Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Expenses
Accrued employee compensation and benefits	$ 3,271	$ 2,069
Accrued warranty	1,593	1,265
Accrued professional fees	710	975
Accrued other	1,387	729
Total accrued expenses	$ 6,961	$ 5,038