Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Expenses
Accrued compensation	$ 1,958	$ 1,719
Accrued contracted costs	760	1,726
Accrued other	295
Accrued professional fees	268	356
Accrued severance		396
Total	$ 3,281	$ 4,197