REGENXBIO (RGNX) 10-Q 3 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Apr. 27, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Trading Symbol	RGNX
Entity Registrant Name	REGENXBIO Inc.
Entity Central Index Key	0001590877
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-37553
Entity Tax Identification Number	47-1851754
Entity Address, Address Line One	9804 Medical Center Drive
Entity Address, City or Town	Rockville
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20850
City Area Code	240
Local Phone Number	552-8181
Entity Common Stock, Shares Outstanding		43,466,186
Document Transition Report	false
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Entity Incorporation, State or Country Code	DE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 70,091	$ 96,952
Marketable securities	261,726	267,690
Accounts receivable	18,861	28,082
Prepaid expenses	15,521	13,900
Other current assets	23,003	9,352
Total current assets	389,202	415,976
Marketable securities	141,709	200,560
Accounts receivable, net	1,300	1,504
Property and equipment, net	141,573	141,685
Operating lease right-of-use assets	63,726	65,116
Restricted cash	2,030	2,030
Other assets	8,290	6,397
Total assets	747,830	833,268
Current liabilities
Accounts payable	23,283	27,213
Accrued expenses and other current liabilities	31,709	46,794
Deferred revenue	1,311	1,829
Operating lease liabilities	6,303	5,997
Liability related to sale of future royalties	49,728	48,601
Total current liabilities	112,334	130,434
Operating lease liabilities	86,992	88,802
Liability related to sale of future royalties	77,382	89,005
Other liabilities	5,983	8,832
Total liabilities	282,691	317,073
Stockholders’ equity
Preferred stock; $0.0001 par value; 10,000 shares authorized, no shares issued and outstanding at March 31, 2023 and December 31, 2022
Common stock; $0.0001 par value; 100,000 shares authorized at March 31, 2023 and December 31, 2022; 43,465 and 43,299 shares issued and outstanding at March 31, 2023 and December 31, 2022, respectively	4	4
Additional paid-in capital	984,986	973,145
Accumulated other comprehensive loss	(11,622)	(15,401)
Accumulated deficit	(508,229)	(441,553)
Total stockholders’ equity	465,139	516,195
Total liabilities and stockholders’ equity	$ 747,830	$ 833,268

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	43,465,000	43,299,000
Common stock, shares outstanding	43,465,000	43,299,000

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues
Revenues	$ 19,138	$ 22,218
Operating Expenses
Cost of revenues	4,112	15,717
Research and development	58,516	55,627
General and administrative	22,634	22,318
Other operating expenses	33	83
Total operating expenses	85,295	93,745
Loss from operations	(66,157)	(71,527)
Other Income (Expense)
Interest income from licensing	70	94
Investment income	2,166	799
Interest expense	(2,755)	(6,130)
Total other income (expense)	(519)	(5,237)
Loss before income taxes	(66,676)	(76,764)
Income Tax Benefit		41
Net loss	(66,676)	(76,723)
Other Comprehensive Income (Loss)
Unrealized gain (loss) on available-for-sale securities, net	3,779	(9,381)
Total other comprehensive income (loss)	3,779	(9,381)
Comprehensive loss	$ (62,897)	$ (86,104)
Net loss per share, basic	$ (1.53)	$ (1.79)
Net loss per share, diluted	$ (1.53)	$ (1.79)
Weighted-average common shares outstanding, basic	43,451	42,944
Weighted-average common shares outstanding, diluted	43,451	42,944
License and royalty [Member]
Revenues
Revenues	$ 19,138	$ 22,218

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional paid in capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2021	$ 764,298	$ 4	$ 928,095	$ (2,569)	$ (161,232)
Balances (Shares) at Dec. 31, 2021		42,831
Vesting of restricted stock units, net of tax	(284)		(284)
Vesting of restricted stock units, net of tax, shares		52
Exercise of stock options, net of tax	337		337
Exercise of stock options, net of tax, shares		76
Issuance of common stock under employee stock purchase plan	622		622
Issuance of common stock under employee stock purchase plan, shares		22
Stock-based compensation expense	10,800		10,800
Unrealized gain (loss) on available-for-sale securities, net	(9,381)			(9,381)
Net loss	(76,723)				(76,723)
Balances at Mar. 31, 2022	689,669	$ 4	939,570	(11,950)	(237,955)
Balances (Shares) at Mar. 31, 2022		42,982
Balances at Dec. 31, 2022	516,195	$ 4	973,145	(15,401)	(441,553)
Balances (Shares) at Dec. 31, 2022		43,299
Vesting of restricted stock units, net of tax	(419)		(419)
Vesting of restricted stock units, net of tax, shares		99
Exercise of stock options, net of tax	471		471
Exercise of stock options, net of tax, shares		37
Issuance of common stock under employee stock purchase plan	583		583
Issuance of common stock under employee stock purchase plan, shares		30
Stock-based compensation expense	11,206		11,206
Unrealized gain (loss) on available-for-sale securities, net	3,779			3,779
Net loss	(66,676)				(66,676)
Balances at Mar. 31, 2023	$ 465,139	$ 4	$ 984,986	$ (11,622)	$ (508,229)
Balances (Shares) at Mar. 31, 2023		43,465

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities
Net loss	$ (66,676)	$ (76,723)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	11,206	10,800
Depreciation and amortization	4,178	2,591
Net amortization of premiums on marketable debt securities	682	1,460
Imputed interest income from licensing	(70)	(94)
Non-cash interest expense	(574)	54
Other non-cash adjustments	(52)	(43)
Changes in operating assets and liabilities
Accounts receivable	9,495	5,689
Prepaid expenses	(1,621)	210
Other current assets	(13,651)	3,042
Operating lease right-of-use assets	1,390	979
Other assets	(1,893)	(2,101)
Accounts payable	(3,103)	16,755
Accrued expenses and other current liabilities	(15,443)	(26,473)
Deferred revenue	(433)
Operating lease liabilities	(1,504)	1,008
Other liabilities	(2,849)	6,935
Net cash used in operating activities	(80,918)	(55,911)
Cash flows from investing activities
Purchases of marketable debt securities		(129,486)
Maturities of marketable debt securities	67,912	49,862
Purchases of property and equipment	(4,818)	(10,967)
Net cash provided by (used in) investing activities	63,094	(90,591)
Cash flows from financing activities
Proceeds from exercise of stock options	471	337
Taxes paid related to net settlement of stock-based awards	(419)	(284)
Proceeds from issuance of common stock under employee stock purchase plan	583	622
Repayments under liability related to sale of future royalties, net of imputed interest	(9,672)	(7,509)
Net cash used in financing activities	(9,037)	(6,834)
Net decrease in cash and cash equivalents and restricted cash	(26,861)	(153,336)
Cash and cash equivalents and restricted cash
Beginning of period	98,982	347,239
End of period	$ 72,121	$ 193,903

