Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Rate Reconciliation [Line Items]
Income before income taxes	$ 1,566	$ 2,214	$ 5,372	$ 2,540	$ 1,194	$ 3,679	$ 4,351	$ 4,198	$ 11,692	$ 13,423	$ 11,138
Expected tax at statutory rate									3,975	4,564	3,787
Adjustments due to:
Difference between U.S. and foreign tax									(2,031)	(1,910)	(1,471)
State income and franchise taxes									(326)	563	122
Business tax credits									(236)	(115)
Permanent differences									567	118	(172)
Change in valuation allowance									(1,981)	1,216	727
Other									43	(358)	(25)
Provision (benefit) for income taxes	$ 3,463	$ 1,059	$ 1,500	$ 915	$ 929	$ 1,141	$ 738	$ 1,269	$ 11	$ 4,078	$ 2,968
Expected tax at statutory rate									34.00%	34.00%	34.00%
Adjustments due to:
Difference between U.S. and foreign tax									(17.40%)	(14.20%)	(13.20%)
State income and franchise taxes									(2.80%)	4.20%	1.10%
Business tax credits									(2.00%)	(0.90%)
Permanent differences									4.80%	0.90%	(1.50%)
Change in valuation allowance									(16.90%)	9.10%	6.50%
Other									0.40%	(2.70%)	(0.20%)
Provision (benefit) for income taxes									0.10%	30.40%	26.70%