Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Rate Reconciliation [Line Items]
Income before income taxes	$ 1,194	$ 3,679	$ 4,351	$ 4,198	$ 242	$ 2,255	$ 3,243	$ 5,398	$ 13,423	$ 11,138	$ 23,014
Expected tax at statutory rate									4,564	3,787	7,825
Adjustments due to:
Difference between U.S. and foreign tax									(1,910)	(1,471)	(1,228)
State income and franchise taxes									563	122	1,122
Business tax credits									(115)
Permanent differences									118	(172)	(298)
Change in valuation allowance									1,216	727	(509)
Other									(358)	(25)	9
Provision (benefit) for income taxes	$ 929	$ 1,141	$ 738	$ 1,269	$ 640	$ 789	$ 418	$ 1,121	$ 4,078	$ 2,968	$ 6,921
Expected tax at statutory rate									34.00%	34.00%	34.00%
Adjustments due to:
Difference between U.S. and foreign tax									(14.20%)	(13.20%)	(5.30%)
State income and franchise taxes									4.20%	1.10%	4.90%
Business tax credits									(0.90%)
Permanent differences									0.90%	(1.50%)	(1.30%)
Change in valuation allowance									9.10%	6.50%	(2.20%)
Other									(2.70%)	(0.20%)
Provision (benefit) for income taxes									30.40%	26.70%	30.10%