Income Taxes - Reconciliation of Provision for Income Taxes to Statutory Federal Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Expected federal income tax at statutory rate	$ 8,835	$ 5,951	$ 3,635
State income taxes, net of federal tax effect	1,933	1,293	417
Tax impact of foreign activity	(108)	57	(105)
Nondeductible executive compensation	940	902	530
Nondeductible expenses	329	351	268
Change in valuation allowance		(4)	16
Change in state deferred rate	47	38	(134)
Research and development credit	(1,252)	(1,843)	(227)
Tax impact of Tax Cuts and Jobs Act			6,796
Tax impact of stock activity	(2,518)	(2,438)	(925)
Other	152	161	71
Total provision for income taxes	$ 8,358	$ 4,468	$ 10,342