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Stock-based Compensation (Weighted Average Grant Date Fair Value) (Details) - $ / shares
12 Months Ended
Dec. 29, 2017
Dec. 30, 2016
Jan. 01, 2016
Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average grant-date fair value (in dollars per share) $ 11.42 $ 4.77 $ 2.55
ESPP [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average grant-date fair value (in dollars per share) $ 6.00 $ 2.17 $ 1.20