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Fair Value Measures - Additional Information (Detail) - USD ($)
$ in Thousands
Sep. 26, 2015
Dec. 27, 2014
Sep. 27, 2014
Dec. 28, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Cash and cash equivalents balance $ 134,612 $ 76,402 $ 57,178 $ 49,524
Money market fund $ 126,500 $ 68,800