0001410939-21-000051 | 10-Q | XBRL Viewer

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Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2021	Nov. 05, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-36080
Entity Registrant Name	IVERIC bio, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8185347
Entity Address, Address Line One	Five Penn Plaza
Entity Address, Address Line Two	Suite 2372
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10001
City Area Code	212
Local Phone Number	845-8200
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	ISEE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Smaller Reporting Company	true
Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		114,641,279
Entity Central Index Key	0001410939
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3

Condensed Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 179,879	$ 66,373
Available for sale securities	62,091	143,674
Prepaid expenses and other current assets	4,070	4,791
Income tax receivable	0	1,765
Total current assets	246,040	216,603
Property and equipment, net	2	26
Right-of-use asset, net	1,748	120
Other assets	0	5
Total assets	247,790	216,754
Current liabilities
Accrued research and development expenses	11,368	12,284
Accounts payable and accrued expenses	8,130	12,792
Lease liability	945	54
Total current liabilities	20,443	25,130
Lease liability, non-current	861	61
Total liabilities	21,304	25,191
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, 104,237,878 and 90,120,797 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	104	90
Additional paid-in capital	872,955	756,543
Accumulated deficit	(646,562)	(565,073)
Accumulated other comprehensive income	(11)	3
Total stockholders' equity	226,486	191,563
Total liabilities and stockholders' equity	$ 247,790	$ 216,754

Condensed Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
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)	104,237,878	90,120,797
Common stock, shares outstanding (in shares)	104,237,878	90,120,797

Condensed Unaudited Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 17,935,000	$ 18,841,000	$ 59,972,000	$ 45,311,000
General and administrative	6,648,000	6,643,000	21,688,000	17,930,000
Total operating expenses	24,583,000	25,484,000	81,660,000	63,241,000
Loss from operations	(24,583,000)	(25,484,000)	(81,660,000)	(63,241,000)
Interest income	42,000	33,000	184,000	437,000
Other expense, net	(10,000)	1,000	(13,000)	(6,000)
Loss before income tax benefit	(24,551,000)	(25,450,000)	(81,489,000)	(62,810,000)
Income tax benefit	0	0	0	3,695,000
Net loss	(24,551,000)	(25,450,000)	(81,489,000)	(59,115,000)
Comprehensive loss	$ (24,565,000)	$ (25,449,000)	$ (81,503,000)	$ (59,114,000)
Net loss per common share:
Basic (in dollars per share)	$ (0.23)	$ (0.27)	$ (0.84)	$ (0.87)
Diluted (in dollars per share)	$ (0.23)	$ (0.27)	$ (0.84)	$ (0.87)
Weighted average common shares outstanding:
Basic (in shares)	105,217	92,675	97,370	67,931
Diluted (in shares)	105,217	92,675	97,370	67,931

Condensed Unaudited Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Underwritten Offering	Private Placement	Preferred Stock	Common Stock	Common Stock Underwritten Offering	Common Stock Private Placement	Additional paid-in capital	Additional paid-in capital Underwritten Offering	Additional paid-in capital Private Placement	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period (in shares) at Dec. 31, 2019				0	49,627
Balance at beginning of period at Dec. 31, 2019	$ 117,203			$ 0	$ 50			$ 597,679			$ (480,526)	$ 0
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under employee stock compensation plan (in shares)					105
Issuance of common stock under employee stock compensation plans	179							179
Share-based compensation	2,324							2,324
Net loss	(15,076)										(15,076)
Balance at end of period (in shares) at Mar. 31, 2020				0	49,732
Balance at end of period at Mar. 31, 2020	104,630			$ 0	$ 50			600,182			(495,602)	0
Balance at beginning of period (in shares) at Dec. 31, 2019				0	49,627
Balance at beginning of period at Dec. 31, 2019	117,203			$ 0	$ 50			597,679			(480,526)	0
Increase (Decrease) in Stockholders' Equity
Net loss	(59,115)
Balance at end of period (in shares) at Sep. 30, 2020				0	89,554
Balance at end of period at Sep. 30, 2020	214,586			$ 0	$ 90			754,136			(539,641)	1
Balance at beginning of period (in shares) at Mar. 31, 2020				0	49,732
Balance at beginning of period at Mar. 31, 2020	104,630			$ 0	$ 50			600,182			(495,602)	0
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs (in shares)						28,503	8,649
Issuance of common stock, net of issuance costs		$ 116,883	$ 33,237			$ 28	$ 9		$ 116,855	$ 33,228
Issuance of common stock under the exercise of pre-funded warrants (in shares)					2,500
Issuance of common stock under the exercise of pre-funded warrants	0				$ 2			(2)
Issuance of common stock under employee stock compensation plan (in shares)					105
Issuance of common stock under employee stock compensation plans	7							7
Share-based compensation	1,873							1,873
Net loss	(18,589)										(18,589)
Balance at end of period (in shares) at Jun. 30, 2020				0	89,489
Balance at end of period at Jun. 30, 2020	238,041			$ 0	$ 89			752,143			(514,191)	0
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under employee stock compensation plan (in shares)					65
Issuance of common stock under employee stock compensation plans	147				$ 1			146
Share-based compensation	1,847							1,847
Net loss	(25,450)										(25,450)
Unrealized loss on available for sale securities, net of tax	1											1
Balance at end of period (in shares) at Sep. 30, 2020				0	89,554
Balance at end of period at Sep. 30, 2020	214,586			$ 0	$ 90			754,136			(539,641)	1
Balance at beginning of period (in shares) at Dec. 31, 2020				0	90,121
Balance at beginning of period at Dec. 31, 2020	191,563			$ 0	$ 90			756,543			(565,073)	3
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under employee stock compensation plan (in shares)					49
Issuance of common stock under employee stock compensation plans	129							129
Share-based compensation	2,292							2,292
Net loss	(26,795)										(26,795)
Unrealized loss on available for sale securities, net of tax	(1)											(1)
Balance at end of period (in shares) at Mar. 31, 2021				0	90,170
Balance at end of period at Mar. 31, 2021	167,188			$ 0	$ 90			758,964			(591,868)	2
Balance at beginning of period (in shares) at Dec. 31, 2020				0	90,121
Balance at beginning of period at Dec. 31, 2020	191,563			$ 0	$ 90			756,543			(565,073)	3
Increase (Decrease) in Stockholders' Equity
Net loss	(81,489)
Balance at end of period (in shares) at Sep. 30, 2021				0	104,238
Balance at end of period at Sep. 30, 2021	226,486			$ 0	$ 104			872,955			(646,562)	(11)
Balance at beginning of period (in shares) at Mar. 31, 2021				0	90,170
Balance at beginning of period at Mar. 31, 2021	167,188			$ 0	$ 90			758,964			(591,868)	2
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under employee stock compensation plan (in shares)					217
Issuance of common stock under employee stock compensation plans	448							448
Share-based compensation	2,079							2,079
Net loss	(30,143)										(30,143)
Unrealized loss on available for sale securities, net of tax	1											1
Balance at end of period (in shares) at Jun. 30, 2021				0	90,387
Balance at end of period at Jun. 30, 2021	139,573			$ 0	$ 90			761,491			(622,011)	3
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs (in shares)						13,398
Issuance of common stock, net of issuance costs		$ 107,757				$ 14			$ 107,743
Issuance of common stock under employee stock compensation plan (in shares)					453
Issuance of common stock under employee stock compensation plans	1,095							1,095
Share-based compensation	2,626							2,626
Net loss	(24,551)										(24,551)
Unrealized loss on available for sale securities, net of tax	(14)											(14)
Balance at end of period (in shares) at Sep. 30, 2021				0	104,238
Balance at end of period at Sep. 30, 2021	$ 226,486			$ 0	$ 104			$ 872,955			$ (646,562)	$ (11)