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2023
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business	1. Nature of Business REGENXBIO Inc. (the Company) is a clinical-stage biotechnology company seeking to improve lives through the curative potential of gene therapy. The Company has developed a broad pipeline of gene therapy product candidates using its proprietary adeno-associated virus (AAV) gene delivery platform (NAV Technology Platform), which consists of exclusive rights to over 100 novel AAV vectors, including AAV7, AAV8 and AAV9. In addition to its internal product development efforts, the Company also selectively licenses the NAV® Technology Platform to other leading biotechnology and pharmaceutical companies (NAV Technology Licensees). As of March 31, 2023, the NAV Technology Platform was being applied by NAV Technology Licensees in one commercially available product, Zolgensma®, and in the preclinical and clinical development of a number of licensed products. Additionally, the Company has licensed intellectual property rights to collaborators for the joint development and commercialization of certain product candidates. The Company was formed in 2008 in the State of Delaware and is headquartered in Rockville, Maryland. The Company has incurred cumulative losses since inception and as of March 31, 2023, had generated an accumulated deficit of $ 508.2 million. The Company's ability to transition to recurring profitability is dependent upon achieving a level of revenues adequate to support its cost structure, which depends heavily on the successful development, approval and commercialization of its product candidates. The Company may never achieve recurring profitability, and unless and until it does, the Company will continue to need to raise additional capital, to the extent possible. As of March 31, 2023, the Company had cash, cash equivalents and marketable securities of $ 473.5 million, which management believes is sufficient to fund operations for at least the next 12 months from the date these consolidated financial statements were issued.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). The interim unaudited consolidated financial statements have been prepared on the same basis as the annual audited consolidated financial statements as of and for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, which was filed with the SEC on February 28, 2023. Certain information and footnote disclosures required by GAAP which are normally included in the Company’s annual consolidated financial statements have been omitted pursuant to SEC rules and regulations for interim reporting. In the opinion of management, the accompanying consolidated financial statements reflect all adjustments, which are normal and recurring in nature, necessary for fair financial statement presentation. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year, any other interim periods, or any future year or period. These interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2022, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosure of contingent assets and liabilities for the periods presented. Management bases its estimates on historical experience and various other factors that it believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities, and other reported amounts, that are not readily apparent from other sources. Actual results may differ materially from these estimates. Significant estimates are used in the following areas, among others: license and royalty revenue, the allowance for credit losses, accrued research and development expenses and other accrued liabilities, stock-based compensation expense, interest expense under the liability related to the sale of future royalties, income taxes and the fair value of financial instruments. Reclassifications Certain amounts reported in prior periods have been reclassified to conform to current period financial statement presentation. These reclassifications are not material and have no effect on previously reported financial position, results of operations and cash flows. Restricted Cash Restricted cash includes money market mutual funds and other deposits used to collateralize irrevocable letters of credit required under the Company’s lease agreements and certain other agreements with third parties. The following table provides a reconciliation of cash and cash equivalents and restricted cash as reported on the consolidated balance sheets to the total of these amounts as reported at the end of the period in the consolidated statements of cash flows (in thousands): As of March 31, 2023 2022 Cash and cash equivalents $ 70,091 $ 191,873 Restricted cash 2,030 2,030 Total cash and cash equivalents and restricted cash $ 72,121 $ 193,903 Accounts Receivable Accounts receivable primarily consist of consideration due to the Company resulting from its license agreements with customers. Accounts receivable include amounts invoiced to licensees as well as rights to consideration which have not yet been invoiced, including unbilled royalties, and for which payment is conditional solely upon the passage of time. If a licensee elects to terminate a license prior to the end of the license term, the licensed intellectual property is returned to the Company and any accounts receivable from the licensee which are not contractually payable to the Company are charged off as a reduction of license revenue in the period of the termination. Accounts receivable which are not expected to be received by the Company within 12 months from the reporting date are stated net of a discount to present value and recorded as non-current assets on the consolidated balance sheets. The present value discount is recognized as a reduction of revenue in the period in which the accounts receivable are initially recorded and is accreted as interest income from licensing over the term of the receivables. Accounts receivable are stated net of an allowance for credit losses, if deemed necessary based on the Company’s evaluation of collectability and potential credit losses. Management assesses the collectability of its accounts receivable using the specific identification of account balances, and considers the credit quality and financial condition of its significant customers, historical information regarding credit losses and the Company’s evaluation of current and expected future economic conditions. If necessary, an allowance for credit losses is recorded against accounts receivable such that the carrying value of accounts receivable reflects the net amount expected to be collected. Accounts receivable balances are written off against the allowance for credit losses when the potential for collectability is considered remote. Please refer to Note 8 for further information regarding the allowance for credit losses related to accounts receivable. Fair Value of Financial Instruments The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. Accounting Standards Codification (ASC) 820, Fair Value Measurements and Disclosures , establishes a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The three levels of the fair value hierarchy are described below: • Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2—Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. • Level 3—Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The fair values of the Company’s Level 2 instruments are based on quoted market prices or broker or dealer quotations for similar assets. These investments are initially valued at the transaction price and subsequently valued utilizing third party pricing providers or other market observable data. Please refer to Note 4 for further information on the fair value measurement of the Company’s financial instruments. Net Loss Per Share Basic net loss per share is calculated by dividing net loss applicable to common stockholders by the weighted-average common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting the weighted-average common shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. Contingently convertible shares in which conversion is based on non-market-priced contingencies are excluded from the calculations of both basic and diluted net loss per share until the contingency has been fully met. For purposes of the diluted net loss per share calculation, common stock equivalents are excluded from the calculation of diluted net loss per share if their effect would be anti-dilutive.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2023
Investments Debt And Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities The following tables present a summary of the Company’s marketable securities, which consist solely of available-for-sale debt securities (in thousands): Amortized Cost Unrealized Unrealized Fair Value March 31, 2023 U.S. government and agency securities $ 101,176 $ — $ ( 2,567 ) $ 98,609 Certificates of deposit 7,554 — ( 221 ) 7,333 Corporate bonds 305,468 5 ( 7,980 ) 297,493 $ 414,198 $ 5 $ ( 10,768 ) $ 403,435 Amortized Cost Unrealized Unrealized Fair Value December 31, 2022 U.S. government and agency securities $ 134,485 $ — $ ( 3,492 ) $ 130,993 Certificates of deposit 7,555 1 ( 248 ) 7,308 Corporate bonds 340,752 — ( 10,803 ) 329,949 $ 482,792 $ 1 $ ( 14,543 ) $ 468,250 As of March 31, 2023 and December 31, 2022 , no available-for-sale debt securities had remaining maturities greater than three years. The amortized cost of marketable debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, or to the earliest call date for callable debt securities purchased at a premium. As of March 31, 2023 and December 31, 2022 , the balance in accumulated other comprehensive loss consisted solely of unrealized gains and losses on available-for-sale debt securities, net of reclassification adjustments for realized gains and losses and income tax effects. The Company uses the aggregate portfolio approach to release the tax effects of unrealized gains and losses on available-for-sale debt securities in accumulated other comprehensive loss. Realized gains and losses from the sale or maturity of marketable securities are based on the specific identification method and are included in results of operations as investment income. Unrealized gain (loss) on available-for-sale securities, net, as presented in the consolidated statements of operations and comprehensive loss consisted of the following (in thousands): Three Months Ended March 31, 2023 2022 Unrealized gain (loss) before reclassifications $ 3,779 $ ( 9,381 ) Realized losses (gains) reclassified to investment income — — Income tax expense — — Unrealized gain (loss) on available-for-sale securities, net $ 3,779 $ ( 9,381 ) The following tables present the fair values and unrealized losses of available-for-sale debt securities held by the Company in an unrealized loss position for less than 12 months and 12 months or greater (in thousands): Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized March 31, 2023 U.S. government and agency securities $ 33,920 $ ( 386 ) $ 64,689 $ ( 2,181 ) $ 98,609 $ ( 2,567 ) Certificates of deposit 3,379 ( 51 ) 3,484 ( 170 ) 6,863 ( 221 ) Corporate bonds 8,082 ( 168 ) 288,197 ( 7,812 ) 296,279 ( 7,980 ) $ 45,381 $ ( 605 ) $ 356,370 $ ( 10,163 ) $ 401,751 $ ( 10,768 ) Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized December 31, 2022 U.S. government and agency securities $ 91,498 $ ( 2,014 ) $ 38,495 $ ( 1,478 ) $ 129,993 $ ( 3,492 ) Certificates of deposit 4,484 ( 144 ) 2,087 ( 104 ) 6,571 ( 248 ) Corporate bonds 106,707 ( 3,866 ) 223,242 ( 6,937 ) 329,949 ( 10,803 ) $ 202,689 $ ( 6,024 ) $ 263,824 $ ( 8,519 ) $ 466,513 $ ( 14,543 ) As of March 31, 2023 , available-for-sale debt securities held by the Company which were in an unrealized loss position consisted of 122 investment grade security positions. The Company has the intent and ability to hold such securities until recovery, and based on the credit quality of the issuers and low severity of each unrealized loss position relative to its amortized cost basis, the Company did not identify any credit losses associated with its available-for-sale debt securities. The Company did no t record an allowance for credit losses on its available-for-sale debt securities as of March 31, 2023 or December 31, 2022. The Company did no t recognize any impairment or credit losses on available-for-sale debt securities during the three months ended March 31, 2023 and 2022.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	4. Fair Value of Financial Instruments Financial instruments reported at fair value on a recurring basis include cash equivalents and marketable securities. The following tables present the fair value of cash equivalents and marketable securities in accordance with the hierarchy discussed in Note 2 (in thousands): Quoted Significant prices other Significant in active observable unobservable markets inputs inputs (Level 1) (Level 2) (Level 3) Total March 31, 2023 Cash equivalents: Money market mutual funds $ — $ 35,777 $ — $ 35,777 Total cash equivalents — 35,777 — 35,777 Marketable securities: U.S. government and agency securities — 98,609 — 98,609 Certificates of deposit — 7,333 — 7,333 Corporate bonds — 297,493 — 297,493 Total marketable securities — 403,435 — 403,435 Total cash equivalents and marketable securities $ — $ 439,212 $ — $ 439,212 Quoted Significant prices other Significant in active observable unobservable markets inputs inputs (Level 1) (Level 2) (Level 3) Total December 31, 2022 Cash equivalents: Money market mutual funds $ — $ 58,611 $ — $ 58,611 Corporate bonds — 993 — 993 Total cash equivalents — 59,604 — 59,604 Marketable securities: U.S. government and agency securities — 130,993 — 130,993 Certificates of deposit — 7,308 — 7,308 Corporate bonds — 329,949 — 329,949 Total marketable securities — 468,250 — 468,250 Total cash equivalents and marketable securities $ — $ 527,854 $ — $ 527,854 Management estimates that the carrying values of its current accounts receivable, other current assets, accounts payable, accrued expenses and other current liabilities approximate fair value due to the short-term nature of those instruments. Accounts receivable which contain non-current portions and certain non-current payables reported as other liabilities are recorded at their present values using a discount rate that is based on prevailing market rates on the date the amounts were initially recorded. Management does not believe there have been any significant changes in market conditions or credit quality that would cause the discount rates initially used to be materially different from those that would be used as of March 31, 2023 to determine the present value of these instruments. Accordingly, management estimates that the carrying values of its non-current accounts receivable and other liabilities approximate the fair value of those instruments. Management estimates that the carrying value of the liability related to the sale of future royalties approximates fair value. As discussed in Note 6 , the carrying value of the liability related to the sale of future royalties is based on the Company’s estimate of future royalties expected to be paid by the Company over the life of the arrangement, which are considered Level 3 inputs.

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2023
Property Plant And Equipment [Abstract]
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net consists of the following (in thousands): March 31, 2023 December 31, 2022 Laboratory and manufacturing equipment $ 73,456 $ 71,801 Computer equipment and software 5,645 4,910 Furniture and fixtures 6,968 6,965 Leasehold improvements 101,071 99,397 Total property and equipment 187,140 183,073 Accumulated depreciation and amortization ( 45,567 ) ( 41,388 ) Property and equipment, net $ 141,573 $ 141,685

