Property, Plant, and Equipment, Net - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 29, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 36,777	$ 35,412
Less: Accumulated depreciation	13,998	11,997
Net property, plant, and equipment, net	22,779	23,415
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,663	1,663
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,027	5,934
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life, years	23 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life, years	40 years
Shop equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 23,007	22,982
Shop equipment | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life, years	7 years
Shop equipment | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life, years	10 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,248	1,234
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life, years	3 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life, years	10 years
Office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,936	1,866
Office equipment | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life, years	3 years
Office equipment | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life, years	7 years
Mobile equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 152	190
Depreciable life, years	3 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 2,745	$ 1,543