Product Warranty Reserve - Roll Forward of Product Warranty Reserve (Detail) - Warranty Reserves [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning of period balance	$ 1,076	$ 1,058	$ 714
Additions charged to costs and expenses	97	347	649
Warranty usage	(133)	(399)	(269)
Currency translation	(112)	70	(36)
End of period balance	$ 928	$ 1,076	$ 1,058