Liability Related to Sale of Fu

Liability Related to Sale of Future Royalties	3 Months Ended
	Mar. 31, 2023
Liability Related To Sale Of Future Royalties [Abstract]
Liability Related to Sale of Future Royalties	6. Liability Related to Sale of Future Royalties In December 2020, the Company entered into a royalty purchase agreement (the Royalty Purchase Agreement) with entities managed by Healthcare Royalty Management, LLC (collectively, HCR). Under the agreement, HCR purchased the Company’s rights to a capped amount of Zolgensma royalty payments under the Company’s license agreement (the Novartis License) with Novartis Gene Therapies, Inc. (formerly AveXis, Inc.) (Novartis Gene Therapies), including $ 4.0 million of royalty payments received by the Company in the fourth quarter of 2020 (the Pledged Royalties). In consideration for these rights, HCR paid the Company $ 200.0 million (the Purchase Price), less $4.0 million representing the payment of the Pledged Royalties to HCR. Beginning upon the effective date of the Royalty Purchase Agreement, Zolgensma royalty payments, up to a specified threshold, shall be paid to HCR, net of upstream royalties payable by the Company to certain licensors in accordance with existing license agreements. Pursuant to the Royalty Purchase Agreement, the total amount of royalty payments to be received by HCR under the agreement is subject to an increasing cap (the Cap Amount) equal to (i) $ 260.0 million applicable for the period from the effective date of the Royalty Purchase Agreement through November 7, 2024, and (ii) $ 300.0 million applicable for the period from November 8, 2024 through the effective date of termination of the Novartis License. If, on or prior to the defined dates for each Cap Amount, the total amount of royalty payments received by HCR equals or exceeds the Cap Amount applicable to such date, the Royalty Purchase Agreement will automatically terminate and all rights to the Zolgensma royalty payments will revert back to the Company. The Company has no obligation to repay any amounts to HCR if total future Zolgensma royalty payments are not sufficient to achieve the applicable Cap Amount prior to the termination of the Novartis License. The Company has a call option to repurchase its rights to the purchased royalties from HCR for a repurchase price equal to, as of the option exercise date, $ 300.0 million minus the total amount of royalty payments received by HCR; provided, however, that with respect to a call option exercised on or before November 7, 2024, in the event that the then applicable Cap Amount minus the total amount of royalty payments received by HCR is less than $ 1.0 million, the repurchase price shall equal such difference. The proceeds received from HCR of $ 196.0 million were recorded as a liability, net of transaction costs of $ 3.5 million, which is amortized over the estimated life of the arrangement using the effective interest method. In order to determine the amortization of the liability, the Company is required to estimate the total amount of future royalty payments to be received by HCR, subject to the Cap Amount, over the life of the arrangement. The total amount of royalty payments received by HCR under the Royalty Purchase Agreement, less the net proceeds received by the Company of $ 192.5 million, is recorded as interest expense over the life of the arrangement using the effective interest method. Due to its continuing involvement in the Novartis License, the Company continues to recognize royalty revenue on net sales of Zolgensma and records the royalty payments to HCR as a reduction of the liability when paid. As such payments are made to HCR, the balance of the liability will be effectively repaid over the life of the Royalty Purchase Agreement. The Company estimates the effective interest rate used to record interest expense under the Royalty Purchase Agreement based on its estimate of future royalty payments to be received by HCR. As of March 31, 2023, the estimated effective interest rate under the Royalty Purchase Agreement was 7.7 % . Over the life of the arrangement, the actual effective interest rate will be affected by the amount and timing of the royalty payments received by HCR and changes in the Company’s forecasted royalties. At each reporting date, the Company reassesses its estimate of total future royalty payments to be received by HCR at the applicable Cap Amount, and prospectively adjusts the effective interest rate and amortization of the liability, as necessary. The following table presents the changes in the liability related to the sale of future royalties under the Royalty Purchase Agreement with HCR (in thousands): Liability Related to Sale of Future Royalties Balance at December 31, 2022 $ 137,606 Zolgensma royalties paid to HCR ( 13,001 ) Interest expense recognized 2,505 Balance at March 31, 2023 127,110 Current portion of liability related to sale of future royalties ( 49,728 ) Non-current portion of liability related to sale of future royalties $ 77,382

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies The Trustees of the University of Pennsylvania In February 2009, the Company entered into a license agreement (the Penn License), which has been amended from time to time, with The Trustees of the University of Pennsylvania (together with the University of Pennsylvania, Penn) for exclusive, worldwide rights to certain patents owned by Penn underlying the Company’s NAV Technology Platform, as well as exclusive rights to certain data, results and other information. In March 2022, the Company and Penn entered into a letter agreement (the Penn Letter Agreement) pursuant to which the Company will pay to Penn a total of $ 20.0 million, consisting of (i) $ 8.0 million paid in April 2022 to satisfy payment of any sublicense fees due or owed in the future under the Penn License as a result of the Company’s collaboration and license agreement with AbbVie Global Enterprises Ltd., and (ii) $ 12.0 million to satisfy any other past or future obligations of the Company to pay sublicense fees under the Penn License, which is payable in four equal annual installments of $ 3.0 million beginning in March 2023. The Penn Letter Agreement amended the Penn License to remove the Company’s obligations to pay sublicense fees under the license agreement. The Company remains obligated to pay Penn royalties on net sales of licensed products, milestone fees and reimbursement of certain patent maintenance costs in accordance with the Penn License. The Company recognized a charge of $ 9.2 million as cost of revenues upon the execution of Penn Letter Agreement in March 2022, which consisted of $ 17.3 million representing the present value of the $ 20.0 million payable under the Penn Letter Agreement, less $ 8.1 million in sublicense fees previously recognized as expense by the Company in prior periods and accrued as liabilities prior to the effectiveness of the Penn Letter Agreement. The present value discount is accreted as interest expense over the contractual payment period using the effective interest method. In addition to other amounts payable under the Penn License, as of March 31, 2023, the Company had recorded a total of $ 7.4 million payable under the Penn Letter Agreement, net of present value discount, of which $ 2.2 million was included in accrued expenses and other current liabilities and $ 5.2 million was included in other liabilities on the consolidated balance sheet.

