Commitments and Contingencies - Additional Information (Detail) $ in Millions			1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 15, 2024 USD ($)	Jul. 18, 2024 USD ($)	Nov. 30, 2022 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2020 Suite	Oct. 31, 2018 Suite
Commitments And Contingencies [Line Items]
Amendment Implemented Fee				$ 60.0
First Installments [Member]
Commitments And Contingencies [Line Items]
Installments Date of implemented fee				Mar. 01, 2024
Amendment Implemented Fee				$ 20.0
US [Member]
Commitments And Contingencies [Line Items]
Loss Contingency Damages Awarded Value	$ 115.2
Royalty Damages	$ 0.8
Thermo Fisher Scientific, Inc. [Member]
Commitments And Contingencies [Line Items]
Research and development expense					$ 0.0	$ 0.0	$ 54.0
CRO [Member]
Commitments And Contingencies [Line Items]
Cancellable future commitments					594.5
CRO [Member] | Other Funding Commitments [Member]
Commitments And Contingencies [Line Items]
Expenditures incurred by CROs					110.1	$ 112.2	$ 78.7
Supply Agreement [Member] | Research and Development Expense [Member]
Commitments And Contingencies [Line Items]
Research and development expense					29.2
Supply Agreement [Member] | Thermo Fisher Scientific, Inc. [Member]
Commitments And Contingencies [Line Items]
Non-Cash Contract Termination Cost					$ 62.7
Supply Agreement [Member] | Thermo Fisher Scientific, Inc. [Member] | Research and Development Expense [Member]
Commitments And Contingencies [Line Items]
Research and development expense		$ 55.4
Catalent Agreements [Member]
Commitments And Contingencies [Line Items]
Recognition Of Right Of Use Asset			$ 19.2
Increase in long-term deposits manufacturing			$ 3.9
Catalent Agreements [Member] | Paragon [Member]
Commitments And Contingencies [Line Items]
Number of dedicated clean room suites | Suite								4	2
Number of additional clean room suites available on optional reserve | Suite									2
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. In January 2025, the Company modified certain terms of the Aldevron Agreements which extended the term of the agreement through December 31, 2028 (the “Aldevron Amendment”). As a result of the Aldevron Amendment, 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, 2028. Both parties have the right to early terminate without additional penalty. The Company has determined that the Aldevron Amendment does not contain an embedded lease because it does not convey the right to control the use of Aldevron’s facility or related equipment therein.
Roche Agreement [Member] | Thermo Fisher Scientific, Inc. [Member] | Research and Development Expense [Member]
Commitments And Contingencies [Line Items]
Research and development expense					$ 36.5