Income Taxes - Reconciliation of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax expense at statutory rate	$ (6,462)	$ (12,812)	$ 956
State income taxes, net of federal benefit	(1,400)	(1,564)	(13)
Foreign tax rate difference	1,999	(1,954)	(1,003)
Research and development credit	(662)	(753)	(919)
Change in valuation allowance	(3,736)	8,485	464
Equity based compensation	(42)	(25)	(390)
Impact of permanent differences of non-deductible cost	(602)	1,550	727
Provision to return adjustments & deferred adjustments	(572)	356	(654)
Change in enacted tax rates	(1,138)	359	58
Global intangible low-taxed income (“GILTI”)	0	1,795	402
Intangible & goodwill impairment	0	4,999	0
Other	440	697	0
Impact of intra-entity IP transfers	(19,227)	0	0
Income tax (benefit) expense	$ (31,402)	$ 1,133	$ (372)