Other Income (Expense), Net - Components of Other Income (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Income and Expenses [Abstract]
Interest income	$ 930,000	$ 95,000	$ 300,000
Rental income, net	792,000	792,000	792,000
(Loss) gain on disposal of equipment	(72,000)	13,000	38,000
Foreign currency gains (losses), net	(336,000)	181,000	(108,000)
Other	(111,000)	12,000	44,000
Total other income (expense), net	$ 1,203,000	$ 1,093,000	$ 1,066,000