ 9,500
Expected weighted average period to recognize share-based compensation costs						2 years 15 days
Employees \| Restricted stock units
Stock Option and Compensation Plans
Share-based compensation expense				800	900	$ 2,500	3,400
Expected weighted average period to recognize share-based compensation costs						1 year 3 months 18 days
Unrecognized compensation costs, net of estimated forfeitures				3,200		$ 3,200
Consultants \| Non-employee Options
Stock Option and Compensation Plans
Share-based compensation expense				0	100	100	300
Unrecognized share-based compensation costs for option awards, net of estimated forfeitures				100		$ 100
Expected weighted average period to recognize share-based compensation costs						1 year 6 months
Consultants \| Restricted stock units
Stock Option and Compensation Plans
Share-based compensation expense				0	$ 100	$ 0	$ 300
Expected weighted average period to recognize share-based compensation costs						1 year 1 month 21 days
Unrecognized compensation costs, net of estimated forfeitures				$ 0		$ 0
Maximum \| ESPP
Stock Option and Compensation Plans
Number of shares reserved for issuance under the Plan (in shares)		1,000,000
2013 Plan
Stock Option and Compensation Plans
Number of shares of common stock available for issuance under the Plan (in shares)				2,386,868		2,386,868
Annual increase in shares reserved for issuance under the Plan (in shares)			2,542,372
Annual increase in shares reserved for issuance under the Plan (as a percent)	4.00%		4.00%
Increase in number of shares available under the Plan (in shares)	1,444,000							6,898,000
2013 Plan \| Maximum
Stock Option and Compensation Plans
Number of shares reserved for issuance under the Plan (in shares)			3,359,641
2007 Plan
Stock Option and Compensation Plans
Number of shares of common stock available for issuance under the Plan (in shares)			739,317

Stock Option and Compensation Plans - Summary of Stock Option Activity (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Number of Shares Underlying Options
Outstanding at beginning of year (in shares) \| shares	5,284
Granted (in shares) \| shares	226
Forfeited (in shares) \| shares	(655)
Outstanding at end of year (in shares) \| shares	4,855
Weighted Average Exercise Price
Outstanding at beginning of year (in dollars per share) \| $ / shares	$ 19.58
Granted (in dollars per share) \| $ / shares	2.65
Forfeited (in dollars per share) \| $ / shares	37.12
Outstanding at end of year (in dollars per share) \| $ / shares	$ 16.42
Options exercisable at end of year (in shares) \| shares	2,177
Weighted average grant date fair value (per share) of options granted during the period (in dollars per share) \| $ / shares	$ 1.88

Stock Option and Compensation Plans - Options Outstanding and Exercisable by Exercise Price and Options Exercised (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($) $ / shares shares
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	4,855
Weighted Average Remaining Life (Years)	7 years 8 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 16.42
Aggregate Intrinsic Value of Options Outstanding \| $	$ 44
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	2,177
Weighted Average Exercise Price (in dollars per share)	$ 28.37
Aggregate Intrinsic Value of Options Exercisable \| $	$ 44
$0.12-$10.03
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	3,176
Weighted Average Remaining Life (Years)	8 years 8 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 3.61
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	673
Weighted Average Exercise Price (in dollars per share)	$ 4.99
Exercise prices, low end of range (in dollars per share)	0.12
Exercise prices, high end of range (in dollars per share)	$ 10.03
$10.04-$20.00
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	133
Weighted Average Remaining Life (Years)	4 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 13.68
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	133
Weighted Average Exercise Price (in dollars per share)	$ 13.68
Exercise prices, low end of range (in dollars per share)	10.04
Exercise prices, high end of range (in dollars per share)	$ 20.00
$20.01-$30.00
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	114
Weighted Average Remaining Life (Years)	5 years 1 month 6 days
Weighted Average Exercise Price (in dollars per share)	$ 24.69
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	114
Weighted Average Exercise Price (in dollars per share)	$ 24.69
Exercise prices, low end of range (in dollars per share)	20.01
Exercise prices, high end of range (in dollars per share)	$ 30.00
$30.01-$40.00
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	681
Weighted Average Remaining Life (Years)	4 years 8 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 33.12
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	680
Weighted Average Exercise Price (in dollars per share)	$ 33.12
Exercise prices, low end of range (in dollars per share)	30.01
Exercise prices, high end of range (in dollars per share)	$ 40.00
$40.01-$55.00
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	514
Weighted Average Remaining Life (Years)	6 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 46.54
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	401
Weighted Average Exercise Price (in dollars per share)	$ 46.34
Exercise prices, low end of range (in dollars per share)	40.01
Exercise prices, high end of range (in dollars per share)	$ 55.00
$55.01-$73.22
Options Outstanding
Total Shares Underlying Options Outstanding (in shares) \| shares	237
Weighted Average Remaining Life (Years)	7 years 3 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 72.32
Options Exercisable
Number of Shares for which Options are Exercisable (in shares) \| shares	176
Weighted Average Exercise Price (in dollars per share)	$ 72.01
Exercise prices, low end of range (in dollars per share)	55.01
Exercise prices, high end of range (in dollars per share)	$ 73.22

