Accounts Receivable - Schedule of Changes in Low Yield Compensation Reserve (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Beginning balance	$ (432)	$ (480)	$ (1,100)
Reversal (Provision)	(362)	(29)	69
Usage	22	63	512
Translation adjustments	(72)	14	39
Ending balance	$ (844)	$ (432)	$ (480)