Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Expenses
Payroll and related costs	$ 1,364	$ 1,323
Clinical studies and drug development	2,781	156
Professional fees	204	113
Other	88	25
Total accrued expenses	$ 4,437	$ 1,617