Condensed Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net loss	$ (81,489)	$ (59,115)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and other expense	24	108
Amortization of premium and discounts on investment securities	918	115
Share-based compensation	6,997	6,044
Changes in operating assets and liabilities:
Income tax receivable	1,765	0
Prepaid expense and other assets	726	542
Accrued interest receivable	449	(112)
Accrued research and development expenses	(916)	6,007
Accounts payable and accrued expenses	(4,662)	1,383
Change in working capital	63	0
Net cash used in operating activities	(76,125)	(45,028)
Investing Activities
Purchase of marketable securities	(56,245)	(108,305)
Maturities of marketable securities	136,447	0
Net cash provided by (used in) investing activities	80,202	(108,305)
Financing Activities
Proceeds from employee stock plan purchases	1,672	333
Net cash provided by financing activities	109,429	150,453
Net increase (decrease) in cash and cash equivalents	113,506	(2,880)
Cash and cash equivalents
Beginning of period	66,373	125,699
End of period	179,879	122,819
Supplemental disclosure of cash paid
Income tax refunds received	1,765	3,327
Underwritten Offering
Financing Activities
Proceeds from issuance of common stock	107,757	116,883
Private Placement
Financing Activities
Proceeds from issuance of common stock	$ 0	$ 33,237

Business	9 Months Ended
Business	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business	Business Description of Business and Organization IVERIC bio, Inc. (“the Company” or “IVERIC”) is a science-driven biopharmaceutical company focused on the discovery and development of novel treatments for retinal diseases with significant unmet medical needs. The Company is committed to having a positive impact on patients’ lives by delivering high-quality, safe and effective treatments designed to address debilitating retina diseases including all stages of age-related macular degeneration (“AMD”). The Company’s lead asset is its clinical stage product candidate Zimura® (avacincaptad pegol), a complement C5 inhibitor. It is currently targeting the following diseases with Zimura: •Geographic Atrophy (“GA”), which is the advanced stage of AMD, and is characterized by marked thinning or atrophy of retinal tissue, leading to irreversible loss of vision; •intermediate AMD, which is an earlier stage of AMD that precedes GA; and •autosomal recessive Stargardt disease (“STGD1”), which is an orphan inherited condition characterized by progressive damage to the central portion of the retina (the “macula”) and other retinal tissue, leading to loss of vision. In July 2021, the Company completed patient enrollment for GATHER2, its Phase 3 clinical trial evaluating the safety and efficacy of Zimura for the treatment of GA secondary to AMD. The Company has also received a written agreement from the U.S. Food and Drug Administration (“FDA”) under a Special Protocol Assessment for the overall design of GATHER2. The Company expects topline data from the GATHER2 trial to become available during the second half of 2022, approximately one year after the enrollment of the last patient plus the time needed for database lock and analysis. The Company also plans to initiate a Phase 3 clinical trial evaluating Zimura for patients with intermediate AMD during 2022. The Company expects data from this trial, if positive, together with other supportive data, may be sufficient to file a supplemental new drug application with the FDA and a supplemental marketing authorization application with the European Medicines Agency. In addition to Zimura, the Company is developing its preclinical product candidate IC-500, a High temperature requirement A serine peptidase 1 protein (“HtrA1”) inhibitor, for GA secondary to AMD and potentially other age-related retinal diseases. Based on current timelines, the Company expects to submit an investigational new drug application to the FDA for IC-500 during the second half of 2022. The Company’s portfolio also includes two preclinical stage gene therapy product candidates (IC-100 and IC-200) and several ongoing gene therapy research programs, each of which uses adeno-associated virus (“AAV”) for gene delivery. These AAV mediated gene therapy programs are targeting the following orphan inherited retinal diseases (“IRDs”): •rhodopsin-mediated autosomal dominant retinitis pigmentosa (“RHO-adRP”), which is characterized by progressive and severe bilateral loss of vision leading to blindness; •IRDs associated with mutations in the BEST1 gene, including Best vitelliform macular dystrophy (“Best disease”); •Leber Congenital Amaurosis type 10 (“LCA10”), which is characterized by severe bilateral loss of vision at or soon after birth; •STGD1; and •IRDs associated with mutations in the USH2A gene, which include Usher syndrome type 2A, and USH2A-associated non-syndromic autosomal recessive retinitis pigmentosa. As the Company focuses its efforts on and prioritizes the development of Zimura, it has been considering its development options for IC-100 and IC-200, which the Company has been developing for RHO-adRP and BEST1-related IRDs, respectively. It currently plans to seek a collaborator or licensee for the future development and potential commercialization of these product candidates.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2021

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 (“Annual Report”) for the year ended December 31, 2020 filed with the Securities and Exchange Commission (“SEC”) on March 4, 2021.

Basis of Presentation and Consolidation

In the opinion of management, the Company’s condensed consolidated financial statements include all adjustments, consisting of normal recurring accruals, necessary for a fair statement of the Company’s financial statements for interim periods in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The information included in this quarterly report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements and the accompanying notes included in the Annual Report.

The year-end condensed consolidated balance sheet data presented for comparative purposes was derived from the Company’s audited financial statements but does not include all disclosures required by U.S. GAAP. The results of operations for the nine months ended September 30, 2021 are not necessarily indicative of the operating results for the full year or for any other subsequent interim period.

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 reportable segment.

Use of Estimates

The preparation of financial statements and related disclosures in conformity with U.S. 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 Consolidated 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, 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.

Available for Sale Securities

The Company considers securities with original maturities of greater than 90 days 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 other comprehensive income.

On a quarterly basis, the Company reviews the status of each security in an unrealized loss position, to evaluate the existence of potential credit losses. The Company first considers whether it intends to sell, or if it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through income. For securities that do not meet this criteria, the Company considers a number of factors to determine if the decline in fair value has resulted from credit losses or other factors, including but not limited to: (1) the extent of the decline; (2) changes to the rating of the security by a rating agency; (3) any adverse conditions specific to the security; and (4) other market conditions that may affect the fair value of the security. If this assessment indicates that a credit loss exists and the present value of cash flows expected to be collected is less than the amortized cost basis, an allowance for credit losses is required for the credit loss. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income.

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.

Accounting Standards Codification, or 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 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 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.

Concentration of Credit Risk

The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash, cash equivalents and available for sale securities. The Company maintains its cash in bank accounts, the balances of which generally exceed federally insured limits. The Company maintains its cash equivalents and available for sale securities in investments in money market funds, in U.S. Treasury securities, asset-backed securities and investment-grade corporate debt securities with original maturities of 90 days or less.

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 historically relied upon a single third-party manufacturer to provide the drug substance for Zimura on a purchase order basis. The Company also historically relied upon a single third-party manufacturer to provide fill/finish services for clinical supplies of Zimura. The Company has engaged one additional third-party manufacturer to provide drug substance for Zimura and one additional 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 on a purchase order basis the polyethylene glycol starting material used to manufacture Zimura. 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 currently relies exclusively upon a single third-party contract manufacturer for IC-100 and IC-200 and also relies on sole-source suppliers for certain starting materials used in the manufacture of such product candidates. The Company currently relies upon a single third-party contract manufacturer to conduct process development, scale-up and GMP manufacture of the drug substance for IC-500 for preclinical toxicology studies and early-stage clinical trials and a single third-party contract manufacturer to conduct fill/finish services for IC-500. 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, different business objectives, financial difficulties, insolvency or the COVID-19 pandemic, 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 Consolidated Statements of Operations and Comprehensive Loss. Foreign exchange transaction gains and losses are included in the results of operations and are not material in the Company's financial statements.

Leases

The Company determines if an arrangement contains a lease at inception. For arrangements where the Company is the lessee, it recognizes a right-of-use (“ROU”) asset and operating lease liability on the Company's Consolidated Balance Sheet. ROU lease assets represent the Company's right to use the underlying asset for the lease term and the lease obligation represents the Company's commitment to make the lease payments arising from the lease. Right-of-use lease assets and obligations are recognized at the commencement date based on the present value of remaining lease payments over the lease term. As the Company’s leases do not provide an implicit discount rate, the Company has used an estimated incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. ROU lease asset includes any lease payments made prior to commencement and excludes any lease incentives. The lease term may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term, subject to any changes in the lease or expectations regarding the terms. Variable lease costs such as common area costs and property taxes are expensed as incurred. For all office lease agreements the Company combines lease and nonlease components. Leases with an initial term of 12 months or less are not recorded on the Company's Consolidated Balance Sheet.

Property and Equipment

Property and equipment, which consists mainly of clinical and laboratory equipment, 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 preclinical and clinical testing of the Company’s product candidates and costs associated with its gene therapy research programs. The Company's 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 contract development and manufacturing organizations (“CDMOs”) and other vendors for the production and analysis 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, in-process research and development, 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 collaborators.

