Accrued Expenses and Long-term Liabilities - Schedule of Long Term Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Warrant liability	$ 316	$ 361
Uncertain tax positions	3,952	3,838
Other	4,268	4,319
Total other long-term liabilities	$ 4,268	$ 4,319