Income Taxes - Reconciliation of Provision for Income Taxes (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S statutory income taxes rate	21.00%	35.00%	35.00%
Non-deductible expenses	(2.20%)	(6.80%)	(2.50%)
Foreign taxes rate differential	13.20%	15.10%	(14.20%)
Change in valuation allowance	(62.30%)	(11.90%)	(30.00%)
State income taxes	(4.50%)	18.70%	2.30%
Share based compensation	(4.50%)	(4.50%)	1.20%
Change in unrecognized taxes expense	0.30%	(0.80%)	(0.70%)
Other	0.70%	(71.90%)	0.40%
Effective taxes rate	(38.30%)	(27.10%)	(8.50%)