Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets
Leases	$ 221	$ 233
Employee benefits	1,465	1,208
Accrued losses on uncompleted contracts	2,076	2,572
Stock based compensation expense	351	247
Federal net operating losses	22,444	21,724
State net operating losses	3,493	3,299
R&D and other tax credits	1,013	938
Other	481	545
Total deferred tax assets	31,544	30,766
Deferred tax liabilities
Property, plant and equipment	(1,051)	(1,285)
Prepaid insurance	(497)	(231)
Total deferred tax liabilities	(1,548)	(1,516)
Net deferred tax assets	29,996	29,250
Valuation allowance	(30,100)	(29,331)
Net deferred taxes	$ (104)	$ (81)