Other Accrued Liabilities, Components of Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Other Accrued Liabilities [Abstract]
Accrued warranty, current	$ 54	$ 87	$ 107
Accrued compensation, including commissions and vacation	1,578	891
Accrued state sales, use and other taxes	3,152	3,105
Accrued professional fees and other accrued liabilities	764	607
Total other accrued liabilities	$ 5,548	$ 4,690