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, non-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 only when the performance-based milestone is deemed probable of achievement. If performance-based milestones are later determined not to be probable of achievement, then all previously recorded stock-based compensation expense associated with such options will be reversed during the period in which the Company makes this determination.

The Company estimates forfeitures at the time of grant and revises those estimates in subsequent periods if actual forfeitures differ from its estimates. The Company uses historical data to estimate pre-vesting forfeitures and record share-based compensation expense only for those awards that are expected to vest. To the extent that actual forfeitures differ from the Company's estimates, the difference is recorded as a cumulative adjustment in the period the estimates were revised.

Stock Options

The Company estimates the fair value of stock options granted to employees, non-employee directors and consultants on the date of grant using the Black-Scholes option-pricing model. The Company's computation of stock-price volatility is based on daily historical volatility during the time period that corresponds to the expected option term. The Company's computation of expected term is determined using the expected term of stock option grants to employees based on an analysis of actual option exercises. 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.

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 nine month periods ended September 30, 2021 and 2020:


	Three Months Ended September 30,		Nine Months Ended September 30,
	2021	2020	2021	2020
Expected common stock price volatility	113%	117%	113%	117%
Risk-free interest rate	0.68%-0.84%	0.22%-0.26%	0.31%-0.96%	0.22%-1.34%
Expected term of options (years)	5.2	4.8	5.2	4.6
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 Company's board of directors adopted the ESPP pursuant to which the Company may sell up to an aggregate of 1,000,000 shares of its 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.

Recent Accounting Pronouncements

The Company has evaluated recent accounting pronouncements through the date the financial statements were issued and filed with the SEC and believes that there are none that will have a material impact on the Company’s financial statements.

Common Stock	9 Months Ended
Common Stock	Sep. 30, 2021
Equity [Abstract]
Common Stock	Common Stock In July 2021, the Company completed an underwritten public offering in which the Company sold 13,397,500 shares of its common stock, which included the exercise in full of the underwriters’ option to purchase an additional 1,747,500 shares of the Company’s common stock, at a price to the public of $8.60 per share and at a price to the underwriters of $8.084 per share. The net proceeds from the July 2021 public offering, after deducting underwriting discounts and commissions and other expenses payable by the Company totaling approximately $7.4 million, was approximately $107.8 million. In June 2020, the Company completed an underwritten public offering in which the Company sold 28,503,220 shares of its common stock, which included the exercise in full of the underwriters’ option to purchase additional shares of the Company’s common stock, at a price to the public of $4.100 per share and at a price to the underwriters of $3.854 per share. The Company also sold to certain investors in lieu of common stock, pre-funded warrants to purchase 1,914,280 shares of its common stock at a price to the public of $4.099 per share underlying each pre-funded warrant, and at a price to the underwriters of $3.853 per share underlying each pre-funded warrant. Concurrently with the June 2020 public offering, the Company completed a private placement in which the Company sold 8,649,453 shares of its common stock to affiliates of Vivo Capital, LLC and Samsara BioCapital, LP, at a sale price equal to the price to the public in the underwritten public offering. The net proceeds from the June 2020 public offering and private placement, after deducting underwriting discounts, underwriting and placement agent commissions and other expenses totaling approximately $10.1 million, was approximately $150.1 million. The Company evaluated the pre-funded warrants for liability or equity classification in accordance with the provisions of ASC 480, Distinguishing Liabilities from Equity, and ASC 815-40, Derivatives and Hedging. Based on the provisions governing the pre-funded warrants in the applicable agreement, the Company determined that the pre-funded warrants meet the criteria required to be classified as an equity award subject to the guidance in ASC 815-10 and 815-40 and should effectively be treated as outstanding common shares in both basic and diluted earnings per share calculations.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Net Loss Per Common Share

9 Months Ended

Sep. 30, 2021

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 and pre-funded warrants outstanding during the period. Basic and diluted shares outstanding includes the weighted average effect of the Company's outstanding pre-funded warrants as the exercise of such pre-funded warrants requires nominal consideration to be given for the delivery of the corresponding shares of common stock. As of September 30, 2021 and September 30, 2020, the Company had 3,164,280 pre-funded warrants outstanding, which if exercised, would increase the number of shares of common stock issued and outstanding. For the periods when 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,
	2021		2020		2021		2020
Basic and diluted net loss per common share calculation:
Net loss	$	(24,551)	$	(25,450)	$	(81,489)	$	(59,115)
Weighted average common shares outstanding - basic and dilutive	105,217		92,675		97,370		67,931
Net loss per share of common stock - basic and diluted	$	(0.23)	$	(0.27)	$	(0.84)	$	(0.87)

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,
	2021	2020	2021	2020
Stock options outstanding	9,089	7,426	9,089	7,426
Restricted stock units	1,903	1,727	1,903	1,727
Total	10,992	9,153	10,992	9,153

Cash, Cash Equivalents and Available for Sale Securities

9 Months Ended

Sep. 30, 2021

Cash, Cash Equivalents, and Short-term Investments [Abstract]

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, 2021 and December 31, 2020, the Company had cash and cash equivalents of approximately $179.9 million and $66.4 million, respectively. Cash and cash equivalents included cash of $97.0 million at September 30, 2021 and $8.4 million at December 31, 2020. Cash and cash equivalents at September 30, 2021 and December 31, 2020 included $82.9 million and $58.0 million, respectively, 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. As of September 30, 2021 and December 31, 2020, the Company held available for sale securities of $62.1 million and $143.7 million, respectively, all of which have maturities of less than one year.

The Company evaluates securities with unrealized losses, if any, to determine whether the decline in fair value has resulted from credit loss or other factors. The Company has determined that there were no credit losses in fair value of its investments as of September 30, 2021. Factors considered in determining whether a loss resulted from a credit loss or other factors included the length of time and extent to which the investment’s fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, the extent of the loss related to credit of the issuer, the expected cash flows from the security, the Company’s intent to sell the security, and whether or not the Company will be required to sell the security before the recovery of its amortized cost.

The Company classifies these securities as available for sale. However, the Company has not sold and does not currently intend to sell its investments and the Company believes it is more likely than not that the Company will recover the carrying value of these investments.

The Company believes that its existing cash, cash equivalents and available for sale securities as of September 30, 2021 will be sufficient to fund its currently planned capital expenditure requirements and operating expenses for at least the next 12 months from the filing of this Quarterly Report on Form 10-Q. See Note 10 to the Financial Statements for information about the Company’s follow-on public offering completed in October 2021.

Available for sale securities, including carrying value and estimated fair values, are summarized as follows:


	As of September 30, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	8,999	$	—	$	—	$	8,999
Corporate debt securities	43,614		—		(8)		43,606
Asset-backed securities	9,489		—		(3)		9,486
Total	$	62,102	$	—	$	(11)	$	62,091


	As of December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	54,225	$	8	$	—	$	54,233
Corporate debt securities	79,282		4		(10)		79,276
Asset-backed securities	10,164		1		—		10,165
Total	$	143,671	$	13	$	(10)	$	143,674

The Company’s available for sale securities are reported at fair value on the Company’s balance sheet. Unrealized gains (losses) are reported within other comprehensive income 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 income associated with the unrealized gain on available for sale securities during the three and nine months ended September 30, 2021 and 2020, respectively, were as follows:


	Three months ended September 30,				Nine Months Ended September 30, 2021
	2021		2020		2021		2020
Beginning balance	$	3	$	—	$	3	$	—
Current period changes in fair value before reclassifications, net of tax	(14)		1		(14)		1
Amounts reclassified from accumulated other comprehensive income, net of tax	—		—		—		—
Total other comprehensive income (loss)	$	(14)	$	1	(14)		1
Ending balance	$	(11)	$	1	$	(11)	$	1

Share-Based Compensation

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Share-Based Compensation

Pursuant to the evergreen provisions of the Company's 2013 stock incentive plan (the “2013 Plan”), annual increases have resulted in the addition of an aggregate of approximately 13,081,000 additional shares to the 2013 Plan, including for 2021, an increase of approximately 2,542,000 shares. As of September 30, 2021, the Company had approximately 3,031,000 shares available for grant under the 2013 Plan.

