License, Collaboration and Success Payment Agreements - Narrative (Details)		1 Months Ended		12 Months Ended
	Oct. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)	May 31, 2019 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) $ / shares	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($) $ / shares	Dec. 31, 2019 USD ($) collaboration_target	Oct. 31, 2020 USD ($) $ / shares	Jun. 30, 2020 USD ($)	Dec. 31, 2018 USD ($) $ / shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reduction in net loss				$ (342,994,000)	$ (234,632,000)	$ (183,118,000)
Reduction in net loss per common share, basic (in dollars per share) | $ / shares				$ (1.31)	$ (0.93)	$ (0.74)
Reduction in net loss per common share, diluted (in dollars per share) | $ / shares				$ (1.31)	$ (0.93)	$ (0.74)
Impairment of other investments				$ 13,001,000	$ 12,923,000	$ 5,000,000
Gain on other investments				0	0	2,923,000
PACT
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Impairment of other investments		$ 36,400,000
Other Investment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Impairment of other investments				13,000,000.0	12,900,000	5,000,000.0
Series A Convertible Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Convertible preferred stock, par value (in dollars per share) | $ / shares								$ 1.83		$ 1.83
PACT
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Gain on other investments	$ 2,900,000
PACT | Other Investment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Impairment of other investments					2,900,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential aggregate success payments				0
Term of success payment agreement										9 years
Trigger period from IPO date										1 year
Trigger period thereafter										2 years
Fair value of potential success payments due				100,000	700,000
Success payment expense/(gain)				(500,000)	(1,900,000)	(3,900,000)
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Fred Hutch | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance										10
Potential aggregate success payments										$ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares										$ 18.29
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Fred Hutch | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance										50
Potential aggregate success payments										$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares										$ 91.44
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential aggregate success payments				0
Term of success payment agreement								9 years
Trigger period from IPO date								1 year
Trigger period thereafter								2 years
Success payment expense/(gain)				(600,000)	(900,000)	(1,200,000)
Annual license maintenance payments							$ 50,000
Term of collaborative arrangement for research								4 years
Aggregate research payments due								$ 12,000,000
Research and development				2,300,000	3,000,000.0	3,000,000.0
Success payment liability				300,000	900,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Stanford | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance								10
Potential aggregate success payments								$ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares								$ 18.29
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Stanford | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance								50
Potential aggregate success payments								$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares								$ 91.44
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | GSK
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue				0	$ 0	84,700,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | GSK | Adjustment To Revenue Related To Change In Estimate
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue						83,600,000
Reduction in net loss						$ 83,600,000
Reduction in net loss per common share, basic (in dollars per share) | $ / shares					$ 0.34	$ 0.34
Reduction in net loss per common share, diluted (in dollars per share) | $ / shares					$ 0.34	$ 0.34
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | GSK | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of collaboration targets | collaboration_target							2
Number of additional targets to nominate | collaboration_target							7
Contract liabilities			$ 45,000,000	0
Stock purchase agreement portion of transaction price			58,600,000
Transaction price			$ 103,600,000
Contract assets				$ 0
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | GSK | Series AA Convertible Preferred Stock | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock sold under Stock Purchase Program (in shares) | shares			30,253,189
Price per share of stock sold under Stock Purchase Program (in dollars per share) | $ / shares			$ 6.78
Fair value per share of stock sold under Stock Purchase Program (in dollars per share) | $ / shares			$ 4.84
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | PACT
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Strategic equity investment									$ 36,400,000