Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
Apr. 01, 2017	Mar. 26, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 5,352	$ 3,467
Other comprehensive income (loss):
Change in foreign currency translation adjustment	1,945	952
Net change on unrealized gains on available-for-sale investments	(9)	35
Other comprehensive income (loss):	1,936	987
Comprehensive income	$ 7,288	$ 4,454

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831270

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Amount after 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 and reclassification adjustments of other comprehensive income (loss).

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