Income Taxes - Reconciliation of the Company's Effective Income Tax Rate to the Federal Statutory Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal income tax at the statutory rate	$ 11,024	$ 12,347	$ 11,236
State income taxes, net of federal benefit	889	1,061	1,433
Difference between statutory and foreign tax rates	1,521	2,442	0
Permanent differences	(457)	(205)	98
Research and development	(1,928)	(1,050)	(452)
Return to provision adjustment	327	(67)	28
Change in liability for unrecognized tax benefits	700	(156)	202
Incentive stock option benefit	(77)	(144)	(616)
Change in valuation allowance	1,779	1,200	500
Tax effects of intercompany transactions	630	0	0
Other	(208)	0	(36)
Provision for income taxes	$ 14,200	$ 15,428	$ 12,393
Effective tax rate	45.10%	43.60%	38.40%