Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued Expenses
Accrued contracted research costs	$ 1,785	$ 737
Accrued compensation	1,026	1,365
Accrued professional fees	540	370
Accrued other	301	98
Accrued franchise tax	43	40
Total	$ 3,695	$ 2,610