Summary of Available-for-Sale Securities (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 60,456,000	$ 83,828,000
Gross Unrealized Gain	26,000	50,000
Gross Unrealized Loss	(1,215,000)	(2,837,000)
Allowance for Credit Loss	0	0	$ 0
Fair Value	59,267,000	81,041,000
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,062,000	14,472,000
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Allowance for Credit Loss	0	0
Fair Value	5,062,000	14,472,000
United States government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,652,000	27,200,000
Gross Unrealized Gain	16,000	41,000
Gross Unrealized Loss	(314,000)	(818,000)
Allowance for Credit Loss	0	0
Fair Value	19,354,000	26,423,000
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	32,395,000	38,496,000
Gross Unrealized Gain	3,000	2,000
Gross Unrealized Loss	(638,000)	(1,703,000)
Allowance for Credit Loss	0	0
Fair Value	31,760,000	36,795,000
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,347,000	3,660,000
Gross Unrealized Gain	7,000	7,000
Gross Unrealized Loss	(263,000)	(316,000)
Allowance for Credit Loss		0
Fair Value	$ 3,091,000	$ 3,351,000