Commitments and Contingencies - Additional Information (Detail) $ in Thousands	1 Months Ended				12 Months Ended
	Nov. 30, 2022 USD ($)	Oct. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Oct. 31, 2018 Suite	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) Suite	Jun. 30, 2018 Suite	Jun. 30, 2018 mo
Commitments And Contingencies [Line Items]
Right of use assets					$ 64,954	$ 45,531
Thermo Fisher Scientific, Inc. [Member]
Commitments And Contingencies [Line Items]
Research and development expense					54,000	0	$ 0
CRO [Member]
Commitments And Contingencies [Line Items]
Cancellable future commitments					480,800
CRO [Member] | Other Funding Commitments [Member]
Commitments And Contingencies [Line Items]
Expenditures incurred by CROs					$ 78,700	$ 47,900	$ 40,400
Supply Agreement [Member] | Thermo Fisher Scientific, Inc. [Member]
Commitments And Contingencies [Line Items]
Number of dedicated clean room suites								4	4
Agreement expiration date				Dec. 31, 2028
Supply Agreement [Member] | Thermo Fisher Scientific, Inc. [Member] | Research and Development Expense [Member]
Commitments And Contingencies [Line Items]
Derecognition of right of use asset		$ 23,400
Derecognition of lease liabilities		20,100
Recognition of loss		3,300
Non refundable advance payments		$ 21,100
Catalent Agreements [Member]
Commitments And Contingencies [Line Items]
Recognition Of Lease Liabilities	$ 19,200
Recognition Of Right Of Use Asset	19,200
Increase in long-term deposits manufacturing	3,900
Decrease in short-term deposits manufacturing	$ 3,900
Catalent Agreements [Member] | Research and Development Expense [Member]
Commitments And Contingencies [Line Items]
Derecognition of right of use asset			$ 22,800
Derecognition of lease liabilities			20,000
Recognition of loss			$ 2,800
Catalent Agreements [Member] | Paragon [Member]
Commitments And Contingencies [Line Items]
Number of dedicated clean room suites | Suite				2			4
Number of additional clean room suites available on optional reserve | Suite				2
Agreement expiration date				Dec. 31, 2024
Clinical and Commercial Supply Agreement [Member] | Aldevron LLC [Member]
Commitments And Contingencies [Line Items]
Agreement expiration date					Dec. 31, 2026
Agreement expiration description					The Company has the option to extend the term of the Aldevron Agreements by one year if the Company delivers a written notice of its intention to extend to Aldevron no later than June 1, 2025. Both parties have the right to early terminate without additional penalty. The Company has determined that the Aldevron Agreements do not contain an embedded lease because it does not convey the right to control the use of Aldevron’s facility or related equipment therein.