Accrued Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Expense
Accrued expense	$ 770	$ 975
Accrued clinical trial expenses		400
Accrued vacation and bonus expenses	400	400
Manufacturing expenses	100	100
Accrued legal and patent fees	100
Other accrued expenses	$ 100	$ 100