License and Collaboration Agree

License and Collaboration Agreements	3 Months Ended
	Mar. 31, 2023
Organization Consolidation And Presentation Of Financial Statements [Abstract]
License and Collaboration Agreements	8. License and Collaboration Agreements License and Royalty Revenue As of March 31, 2023 , the Company’s NAV Technology Platform was being applied by NAV Technology Licensees in one commercially available product, Zolgensma, and in the development of a number of licensed products. Additionally, the Company has licensed intellectual property rights to collaborators for the joint development of certain product candidates. Consideration to the Company under its license agreements may include: (i) up-front and annual fees, (ii) milestone payments based on the achievement of certain development and sales-based milestones, (iii) sublicense fees, (iv) royalties on sales of licensed products and (v) other consideration payable upon optional goods and services purchased by licensees. Sublicense fees vary by license and range from a mid-single digit percentage to a low-double digit percentage of license fees received by licensees as a result of sublicenses. Royalties on net sales of commercialized products vary by license and range from a mid-single digit percentage to a low double-digit percentage of net sales by licensees. License and royalty revenue consisted of the following (in thousands): Three Months Ended March 31, 2023 2022 Zolgensma royalties $ 16,125 $ 21,539 Other license and royalty revenue 3,013 679 Total license and royalty revenue $ 19,138 $ 22,218 Outstanding development milestone payments are evaluated each reporting period and are only included in the transaction price of each license and recognized as license revenue to the extent the milestones are considered probable of achievement. Sales-based milestones are excluded from the transaction price of each license agreement and recognized as royalty revenue in the period of achievement. As of March 31, 2023, the Company’s license agreements, excluding additional licenses that could be granted upon the exercise of options by licensees, contained unachieved milestones which could result in aggregate milestone payments to the Company of up to $ 1.56 billion, including (i) $ 537.8 million upon the commencement of various stages of clinical trials, (ii) $ 17.0 million upon the submission of regulatory approval filings, (iii) $ 133.0 million upon the approval of commercial products by regulatory agencies and (iv) $ 875.0 million upon the achievement of specified sales targets for licensed products, including milestones payable upon the first commercial sales of licensed products. To the extent the milestone payments are realized by the Company, the Company will be obligated to pay sublicense fees to licensors based on a specified percentage of the fees earned by the Company. The achievement of these milestones is highly dependent on the successful development and commercialization of licensed products and it is at least reasonably possible that some or all of the milestone fees will not be realized by the Company. Changes in Accounts Receivable, Contract Assets and Deferred Revenue The following table presents the balances of the Company’s net accounts receivable, contract assets and deferred revenue, as well as other information regarding revenue recognized during the periods presented (in thousands): Three Months Ended March 31, 2023 2022 Accounts receivable, net, current and non-current: Beginning of period $ 29,586 $ 34,701 End of period $ 20,161 $ 29,106 Contract assets: Beginning of period $ — $ 1,074 End of period $ 2,000 $ 1,126 Deferred revenue, current and non-current: Beginning of period $ 1,829 $ 3,333 End of period $ 1,311 $ 3,333 Revenue recognized during the period from: Amounts included in deferred revenue at beginning of period $ 930 $ — Performance obligations satisfied in previous periods $ 18,132 $ 21,541 Contract assets as of March 31, 2023 are included in other current assets on the consolidated balance sheet. The Company did no t record any contract assets as of December 31, 2022. As of March 31, 2023, the Company had recorded deferred revenue of $ 1.3 million which represents consideration received or unconditionally due from licensees for performance obligations that have not yet been satisfied by the Company. Unsatisfied performance obligations as of March 31, 2023 consisted of research and development services to be performed by the Company related to licensed products, which will be satisfied as the research and development services are performed. As of March 31, 2023, the aggregate transaction price of the Company’s license agreements allocated to performance obligations not yet satisfied, or partially satisfied, was $ 2.7 million, which is expected to be satisfied over a period of approximately two years . Revenue recognized from performance obligations satisfied in previous periods, as presented in the table above, was primarily attributable to Zolgensma royalties and changes in the transaction prices of the Company’s license agreements. Changes in transaction prices were primarily attributable to development milestones achieved or deemed probable of achievement during the periods which were previously not considered probable of achievement, resulting in a cumulative catch-up adjustment to revenue. Revenue recognized during the three months ended March 31, 2023 and 2022 resulting from performance obligations satisfied in previous periods included $ 2.0 million and zero , respectively, in cumulative catch-up adjustments for changes in the probability of achievement of development milestones. Accounts Receivable, Contract Assets and the Allowance for Credit Losses Accounts receivable, net consisted of the following (in thousands): March 31, 2023 December 31, 2022 Current accounts receivable: Billed to customers $ 250 $ 280 Unbilled Zolgensma royalties 17,809 27,027 Other unbilled 802 775 Allowance for credit losses — — Current accounts receivable, net 18,861 28,082 Non-current accounts receivable: Due from Abeona, net of present value discount 4,256 4,152 Other unbilled 1,300 1,504 Allowance for credit losses ( 4,256 ) ( 4,152 ) Non-current accounts receivable, net 1,300 1,504 Total accounts receivable, net $ 20,161 $ 29,586 The following table presents the changes in the allowance for credit losses related to accounts receivable and contract assets for the three months ended March 31, 2023 (in thousands): Allowance for Credit Losses Accounts Receivable Contract Assets Balance at December 31, 2022 $ 4,152 $ — Changes in present value discount of receivables 104 — Balance at March 31, 2023 $ 4,256 $ — The Company’s allowance for credit losses as of March 31, 2023 and December 31, 2022 was related solely to accounts receivable from Abeona Therapeutics Inc. (Abeona). Please refer to the section below, Settlement Agreement with Abeona Therapeutics, for further information regarding amounts due from Abeona and the associated allowance for credit losses. The Company did no t record a provision for credit losses for the three months ended March 31, 2023 and 2022. Zolgensma License with Novartis Gene Therapies In March 2014, the Company entered into an exclusive license agreement (as amended, the Novartis License) with Novartis Gene Therapies (formerly AveXis, Inc.). Under the Novartis License, the Company granted Novartis Gene Therapies an exclusive, worldwide commercial license, with rights to sublicense, to the NAV Technology Platform, as well as other certain rights, for the treatment of spinal muscular atrophy (SMA) in humans by in vivo gene therapy. In 2019, Novartis Gene Therapies launched commercial sales of Zolgensma, a licensed product under the Novartis License. In accordance with the Novartis License, the Company recognizes royalty revenue on net sales of Zolgensma. The Company recognized the following amounts under the Novartis License (in thousands): Three Months Ended March 31, 2023 2022 Zolgensma royalties $ 16,125 $ 21,539 Total license and royalty revenue $ 16,125 $ 21,539 Interest income from licensing $ 8 $ 5 As of March 31, 2023 and December 31, 2022, the Company had recorded total accounts receivable of $ 18.0 million and $ 27.3 million, respectively, from Novartis Gene Therapies under the Novartis License, which consisted primarily of Zolgensma royalties receivable. The Zolgensma royalties receivable recorded as of March 31, 2023 included $ 13.0 million expected to be paid to HCR in accordance with the Royalty Purchase Agreement discussed in Note 6. The Company recognizes royalty revenue from net sales of Zolgensma in the period in which the underlying products are sold by Novartis Gene Therapies, which in certain cases may require the Company to estimate royalty revenue for periods of net sales which have not yet been reported to the Company. Estimated royalties are reconciled to actual amounts reported in subsequent periods, and any differences are recognized as an adjustment to royalty revenue in the period the royalties are reported. Settlement Agreement with Abeona Therapeutics In November 2021, the Company entered into a settlement agreement and mutual release with Abeona (the Settlement Agreement) related to claims associated with a license agreement between the parties which was terminated in May 2020. The Settlement Agreement resolved all arbitration and legal proceedings and mutually released each party from any and all claims under the terminated license agreement. Pursuant to the Settlement Agreement, Abeona will pay the Company a total of $ 30.0 million as follows: (i) $ 20.0 million which was paid in November 2021, (ii) $ 5.0 which was paid in November 2022, and (iii) $ 5.0 million payable on the earlier of the third anniversary of the Settlement Agreement in November 2024 or the closing of a specified type of transaction by Abeona. As of March 31, 2023 and December 31, 2022, the Company had recorded gross, non-current accounts receivable of $ 4.3 million and $ 4.2 million, respectively, from Abeona under the Settlement Agreement. The gross accounts receivable of $ 4.3 million as of March 31, 2023 consisted of the $ 5.0 million payment due by November 2024, net of discount to present value. While the Company anticipates taking appropriate measures to enforce the full collection of all amounts due from Abeona under the Settlement Agreement, the Company assessed the collectability of the accounts receivable from Abeona as it relates to credit risk. In performing this assessment, the Company evaluated Abeona’s credit profile and financial condition, as well its expectations regarding Abeona’s future cash flows and ability to satisfy the contractual obligations of the Settlement Agreement. As a result of its analysis, the Company recorded an allowance for credit losses of $ 4.3 million and $ 4.2 million as of March 31, 2023 and December 31, 2022, respectively, related to the non-current accounts receivable due from Abeona. No provision for credit losses was recorded for the three months ended March 31, 2023 and 2022 related to the receivable from Abeona. The present value discount of the non-current accounts receivable from Abeona is accreted as interest income from licensing through the contractual due date using the effective interest method. The Company has elected to record increases in the allowance for credit losses associated with the accretion of the present value discount of the receivable as a reduction of the associated interest income, resulting in no interest income recognized during the periods related to the accretion of the present value discount on the non-current receivable from Abeona. Collaboration Agreements AbbVie Collaboration and License Agreement Effective in November 2021, the Company entered into a collaboration and license agreement with AbbVie Global Enterprises Ltd. (AbbVie), a subsidiary of AbbVie Inc., to jointly develop and commercialize ABBV-RGX-314, the Company’s product candidate for the treatment of wet age-related macular degeneration (wet AMD), diabetic retinopathy (DR) and other chronic retinal diseases (the AbbVie Collaboration Agreement). Pursuant to the AbbVie Collaboration Agreement, the Company granted AbbVie a co-exclusive license to develop and commercialize ABBV-RGX-314 in the United States and an exclusive license to develop and commercialize ABBV-RGX-314 outside the United States. The Company and AbbVie will collaborate to develop ABBV-RGX-314 in the United States, and AbbVie will be responsible for the development of ABBV-RGX-314 in specified markets outside the United States. Through December 31, 2022, the Company was responsible for the development expenses related to certain ongoing clinical trials of ABBV-RGX-314 and the parties shared the additional development expenses related to ABBV-RGX-314. Beginning on January 1, 2023, AbbVie is responsible for the majority of all ABBV-RGX-314 development expenses. The Company will lead the manufacturing of ABBV-RGX-314 for clinical development and U.S. commercial supply, and AbbVie will lead the manufacturing of ABBV-RGX-314 for commercial supply outside the United States. Manufacturing expenses will be allocated between the parties in accordance with the terms of the AbbVie Collaboration Agreement and supply agreements determined in accordance with the agreement. If requested by AbbVie, the Company will manufacture up to a specified portion of ABBV-RGX-314 for commercial supply outside the United States at a price specified in the agreement. AbbVie will lead the commercialization of ABBV-RGX-314 globally, and the Company will participate in U.S. commercialization efforts as provided under a commercialization plan determined in accordance with the agreement. The Company and AbbVie will share equally in the net profits and net losses associated with the commercialization of ABBV-RGX-314 in the United States. Outside the United States, AbbVie will be responsible, at its sole cost, for the commercialization of ABBV-RGX-314. In consideration for the rights granted under the AbbVie Collaboration Agreement, AbbVie paid the Company an up-front fee of $ 370.0 million upon the effective date of the agreement in November 2021 and is required to pay to the Company up to $ 1.38 billion upon the achievement of specified development and sales-based milestones, of which $ 562.5 million are based on development milestones and $ 820.0 million are sales-based milestones. AbbVie is also required to pay to the Company tiered royalties on net sales of ABBV-RGX-314 outside the United States at percentages in the mid-teens to low twenties, subject to specified offsets and reductions. The Company applied the requirements of Topic 606 to the AbbVie Collaboration Agreement for the units of account in which AbbVie was deemed to be a customer. The Company determined that there is only one material performance obligation under the agreement for the delivery of the intellectual property license to develop and commercialize ABBV-RGX-314 globally. The intellectual property licensed to AbbVie includes the rights to certain patents, data, know-how and other rights developed and owned by the Company, as well as other intellectual property rights exclusively licensed by the Company from various third parties. As of March 31, 2023 and December 31, 2022, the transaction price of the AbbVie Collaboration Agreement was $ 370.0 million, which consisted solely of the up-front payment received from AbbVie in November 2021. The $370.0 million transaction price was fully recognized as revenue upon the delivery of the license to AbbVie in November 2021. Variable consideration under the AbbVie Collaboration Agreement, which has been excluded from the transaction price, includes $ 562.5 million in payments for development milestones that have not yet been achieved and were not considered probable of achievement. Additionally, the transaction price excludes sales-based milestone payments of $ 820.0 million and royalties on net sales of ABBV-RGX-314 outside the United States. Development milestones will be added to the transaction price and recognized as revenue upon achievement, or if deemed probable of achievement. In accordance with the sale- or usage-based royalty exception under Topic 606, royalties on net sales and sales-based milestones will be recognized as revenue in the period the underlying sales occur or milestones are achieved. There were no changes in the transaction price of the AbbVie Collaboration Agreement, and no revenue was recognized, during the three months ended March 31, 2023 and 2022. The Company applied the requirements of Topic 808 to the AbbVie Collaboration Agreement for the units of account which were deemed to be a collaborative arrangement. Both the Company and AbbVie will perform various activities related to the development, manufacturing and commercialization of ABBV-RGX-314 in the United States. Development costs are shared between the parties in accordance with the terms of the AbbVie Collaboration Agreement, and the parties will share equally in the net profits and losses derived from sales of ABBV-RGX-314 in the United States. The Company accounts for payments to and from AbbVie for the sharing of development and commercialization costs in accordance with its accounting policy for collaborative arrangements. Amounts owed to AbbVie for the Company’s share of development costs or commercialization costs incurred by AbbVie are recorded as research and development expense or general and administrative expense, respectively, in the period the costs are incurred. Amounts owed to the Company for AbbVie’s share of development costs or commercialization costs incurred by the Company are recorded as a reduction of research and development expense or general and administrative expense, respectively, in the period the costs are incurred. At the end of each reporting period, the Company records a net amount due to or from AbbVie as a result of the cost-sharing arrangement. As of March 31, 2023 and December 31, 2022, the Company had recorded $ 18.2 million and $ 6.2 million, respectively, due from AbbVie for net reimbursement of costs incurred for activities performed under AbbVie Collaboration Agreement, which was included in other current assets on the consolidated balance sheets. The Company recognized the following amounts under the AbbVie Collaboration Agreement (in thousands): Three Months Ended March 31, 2023 2022 Net cost reimbursement to (from) AbbVie included in: Research and development expense $ ( 18,474 ) $ ( 2,882 ) General and administrative expense 142 ( 92 ) Total net cost reimbursement to (from) AbbVie $ ( 18,332 ) $ ( 2,974 )

