Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Expenses
Drugs and clinical trial expenses	$ 1,215	$ 1,887
Accrued salaries, benefits and travel related costs	1,570	774
Professional and consultant fees	126	181
Legal expenses	140	105
Other administrative accruals	69	109
Accrued expenses	3,120	$ 3,056
Operating lease liabilities current portion	$ 164