Accrued Expenses - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Development costs	$ 852	$ 931
Employee compensation	352	573
Professional fees	413	194
Interest	0	88
Other	157	8
Total accrued expenses	$ 1,774	$ 1,794