License and Research Agreements - Additional Information (Details) - USD ($)			1 Months Ended						3 Months Ended					6 Months Ended		113 Months Ended
	Jan. 01, 2023	Jul. 01, 2022	Apr. 30, 2022	Jan. 31, 2022	May 31, 2021	Jan. 31, 2021	Mar. 31, 2020	Aug. 31, 2019	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue									$ 89,343,000		$ 86,975,000			$ 169,278,000	$ 186,370,000
Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue									4,400,000					4,400,000			$ 9,100,000
Revenue recognized									1,500,000					4,700,000
Revenue recognized											22,000,000.0				64,700,000
Receivable related to Daiichi Sankyo license agreement									0					$ 0			100,000
Regeneron
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payments of collaboration				$ 30,000,000.0
Intangible assets, remaining amortization period														10 years 6 months
Eligible future milestone payments				$ 63,000,000.0
Costs of goods sold related to amortization of intangible asset									700,000					$ 1,400,000
Development costs									1,300,000					$ 2,000,000.0
Sales										$ 0
Regeneron | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit loss sharing percentage on net sales														40.00%
Regeneron | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit loss sharing percentage on net sales				20.00%
Abeona
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development and transition costs														$ 2,100
Abeona | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Eligible future milestone payments									1,000.0					1,000.0
Product Sales
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue									30,832,000		18,346,000			$ 57,516,000	34,859,000
License and Collaboration Agreement | Mereo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment for in-process research and development expense												$ 50,000,000.0
Payments made under agreement						$ 50,000,000.0
License and Collaboration Agreement | Maximum | Mereo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future contingent milestone payments						$ 254,000,000.0
License and Collaboration Agreement | Abeona
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales receives														10.00%
Commercial milestone payments					$ 30,000,000.0
Kyowa Kirin Collaboration | License Agreement | Prepaid Expenses and Other Current Assets
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement other receivables									2,900,000					$ 2,900,000			16,000,000.0
Kyowa Kirin Collaboration | License Agreement | Product Sales
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue									12,400,000		$ 2,900,000			21,800,000	$ 8,800,000
Kyowa Kirin Collaboration | License Agreement | Profit Share Revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement accounts receivable									20,100,000					20,100,000			20,200,000
Kyowa Kirin Collaboration | License Agreement | Commercial and Development Activity Reimbursements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement accrued liabilities									$ 4,800,000					$ 4,800,000			$ 2,300,000
Kyowa Kirin Collaboration | License Agreement | Scenario Forecast
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit loss sharing percentage on net sales	30.00%															35.00%
Kyowa Kirin Collaboration | License Agreement | Profit Share Territory
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of right to receive royalty payments on net sales		30.00%
Remaining profit or loss share percentage on commercializing products														50.00%
Kyowa Kirin Collaboration | License Agreement | Profit Share Territory | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Tiered double-digit revenue share percentage entitled to receive														30.00%
Kyowa Kirin Collaboration | License Agreement | Profit Share Territory | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Tiered double-digit revenue share percentage entitled to receive														20.00%
Kyowa Kirin Collaboration | License Agreement | Royalty Revenue in European Territory
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales receives														10.00%
Program Agreement and Unitholder Option Agreement | GeneTx Biotherapeutics LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment for exclusive option to acquisition								$ 20,000,000.0
Business acquisition option exercise period, description														the Company made an upfront payment of $20.0 million for an exclusive option to acquire GeneTx, which was exercisable any time prior to 30 days following FDA acceptance of the IND for GTX-102.
Option extension Premium								$ 25,000,000.0
Acquisition cost			$ 75,000,000.0
License and Technology Access Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received														$ 125,000,000.0
Deferred revenue										$ 25,000,000.0
Premium from stock purchase agreement														19,700,000
Transaction price of license agreement														183,400,000
Estimated reimbursement of delivering license and technology services														5,700,000
License and Technology Access Agreement | PCL and HEK293 Platform | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue																		$ 25,000,000.0
License and Technology Access Agreement | License Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized														178,900,000
Stock Purchase Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock in connection with license agreement, net of issuance costs, shares													1,243,913
Proceeds from issuance of common stock in connection with license agreement													$ 75,000,000.0
Issuance of common stock in connection with license agreement, net of issuance costs							$ 55,300,000
Stock price							$ 44.43						$ 44.43
Premium from stock purchase agreement							$ 19,700,000
Sublicense Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received														$ 8,000,000.0