Income Taxes - Reconciliation of Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory tax rate	12.50%	12.50%
International tax rates differential	5.00%	8.90%
Change in valuation allowance	(11.40%)	(4.70%)
Change in fair value of nondeductible contingent consideration	(3.10%)	(3.80%)
Nondeductible stock-based compensation	(0.40%)	(1.10%)
Unrecognized tax benefits	(0.90%)	(1.50%)
State and local income taxes, net of federal	0.00%	0.10%
Nondeductible interest expense	(1.20%)	0.00%
Other	2.20%	5.60%
Effective income tax rate	2.70%	16.00%
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax benefit - at statutory tax rate	$ (1,673)	$ (1,820)
International tax rates differential	(668)	(1,298)
Change in valuation allowance	1,520	690
Change in fair value of nondeductible contingent consideration	413	551
Nondeductible stock-based compensation	51	160
Unrecognized tax benefits	124	220
State and local income taxes, net of federal	2	(19)
Nondeductible interest expense	157	0
Other	(300)	(811)
Income tax benefit - at effective income tax rate	$ (374)	$ (2,327)