Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accrued Expenses and Other Current Liabilities
Drugs and clinical trial expenses	$ 1,429	$ 1,887
Accrued salaries, benefits and travel related costs	1,172	774
Professional and consultant fees	409	181
Legal expenses	377	105
Other administrative accruals		109
Accrued expenses	3,387	$ 3,056
Operating lease liabilities current portion	161
Insurance premiums payable	$ 361