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Restructuring and Related Activities - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Restructuring, number of positions eliminated \| employee				47
Restructuring, number of positions eliminated, period, percent				32.00%
Research and development	$ 18,942	$ 27,692	$ 39,553	$ 63,223
Impairment of Leasehold		10,000	10,000
Asset, Impairment Loss	$ 0	12,150	0	12,150
Leasehold improvements
Restructuring Cost and Reserve [Line Items]
Impairment of Leasehold		7,400
Right Of Use Asset
Restructuring Cost and Reserve [Line Items]
Impairment of Leasehold		2,600
Lab equipment
Restructuring Cost and Reserve [Line Items]
Asset, Impairment Loss		2,200
Severance and Wind Down Costs
Restructuring Cost and Reserve [Line Items]
Research and development		$ 400		$ 400
Cash Severance Costs, Benefits, and Transition Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 1,800