Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accrued Expenses
Payroll and related costs	$ 378	$ 631
Clinical trials and drug development	1,356	1,188
Professional fees	180	190
Other	409	152
Total accrued expenses	$ 2,323	$ 2,161