Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued professional fees	$ 322	$ 526
Accrued compensation	462	631
Accrued other	476	394
Total accrued expenses	$ 1,260	$ 1,551