Income Taxes - Schedule of Significant Components of the Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 19,167	$ 16,389
Research and development credits	4,982	4,398
Other state credits	3,372	1,922
Inventory	2,693	1,718
Allowances and bad debts	1,356	1,009
Accrued warranty	8,441	6,344
Accrued wages and benefits	240	1,294
Other accrued expenses	1,789	1,393
Stock-based compensation	223	205
Capitalized research and development costs	210	486
163(j) disallowed interest	2,305	1,688
Intangible amortization	1,357	1,855
Contract liabilities	3,307	3,583
Operating lease liability	4,934	5,989
Other	612	356
Total deferred tax assets	54,988	48,629
Valuation allowance	(48,056)	(41,709)
Total deferred tax assets, net of valuation allowance	6,932	6,920
Deferred tax liabilities:
ROU operating lease asset	(4,545)	(5,652)
Tax depreciation in excess of book depreciation on property, plant and equipment	(3,273)	(2,373)
Total deferred tax liabilities	(7,818)	(8,025)
Net deferred tax liability	$ (886)	$ (1,105)