Leases - Additional Information (Details) $ in Thousands	1 Months Ended			12 Months Ended
	Sep. 30, 2023 USD ($)	Jul. 31, 2022 USD ($) ft²	May 31, 2022 USD ($) ft²	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Undiscounted minimum lease payments				$ 95,488
Research and development accrued expenses				133,849	$ 149,555
Finance lease liabilities, current				39,283	33,060
Finance lease liabilities, non-current					20,871
Right-of-use assets with no alternative future use				18,871	$ 63,321
Undiscounted finance lease value				$ 40,368
Lonza
Lessee, Lease, Description [Line Items]
Prior notification period to terminate arrangement				12 months
Finance lease expiration date				2024-12
Undiscounted finance lease value	$ 51,700
Discounted value using the expected payment timeline	$ 48,500
Incremental borrowing rate	10.80%
Increase in lease liability	$ 15,900
Redwood, California
Lessee, Lease, Description [Line Items]
Square feet of space | ft²			51,822
Lease term			11 years 8 months 12 days
Option to extend lease				The Redwood City lease provides for an optional five-year extension.
Option to extend lease term			5 years
Lease includes allowance for tenant improvements			$ 9,800
Rockville, Maryland
Lessee, Lease, Description [Line Items]
Square feet of space | ft²		57,902
Lease term		12 years 10 months 24 days
Option to extend lease				The Rockville lease provides for optional two five-year extensions.
Option to extend lease term		5 years
Lease includes allowance for tenant improvements		$ 12,100		$ 2,800
Tenant Improvement Allowance				$ 2,900
Office and Laboratory Space | Rockville, Maryland
Lessee, Lease, Description [Line Items]
Lease expiration year				2030