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2023
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	9. Stock-based Compensation Effective January 2023, an additional 1,731,940 shares were authorized for issuance under the 2015 Equity Incentive Plan (the 2015 Plan). As of March 31, 2023, the total number of shares of common stock authorized for issuance under the 2015 Plan and the 2014 Stock Plan (the 2014 Plan) was 17,357,140 , of which 2,261,930 remained available for future grants under the 2015 Plan. Stock-based Compensation Expense The Company’s stock-based compensation expense by award type was as follows (in thousands): Three Months Ended March 31, 2023 2022 Stock options $ 8,177 $ 9,267 Restricted stock units 2,781 1,254 Employee stock purchase plan 248 279 $ 11,206 $ 10,800 As of March 31, 2023, the Company had $ 91.8 million of unrecognized stock-based compensation expense related to stock options, restricted stock units and the 2015 Employee Stock Purchase Plan (the 2015 ESPP), which is expected to be recognized over a weighted-average period of 2.8 years. The Company recorded aggregate stock-based compensation expense in the consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended March 31, 2023 2022 Research and development $ 6,070 $ 5,670 General and administrative 5,136 5,130 $ 11,206 $ 10,800 Stock Options The following table summarizes stock option activity under the 2014 Plan and 2015 Plan (in thousands, except per share data): Weighted- average Weighted- Remaining average Contractual Aggregate Exercise Life Intrinsic Shares Price (Years) Value (a) Outstanding at December 31, 2022 7,668 $ 34.43 6.5 $ 15,783 Granted 1,485 $ 22.27 Exercised ( 37 ) $ 12.68 Cancelled or forfeited ( 120 ) $ 33.47 Outstanding at March 31, 2023 8,996 $ 32.52 6.8 $ 10,274 Exercisable at March 31, 2023 5,739 $ 33.83 5.6 $ 10,274 Vested and expected to vest at March 31, 2023 8,996 $ 32.52 6.8 $ 10,274 (a) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money at the dates reported. The weighted-average grant date fair value per share of options granted during the three months ended March 31, 2023 was $ 13.97 . During the three months ended March 31, 2023, the total number of stock options exercised was 37,150 , resulting in total proceeds of $ 0.5 million. The total intrinsic value of options exercised during the three months ended March 31, 2023 was $ 0.4 million. Restricted Stock Units The following table summarizes restricted stock unit activity under the 2015 Plan (in thousands, except per share data): Weighted-average Grant Date Shares Fair Value Unvested balance at December 31, 2022 613 $ 35.41 Granted 957 $ 22.27 Vested ( 118 ) $ 39.19 Forfeited ( 37 ) $ 27.62 Unvested balance at March 31, 2023 1,415 $ 26.41 The total intrinsic value of restricted stock units vested during the three months ended March 31, 2023 was $ 2.7 million. Employee Stock Purchase Plan As of March 31, 2023, the total number of shares of common stock authorized for issuance under the 2015 ESPP was 1,426,994 , of which 1,091,529 remained available for future issuance. During the three months ended March 31, 2023 , 30,223 shares of common stock were issued under the 2015 ESPP.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The Company evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets as of March 31, 2023 and December 31, 2022. Based on the Company’s history of operating losses, and other relevant facts and circumstances, the Company concluded that it was more likely than not that the benefit of its deferred tax assets will not be realized. Accordingly, the Company provided a full valuation allowance for its net deferred tax assets as of March 31, 2023 and December 31, 2022.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	11. Related Party Transactions FOXKISER LLP From 2016 until June 2022, the Company was a party to professional services agreements with FOXKISER LLP (FOXKISER), an affiliate of certain stockholders of the Company and an affiliate of a member of the Company’s Board of Directors, pursuant to which the Company paid a fixed monthly fee in consideration for certain strategic services provided by FOXKISER. The agreement with FOXKISER was terminated effective June 2022. Expenses incurred under the agreement with FOXKISER were zero and $ 1.2 million for the three months ended March 31, 2023 and 2022, respectively, and were recorded as research and development expenses in the consolidated statements of operations and comprehensive loss.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	12. Net Loss Per Share Since the Company incurred net losses for the three months ended March 31, 2023 and 2022, common stock equivalents were excluded from the calculation of diluted net loss per share for such periods as their effect would be anti-dilutive. Accordingly, basic and diluted net loss per share were the same for such periods. The following potentially dilutive common stock equivalents outstanding at the end of the period were excluded from the computations of weighted-average diluted common shares for the periods indicated as their effects would be anti-dilutive (in thousands): Three Months Ended March 31, 2023 2022 Stock options issued and outstanding 8,996 8,172 Unvested restricted stock units outstanding 1,415 471 Employee stock purchase plan 58 37 10,469 8,680

Supplemental Disclosures

Supplemental Disclosures	3 Months Ended
	Mar. 31, 2023
Payables And Accruals [Abstract]
Supplemental Disclosures	13. Supplemental Disclosures Other Current Assets Other current assets consisted of the following (in thousands): March 31, 2023 December 31, 2022 Net cost reimbursement due from collaborators $ 18,362 $ 6,294 Accrued interest on investments 2,004 2,210 License revenue contract assets 2,000 — Other 637 848 $ 23,003 $ 9,352 Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2023 December 31, 2022 Accrued external research and development expenses $ 11,261 $ 9,216 Accrued personnel costs 8,678 18,071 Accrued sublicense fees and royalties 7,281 15,768 Accrued external general and administrative expenses 2,577 2,187 Accrued purchases of property and equipment 913 806 Other accrued expenses and current liabilities 999 746 $ 31,709 $ 46,794 Supplemental Disclosures of Non-cash Investing and Financing Activities Purchases of property and equipment included in accounts payable and accrued expenses and other current liabilities were $ 1.8 million as of March 31, 2023, a net decrease of $ 0.8 million from December 31, 2022, and $ 5.4 million as of March 31, 2022, a net decrease of $ 4.7 million from December 31, 2021. Proceeds due to the Company for sales of non-marketable equity securities included in other current assets as of March 31, 2022 were $ 0.6 million. No such amounts were recorded as of March 31, 2023.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). The interim unaudited consolidated financial statements have been prepared on the same basis as the annual audited consolidated financial statements as of and for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, which was filed with the SEC on February 28, 2023. Certain information and footnote disclosures required by GAAP which are normally included in the Company’s annual consolidated financial statements have been omitted pursuant to SEC rules and regulations for interim reporting. In the opinion of management, the accompanying consolidated financial statements reflect all adjustments, which are normal and recurring in nature, necessary for fair financial statement presentation. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year, any other interim periods, or any future year or period. These interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2022, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosure of contingent assets and liabilities for the periods presented. Management bases its estimates on historical experience and various other factors that it believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities, and other reported amounts, that are not readily apparent from other sources. Actual results may differ materially from these estimates. Significant estimates are used in the following areas, among others: license and royalty revenue, the allowance for credit losses, accrued research and development expenses and other accrued liabilities, stock-based compensation expense, interest expense under the liability related to the sale of future royalties, income taxes and the fair value of financial instruments.
Reclassifications	Reclassifications Certain amounts reported in prior periods have been reclassified to conform to current period financial statement presentation. These reclassifications are not material and have no effect on previously reported financial position, results of operations and cash flows.
Restricted Cash	Restricted Cash Restricted cash includes money market mutual funds and other deposits used to collateralize irrevocable letters of credit required under the Company’s lease agreements and certain other agreements with third parties. The following table provides a reconciliation of cash and cash equivalents and restricted cash as reported on the consolidated balance sheets to the total of these amounts as reported at the end of the period in the consolidated statements of cash flows (in thousands): As of March 31, 2023 2022 Cash and cash equivalents $ 70,091 $ 191,873 Restricted cash 2,030 2,030 Total cash and cash equivalents and restricted cash $ 72,121 $ 193,903
Accounts Receivable	Accounts Receivable Accounts receivable primarily consist of consideration due to the Company resulting from its license agreements with customers. Accounts receivable include amounts invoiced to licensees as well as rights to consideration which have not yet been invoiced, including unbilled royalties, and for which payment is conditional solely upon the passage of time. If a licensee elects to terminate a license prior to the end of the license term, the licensed intellectual property is returned to the Company and any accounts receivable from the licensee which are not contractually payable to the Company are charged off as a reduction of license revenue in the period of the termination. Accounts receivable which are not expected to be received by the Company within 12 months from the reporting date are stated net of a discount to present value and recorded as non-current assets on the consolidated balance sheets. The present value discount is recognized as a reduction of revenue in the period in which the accounts receivable are initially recorded and is accreted as interest income from licensing over the term of the receivables. Accounts receivable are stated net of an allowance for credit losses, if deemed necessary based on the Company’s evaluation of collectability and potential credit losses. Management assesses the collectability of its accounts receivable using the specific identification of account balances, and considers the credit quality and financial condition of its significant customers, historical information regarding credit losses and the Company’s evaluation of current and expected future economic conditions. If necessary, an allowance for credit losses is recorded against accounts receivable such that the carrying value of accounts receivable reflects the net amount expected to be collected. Accounts receivable balances are written off against the allowance for credit losses when the potential for collectability is considered remote. Please refer to Note 8 for further information regarding the allowance for credit losses related to accounts receivable.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. Accounting Standards Codification (ASC) 820, Fair Value Measurements and Disclosures , establishes a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The three levels of the fair value hierarchy are described below: • Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2—Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. • Level 3—Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The fair values of the Company’s Level 2 instruments are based on quoted market prices or broker or dealer quotations for similar assets. These investments are initially valued at the transaction price and subsequently valued utilizing third party pricing providers or other market observable data. Please refer to Note 4 for further information on the fair value measurement of the Company’s financial instruments.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss applicable to common stockholders by the weighted-average common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting the weighted-average common shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. Contingently convertible shares in which conversion is based on non-market-priced contingencies are excluded from the calculations of both basic and diluted net loss per share until the contingency has been fully met. For purposes of the diluted net loss per share calculation, common stock equivalents are excluded from the calculation of diluted net loss per share if their effect would be anti-dilutive.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Reconciliation of Cash and Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash and cash equivalents and restricted cash as reported on the consolidated balance sheets to the total of these amounts as reported at the end of the period in the consolidated statements of cash flows (in thousands): As of March 31, 2023 2022 Cash and cash equivalents $ 70,091 $ 191,873 Restricted cash 2,030 2,030 Total cash and cash equivalents and restricted cash $ 72,121 $ 193,903

