Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Rate Reconciliation [Line Items]
Income before income taxes	$ 26,151	$ 21,436	$ 7,248
Expected tax at statutory rate	5,492	4,502	2,537
Adjustments due to:
Difference between U.S. and foreign tax	436	345	(1,797)
State income and franchise tax	(179)	91	(307)
Business tax credits	(2,746)	(1,760)	(708)
Stock-based compensation expense	(1,877)	(1,213)	(946)
Transaction costs			1,232
U.S. taxation of foreign earnings	2,227	2,190
Executive compensation	841	367	265
Other	92	97	205
Change in U.S. federal tax rates			(12,839)
Change in U.S. state tax rates	0	748	(151)
Change in Netherlands tax rate	(193)	(388)
Transition tax	0	(1,338)	3,266
Uncertain tax provisions	1,069	1,021	241
Change in valuation allowance	(125)	125	(12,164)
Return to provision adjustments	(79)	33	(161)
Other	(218)	(1)	222
Income tax (benefit) provision	$ 4,740	$ 4,819	$ (21,105)
Expected tax at statutory rate	21.00%	21.00%	35.00%
Adjustments due to:
Difference between U.S. and foreign tax	1.70%	1.60%	(24.80%)
State income and franchise tax	(0.70%)	0.40%	(4.20%)
Business tax credits	(10.50%)	(8.20%)	(9.80%)
Stock-based compensation expense	(7.20%)	(5.70%)	(13.10%)
Transaction costs	0.00%	0.00%	17.00%
U.S. taxation of foreign earnings	8.50%	10.20%	0.00%
Executive compensation	3.20%	1.70%	3.70%
Other	0.40%	0.50%	2.80%
Change in U.S. federal tax rates	0.00%	0.00%	(177.10%)
Change in U.S. state tax rates	0.00%	3.50%	(2.10%)
Change in Netherlands tax rate	(0.70%)	(1.80%)	0.00%
Transition tax	0.00%	(6.20%)	45.10%
Uncertain tax provisions	4.10%	4.80%	3.30%
Change in valuation allowance	(0.50%)	0.60%	(167.80%)
Return to provision adjustments	(0.30%)	0.20%	(2.20%)
Other	(0.80%)	(0.10%)	3.00%
Income tax (benefit) provision	18.10%	22.50%	(291.20%)