In October 2019, the Company's board of directors adopted its 2019 Inducement Stock Incentive Plan (the “2019 Inducement Plan”) to reserve initially 1,000,000 shares of its common stock to be used exclusively for grants of awards to individuals who were not previously employees or directors of the Company as a material inducement to such individuals’ entry into employment with the Company within Rule 5635(c)(4) of the Nasdaq Listing Rules. The terms and conditions of the 2019 Inducement Plan are substantially similar to those of the 2013 Plan. In March 2020, the Company's board of directors amended the 2019 Inducement Plan to reserve an additional 1,000,000 shares of its common stock for issuance under the plan, and in February 2021 and September 2021, the Company's board of directors further amended the 2019 Inducement Plan to reserve an additional 600,000 shares, and an additional 1,000,000 shares, respectively, of its common stock for issuance under the plan. As of September 30, 2021, the Company had approximately 1,314,000 shares available for grant under the 2019 Inducement Plan.

Share-based compensation expense, net of estimated forfeitures, 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. Stock-based compensation by award type was as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Stock options	$	1,485	$	1,089	$	3,997	$	3,556
Restricted stock units	1,101		723		2,896		2,411
Employee stock purchase plan	40		35		104		77
Total	$	2,626	$	1,847	$	6,997	$	6,044

The Company allocated stock-based compensation expense in the Company’s Consolidated Statements of Operations and Comprehensive Loss as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	1,476	$	882	$	4,138	$	2,986
General and administrative	1,150		965		2,859		3,058
Total	$	2,626	$	1,847	$	6,997	$	6,044

Stock Options

A summary of the stock option activity, weighted average exercise prices, options outstanding, exercisable and expected to vest as of September 30, 2021 is as follows (in thousands except weighted average exercise price):


	Number of Shares Underlying Options	Weighted Average Exercise Price
Outstanding, December 31, 2020	8,928	$	9.22
Granted	969	$	7.84
Exercised	(487)	$	2.89
Forfeited	(321)	$	4.49


Outstanding, September 30, 2021	9,089	$	9.85
Vested and exercisable, September 30, 2021	5,154	$	12.71
Vested and expected to vest, September 30, 2021	8,768	$	9.99

As of September 30, 2021, there were approximately $15.3 million of unrecognized compensation costs, net of estimated forfeitures, related to stock option awards grants, which are expected to be recognized over a remaining weighted average period of 3.0 years.

RSUs

The following table presents a summary of the Company's outstanding RSU awards granted as of September 30, 2021 (in thousands except weighted average grant-date fair value):


	Restricted Stock Units	Weighted Average Grant-Date Fair Value
Outstanding, December 31, 2020	1,958	$	6.95
Awarded	329	$	7.44
Vested	(181)	$	4.32
Forfeited	(203)	$	21.60
Outstanding, September 30, 2021	1,903	$	5.76
Outstanding, Expected to vest	1,750	$	5.76

As of September 30, 2021, there were approximately $7.5 million of unrecognized compensation costs, net of estimated forfeitures, related to RSUs grants, which are expected to be recognized over a remaining weighted average period of 2.7 years.

ESPP

As of September 30, 2021, there were 753,410 shares available for future purchases under the ESPP. There were 27,529 and 32,821 shares issued under the ESPP during the three months ended September 30, 2021 and 2020, respectively. There were 51,951 and 76,402 shares of common stock issued under the ESPP during the nine months ended September 30, 2021 and 2020, respectively. Cash proceeds from ESPP purchases were $146 thousand and $147 thousand during the nine months ended September 30, 2021 and 2020, respectively.

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three and nine months ended September 30, 2021 and the three months ended September 2020, the Company recorded no income tax benefit. For the nine months ended September 30, 2020, the Company recorded a $3.7 million income tax benefit primarily to reflect a settlement of a local tax audit. In response to the COVID-19 pandemic, the U.S. Congress enacted the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) on March 27, 2020. The CARES Act provides numerous tax provisions and other stimulus measures, including the immediate refund of minimum tax credits. In April 2021, the Company received the remaining balance, approximately $1.8 million, of its minimum tax credits refund. 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.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Fair Value Measurements

9 Months Ended

Sep. 30, 2021

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 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, 2021:


	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*	$	82,872	$	—	$	—
Investments in U.S. Treasury securities	$	8,999	$	—	$	—
Investments in corporate debt securities	$	—	$	43,606	$	—
Investments in asset-backed securities	$	—	$	9,486	$	—

*Investments in money market funds are reflected in cash and cash equivalents in the accompanying Consolidated Balance Sheets.


	Fair Value Measurement Using
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money market funds*	$	58,042	$	—	$	—

Investments in U.S. Treasury securities	54,233		—		—
Investments in corporate debt securities	$	—	$	79,275	$	—
Investments in asset-backed securities	—		10,166		—

