Investment Securities - Summary of Investment Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 452,801	$ 490,419
Unrealized Gains	4	21
Unrealized (Losses)	(2,272)	(4,211)
Estimated Fair Value	450,533	486,229
U.S. Government Agency Securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	219,575	188,465
Unrealized Gains	3	14
Unrealized (Losses)	(1,203)	(1,729)
Estimated Fair Value	218,375	186,750
FDIC Certificates of Deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	5,132	4,155
Unrealized Gains	0	3
Unrealized (Losses)	(58)	(72)
Estimated Fair Value	5,074	4,086
Certificates of Deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	65,000	7,500
Unrealized Gains	0	0
Unrealized (Losses)	0	0
Estimated Fair Value	65,000	7,500
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	74,541	100,711
Unrealized Gains	0	3
Unrealized (Losses)	(207)	(269)
Estimated Fair Value	74,334	100,445
Corporate Notes/Bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	88,553	189,588
Unrealized Gains	1	1
Unrealized (Losses)	(804)	(2,141)
Estimated Fair Value	$ 87,750	$ 187,448