Commitments and Contingencies - Additional Information (Detail)			1 Months Ended		12 Months Ended
	Aug. 29, 2023	Mar. 31, 2022	Oct. 31, 2023 USD ($) shares	Sep. 30, 2021 demand	Dec. 31, 2023 USD ($) milestone shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Mar. 31, 2023 USD ($)
Other Commitments [Line Items]
Unrecorded unconditional purchase obligation, term (in years)	5 years	4 years
Unrecorded unconditional purchase obligation, year one					$ 8,000,000			$ 10,000,000
Unrecorded unconditional purchase obligation, year two					28,000,000			13,000,000
Unrecorded unconditional purchase obligation, year three					54,000,000			16,000,000
Unrecorded unconditional purchase obligation, year four					86,000,000			19,000,000
Unrecorded unconditional purchase obligation, year five					113,000,000
Unrecorded unconditional purchase obligation					$ 286,100,000			$ 58,000,000
Number of milestones | milestone					2
Research and development					$ 580,621,000	$ 1,052,643,000	$ 1,149,662,000
Number of demands per calendar year | demand				2
Common Stock
Other Commitments [Line Items]
Issuance of common stock for a business acquisition (in shares) | shares					4,771,000	114,517,000	1,634,000
StrideBio
Other Commitments [Line Items]
Asset acquisition, consideration transferred					$ 0
Royalty received from licensing revenue					0.10
Royalty received from license or sale of a product					0.40
StrideBio | Common Stock
Other Commitments [Line Items]
Research and development			$ 800,000
StrideBio | Common Class A
Other Commitments [Line Items]
Fair value of assets acquired			$ 7,600,000
Issuance of common stock for a business acquisition (in shares) | shares			4,800,000
Asset acquisition, consideration transferred			$ 21,300,000
StrideBio | Common Class A | Common Stock
Other Commitments [Line Items]
Research and development			$ 6,800,000
Google Cloud | Cloud and Artificial Intelligence
Other Commitments [Line Items]
Revenue, remaining performance obligation, variable consideration amount					$ 56,300,000
Google Cloud | Cloud and Artificial Intelligence | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Other Commitments [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period (in years)					3 years