Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Expenses
Payroll and related costs	$ 880	$ 631
Clinical trials and drug development	681	1,188
Professional fees	101	190
Other	113	152
Total accrued expenses	$ 1,775	$ 2,161