Investments - Summary of Gross Unrealized Gains and Losses and Credit Losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 547,583	$ 683,006
Gross Unrealized Gains	25	437
Gross Unrealized Losses	(716)	(1,251)
Fair Value	546,892	682,192
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	84,623	167,165
Gross Unrealized Gains	0	107
Gross Unrealized Losses	(115)	(347)
Fair Value	84,508	166,925
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	205,746	210,491
Gross Unrealized Gains	6	191
Gross Unrealized Losses	(358)	(484)
Fair Value	205,394	210,198
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	109,641	97,698
Gross Unrealized Gains	15	99
Gross Unrealized Losses	(166)	(122)
Fair Value	109,490	97,675
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	67,152	23,360
Gross Unrealized Gains	3	11
Gross Unrealized Losses	(1)	(1)
Fair Value	67,154	23,370
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,109	46,935
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(1)	(38)
Fair Value	45,109	46,900
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,203	8,830
Fair Value	2,203	8,830
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,109	128,527
Gross Unrealized Gains		26
Gross Unrealized Losses	(75)	(259)
Fair Value	$ 33,034	$ 128,294