License and Collaboration Agreements - Narrative (Details) - USD ($) $ in Thousands			1 Months Ended					12 Months Ended
		Sep. 28, 2024	Dec. 31, 2022	Feb. 28, 2021	Oct. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2024	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	[1]							$ 155,289	$ 147,905
Collaboration revenue								2,983	0
Broad Institute | Collaborative Arrangement, License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment							$ 500
Clinical and regulatory milestone payments, per product							20,000	2,000
Sales-based milestone payments, per product							$ 54,000	3,000
Broad Institute | Collaborative Arrangement, 2022 License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty percentage (in percent)			0.20%
Broad Institute, Inc. and Harvard University | Collaborative Agreement, Pledge
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Pledge commitment				$ 5,000
Pledge commitment term (in years)				14 years
Research and development								5,000	5,000
Beam Therapeutics | Collaborative Arrangement, Related Party
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Profit share option, term to exercise (in days)							30 days
Revenue, remaining performance obligation, variable consideration received								0	0
Revenue, remaining performance obligation							$ 5,200
Collaboration revenue								$ 0	$ 0
Beam Therapeutics | Collaborative Arrangement, Related Party | Non-Sickle Cell Disease
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Profit share option, amount							5,000
Beam Therapeutics | Collaborative Arrangement, Related Party | Sickle Cell Disease
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Profit share option, amount							$ 10,000
Beam Therapeutics | Collaborative Arrangement, Related Party | Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued to collaborating party (in shares)						200,307	1,608,337
Fair value of stock issued					$ 200
Stock consideration and collaboration revenue					$ 5,500
Juno Therapeutics, Inc. | Collaborative Arrangement, Research Collaboration and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment		$ 55,000
Milestone payments		3,500,000
Preclinical milestones		185,000
Developmental milestones		1,200,000
Commercialization milestones		2,100,000
Juno Therapeutics, Inc. | Collaborative Arrangement, Research Collaboration and License Agreement | Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Fair value of stock issued		$ 55,000
Juno Therapeutics, Inc. | Collaborative Arrangement, Stock Purchase Agreement | Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued to collaborating party (in shares)		11,006,163
Fair value of stock issued		$ 55,000
Juno Therapeutics, Inc. | Collaborative Arrangement, BMS Collaboration Agreement Accounting
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment		$ 72,000

[1] Includes related party amounts of $— million and $0.6 million for the years ended December 31, 2024 and 2023, respectively.