Equipment and Leasehold Improvements - Summary of Equipment and Leasehold Improvements (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 28, 2018	Dec. 29, 2017
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 104,421	$ 103,017
Less: accumulated depreciation and amortization	(39,869)	(34,639)
Equipment and leasehold improvements, net	64,552	68,378
Land
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 1,170	1,170
Buildings
Property, Plant and Equipment [Line Items]
Useful lives	20 years
Equipment and leasehold improvements, gross	$ 1,489	1,292
Machinery and equipment
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 17,672	16,183
Machinery and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives	5 years
Machinery and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives	10 years
Computers, data processing and other equipment
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 10,672	9,924
Computers, data processing and other equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives	3 years
Computers, data processing and other equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 57,655	53,653
Leasehold improvements \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Leasehold improvements \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives	22 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Equipment and leasehold improvements, gross	$ 3,287	3,100
Vehicles
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 3,082	2,570
Vehicles \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives	5 years
Vehicles \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Other
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Equipment and leasehold improvements, gross	$ 95	95
Construction-in-process
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 9,299	$ 15,030

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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