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2023
Investments Debt And Equity Securities [Abstract]
Summary of Company Marketable Securities	The following tables present a summary of the Company’s marketable securities, which consist solely of available-for-sale debt securities (in thousands): Amortized Cost Unrealized Unrealized Fair Value March 31, 2023 U.S. government and agency securities $ 101,176 $ — $ ( 2,567 ) $ 98,609 Certificates of deposit 7,554 — ( 221 ) 7,333 Corporate bonds 305,468 5 ( 7,980 ) 297,493 $ 414,198 $ 5 $ ( 10,768 ) $ 403,435 Amortized Cost Unrealized Unrealized Fair Value December 31, 2022 U.S. government and agency securities $ 134,485 $ — $ ( 3,492 ) $ 130,993 Certificates of deposit 7,555 1 ( 248 ) 7,308 Corporate bonds 340,752 — ( 10,803 ) 329,949 $ 482,792 $ 1 $ ( 14,543 ) $ 468,250
Summary of unrealized loss on available-for-sale securities, net, presented in the consolidated statements of operations and comprehensive loss	Unrealized gain (loss) on available-for-sale securities, net, as presented in the consolidated statements of operations and comprehensive loss consisted of the following (in thousands): Three Months Ended March 31, 2023 2022 Unrealized gain (loss) before reclassifications $ 3,779 $ ( 9,381 ) Realized losses (gains) reclassified to investment income — — Income tax expense — — Unrealized gain (loss) on available-for-sale securities, net $ 3,779 $ ( 9,381 )
Summary of Fair Values and Unrealized Losses of Marketable Securities Held by the Company in an Unrealized Loss Position for Less Than 12 months and 12 Months or Greater	The following tables present the fair values and unrealized losses of available-for-sale debt securities held by the Company in an unrealized loss position for less than 12 months and 12 months or greater (in thousands): Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized March 31, 2023 U.S. government and agency securities $ 33,920 $ ( 386 ) $ 64,689 $ ( 2,181 ) $ 98,609 $ ( 2,567 ) Certificates of deposit 3,379 ( 51 ) 3,484 ( 170 ) 6,863 ( 221 ) Corporate bonds 8,082 ( 168 ) 288,197 ( 7,812 ) 296,279 ( 7,980 ) $ 45,381 $ ( 605 ) $ 356,370 $ ( 10,163 ) $ 401,751 $ ( 10,768 ) Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized December 31, 2022 U.S. government and agency securities $ 91,498 $ ( 2,014 ) $ 38,495 $ ( 1,478 ) $ 129,993 $ ( 3,492 ) Certificates of deposit 4,484 ( 144 ) 2,087 ( 104 ) 6,571 ( 248 ) Corporate bonds 106,707 ( 3,866 ) 223,242 ( 6,937 ) 329,949 ( 10,803 ) $ 202,689 $ ( 6,024 ) $ 263,824 $ ( 8,519 ) $ 466,513 $ ( 14,543 )

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Cash Equivalents and Marketable Securities	The following tables present the fair value of cash equivalents and marketable securities in accordance with the hierarchy discussed in Note 2 (in thousands): Quoted Significant prices other Significant in active observable unobservable markets inputs inputs (Level 1) (Level 2) (Level 3) Total March 31, 2023 Cash equivalents: Money market mutual funds $ — $ 35,777 $ — $ 35,777 Total cash equivalents — 35,777 — 35,777 Marketable securities: U.S. government and agency securities — 98,609 — 98,609 Certificates of deposit — 7,333 — 7,333 Corporate bonds — 297,493 — 297,493 Total marketable securities — 403,435 — 403,435 Total cash equivalents and marketable securities $ — $ 439,212 $ — $ 439,212 Quoted Significant prices other Significant in active observable unobservable markets inputs inputs (Level 1) (Level 2) (Level 3) Total December 31, 2022 Cash equivalents: Money market mutual funds $ — $ 58,611 $ — $ 58,611 Corporate bonds — 993 — 993 Total cash equivalents — 59,604 — 59,604 Marketable securities: U.S. government and agency securities — 130,993 — 130,993 Certificates of deposit — 7,308 — 7,308 Corporate bonds — 329,949 — 329,949 Total marketable securities — 468,250 — 468,250 Total cash equivalents and marketable securities $ — $ 527,854 $ — $ 527,854

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2023
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment, net consists of the following (in thousands): March 31, 2023 December 31, 2022 Laboratory and manufacturing equipment $ 73,456 $ 71,801 Computer equipment and software 5,645 4,910 Furniture and fixtures 6,968 6,965 Leasehold improvements 101,071 99,397 Total property and equipment 187,140 183,073 Accumulated depreciation and amortization ( 45,567 ) ( 41,388 ) Property and equipment, net $ 141,573 $ 141,685

Liability Related to Sale of _2

Liability Related to Sale of Future Royalties (Tables)	3 Months Ended
	Mar. 31, 2023
Liability Related To Sale Of Future Royalties [Abstract]
Schedule of Changes in Liability Related to Sale of Future Royalties	The following table presents the changes in the liability related to the sale of future royalties under the Royalty Purchase Agreement with HCR (in thousands): Liability Related to Sale of Future Royalties Balance at December 31, 2022 $ 137,606 Zolgensma royalties paid to HCR ( 13,001 ) Interest expense recognized 2,505 Balance at March 31, 2023 127,110 Current portion of liability related to sale of future royalties ( 49,728 ) Non-current portion of liability related to sale of future royalties $ 77,382

License and Collaboration Agr_2

License and Collaboration Agreements (Tables)	3 Months Ended
	Mar. 31, 2023
Schedule Of License and Royalty Revenue	License and royalty revenue consisted of the following (in thousands): Three Months Ended March 31, 2023 2022 Zolgensma royalties $ 16,125 $ 21,539 Other license and royalty revenue 3,013 679 Total license and royalty revenue $ 19,138 $ 22,218
Summary of Changes in Balances of Receivables, Contract Assets and Deferred Revenue	The following table presents the balances of the Company’s net accounts receivable, contract assets and deferred revenue, as well as other information regarding revenue recognized during the periods presented (in thousands): Three Months Ended March 31, 2023 2022 Accounts receivable, net, current and non-current: Beginning of period $ 29,586 $ 34,701 End of period $ 20,161 $ 29,106 Contract assets: Beginning of period $ — $ 1,074 End of period $ 2,000 $ 1,126 Deferred revenue, current and non-current: Beginning of period $ 1,829 $ 3,333 End of period $ 1,311 $ 3,333 Revenue recognized during the period from: Amounts included in deferred revenue at beginning of period $ 930 $ — Performance obligations satisfied in previous periods $ 18,132 $ 21,541
Summary of Accounts Receivables, net	Accounts receivable, net consisted of the following (in thousands): March 31, 2023 December 31, 2022 Current accounts receivable: Billed to customers $ 250 $ 280 Unbilled Zolgensma royalties 17,809 27,027 Other unbilled 802 775 Allowance for credit losses — — Current accounts receivable, net 18,861 28,082 Non-current accounts receivable: Due from Abeona, net of present value discount 4,256 4,152 Other unbilled 1,300 1,504 Allowance for credit losses ( 4,256 ) ( 4,152 ) Non-current accounts receivable, net 1,300 1,504 Total accounts receivable, net $ 20,161 $ 29,586
Summary of Changes in Allowance For Credit Losses	The following table presents the changes in the allowance for credit losses related to accounts receivable and contract assets for the three months ended March 31, 2023 (in thousands): Allowance for Credit Losses Accounts Receivable Contract Assets Balance at December 31, 2022 $ 4,152 $ — Changes in present value discount of receivables 104 — Balance at March 31, 2023 $ 4,256 $ —
Schedule of AbbVie Collaboration Agreement	The Company recognized the following amounts under the AbbVie Collaboration Agreement (in thousands): Three Months Ended March 31, 2023 2022 Net cost reimbursement to (from) AbbVie included in: Research and development expense $ ( 18,474 ) $ ( 2,882 ) General and administrative expense 142 ( 92 ) Total net cost reimbursement to (from) AbbVie $ ( 18,332 ) $ ( 2,974 )
Novartis Gene Therapies [Member]
Schedule Of License and Royalty Revenue	The Company recognized the following amounts under the Novartis License (in thousands): Three Months Ended March 31, 2023 2022 Zolgensma royalties $ 16,125 $ 21,539 Total license and royalty revenue $ 16,125 $ 21,539 Interest income from licensing $ 8 $ 5

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Stock-Based Compensation Expense by Award Type	The Company’s stock-based compensation expense by award type was as follows (in thousands): Three Months Ended March 31, 2023 2022 Stock options $ 8,177 $ 9,267 Restricted stock units 2,781 1,254 Employee stock purchase plan 248 279 $ 11,206 $ 10,800
Stock-Based Compensation Expense	The Company recorded aggregate stock-based compensation expense in the consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended March 31, 2023 2022 Research and development $ 6,070 $ 5,670 General and administrative 5,136 5,130 $ 11,206 $ 10,800
Summary of Unvested RSUs Activity Under 2015 Plan	The following table summarizes restricted stock unit activity under the 2015 Plan (in thousands, except per share data): Weighted-average Grant Date Shares Fair Value Unvested balance at December 31, 2022 613 $ 35.41 Granted 957 $ 22.27 Vested ( 118 ) $ 39.19 Forfeited ( 37 ) $ 27.62 Unvested balance at March 31, 2023 1,415 $ 26.41
2014 and 2015 Equity Incentive Plan [Member]
Summary of Stock Option Activity	The following table summarizes stock option activity under the 2014 Plan and 2015 Plan (in thousands, except per share data): Weighted- average Weighted- Remaining average Contractual Aggregate Exercise Life Intrinsic Shares Price (Years) Value (a) Outstanding at December 31, 2022 7,668 $ 34.43 6.5 $ 15,783 Granted 1,485 $ 22.27 Exercised ( 37 ) $ 12.68 Cancelled or forfeited ( 120 ) $ 33.47 Outstanding at March 31, 2023 8,996 $ 32.52 6.8 $ 10,274 Exercisable at March 31, 2023 5,739 $ 33.83 5.6 $ 10,274 Vested and expected to vest at March 31, 2023 8,996 $ 32.52 6.8 $ 10,274 (a) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money at the dates reported.

