Accrued Expense (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Accrued Expense
Accrued expense	$ 608	$ 770
Accrued vacation and bonus expenses	300	400
Manufacturing and testing services	100
Professional and consulting fees	100
Accrued legal and patent fees	$ 100	100
Other accrued expenses		100
Manufacturing expenses		$ 100