CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 4,968	$ (2,139)	$ (12,129)
Defined benefit plans:
Net change in plan assets	(498)	(485)	316
Reclassification into other income (expense), net	101	73	101
Foreign currency translation gain	242	387	224
Tax effect	(15)	(75)	(111)
Other comprehensive income (loss), net of tax	(170)	(100)	530
Comprehensive income (loss)	$ 4,798	$ (2,239)	$ (11,599)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount before tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount, before tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for net period benefit cost (credit) of defined benefit plan.

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