*Investments in money market funds are reflected in cash and cash equivalents in the accompanying Consolidated 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, 2021.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Zimura - Archemix Corp. The Company is party to an agreement with Archemix Corp. (“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 (the “C5 License Agreement”). Under the C5 License Agreement, for each anti-C5 aptamer product that the Company may develop under the agreement, including Zimura, the Company is obligated to make additional payments to Archemix of up to an aggregate of $50.5 million if the Company achieves specified development, clinical and regulatory milestones, with $24.5 million of such payments relating to a first indication, $23.5 million of such payments relating to second and third indications and $2.5 million of such payments relating to sustained delivery applications. Under the C5 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 License Agreement. The Company is not obligated to pay Archemix a running royalty based on net product sales in connection with the C5 License Agreement. IC-100 - University of Florida and the University of Pennsylvania Under its exclusive license agreement with the University of Florida Research Foundation, Incorporated (“UFRF”) and the University of Pennsylvania (“Penn”) for rights to IC-100, the Company is obligated to make payments to UFRF, for the benefit of Penn and UFRF (together, the “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, for the benefit of the Licensors, a low single-digit percentage of net sales of licensed products. The Company is also obligated to pay UFRF, for the benefit of the Licensors, a double-digit percentage of specified non-royalty payments the Company may receive from any third-party sublicensee of the licensed patent rights. 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, for the benefit of the 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 candidate. In addition, if the Company sells such a priority review voucher to a third party, the Company will be obligated to pay UFRF, for the benefit of the Licensors, a low double-digit percentage of any consideration received from such third party in connection with such sale. IC-200 - University of Pennsylvania and the University of Florida Under its exclusive license agreement with Penn and UFRF for rights to IC-200, the Company is obligated to make payments to Penn, for the benefit of the Licensors, of up to an aggregate of $15.7 million if the Company achieves specified clinical, marketing approval and reimbursement approval milestones with respect to one licensed product and up to an aggregate of an additional $3.1 million if the Company achieves these same milestones with respect to a different licensed product. In addition, the Company is obligated to make payments to Penn, for the benefit of the Licensors, of up to an aggregate of $48.0 million if the Company achieves specified commercial sales milestones with respect to one licensed product and up to an aggregate of an additional $9.6 million if the Company achieves these same milestones with respect to a different licensed product. The Company is also obligated to pay Penn, for the benefit of the Licensors, a low single-digit percentage of net sales of licensed products. The Company is also obligated to pay Penn, for the benefit of the Licensors, a high single-digit to a mid-teen percentage of specified non-royalty payments the Company may receive from any third-party sublicensee of the licensed patent rights, with the applicable percentage based upon the stage of development of the sublicensed product at the time the Company enters into the sublicense. 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 outside the scope of the agreement, the Company will be obligated to pay Penn, for the benefit of the 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 candidate. In addition, if the Company sells such a priority review voucher to a third party, the Company will be obligated to pay Penn, for the benefit of the Licensors, a high single-digit percentage of any consideration received from such third party in connection with such sale. miniCEP290 Program - University of Massachusetts Under its exclusive license agreement with the University of Massachusetts (“UMass”) for its miniCEP290 program, which targets LCA10, which is associated with mutations in the CEP290 gene, the Company is obligated to pay UMass up to an aggregate of $14.75 million in cash and issue up to 75,000 shares of common stock of the Company if the Company achieves specified clinical and regulatory milestones with respect to a licensed product. In addition, the Company is obligated to pay UMass up to an aggregate of $48.0 million if the Company achieves specified commercial sales milestones with respect to a licensed product. The Company is also obligated to pay UMass royalties at a low single-digit percentage of net sales of licensed products. If the Company or any of its affiliates sublicenses any of the licensed patent rights or know-how to a third party, the Company will be obligated to pay UMass a high single-digit to a mid-tens percentage of the consideration received in exchange for such sublicense, with the applicable percentage based upon the stage of development of the licensed products at the time the Company or the applicable affiliate enters into the sublicense. If the Company receives a 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 outside the scope of the agreement, the Company will be obligated to pay UMass a low-tens percentage of the fair market value of the priority review voucher at the time of approval of such product candidate and a low-twenties percentage of the fair market value of the priority review voucher at the time of achievement of a specified commercial sales milestone for such product candidate. In addition, if the Company sells such a priority review voucher to a third party, the Company will be obligated to pay UMass a low-thirties percentage of any consideration received from such third party in connection with such sale. IC-500 - Former Equityholders of Inception 4 Under the agreement and plan of merger between the Company and Inception 4, Inc. (“Inception 4”), pursuant to which the Company acquired IC-500 and its other HtrA1 inhibitors (the “Inception 4 Merger Agreement”), the Company is obligated to make payments to the former equityholders of Inception 4 of up to an aggregate of $105 million, subject to the terms and conditions of the Inception 4 Merger Agreement, if the Company achieves certain specified clinical and regulatory milestones with respect to IC-500 or any other product candidate from its HtrA1 inhibitor program, with $45 million of such potential payments relating to GA and $60 million of such potential payments relating to wet AMD. Under the Inception 4 Merger Agreement, the Company does not owe any commercial milestones or royalties based on net sales. The future milestone payments will be payable in the form of shares of the Company's common stock, calculated based on the price of its common stock over a five-trading day period preceding the achievement of the relevant milestone, unless and until the issuance of such shares would, together with all other shares issued in connection with the acquisition, exceed an overall maximum limit of approximately 7.2 million shares, which is equal to 19.9% of the number of issued and outstanding shares of the Company's common stock as of the close of business on the business day prior to the closing date of the Inception 4 acquisition, and will be payable in cash thereafter. The Inception 4 Merger Agreement also includes customary indemnification obligations to the former equityholders of Inception 4, including for breaches of the representations and warranties, covenants and agreements of the Company and its subsidiaries (other than Inception 4) in the Inception 4 Merger Agreement. 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 and CDMOs represent significant costs in preclinical and clinical development. Subject to required notice periods and the Company’s obligations under binding purchase orders and any cancellation fees that the Company may be obligated to pay, 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. IVERIC bio, Inc., 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. IVERIC bio, Inc., et al., No. 1:17-cv-01758. These cases were consolidated on March 13, 2018. On June 4, 2018, the 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. On September 18, 2019, the court issued an order dismissing some, but not all, of the allegations in the CAC. On November 18, 2019, the Company and the individual defendants filed an answer to the complaint. On June 12, 2020, the lead plaintiff filed a motion for class certification. On August 11, 2020, the defendants filed a notice of non-opposition to lead plaintiff's motion for class certification. On April 23, 2021, the court issued an order staying the action until July 1, 2021, 10 days after a mediation scheduled for June 21, 2021. On July 1, 2021, following the June 21, 2021 mediation, the parties notified the court that they had reached an agreement in principle to settle the class action. On September 8, 2021, the parties executed a settlement agreement, which has been submitted to the court for approval. The Company does not expect this settlement, if finalized as currently contemplated, to have a material impact on its financial condition. 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. On December 14, 2018, the Company filed a motion to dismiss the complaint. On September 19, 2019, the court denied its motion to dismiss this complaint. This matter was subsequently referred to a special litigation committee (“SLC”) of the Company's board of directors. On February 18, 2020, the Company filed an answer to the complaint. The Company and the plaintiff agreed to stay this litigation while the SLC conducts its investigation. On May 4, 2020, the court approved the stipulation and stayed the litigation through November 1, 2020. By agreement of the parties, the court has since extended the stay through June 26, 2021. The Company also entered into tolling agreements with the defendant directors to December 2021. The SLC and the plaintiffs in this derivative matter and the one described below recently agreed in principle on a settlement and are conducting settlement agreement discussions. On October 16, 2018, the Company’s board of directors received a shareholder demand to investigate and commence legal proceedings against certain members of the Company’s board of directors. The demand alleges facts that are substantially similar to the facts alleged in the CAC and the Pacheco complaint and asserts claims that are substantially similar to the claims asserted in the Pacheco complaint. On January 30, 2019, the Company’s board of directors received a second shareholder demand from a different shareholder to investigate and commence legal proceedings against certain current and former members of the Company’s board of directors based on allegations that are substantially similar to the allegations contained in the first demand letter. These shareholder demands were referred to a demand review committee of the Company's board of directors. On May 6, 2021, the shareholders who served the October 16, 2018 demand filed a shareholder derivative action against current and former members of the Company’s Board of Directors and certain current and former officers of the Company in the New York Supreme Court, captioned Brian Ferber et al., derivatively on behalf of Ophthotech Corporation v. Axel Bolte et al., Index No. 154462/2021. The complaint asserts the same claims as those asserted in the Pacheco complaint and is based on factual allegations that are materially similar to the allegations in the Pacheco complaint. On June 22, 2021, the parties filed a stipulation staying the Ferber action until 60 days after the SLC concludes its investigation. The Company has entered into tolling agreements with the directors named in the demands to December 2021. The SLC and the plaintiffs in this derivative matter and the one described above recently agreed in principle on a settlement and are conducting settlement agreement discussions. The Company denies any and all allegations of wrongdoing and intends to vigorously defend against these lawsuits. The Company is unable, however, to predict the outcome of these matters, including that of the settlement agreement discussions, 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 its business plan 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.

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsIn October 2021, the Company completed an underwritten public offering in which the Company sold 10,350,000 shares of its common stock, which included the exercise in full of the underwriters’ option to purchase 1,350,000 shares of the Company’s common stock, at a price to the public of $16.75 per share and at a price to the underwriters of $15.745 per share. The net proceeds from the October 2021 public offering, after deducting underwriting discounts and commissions and other expenses payable by the Company totaling approximately $10.8 million, was approximately $162.6 million.

