Derivatives and Hedging Activities Assets Liabilities Balance Sheet Location (Details) - Foreign Exchange Contract [Member] - USD ($) $ in Thousands	Sep. 28, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	$ 5	$ 33
Derivative Liability, Current	195	4
Not Designated as Hedging Instrument [Member] \| Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	5	33
Not Designated as Hedging Instrument [Member] \| Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	$ 195	$ 4

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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