Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued Expenses
Accrued contracted research costs	$ 1,567	$ 737
Accrued compensation	545	1,365
Accrued professional fees	528	370
Accrued other	312	98
Accrued franchise tax	50	40
Total	$ 3,002	$ 2,610