Summary of Significant Accounting Policies - (Policies)	9 Months Ended
Summary of Significant Accounting Policies - (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and ConsolidationIn the opinion of management, the Company’s condensed consolidated financial statements include all adjustments, consisting of normal recurring accruals, necessary for a fair statement of the Company’s financial statements for interim periods in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”).
Consolidation	The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The information included in this quarterly report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements and the accompanying notes included in the Annual Report.The year-end condensed consolidated balance sheet data presented for comparative purposes was derived from the Company’s audited financial statements but does not include all disclosures required by U.S. GAAP. The results of operations for the nine months ended September 30, 2021 are not necessarily indicative of the operating results for the full year or for any other subsequent interim period.
Segment and geographic information	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.
Use of Estimates	Use of Estimates The preparation of financial statements and related disclosures in conformity with U.S. 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 Consolidated 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, accounting for share-based compensation and accounting for income taxes. Actual results could differ from those estimates.
Cash and Cash Equivalents	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.
Available for Sale Securities	Available for Sale Securities The Company considers securities with original maturities of greater than 90 days 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 other comprehensive income. On a quarterly basis, the Company reviews the status of each security in an unrealized loss position, to evaluate the existence of potential credit losses. The Company first considers whether it intends to sell, or if it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through income. For securities that do not meet this criteria, the Company considers a number of factors to determine if the decline in fair value has resulted from credit losses or other factors, including but not limited to: (1) the extent of the decline; (2) changes to the rating of the security by a rating agency; (3) any adverse conditions specific to the security; and (4) other market conditions that may affect the fair value of the security. If this assessment indicates that a credit loss exists and the present value of cash flows expected to be collected is less than the amortized cost basis, an allowance for credit losses is required for the credit loss. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income.
Financial Instruments	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. Accounting Standards Codification, or 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 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 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.
Concentration of Credit Risk	Concentration of Credit Risk The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash, cash equivalents and available for sale securities. The Company maintains its cash in bank accounts, the balances of which generally exceed federally insured limits. The Company maintains its cash equivalents and available for sale securities in investments in money market funds, in U.S. Treasury securities, asset-backed securities and investment-grade corporate debt securities with original maturities of 90 days or less. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents and available for sale securities.
Concentration of Suppliers	Concentration of Suppliers The Company historically relied upon a single third-party manufacturer to provide the drug substance for Zimura on a purchase order basis. The Company also historically relied upon a single third-party manufacturer to provide fill/finish services for clinical supplies of Zimura. The Company has engaged one additional third-party manufacturer to provide drug substance for Zimura and one additional 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 on a purchase order basis the polyethylene glycol starting material used to manufacture Zimura. 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 currently relies exclusively upon a single third-party contract manufacturer for IC-100 and IC-200 and also relies on sole-source suppliers for certain starting materials used in the manufacture of such product candidates. The Company currently relies upon a single third-party contract manufacturer to conduct process development, scale-up and GMP manufacture of the drug substance for IC-500 for preclinical toxicology studies and early-stage clinical trials and a single third-party contract manufacturer to conduct fill/finish services for IC-500. 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, different business objectives, financial difficulties, insolvency or the COVID-19 pandemic, 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	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 Consolidated Statements of Operations and Comprehensive Loss. Foreign exchange transaction gains and losses are included in the results of operations and are not material in the Company's financial statements.
Leases	Leases The Company determines if an arrangement contains a lease at inception. For arrangements where the Company is the lessee, it recognizes a right-of-use (“ROU”) asset and operating lease liability on the Company's Consolidated Balance Sheet. ROU lease assets represent the Company's right to use the underlying asset for the lease term and the lease obligation represents the Company's commitment to make the lease payments arising from the lease. Right-of-use lease assets and obligations are recognized at the commencement date based on the present value of remaining lease payments over the lease term. As the Company’s leases do not provide an implicit discount rate, the Company has used an estimated incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. ROU lease asset includes any lease payments made prior to commencement and excludes any lease incentives. The lease term may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term, subject to any changes in the lease or expectations regarding the terms. Variable lease costs such as common area costs and property taxes are expensed as incurred. For all office lease agreements the Company combines lease and nonlease components. Leases with an initial term of 12 months or less are not recorded on the Company's Consolidated Balance Sheet.
Property and Equipment	Property and Equipment Property and equipment, which consists mainly of clinical and laboratory equipment, 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	Research and Development The Company's research and development expenses primarily consist of costs associated with the manufacturing, development and preclinical and clinical testing of the Company’s product candidates and costs associated with its gene therapy research programs. The Company's 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 contract development and manufacturing organizations (“CDMOs”) and other vendors for the production and analysis 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, in-process research and development, 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 collaborators. 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	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	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, non-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 only when the performance-based milestone is deemed probable of achievement. If performance-based milestones are later determined not to be probable of achievement, then all previously recorded stock-based compensation expense associated with such options will be reversed during the period in which the Company makes this determination. The Company estimates forfeitures at the time of grant and revises those estimates in subsequent periods if actual forfeitures differ from its estimates. The Company uses historical data to estimate pre-vesting forfeitures and record share-based compensation expense only for those awards that are expected to vest. To the extent that actual forfeitures differ from the Company's estimates, the difference is recorded as a cumulative adjustment in the period the estimates were revised. Stock Options The Company estimates the fair value of stock options granted to employees, non-employee directors and consultants on the date of grant using the Black-Scholes option-pricing model. The Company's computation of stock-price volatility is based on daily historical volatility during the time period that corresponds to the expected option term. The Company's computation of expected term is determined using the expected term of stock option grants to employees based on an analysis of actual option exercises. 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. 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 Company's board of directors adopted the ESPP pursuant to which the Company may sell up to an aggregate of 1,000,000 shares of its 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements The Company has evaluated recent accounting pronouncements through the date the financial statements were issued and filed with the SEC and believes that there are none that will have a material impact on the Company’s financial statements.

Summary of Significant Accounting Policies - (Tables)

9 Months Ended

Sep. 30, 2021

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,
	2021	2020	2021	2020
Expected common stock price volatility	113%	117%	113%	117%
Risk-free interest rate	0.68%-0.84%	0.22%-0.26%	0.31%-0.96%	0.22%-1.34%
Expected term of options (years)	5.2	4.8	5.2	4.6
Expected dividend yield	—	—	—	—

Net Loss Per Common Share - (Tables)

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Schedule of computation of basic and diluted net 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,
	2021		2020		2021		2020
Basic and diluted net loss per common share calculation:
Net loss	$	(24,551)	$	(25,450)	$	(81,489)	$	(59,115)
Weighted average common shares outstanding - basic and dilutive	105,217		92,675		97,370		67,931
Net loss per share of common stock - basic and diluted	$	(0.23)	$	(0.27)	$	(0.84)	$	(0.87)

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,
	2021	2020	2021	2020
Stock options outstanding	9,089	7,426	9,089	7,426
Restricted stock units	1,903	1,727	1,903	1,727
Total	10,992	9,153	10,992	9,153

Cash, Cash Equivalents and Available for Sale Securities (Tables)

9 Months Ended

Sep. 30, 2021

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Schedule of Available for Sale Securities

Available for sale securities, including carrying value and estimated fair values, are summarized as follows:


	As of September 30, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	8,999	$	—	$	—	$	8,999
Corporate debt securities	43,614		—		(8)		43,606
Asset-backed securities	9,489		—		(3)		9,486
Total	$	62,102	$	—	$	(11)	$	62,091


	As of December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	54,225	$	8	$	—	$	54,233
Corporate debt securities	79,282		4		(10)		79,276
Asset-backed securities	10,164		1		—		10,165
Total	$	143,671	$	13	$	(10)	$	143,674

Schedule of Accumulated Other Comprehensive Income

The


	Three months ended September 30,				Nine Months Ended September 30, 2021
	2021		2020		2021		2020
Beginning balance	$	3	$	—	$	3	$	—
Current period changes in fair value before reclassifications, net of tax	(14)		1		(14)		1
Amounts reclassified from accumulated other comprehensive income, net of tax	—		—		—		—
Total other comprehensive income (loss)	$	(14)	$	1	(14)		1
Ending balance	$	(11)	$	1	$	(11)	$	1

Share-Based Compensation - (Tables)

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Allocation of Share-based Compensation Costs by Award Type

Stock-based compensation by award type was as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Stock options	$	1,485	$	1,089	$	3,997	$	3,556
Restricted stock units	1,101		723		2,896		2,411
Employee stock purchase plan	40		35		104		77
Total	$	2,626	$	1,847	$	6,997	$	6,044

Schedule of Allocation of Share-based Compensation Costs by Financial Statement Line

The Company allocated stock-based compensation expense in the Company’s Consolidated Statements of Operations and Comprehensive Loss as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	1,476	$	882	$	4,138	$	2,986
General and administrative	1,150		965		2,859		3,058
Total	$	2,626	$	1,847	$	6,997	$	6,044

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, 2020	8,928	$	9.22
Granted	969	$	7.84
Exercised	(487)	$	2.89
Forfeited	(321)	$	4.49


Outstanding, September 30, 2021	9,089	$	9.85
Vested and exercisable, September 30, 2021	5,154	$	12.71
Vested and expected to vest, September 30, 2021	8,768	$	9.99

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, 2021 (in thousands except weighted average grant-date fair value):


	Restricted Stock Units	Weighted Average Grant-Date Fair Value
Outstanding, December 31, 2020	1,958	$	6.95
Awarded	329	$	7.44
Vested	(181)	$	4.32
Forfeited	(203)	$	21.60
Outstanding, September 30, 2021	1,903	$	5.76
Outstanding, Expected to vest	1,750	$	5.76

Fair Value Measurements - (Tables)

9 Months Ended

Sep. 30, 2021

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*	$	82,872	$	—	$	—
Investments in U.S. Treasury securities	$	8,999	$	—	$	—
Investments in corporate debt securities	$	—	$	43,606	$	—
Investments in asset-backed securities	$	—	$	9,486	$	—

*Investments in money market funds are reflected in cash and cash equivalents in the accompanying Consolidated Balance Sheets.


