Income Taxes - Schedule of Reconciliation of Theoretical Tax Expense and Actual Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Loss before taxes, as reported in the consolidated statements of operations	$ (28,165)	$ (11,057)	$ (12,880)
Statutory tax rate	21.00%	34.00%	34.00%
Theoretical tax benefits on the above amount at the US statutory tax rate	$ (5,915)	$ (3,759)	$ (4,379)
Income tax at rate other than the U.S. statutory tax rate	692	(1,047)	(6)
Tax advances and non-deductible expenses including equity based compensation expenses	(7,623)	3,123	4,298
Operating losses and other temporary differences for which valuation allowance was provided	15,826	(8,623)	1,885
Research and Development Tax Credit	0	1,126	(1,182)
State tax	(1,221)	(601)	(426)
Impact of rate change	0	10,920	(360)
Change in tax reserve for uncertain tax positions	1,728	(1,576)	(1,209)
Other individually immaterial income tax items	382	72	274
Income tax expense	$ 413	$ 2,787	$ 1,313