Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accrued Expenses
Accrued payroll and related expenses	$ 2,017	$ 2,146
Accrued professional fees	1,466	1,018
Accrued research and development expenses	314	360
Accrued insurance	197	591
Accrued other	385	520
Total	$ 4,379	$ 4,635