Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accrued Expenses
Payroll and related costs	$ 658	$ 631
Clinical trials and drug development	2,716	1,188
Professional fees	197	190
Other	174	152
Total accrued expenses	$ 3,745	$ 2,161