Investments - Summary of Gross Unrealized Gains and Losses and Credit Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 545,147	$ 683,006
Gross Unrealized Gains	92	437
Gross Unrealized Losses	(879)	(1,251)
Fair Value	544,360	682,192
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	136,948	167,165
Gross Unrealized Gains	16	107
Gross Unrealized Losses	(239)	(347)
Fair Value	136,725	166,925
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	182,247	210,491
Gross Unrealized Gains	42	191
Gross Unrealized Losses	(340)	(484)
Fair Value	181,949	210,198
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	83,974	97,698
Gross Unrealized Gains	23	99
Gross Unrealized Losses	(136)	(122)
Fair Value	83,861	97,675
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,349	23,360
Gross Unrealized Gains	9	11
Gross Unrealized Losses	(1)	(1)
Fair Value	30,357	23,370
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,064	46,935
Gross Unrealized Gains	2	3
Gross Unrealized Losses	(7)	(38)
Fair Value	45,059	46,900
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,303	8,830
Fair Value	1,303	8,830
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	65,262	128,527
Gross Unrealized Gains		26
Gross Unrealized Losses	(156)	(259)
Fair Value	$ 65,106	$ 128,294