License, Collaboration, and Success Payment Agreements - Narrative (Details)	1 Months Ended				3 Months Ended
	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	May 31, 2019 $ / shares shares	Mar. 31, 2022 USD ($) performance_obligation	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Apr. 30, 2021 USD ($)	Oct. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) payment collaboration_target representative	Dec. 31, 2018 USD ($) $ / shares
Description Of Organization [Line Items]
Research and development expense					$ 35,830,000		$ 41,529,000
PACT
Description Of Organization [Line Items]
Impairment of other investments						$ 36,400,000
Series A Convertible Preferred Stock
Description Of Organization [Line Items]
Convertible preferred stock, par value (in dollars per share) | $ / shares									$ 1.83		$ 1.83
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Description Of Organization [Line Items]
Annual license maintenance payments											$ 50,000
Aggregate research payments due											$ 12,000,000
Term of collaborative arrangement for research											6 years
Research and development expense					500,000		1,000,000
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					4,400,000	8,500,000
Success payment liability					3,600,000	6,400,000
Success payment expenses					(2,800,000)		8,100,000
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Fifty Times
Description Of Organization [Line Items]
Multiple of initial equity value at issuance											50
Aggregate success payment(s) (in millions)											$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares											$ 91.44
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Minimum
Description Of Organization [Line Items]
Multiple of initial equity value at issuance											10
Aggregate success payment(s) (in millions)											$ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares											$ 18.29
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum
Description Of Organization [Line Items]
Multiple of initial equity value at issuance											50
Aggregate success payment(s) (in millions)											$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares											$ 91.44
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Description Of Organization [Line Items]
Annual license maintenance payments										$ 50,000
Aggregate research payments due									$ 12,000,000
Term of collaborative arrangement for research									4 years
Research and development expense					800,000		800,000
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					5,500,000	9,900,000
Success payment liability					2,100,000	3,100,000
Success payment expenses					(1,000,000.0)		1,900,000
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Fifty Times
Description Of Organization [Line Items]
Multiple of initial equity value at issuance									50
Aggregate success payment(s) (in millions)									$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares									$ 91.44
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License
Description Of Organization [Line Items]
Potential milestone payments due										2,500,000
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Minimum
Description Of Organization [Line Items]
Multiple of initial equity value at issuance									10
Aggregate success payment(s) (in millions)									$ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares									$ 18.29
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum
Description Of Organization [Line Items]
Multiple of initial equity value at issuance									50
Aggregate success payment(s) (in millions)									$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares									$ 91.44
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum | License
Description Of Organization [Line Items]
Potential milestone payments due										$ 3,700,000
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Description Of Organization [Line Items]
Contract liabilities					84,100,000	$ 84,700,000
Revenue recognized					600,000		2,400,000
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License
Description Of Organization [Line Items]
Number of initial collaboration targets | collaboration_target										2
Number of additional collaboration targets | collaboration_target										7
Number of representatives of JSC appointed by company | representative										3
Contract liabilities		$ 45,000,000			$ 0					$ 45,000,000
Revenue, remaining performance obligation, variable consideration amount, number of one-time payments | payment										2
Stock Purchase Agreement portion of transaction price		58,600,000
Transaction price		103,600,000
Number of performance obligations | performance_obligation					2
Revenue recognized					$ 0		0
Contract assets					0
Capitalized contract costs					0
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License | Series AA Convertible Preferred Stock
Description Of Organization [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
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum | License
Description Of Organization [Line Items]
Potential milestone payments, technology validation										$ 200,000,000
Potential milestone payments, within pipeline										400,000,000
Potential milestone payments, not within pipeline										$ 900,000,000
Variable consideration amount								$ 400,000,000
PACT | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Description Of Organization [Line Items]
Upfront payment			$ 50,000,000
Stock purchase agreement, stock purchased (in shares) | shares			17,806,901
Stock purchase agreement, purchase price per share (in dollars per share) | $ / shares			$ 2.81
Stock purchase agreement, fair value per share (in dollars per share) | $ / shares			$ 2.05
Additional purchase price consideration			$ 13,600,000
Total upfront payment paid			63,600,000
PACT | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Other Investment
Description Of Organization [Line Items]
Strategic equity investment			$ 36,400,000
NCI | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Description Of Organization [Line Items]
Research and development expense		100,000
Upfront payment	$ 25,000
Maintenance fees					$ 105,000		$ 75,000
Maximum aggregate development milestone payments	$ 75,000	3,100,000
Maximum aggregate commercial milestone payments		$ 12,000,000