	Fair Value Measurement Using
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets
Investments in money market funds*	$	58,042	$	—	$	—

Investments in U.S. Treasury securities	54,233		—		—
Investments in corporate debt securities	$	—	$	79,275	$	—
Investments in asset-backed securities	—		10,166		—

*Investments in money market funds are reflected in cash and cash equivalents in the accompanying Consolidated Balance Sheets.

Business - Narrative (Details)	Sep. 30, 2021 segment
Adeno-Associated Virus Mediated Gene Therapy Program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of product candidates in preclinical development	2

Summary of Significant Accounting Policies - Segment and Geographic Information (Details)	9 Months Ended
	Sep. 30, 2021 segment
Accounting Policies [Abstract]
Number of operating segments	1
Number of reporting segments	1

Summary of Significant Accounting Policies - Property and Equipment (Details)	9 Months Ended
	Sep. 30, 2021
Minimum
Property and equipment
Estimated useful live (in years)	3 years
Maximum
Property and equipment
Estimated useful live (in years)	10 years

Summary of Significant Accounting Policies - Share-Based Compensation (Details) - shares	1 Months Ended	9 Months Ended
	Apr. 30, 2016	Sep. 30, 2021
Share-Based Compensation
Expected dividend yield		0.00%
Employee stock purchase plan
Share-Based Compensation
Purchase period (in months)	6 months
Employee stock purchase plan \| Maximum
Share-Based Compensation
Number of initial 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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
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	113.00%	117.00%	113.00%	117.00%
Risk-free interest rate, minimum	0.68%	0.22%	0.31%	0.22%
Risk-free interest rate, maximum	0.84%	0.26%	0.96%	1.34%
Expected term of options (years)	5 years 2 months 12 days	4 years 9 months 18 days	5 years 2 months 12 days	4 years 7 months 6 days
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		9 Months Ended
	Jul. 31, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 30, 2021
Subsidiary, Sale of Stock [Line Items]
Payments of stock issuance costs	$ 7,400	$ 10,100
Proceeds from issuance of common stock		$ 150,100
Warrants issued in transaction (in shares)		1,914,280
Public Stock Offering
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)	13,397,500
Sale of stock price (in dollars per share)					$ 8.60
Proceeds from issuance of common stock	$ 107,800
Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)	1,747,500
Sale of stock price (in dollars per share)					$ 8.084
Underwritten Offering
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)		28,503,220
Sale of stock price (in dollars per share)		$ 4.100
Proceeds from issuance of common stock			$ 107,757	$ 116,883
Underwritten Offering, Underwriters
Subsidiary, Sale of Stock [Line Items]
Sale of stock price (in dollars per share)		$ 3.854
Private Placement
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)		8,649,453
Proceeds from issuance of common stock			$ 0	$ 33,237
Exercise price of pre-funded warrants (in dollars per share)		$ 4.099
Private Placement, Underwriters
Subsidiary, Sale of Stock [Line Items]
Exercise price of pre-funded warrants (in dollars per share)		$ 3.853

Net Loss Per Common Share - Narrative (Details) - shares	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Pre-funded warrants outstanding (in shares)	3,164,280	3,164,280

Net Loss Per Common Share -Schedules of Net Loss Per Share and Dilutive Securities (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic and diluted net loss per common share calculation:
Net loss	$ (24,551)	$ (30,143)	$ (26,795)	$ (25,450)	$ (18,589)	$ (15,076)	$ (81,489)	$ (59,115)
Weighted average common shares outstanding - basic (in shares)	105,217			92,675			97,370	67,931
Weighted average common shares outstanding - dilutive (in shares)	105,217			92,675			97,370	67,931
Net loss per share of common stock - basic (in dollars per share)	$ (0.23)			$ (0.27)			$ (0.84)	$ (0.87)
Net loss per share of common stock - diluted (in dollars per share)	$ (0.23)			$ (0.27)			$ (0.84)	$ (0.87)
Anti-dilutive securities
Total (in shares)	10,992			9,153			10,992	9,153
Stock options outstanding
Anti-dilutive securities
Total (in shares)	9,089			7,426			9,089	7,426
Restricted stock units
Anti-dilutive securities
Total (in shares)	1,903			1,727			1,903	1,727

Cash, Cash Equivalents and Available for Sale Securities - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash and cash equivalents	$ 179,879	$ 66,373
Cash	97,000	8,400
Investments in money market funds	82,900	58,000
Available for sale securities	$ 62,091	$ 143,674

Cash, Cash Equivalents and Available for Sale Securities - Schedule of Available for Sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 62,102	$ 143,671
Gross Unrealized Gains	0	13
Gross Unrealized Losses	(11)	(10)
Fair Value	62,091	143,674
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,999	54,225
Gross Unrealized Gains	0	8
Gross Unrealized Losses	0	0
Fair Value	8,999	54,233
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	43,614	79,282
Gross Unrealized Gains	0	4
Gross Unrealized Losses	(8)	(10)
Fair Value	43,606	79,276
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,489	10,164
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(3)	0
Fair Value	$ 9,486	$ 10,165

Cash, Cash Equivalents and Available for Sale Securities - Schedule of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ 139,573	$ 238,041	$ 191,563	$ 117,203
Balance at end of period	226,486	214,586	226,486	214,586
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	3	0	3	0
Current period changes in fair value before reclassifications, net of tax	(14)	1	(14)	1
Amounts reclassified from accumulated other comprehensive income, net of tax	0	0	0	0
Total other comprehensive income (loss)	(14)	1	(14)	1
Balance at end of period	$ (11)	$ 1	$ (11)	$ 1

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=122038336&loc=d3e74512-122707

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Share-Based Compensation - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended		97 Months Ended
	Sep. 30, 2021	Feb. 28, 2021	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Oct. 31, 2019
Stock options
Stock Option and Compensation Plans
Unrecognized share-based compensation costs for option awards, net of estimated forfeitures	$ 15,300			$ 15,300		$ 15,300		$ 15,300
Expected weighted average period to recognize share-based compensation costs (in years)						3 years
Restricted stock units
Stock Option and Compensation Plans
Expected weighted average period to recognize share-based compensation costs (in years)						2 years 8 months 12 days
Unrecognized compensation costs, net of estimated forfeitures	$ 7,500			$ 7,500		$ 7,500		$ 7,500
Employee stock purchase plan
Stock Option and Compensation Plans
Common stock issued (in shares)				27,529	32,821	51,951	76,402
Proceeds from stock plans						$ 146	$ 147
2013 Plan
Stock Option and Compensation Plans
Increase in number of shares available under the Plan (in shares)						2,542,000		13,081,000
Number of shares of common stock available for issuance under the Plan (in shares)	3,031,000			3,031,000		3,031,000		3,031,000
2013 Plan \| Employee stock purchase plan
Stock Option and Compensation Plans
Number of shares available for future purchase (in shares)	753,410			753,410		753,410		753,410
2019 Inducement Plan \| Stock options
Stock Option and Compensation Plans
Increase in number of shares available under the Plan (in shares)	1,000,000	600,000	1,000,000
Number of shares of common stock available for issuance under the Plan (in shares)	1,314,000			1,314,000		1,314,000		1,314,000
Number of initial shares reserved for issuance under the Plan (in shares)									1,000,000

Share-Based Compensation - Summary of Share-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,626	$ 1,847	$ 6,997	$ 6,044
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,485	1,089	3,997	3,556
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,101	723	2,896	2,411
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 40	$ 35	$ 104	$ 77

Share-Based Compensation - Summary of Share-Based Compensation Expense by Financial Statement Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,626	$ 1,847	$ 6,997	$ 6,044
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,476	882	4,138	2,986
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,150	$ 965	$ 2,859	$ 3,058

