Income Taxes - Summary of Changes in Deferred Tax Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Deferred tax valuation allowance, Beginning Balance	$ 2,686	$ 2,193	$ 1,534
Additions	74	1,439	1,256
Deductions	(139)	(70)	(455)
Change in tax legislation		(954)
Translation adjustments	(47)	78	(142)
Deferred tax valuation allowance, Ending Balance	$ 2,574	$ 2,686	$ 2,193