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Schedules for Computation of Diluted Weighted-Average Shares Outstanding	The following potentially dilutive common stock equivalents outstanding at the end of the period were excluded from the computations of weighted-average diluted common shares for the periods indicated as their effects would be anti-dilutive (in thousands): Three Months Ended March 31, 2023 2022 Stock options issued and outstanding 8,996 8,172 Unvested restricted stock units outstanding 1,415 471 Employee stock purchase plan 58 37 10,469 8,680

Supplemental Disclosures (Table

Supplemental Disclosures (Tables)	3 Months Ended
	Mar. 31, 2023
Payables And Accruals [Abstract]
Schedule of Other Current Assets	Other Current Assets Other current assets consisted of the following (in thousands): March 31, 2023 December 31, 2022 Net cost reimbursement due from collaborators $ 18,362 $ 6,294 Accrued interest on investments 2,004 2,210 License revenue contract assets 2,000 — Other 637 848 $ 23,003 $ 9,352
Schedules of Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2023 December 31, 2022 Accrued external research and development expenses $ 11,261 $ 9,216 Accrued personnel costs 8,678 18,071 Accrued sublicense fees and royalties 7,281 15,768 Accrued external general and administrative expenses 2,577 2,187 Accrued purchases of property and equipment 913 806 Other accrued expenses and current liabilities 999 746 $ 31,709 $ 46,794

Nature of Business - Additional

Nature of Business - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ (508,229)	$ (441,553)
Cash, cash equivalents and marketable securities	$ 473,500

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Summary of Reconciliation of Cash and Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 70,091	$ 96,952	$ 191,873
Restricted cash	2,030	$ 2,030	2,030
Total cash and cash equivalents and restricted cash	$ 72,121		$ 193,903

Marketable Securities - Summary

Marketable Securities - Summary of Company Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost / Cost	$ 414,198	$ 482,792
Unrealized Gains	5	1
Unrealized Losses	(10,768)	(14,543)
Fair Value	403,435	468,250
U.S. Government and Agency Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost / Cost	101,176	134,485
Unrealized Losses	(2,567)	(3,492)
Fair Value	98,609	130,993
Certificates of Deposit [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost / Cost	7,554	7,555
Unrealized Gains		1
Unrealized Losses	(221)	(248)
Fair Value	7,333	7,308
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost / Cost	305,468	340,752
Unrealized Gains	5
Unrealized Losses	(7,980)	(10,803)
Fair Value	$ 297,493	$ 329,949

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2023 USD ($) Security	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Investments Debt And Equity Securities [Abstract]
Available for sale debt securities remaining maturities greater than three years	$ 0		$ 0
Number of investment grade fixed income debt security | Security	122
Allowance for credit loss	$ 0		$ 0
Other-than-temporary impaired	$ 0	$ 0

Marketable Securities - Summa_2

Marketable Securities - Summary of unrealized loss on available-for-sale securities, net, presented in the consolidated statements of operations and comprehensive loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Investments Debt And Equity Securities [Abstract]
Unrealized gain (loss) before reclassifications	$ 3,779	$ (9,381)
Unrealized gain (loss) on available-for-sale securities, net	$ 3,779	$ (9,381)

Marketable Securities - Summa_3

Marketable Securities - Summary of Fair Values and Unrealized Losses of Marketable Securities Held by the Company in an Unrealized Loss Position for Less Than 12 months and 12 Months or Greater (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 45,381	$ 202,689
Less than 12 Months, Unrealized Losses	(605)	(6,024)
12 Months or Greater, Fair Value	356,370	263,824
12 Months or Greater, Unrealized Losses	(10,163)	(8,519)
Total, Fair Value	401,751	466,513
Total, Unrealized Losses	(10,768)	(14,543)
U.S. Government and Agency Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	33,920	91,498
Less than 12 Months, Unrealized Losses	(386)	(2,014)
12 Months or Greater, Fair Value	64,689	38,495
12 Months or Greater, Unrealized Losses	(2,181)	(1,478)
Total, Fair Value	98,609	129,993
Total, Unrealized Losses	(2,567)	(3,492)
Certificates of Deposit [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	3,379	4,484
Less than 12 Months, Unrealized Losses	(51)	(144)
12 Months or Greater, Fair Value	3,484	2,087
12 Months or Greater, Unrealized Losses	(170)	(104)
Total, Fair Value	6,863	6,571
Total, Unrealized Losses	(221)	(248)
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	8,082	106,707
Less than 12 Months, Unrealized Losses	(168)	(3,866)
12 Months or Greater, Fair Value	288,197	223,242
12 Months or Greater, Unrealized Losses	(7,812)	(6,937)
Total, Fair Value	296,279	329,949
Total, Unrealized Losses	$ (7,980)	$ (10,803)

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Fair Value of Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Marketable securities:
Fair Value	$ 403,435	$ 468,250
Cash Equivalents and Marketable Securities [Member]
Marketable securities:
Total cash equivalents and marketable securities	439,212	527,854
Corporate Bonds [Member]
Cash equivalents:
Total cash equivalents		993
Marketable securities:
Fair Value	297,493	329,949
Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	35,777	59,604
US Government and Agency Securities [Member]
Cash equivalents:
Total cash equivalents	98,609
Marketable securities:
Fair Value		130,993
Certificates of Deposit [Member]
Marketable securities:
Fair Value	7,333	7,308
Money Market Mutual Funds [Member] | Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	35,777	58,611
Significant Other Observable Inputs (Level 2) [Member]
Marketable securities:
Fair Value	403,435	468,250
Significant Other Observable Inputs (Level 2) [Member] | Cash Equivalents and Marketable Securities [Member]
Marketable securities:
Total cash equivalents and marketable securities	439,212	527,854
Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Cash equivalents:
Total cash equivalents		993
Marketable securities:
Fair Value	297,493	329,949
Significant Other Observable Inputs (Level 2) [Member] | Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	35,777	59,604
Significant Other Observable Inputs (Level 2) [Member] | US Government and Agency Securities [Member]
Cash equivalents:
Total cash equivalents	98,609
Marketable securities:
Fair Value		130,993
Significant Other Observable Inputs (Level 2) [Member] | Certificates of Deposit [Member]
Marketable securities:
Fair Value	7,333	7,308
Significant Other Observable Inputs (Level 2) [Member] | Money Market Mutual Funds [Member] | Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	$ 35,777	$ 58,611

Property and Equipment Net - Sc

Property and Equipment Net - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment	$ 187,140	$ 183,073
Accumulated depreciation and amortization	(45,567)	(41,388)
Property and equipment, net	141,573	141,685
Laboratory and Manufacturing Equipment [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	73,456	71,801
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	5,645	4,910
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	6,968	6,965
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	$ 101,071	$ 99,397

Liability Related to Sale of _3

Liability Related to Sale of Future Royalties - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Liability Related To Sale Of Future Royalties [Line Items]
Repurchase of call option amount	$ 300,000
Interest expense	2,755	$ 6,130
November 7, 2024
Liability Related To Sale Of Future Royalties [Line Items]
Repurchase of call option amount, before exercised	1,000
HCR [Member]
Liability Related To Sale Of Future Royalties [Line Items]
Proceeds from Royalties Received	4,000
Deferred Transaction Cost	3,500
Interest expense	$ 192,500
Interest Rate, Effective Percentage	7.70%
HCR [Member] | Other Noncurrent Liabilities
Liability Related To Sale Of Future Royalties [Line Items]
Proceeds from sale of future royalties	$ 196,000
HCR [Member] | November 7, 2024
Liability Related To Sale Of Future Royalties [Line Items]
Royalty Payment Cap Amount	260,000
HCR [Member] | November 8, 2024
Liability Related To Sale Of Future Royalties [Line Items]
Royalty Payment Cap Amount	300,000
HCR [Member] | Royalty Agreements
Liability Related To Sale Of Future Royalties [Line Items]
Purchase Agreement	$ 200,000

Liability Related to Sale of _4

Liability Related to Sale of Future Royalties -Schedule of Activity Within Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Liability Related To Sale Of Future Royalties [Line Items]
Current portion of liability related to sale of future royalties	$ (49,728)	$ (48,601)
Non-current portion of liability related to sale of future royalties	77,382	$ 89,005
Royalty Agreements
Liability Related To Sale Of Future Royalties [Line Items]
Balance at December 31, 2022	137,606
Zolgensma royalties paid to HCR	(13,001)
Interest expense recognized	2,505
Balance at March 31, 2023	127,110
Current portion of liability related to sale of future royalties	(49,728)
Non-current portion of liability related to sale of future royalties	$ 77,382

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - University of Pennsylvania [Member] $ in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2023 USD ($) Installment
Penn Letter Agreement [Member]
Other Commitments [Line Items]
Amount payable to agreement	$ 20	$ 20
Number of equal annual installments | Installment		4
Related party transaction expense	9.2
Present value of cost of revenue	17.3
Sublicense fees previously recognized	$ 8.1
Amount payable to net present value discount		$ 7.4
Penn Letter Agreement [Member] | Accrued Expenses and Other Current Liabilities [Member]
Other Commitments [Line Items]
Amount payable to net present value discount		2.2
Penn Letter Agreement [Member] | Other Liabilities [Member]
Other Commitments [Line Items]
Amount payable to net present value discount		5.2
Sublicense Fees Due Or Owed in Future [Member]
Other Commitments [Line Items]
Amount payable to agreement		8
Other Past or Future Obligations to Pay Sublicense Fees [Member]
Other Commitments [Line Items]
Amount payable to agreement		12
First Anniversary [Member]
Other Commitments [Line Items]
Amount payable to agreement		$ 3