Stock Option and Compensation Plans - Schedule of Cash Proceeds From and Aggregate Intrinsic Value of Stock Options Exercised (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Cash proceeds from options exercised	$ 0	$ 0	$ 0	$ 33
Aggregate intrinsic value of options exercised	$ 0	$ 0	$ 0	$ 43

Stock Option and Compensation Plans - Summary of Outstanding RSU Awards Granted (Details) - Restricted stock units shares in Thousands	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Restricted Stock Units
Outstanding, beginning of period (in shares) \| shares	327
Vested (in shares) \| shares	(75)
Forfeited (in shares) \| shares	(68)
Outstanding, end of period (in shares) \| shares	184
Weighted Average Grant-Date Fair Value
Outstanding, beginning of period (in dollars per share) \| $ / shares	$ 51.08
Vested (in dollars per share) \| $ / shares	47.52
Forfeited (in dollars per share) \| $ / shares	45.73
Outstanding, end of period (in dollars per share) \| $ / shares	$ 54.22

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property and Equipment
Property and equipment, gross	$ 1,345		$ 1,345		$ 1,345
Accumulated depreciation	(966)		(966)		(827)
Property and equipment, net	379		379		518
Depreciation expense	45	$ 600	$ 139	$ 1,979
Minimum
Property and Equipment
Useful life			3 years
Maximum
Property and Equipment
Useful life			10 years
Manufacturing and clinical equipment
Property and Equipment
Property and equipment, gross	412		$ 412		412
Manufacturing and clinical equipment \| Minimum
Property and Equipment
Useful life			7 years
Manufacturing and clinical equipment \| Maximum
Property and Equipment
Useful life			10 years
Computer, software and other office equipment
Property and Equipment
Useful life			5 years
Property and equipment, gross	$ 933		$ 933		$ 933

Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2018 USD ($)
License Agreements \| Archemix \| C5 Licensed Product \| Achievement of specified clinical and regulatory milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	$ 57.5
License Agreements \| Archemix \| C5 Licensed Product \| First indication \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	30.5
License Agreements \| Archemix \| C5 Licensed Product \| Second and third indication \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	24.5
License Agreements \| Archemix \| C5 Licensed Product \| Sustained delivery applications \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	2.5
License Agreements \| Archemix \| C5 Licensed Product \| Achievement of specified commercial milestones \| Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone	22.5
RHO-adRP License Agreement \| University of Florida Research Foundation (UFRF) \| Specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product
Commitments and contingencies
Amount to be paid on achievement of milestone	23.5
RHO-adRP License Agreement \| University of Florida Research Foundation (UFRF) \| Specified commercial sales milestones with respect to a licensed product
Commitments and contingencies
Amount to be paid on achievement of milestone	$ 70.0

Restructuring Activities - Narrative (Details) - USD ($) $ in Thousands		1 Months Ended	9 Months Ended
	Jan. 26, 2017	Jan. 31, 2017	Sep. 30, 2018	Dec. 31, 2017
Accrued Severance and Other Employee Costs
Restructuring Cost and Reserve [Line Items]
Percent of personnel expected to be effected by reduction in workforce		80.00%
Early termination payment			$ 0
Accrual balance for severance and benefit costs			$ 223	$ 2,529
One Penn Plaza LLC \| Lease Termination
Restructuring Cost and Reserve [Line Items]
Early termination payment		$ 900
Otsuka America Pharmaceutical, Inc. \| Lease Termination
Restructuring Cost and Reserve [Line Items]
Early termination payment	$ 1,200

Restructuring Activities - Severance Costs (Details) - Accrued Severance and Other Employee Costs - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Severance, stock compensation and other employee costs	$ 0	$ 1,343	$ 0	$ 11,875
Restructuring Reserve [Roll Forward]
Beginning Balance			2,529
Accrued restructuring expenses			0
Payments			(2,306)
Ending Balance	223		223
Research and development
Restructuring Cost and Reserve [Line Items]
Severance, stock compensation and other employee costs	0	951	0	6,834
General and administrative
Restructuring Cost and Reserve [Line Items]
Severance, stock compensation and other employee costs	$ 0	$ 392	$ 0	$ 5,041

Subsequent Event (Details) - Inception 4 - Subsequent Event $ / shares in Units, shares in Millions, $ in Millions	Oct. 30, 2018 USD ($) $ / shares shares
Subsequent Event [Line Items]
Number of shares issued in a business combination (in shares) \| shares	5.2
Value of stock issued in a business acquisition	$ 11.8
Business acquisition, share price (USD per share) \| $ / shares	$ 2.26
Contingent consideration, maximum amount	$ 105.0
Cash acquired through acquisition	$ 6.1