Investment Securities - Summary of Investment Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 412,570	$ 490,419
Unrealized Gains	490	21
Unrealized (Losses)	(386)	(4,211)
Estimated Fair Value	412,674	486,229
U.S. Government Agency Securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	150,651	188,465
Unrealized Gains	148	14
Unrealized (Losses)	(204)	(1,729)
Estimated Fair Value	150,595	186,750
FDIC Certificates of Deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	4,410	4,155
Unrealized Gains	2	3
Unrealized (Losses)	(12)	(72)
Estimated Fair Value	4,400	4,086
Certificates of Deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	60,000	7,500
Unrealized Gains	0	0
Unrealized (Losses)	0	0
Estimated Fair Value	60,000	7,500
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	78,610	100,711
Unrealized Gains	59	3
Unrealized (Losses)	(27)	(269)
Estimated Fair Value	78,642	100,445
Corporate Notes/Bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	118,899	189,588
Unrealized Gains	281	1
Unrealized (Losses)	(143)	(2,141)
Estimated Fair Value	$ 119,037	$ 187,448