Income Taxes - Schedule of Significant Components of the Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 16,389	$ 19,006
Research and development credits	4,398	3,858
Other state credits	1,922	1,923
Inventory	1,718	2,203
Allowances and bad debts	1,009	840
Accrued warranty	6,344	5,732
Accrued wages and benefits	1,294	413
Other accrued expenses	1,393	5,281
Stock-based compensation	205	649
Capitalized research and development costs	486	770
163(j) disallowed interest	1,688	1,643
Intangible amortization	1,855	2,240
Contract liabilities	3,583	495
Operating lease liability	5,989
Other	356	847
Total deferred tax assets	48,629	45,900
Valuation allowance	(41,709)	(44,405)
Total deferred tax assets, net of valuation allowance	6,920	1,495
Deferred tax liabilities:
ROU operating lease asset	(5,652)	0
Tax depreciation in excess of book depreciation on property, plant and equipment	(2,373)	(2,142)
Total deferred tax liabilities	(8,025)	(2,142)
Net deferred tax liability	$ (1,105)	$ (647)