Share-Based Compensation - Summary of Stock Option Activity (Details) - Stock options shares in Thousands	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Number of Shares Underlying Options
Outstanding, beginning balance (in shares) \| shares	8,928
Granted (in shares) \| shares	969
Exercised (in shares) \| shares	(487)
Forfeited (in shares) \| shares	(321)
Outstanding, ending balance (in shares) \| shares	9,089
Vested and exercisable, end of period (in shares) \| shares	5,154
Vested and expected to vest, end of period (in shares) \| shares	8,768
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 9.22
Granted (in dollars per share) \| $ / shares	7.84
Exercised (in dollars per share) \| $ / shares	2.89
Forfeited (in dollars per share) \| $ / shares	4.49
Outstanding, ending balance (in dollars per share) \| $ / shares	9.85
Vested and exercisable, end of period (in dollars per share) \| $ / shares	12.71
Vested and expected to vest, end of period (in dollars per share) \| $ / shares	$ 9.99

Share-Based Compensation - Summary of Outstanding RSU Awards Granted (Details) - Restricted stock units shares in Thousands	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Restricted Stock Units
Outstanding, beginning balance (in shares) \| shares	1,958
Awarded (in shares) \| shares	329
Vested (in shares) \| shares	(181)
Forfeited (in shares) \| shares	(203)
Outstanding, ending balance (in shares) \| shares	1,903
Outstanding, expected to vest (in shares) \| shares	1,750
Weighted Average Grant-Date Fair Value
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 6.95
Awarded (in dollars per share) \| $ / shares	7.44
Vested (in dollars per share) \| $ / shares	4.32
Forfeited (in dollars per share) \| $ / shares	21.60
Outstanding, ending balance (in dollars per share) \| $ / shares	5.76
Outstanding, expected to vest (in dollars per share) \| $ / shares	$ 5.76

Income Taxes - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2021	Dec. 31, 2020
Tax Credit Carryforward [Line Items]
Income tax benefit	$ 0	$ 0	$ 0	$ 3,695,000
Income tax receivable	$ 0		$ 0			$ 1,765,000
CARES Act
Tax Credit Carryforward [Line Items]
Income tax receivable					$ 1,800,000

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value Measurements
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	82,872	$ 58,042
Recurring basis \| Quoted prices in active markets for identical assets (Level 1) \| U.S. Treasury securities
Fair Value Measurements
Investments	8,999	54,233
Recurring basis \| Quoted prices in active markets for identical assets (Level 1) \| Corporate debt securities
Fair Value Measurements
Investments	0	0
Recurring basis \| Quoted prices in active markets for identical assets (Level 1) \| Asset-backed securities
Fair Value Measurements
Investments	0	0
Recurring basis \| Significant other observable inputs (Level 2) \| Money market funds
Fair Value Measurements
Investments	0	0
Recurring basis \| Significant other observable inputs (Level 2) \| U.S. Treasury securities
Fair Value Measurements
Investments	0	0
Recurring basis \| Significant other observable inputs (Level 2) \| Corporate debt securities
Fair Value Measurements
Investments	43,606	79,275
Recurring basis \| Significant other observable inputs (Level 2) \| Asset-backed securities
Fair Value Measurements
Investments	9,486	10,166
Recurring basis \| Significant unobservable inputs (Level 3) \| Money market funds
Fair Value Measurements
Investments	0	0
Recurring basis \| Significant unobservable inputs (Level 3) \| U.S. Treasury securities
Fair Value Measurements
Investments	0	0
Recurring basis \| Significant unobservable inputs (Level 3) \| Corporate debt securities
Fair Value Measurements
Investments	0	0
Recurring basis \| Significant unobservable inputs (Level 3) \| Asset-backed securities
Fair Value Measurements
Investments	$ 0	$ 0

Commitments and Contingencies - Narrative (Details) $ in Thousands				1 Months Ended
	Jun. 22, 2021	Apr. 23, 2021	Oct. 30, 2018 USD ($) shares	May 31, 2019 USD ($) licensedProduct shares	Dec. 31, 2018 USD ($)	Sep. 30, 2011 USD ($)
Commitments and contingencies
Number of licensed products \| licensedProduct				1
Litigation stay period (in days)	60 days	10 days
Inception 4
Commitments and contingencies
Contingent consideration arrangements, maximum amount			$ 105,000
Share price calculation base, period (in days)			5 days
Contingent consideration arrangements, maximum amount (in shares) \| shares			7,200,000
Contingent consideration arrangements, contingently issuable shares as a percentage of shares outstanding			19.90%
GA Product \| Inception 4
Commitments and contingencies
Clinical and marketing approval milestones			$ 45,000
Wet AMD Product \| Inception 4
Commitments and contingencies
Clinical and marketing approval milestones			$ 60,000
Archemix \| C5 Licensed Product \| Achievement of specified clinical and regulatory milestones \| Maximum \| License Agreements
Commitments and contingencies
Amount to be paid on achievement of milestone						$ 50,500
Archemix \| C5 Licensed Product \| First indication \| Maximum \| License Agreements
Commitments and contingencies
Amount to be paid on achievement of milestone						24,500
Archemix \| C5 Licensed Product \| Second and third indication \| Maximum \| License Agreements
Commitments and contingencies
Amount to be paid on achievement of milestone						23,500
Archemix \| C5 Licensed Product \| Sustained delivery applications \| Maximum \| License Agreements
Commitments and contingencies
Amount to be paid on achievement of milestone						2,500
Archemix \| C5 Licensed Product \| Achievement of specified commercial milestones \| Maximum \| License Agreements
Commitments and contingencies
Amount to be paid on achievement of milestone						$ 22,500
University of Florida Research Foundation (UFRF) \| Specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product \| RHO-adRP License Agreement
Commitments and contingencies
Amount to be paid on achievement of milestone					$ 23,500
University of Florida Research Foundation (UFRF) \| Specified commercial sales milestones with respect to a licensed product \| RHO-adRP License Agreement
Commitments and contingencies
Amount to be paid on achievement of milestone					$ 70,000
University Of Florida Research Foundation (UFRF) And University Of Pennsylvania (Penn) \| Primary Licensed Product \| Specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product \| Research and Development Expense \| BEST1 License Agreement
Commitments and contingencies
Payments for license fees				$ 15,700
University Of Florida Research Foundation (UFRF) And University Of Pennsylvania (Penn) \| Primary Licensed Product \| Specified commercial sales milestones with respect to a licensed product \| Research and Development Expense \| BEST1 License Agreement
Commitments and contingencies
Payments for license fees				48,000
University Of Florida Research Foundation (UFRF) And University Of Pennsylvania (Penn) \| Other Licensed Product \| Specified clinical, marketing approval and reimbursement approval milestones with respect to a licensed product \| Research and Development Expense \| BEST1 License Agreement
Commitments and contingencies
Payments for license fees				3,100
University Of Florida Research Foundation (UFRF) And University Of Pennsylvania (Penn) \| Other Licensed Product \| Specified commercial sales milestones with respect to a licensed product \| Research and Development Expense \| BEST1 License Agreement
Commitments and contingencies
Payments for license fees				9,600
University Of Massachusetts (UMass) \| miniCEP290 \| Achievement of specified clinical and regulatory milestones \| License Agreements \| Research and Development Expense
Commitments and contingencies
Payments for license fees				$ 14,750
Shares issued for license fees (in shares) \| shares				75,000
University Of Massachusetts (UMass) \| miniCEP290 \| Specified commercial sales milestones with respect to a licensed product \| License Agreements \| Research and Development Expense
Commitments and contingencies
Payments for license fees				$ 48,000

Subsequent Event - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Oct. 31, 2021	Jul. 31, 2021	Jun. 30, 2020	Jul. 30, 2021
Subsequent Event [Line Items]
Payments of stock issuance costs		$ 7,400	$ 10,100
Proceeds from issuance of common stock			$ 150,100
Public Stock Offering
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)		13,397,500
Sale of stock price (in dollars per share)				$ 8.60
Proceeds from issuance of common stock		$ 107,800
Over-Allotment Option
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)		1,747,500
Sale of stock price (in dollars per share)				$ 8.084
Subsequent Event
Subsequent Event [Line Items]
Payments of stock issuance costs	$ 10,800
Proceeds from issuance of common stock	$ 162,600
Subsequent Event \| Public Stock Offering
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)	10,350,000
Sale of stock price (in dollars per share)	$ 16.75
Subsequent Event \| Over-Allotment Option
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)	1,350,000
Sale of stock price (in dollars per share)	$ 15.745