License and Collaboration Agr_3

License and Collaboration Agreements - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Nov. 30, 2021 USD ($)	Mar. 31, 2023 USD ($) ProductCandidate	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
License Revenue [Line Items]
Milestone payment upon commencement of clinical trials in humans		$ 537,800,000
Milestone payment upon submission of regulatory approval filings		17,000,000
Milestone payment upon approval of commercial products by regulatory agencies		133,000,000
Milestone payment upon achievement of specified sales targets for licensed products		875,000,000
Deferred revenue, current and non-current		1,311,000	$ 3,333,000	$ 1,829,000	$ 3,333,000
Contract assets		2,000,000	1,126,000	0	$ 1,074,000
Aggregate transaction price of license agreements		$ 2,700,000
Aggregate transaction price of license agreements, expected satisfaction period		2 years
Revenue recognized upon achievement of development milestones		$ 2,000,000	0
Provision for credit losses		0	0
Accounts receivable, current		18,861,000		28,082,000
Accounts receivable, net		1,300,000		1,504,000
Other Current Assets [Member]
License Revenue [Line Items]
Net cost reimbursement due from collaborators		18,362,000		6,294,000
Due from Abeona		18,362,000		6,294,000
Abb Vie Collaboration And License Agreement
License Revenue [Line Items]
Up-front fee paid	$ 370,000,000
Milestone fee payments upon achievement of various development and commercialization	1,380,000,000
Transaction price of license		370,000,000		370,000,000
Change in transaction price		0
Abb Vie Collaboration And License Agreement | Other Current Assets [Member]
License Revenue [Line Items]
Net cost reimbursement due from collaborators		18,200,000		6,200,000
Due from Abeona		18,200,000		6,200,000
Novartis License Agreement [Member] | Novartis Gene Therapies [Member]
License Revenue [Line Items]
Accounts receivable		18,000,000		27,300,000
November Two Thousand Eighteen License Agreement | Abeona Therapeutics Incorporation | Contract Termination
License Revenue [Line Items]
Settlement agreement payable		30,000,000
November Two Thousand Twenty One License Agreement | Abeona Therapeutics Incorporation | Contract Termination
License Revenue [Line Items]
Settlement agreement payable		20,000,000
November Two Thousand Twenty Two License Agreement | Abeona Therapeutics Incorporation | Contract Termination
License Revenue [Line Items]
Settlement agreement payable		5,000,000
November Two Thousand Twenty Four License Agreement | Abeona Therapeutics Incorporation | Contract Termination
License Revenue [Line Items]
Settlement agreement payable		5,000,000
Settlement Agreement | Abeona Therapeutics Incorporation
License Revenue [Line Items]
Accounts receivable		4,300,000
Accounts receivable, Non-current		4,300,000		4,200,000
Payments due from related party		5,000,000
Allowance for credit losses		4,300,000		4,200,000
Provision for credit losses		0	$ 0
Sales Based Milestones | Abb Vie Collaboration And License Agreement
License Revenue [Line Items]
Milestone fee payments upon achievement of various development and commercialization	820,000,000
Transaction price of license		820,000,000		820,000,000
Development Milestone | Abb Vie Collaboration And License Agreement
License Revenue [Line Items]
Milestone fee payments upon achievement of various development and commercialization	$ 562,500,000
Transaction price of license		562,500,000		$ 562,500,000
Maximum [Member]
License Revenue [Line Items]
Aggregate milestone payment for all the targets		$ 1,560,000
N A V Technology Platform [Member]
License Revenue [Line Items]
Number of commercial product candidates | ProductCandidate		1
HCR [Member] | Novartis License Agreement [Member] | Novartis Gene Therapies [Member]
License Revenue [Line Items]
Accounts receivable, current		$ 13

License and Collaboration Agr_4

License and Collaboration Agreements - Schedule Of License and Royalty Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
License Revenue [Line Items]
Other license and royalty revenue	$ 3,013	$ 679
Total license and royalty revenue	19,138	22,218
Zolgensma Royalties [Member]
License Revenue [Line Items]
Zolgensma royalties	$ 16,125	$ 21,539

License and Collaboration Agr_5

License and Collaboration Agreements - Summary of Changes in Balances of Receivables, Contract Assets and Deferred Revenue (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Accounts receivable, net, current and non-current:
Balance, beginning of period	$ 29,586,000	$ 34,701,000	$ 34,701,000
Balance, end of period	20,161,000	29,106,000	29,586,000
Contract assets:
Balance, beginning of period	0	1,074,000	1,074,000
Balance, end of period	2,000,000	1,126,000	0
Deferred revenue, current and non-current:
Balance, beginning of period	1,829,000	3,333,000	3,333,000
Balance, end of period	1,311,000	3,333,000	1,829,000
Revenue recognized during the period from:
Amounts included in deferred revenue at beginning of period			$ 930,000
Performance obligations satisfied in previous periods	$ 18,132,000	$ 21,541,000

License and Collaboration Agr_6

License and Collaboration Agreements - Summary of Accounts Recerivable, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current accounts receivable:
Billed to customers	$ 250	$ 280
Unbilled Zolgensma royalties	17,809	27,027
Other unbilled	802	775
Current accounts receivable, net	18,861	28,082
Non-current accounts receivable:
Due from Abeona, net of present value discount	4,256	4,152
Other unbilled	1,300	1,504
Allowance for credit losses	(4,256)	(4,152)
Non-current accounts receivable, net	1,300	1,504
Total accounts receivable, net	$ 20,161	$ 29,586

License and Collaboration Agr_7

License and Collaboration Agreements - Summary of Changes in Allowance For Credit Losses (Detail) - Accounts Receivable $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 4,152
Changes in present value discount of receivables	104
Ending Balance	$ 4,256

License and Collaboration Agr_8

License and Collaboration Agreements - Schedule Of License Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
License Revenue [Line Items]
Interest income from licensing	$ 70	$ 94
Novartis Gene Therapies [Member]
License Revenue [Line Items]
Total license and royalty revenue	16,125	21,539
Interest income from licensing	8	5
Zolgensma Royalties [Member]
License Revenue [Line Items]
Total license and royalty revenue	$ 16,125	$ 21,539

License and Collaboration Agr_9

License and Collaboration Agreements -Schedule of AbbVie Collaboration Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net cost reimbursement to (from) AbbVie included in:
Total net cost reimbursement to (from) AbbVie	$ (18,332)	$ (2,974)
Abb Vie Collaboration And License Agreement | Research and Development Expense [Member]
Net cost reimbursement to (from) AbbVie included in:
Total net cost reimbursement to (from) AbbVie	(18,474)	(2,882)
Abb Vie Collaboration And License Agreement | General and Administrative Expense [Member]
Net cost reimbursement to (from) AbbVie included in:
Total net cost reimbursement to (from) AbbVie	$ 142	$ 92

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2023	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense		$ 91.8
Unrecognized stock-based compensation, weighted-average period		2 years 9 months 18 days
Proceeds from stock options exercised including unsettled options		$ 0.5
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units vested		118,000
Total intrinsic values vested		$ 2.7
2015 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional shares to be issued	1,731,940
Common stock shares authorized for issuance		17,357,140
Shares available for future grants		2,261,930
Weighted-average fair values of options granted		$ 13.97
Exercise of stock options, net of tax, shares		37,150
Total intrinsic value of options exercised		$ 0.4
2015 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares authorized for issuance		1,426,994
Shares available for future grants		1,091,529
Common stock shares issued to participants		30,223

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-Based Compensation Expense by Award Type (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 11,206	$ 10,800
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	8,177	9,267
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	2,781	1,254
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 248	$ 279

Stock-based Compensation - St_2

Stock-based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 11,206	$ 10,800
Research and Development Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	6,070	5,670
General and Administrative Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 5,136	$ 5,130

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Stock Option Activity (Detail) - 2014 and 2015 Equity Incentive Plan [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Shares Outstanding, Beginning Balance	7,668
Shares, Granted	1,485
Shares, Exercised	(37)
Shares, Cancelled or forfeited	(120)
Shares Outstanding, Ending Balance	8,996	7,668
Shares, Exercisable	5,739
Shares, Vested and expected to vest	8,996
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted-average Exercise Price Outstanding, Beginning Balance	$ 34.43
Weighted-average Exercise Price, Granted	22.27
Weighted-average Exercise Price, Exercised	12.68
Weighted-average Exercise Price, Cancelled or forfeited	33.47
Weighted-average Exercise Price, Outstanding, Ending Balance	32.52	$ 34.43
Weighted-average Exercise Price, Exercisable	33.83
Weighted-average Exercise Price, Vested and expected to vest	$ 32.52
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-average Remaining Contractual Life (Years) Outstanding	6 years 9 months 18 days	6 years 6 months
Weighted-average Remaining Contractual Life (Years), Exercisable	5 years 7 months 6 days
Weighted-average Remaining Contractual Life (Years), Vested and expected to vest	6 years 9 months 18 days
Aggregate Intrinsic Value Outstanding	$ 10,274	$ 15,783
Aggregate Intrinsic Value, Exercisable	10,274
Aggregate Intrinsic Value, Vested and expected to vest	$ 10,274

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Unvested RSUs Activity Under 2015 Plan (Detail) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested balance at December 31, 2022 | shares	613,000
Shares, Granted | shares	957,000
Vested | shares	(118,000)
Forfeited | shares	(37,000)
Unvested balance at March 31, 2023 | shares	1,415,000
Weighted-average Grant Date Fair Value, Unvested Beginning Balance | $ / shares	$ 35.41
Weighted-average Grant Date Fair Value, Granted | $ / shares	22.27
Weighted-average Grant Date Fair Value, Vested | $ / shares	39.19
Weighted-average Grant Date Fair Value, Forfeited | $ / shares	27.62
Weighted-average Grant Date Fair Value, Unvested Ending Balance | $ / shares	$ 26.41

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
FOXKISER LLP [Member] | Service Agreements [Member] | Research and Development Expense [Member]
Related Party Transaction [Line Items]
Related party transaction expense	$ 0	$ 1,200,000

Net Loss Per Share - Schedules

Net Loss Per Share - Schedules for Computation of Diluted Weighted-Average Shares Outstanding (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted weighted average shares outstanding	10,469	8,680
Stock Options Issued and Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted weighted average shares outstanding	8,996	8,172
Unvested Restricted Stock Units Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted weighted average shares outstanding	1,415	471
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted weighted average shares outstanding	58	37

Supplemental Disclosures - Sche

Supplemental Disclosures - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Other Current Assets [Line Items]
Other current assets	$ 23,003	$ 9,352
Other Current Assets [Member]
Other Current Assets [Line Items]
Net cost reimbursement due from collaborators	18,362	6,294
Accrued Interest on Investments	2,004	2,210
License revenue contract assets	2,000
Other	637	848
Other current assets	$ 23,003	$ 9,352

Supplemental Disclosures - Sc_2

Supplemental Disclosures - Schedules of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Payables And Accruals [Abstract]
Accrued external research and development expenses	$ 11,261	$ 9,216
Accrued personnel costs	8,678	18,071
Accrued sublicense fees and royalties	7,281	15,768
Accrued external general and administrative expenses	2,577	2,187
Accrued purchases of property and equipment	913	806
Other accrued expenses and current liabilities	999	746
Accrued expenses and other current liabilities	$ 31,709	$ 46,794

Supplemental Disclosures - Addi

Supplemental Disclosures - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Payables And Accruals [Abstract]
Purchases of property and equipment included in accounts payable and accrued expenses and other current liabilities	$ 1,800,000
Increase (decrease) in purchases of property and equipment included in accounts payable and accrued expenses and other current liabilities		$ 5,400,000	$ 800,000	$ 4,700,000
Proceeds due to Company for sales of non-marketable equity securities	$ 0	$ 600,000