Income Taxes - Reconciliation of Tax Provision at Statutory U.S. Rate to Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Tax provision at statutory U.S. rate	$ 2,185	$ 5,495	$ 2,551
Increase (decrease) in tax provision resulting from:
State and local taxes, net	(1,903)	(1,792)	(733)
Foreign tax rate differential	(1,810)	(2,079)	(296)
Foreign undistributed earnings, net of credits	1,181	5,329	14,211
Nondeductible items	1,236	1,197	891
Federal research and development credits	(884)	(713)	(620)
Non-territorial income	(1,806)	(1,079)	(1,517)
Withholding tax	1,082	5,454	1,078
Uncertain tax positions	(294)	(159)	1,344
Stock-based compensation	262	213	479
Federal tax rate change	(412)	466	686
Valuation allowance	7,524	8,057	149
Foreign permanent benefit	(856)	(7,077)	(451)
Provision to return	584	0	0
Other	683	930	(161)
Total provision for income taxes	$ 6,772	$ 14,242	$ 17,611