Significant Agreements - Alexion Option and License Agreement (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2021 USD ($) item	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 20, 2023 item	Mar. 04, 2022 item
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deductions		$ 0	$ 0	$ 40,000
Collaboration revenue		$ 80,001	$ 250,008	$ 40,907
Option and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of performance obligations | item						3
Number of material rights | item						3
Pfizer | Option and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment	$ 30,000
Non-refundable upfront payment received	30,000
Allocation of transaction price	15,000
Aggregate milestone payments, if exercise rights	$ 10,000
Pfizer | Second Material Right
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of days written notice required by reporting entity to terminate agreement	90 days
Pfizer | Pfizer Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of transgenes | item					2
Pfizer | Development, regulatory and commercialization milestone | Option and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate maximum milestone payments to be received from collaborative partner	$ 115,000
Pfizer | Sales milestone | Option and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate maximum milestone payments to be received from collaborative partner	$ 175,000
Alexion | Option and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of performance obligations | item	2
Number of material rights | item	2
Number of license options | item	1