Investments - Summary of Fair Value of Available-for-Sale Investments by Type of Security (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 742,160	$ 679,042
Unrealized Losses	(11,906)	(1,088)
Fair Value	730,254	677,954
Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	497,790	298,301
Unrealized Losses	(5,612)	(366)
Fair Value	492,178	297,935
Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	244,370	380,741
Unrealized Losses	(6,294)	(722)
Fair Value	238,076	380,019
U.S treasury bills [Member] | Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	332,729	189,406
Unrealized Losses	(4,150)	(228)
Fair Value	328,579	189,178
U.S treasury bills [Member] | Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	154,076	280,743
Unrealized Losses	(3,775)	(535)
Fair Value	150,301	280,208
U.S agency securities [Member] | Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	165,061	108,895
Unrealized Losses	(1,462)	(138)
Fair Value	163,599	108,757
U.S agency securities [Member] | Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	90,294	99,998
Unrealized Losses	(2,519)	(187)
Fair Value	$ 87,775	$ 99,811