Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued Expenses
Accrued employee compensation and benefits	$ 1,362	$ 3,271
Accrued warranty	1,329	1,593
Accrued professional fees	733	710
Accrued other	926	1,387
Total accrued expenses	$ 4,350	$ 6,961