Income Taxes - Schedule of Significant Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating loss carryforwards	$ 23,937	$ 14,830
Deferred Revenue		5,656
Start-up costs	2,093	2,260
Research and development credits carryforwards	4,450	2,157
Depreciation	(527)	(565)
Other	865	437
Total deferred tax assets	30,818	24,775
Less valuation allowance	$ (30,818)	$ (24,775)