Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Discount rate used to value the projected benefit obligation	1.60%
Actuarial loss on projected benefit obligation	$ 1,835
Actuarial loss on projected benefit obligation, tax effect	624
United States [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Contribution pension plan	$ 167	$ 110	$ 119
Belgium [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Discount rate used to value the projected benefit obligation	1.60%	3.20%
Contribution pension plan	$ 647	$ 572	$ 697