Summary of Available-for-Sale Securities (Detail) - USD ($)	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 77,162,000	$ 83,828,000
Gross Unrealized Gain	84,000	50,000
Gross Unrealized Loss	(2,325,000)	(2,837,000)
Allowance for Credit Loss	0	0	$ 0
Fair Value	74,921,000	81,041,000
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		14,472,000
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Allowance for Credit Loss	0	0
Fair Value	7,845,000	14,472,000
United States government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,222,000	27,200,000
Gross Unrealized Gain	69,000	41,000
Gross Unrealized Loss	(623,000)	(818,000)
Allowance for Credit Loss	0	0
Fair Value	26,668,000	26,423,000
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	38,492,000	38,496,000
Gross Unrealized Gain	4,000	2,000
Gross Unrealized Loss	(1,443,000)	(1,703,000)
Allowance for Credit Loss	0	0
Fair Value	37,053,000	36,795,000
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,603,000	3,660,000
Gross Unrealized Gain	11,000	7,000
Gross Unrealized Loss	(259,000)	(316,000)
Allowance for Credit Loss	0	0
Fair Value	$ 3,355,000	$ 3,351,000