Income Taxes Income Tax Reconciliation, Narrative (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income Tax Disclosure [Abstract]
Change in valuation allowance	$ (569)	$ 1,190	$ 0
Research and development credits		304
Federal tax credits		520
Income taxes paid, net of tax refunds	$ 345us-gaap_IncomeTaxesPaidNet	$ 58us-gaap_IncomeTaxesPaidNet	$ 1,318us-gaap_IncomeTaxesPaidNet

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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-Name Accounting Standards Codification

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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