Marketable Securities - Summary of Cash Equivalents and Marketable Securities Recorded at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Cash equivalents, amortized cost	$ 545,121	$ 517,383
Cash equivalents, gross unrealized gains	1
Cash equivalents, gross unrealized losses	7	1
Cash equivalents, fair value	545,115	517,382
Marketable securities, amortized cost	1,554,252	1,461,200
Marketable securities, gross unrealized gains	8	16
Marketable securities, gross unrealized losses	(16,905)	(5,118)
Marketable securities, fair value	1,537,355	1,456,098
Cash equivalents and marketable securities, amortized cost	2,099,373	1,978,583
Cash equivalents and marketable securities, gross unrealized gains	9	16
Cash equivalents and marketable securities, gross unrealized losses	16,912	5,119
Cash equivalents and marketable securities, fair value	2,082,470	1,973,480
Money Market Funds [Member]
Marketable Securities [Line Items]
Cash equivalents, amortized cost	416,688	507,386
Cash equivalents, fair value	416,688	507,386
Certificates of Deposit [Member]
Marketable Securities [Line Items]
Marketable securities, amortized cost	57,631	45,164
Marketable securities, fair value	57,631	45,164
Commercial Paper [Member]
Marketable Securities [Line Items]
Cash equivalents, amortized cost	116,606	9,997
Cash equivalents, gross unrealized gains	1
Cash equivalents, gross unrealized losses	4	1
Cash equivalents, fair value	116,603	9,996
Marketable securities, amortized cost	305,033	212,805
Marketable securities, gross unrealized gains	5
Marketable securities, gross unrealized losses	(418)	(86)
Marketable securities, fair value	304,620	212,719
US Treasury Securities [Member]
Marketable Securities [Line Items]
Marketable securities, amortized cost	12,126	16,238
Marketable securities, gross unrealized gains		6
Marketable securities, gross unrealized losses	(269)	(52)
Marketable securities, fair value	11,857	16,192
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Cash equivalents, amortized cost	11,827
Cash equivalents, gross unrealized losses	3
Cash equivalents, fair value	11,824
Marketable securities, amortized cost	1,166,163	1,173,659
Marketable securities, gross unrealized gains	3	10
Marketable securities, gross unrealized losses	(15,982)	(4,903)
Marketable securities, fair value	1,150,184	1,168,766
Government-sponsored Enterprise Securities [Member]
Marketable Securities [Line Items]
Marketable securities, amortized cost	13,299	13,334
Marketable securities, gross unrealized losses	(236)	(77)
Marketable securities, fair value	$ 13,063	$ 13,257