Marketable Securities - Summary of Available -for-sale Marketable Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Amortized Cost	$ 820,889	$ 785,473
Gross Unrealized Gains	3,396	522
Gross Unrealized Losses	(99)	(656)
Estimated Fair Value	824,186	785,339
U.S. Treasury and Other Government - Backed Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	432,997	382,260
Gross Unrealized Gains	1,345	302
Gross Unrealized Losses	(53)	(254)
Estimated Fair Value	434,289	382,308
Financial Institution Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	248,197	246,270
Gross Unrealized Gains	1,437	92
Gross Unrealized Losses	(27)	(243)
Estimated Fair Value	249,607	246,119
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	104,174	97,490
Gross Unrealized Gains	584	53
Gross Unrealized Losses	(19)	(135)
Estimated Fair Value	104,739	97,408
Other Asset Backed Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	35,521	59,453
Gross Unrealized Gains	30	75
Gross Unrealized Losses	0	(24)
Estimated Fair Value	$ 35,551	$ 59,504