Consolidated Financial Statement Details - Consolidated Balance Sheets (Details) - USD ($) |
12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Jan. 03, 2021 |
Dec. 29, 2019 |
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| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Trade accounts receivable | $ 70,248,000 | $ 71,113,000 | ||||||||||
| Other receivables | 1,836,000 | 1,098,000 | ||||||||||
| Allowance for doubtful accounts | (2,457,000) | (2,292,000) | ||||||||||
| Accounts receivable—net | 69,627,000 | 69,919,000 | ||||||||||
| Opening | 26,271,000 | 20,405,000 | ||||||||||
| Contract assets additions | 368,142,000 | 358,043,000 | ||||||||||
| Contract assets invoiced | (355,077,000) | (352,177,000) | ||||||||||
| Ending | 39,336,000 | 26,271,000 | ||||||||||
| Raw materials | 50,793,000 | 48,067,000 | ||||||||||
| Parts and other | 482,000 | 586,000 | ||||||||||
| Provision for obsolescence | (1,476,000) | (827,000) | ||||||||||
| Inventories | 49,799,000 | 47,826,000 | ||||||||||
| Property, plant and equipment | 75,864,000 | 72,614,000 | ||||||||||
| Accumulated depreciation, property, plant and equipment | (51,559,000) | (47,304,000) | ||||||||||
| Property, plant and equipment—net | 24,305,000 | 25,310,000 | ||||||||||
| Intangible assets | 21,000,000 | 21,000,000 | ||||||||||
| Intangible assets, accumulated amortization | (11,299,000) | (8,253,000) | ||||||||||
| Total amortization | 9,701,000 | 12,747,000 | ||||||||||
| Goodwill | 18,165,000 | 18,165,000 | ||||||||||
| Payroll | 8,084,000 | 5,504,000 | ||||||||||
| Deferred revenue | 4,152,000 | 0.0 | ||||||||||
| Professional services | 1,284,000 | 612,000 | ||||||||||
| Interest | 426,000 | 483,000 | ||||||||||
| Total | 21,946,000 | 11,164,000 | ||||||||||
| Customer Related [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Other accrued liabilities | 6,177,000 | 2,185,000 | ||||||||||
| Vendor Related [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Other accrued liabilities | 904,000 | 1,742,000 | ||||||||||
| Other Accrued Liabilities [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Other accrued liabilities | 919,000 | 638,000 | ||||||||||
| US [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Total amortization | 2,910,000 | 3,824,000 | ||||||||||
| Goodwill | 5,449,000 | 5,449,000 | ||||||||||
| Mexico [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Total amortization | 6,791,000 | 8,923,000 | ||||||||||
| Goodwill | 12,716,000 | 12,716,000 | ||||||||||
| Customer Relationships [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Intangible assets | 12,350,000 | 12,350,000 | ||||||||||
| Intangible assets, accumulated amortization | (2,649,000) | (1,414,000) | ||||||||||
| Order Backlog [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Intangible assets | 6,990,000 | 6,990,000 | ||||||||||
| Intangible assets, accumulated amortization | (6,990,000) | (5,333,000) | ||||||||||
| Trade Name [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Intangible assets | 1,300,000 | 1,300,000 | ||||||||||
| Intangible assets, accumulated amortization | (1,300,000) | (1,300,000) | ||||||||||
| Non-compete Agreements [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Intangible assets | 360,000 | 360,000 | ||||||||||
| Intangible assets, accumulated amortization | (360,000) | (206,000) | ||||||||||
| Land [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Property, plant and equipment | 1,648,000 | 1,648,000 | ||||||||||
| Buildings [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Property, plant and equipment | [1] | 19,828,000 | 18,985,000 | |||||||||
| Accumulated depreciation, property, plant and equipment | [1] | (11,498,000) | (10,392,000) | |||||||||
| Machinery and Equipment [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Property, plant and equipment | [2],[3] | 44,996,000 | 42,732,000 | |||||||||
| Accumulated depreciation, property, plant and equipment | [2],[3] | (34,182,000) | (31,192,000) | |||||||||
| Furniture and Fixtures [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Property, plant and equipment | [3],[4] | 949,000 | 1,005,000 | |||||||||
| Accumulated depreciation, property, plant and equipment | [3],[4] | (455,000) | (546,000) | |||||||||
| Computer Hardware and Software [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Property, plant and equipment | [3],[5] | 4,056,000 | 3,979,000 | |||||||||
| Accumulated depreciation, property, plant and equipment | [3],[5] | (3,270,000) | (3,289,000) | |||||||||
| Leasehold Improvements [Member] | ||||||||||||
| Condensed Balance Sheet Statements Captions [Line Items] | ||||||||||||
| Property, plant and equipment | [3] | 4,387,000 | 4,265,000 | |||||||||
| Accumulated depreciation, property, plant and equipment | [3] | $ (2,154,000) | $ (1,885,000) | |||||||||
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