Changes in Initial Product Warranty Accrual and Expenses Under Initial and Extended Warranties (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Movement in Standard Product Warranty Accrual
Balance, January 1	$ 1,132	$ 1,110	$ 1,308
Provision for estimated warranty cost	1,747	1,047	806
Warranty expenditures	(1,793)	(1,025)	(1,004)
Balance, December 31	1,086	1,132	1,110
Less: long-term portion of warranty accrual	521	384	245
Current portion of warranty accrual	$ 565	$ 748	$ 865