Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued research and development expenses	$ 654	$ 1,296
Accrued employee bonus compensation	759	1,798
Other accrued expenses	974	707
Total accrued expenses	$ 2,387	$ 3,801