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Significant Accounting Policies - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Jan. 31, 2016
Jan. 25, 2015
Jan. 26, 2014
Restricted cash associated with certain lease commitments $ 0.5 $ 0.5  
Other Intangible Assets and Long-lived Assets [Abstract]      
Percent of realizable undiscounted cash flows used to determine useful life of acquired finite-lived intangible assets, minimum 90.00%    
Sales and Marketing [Abstract]      
Advertising costs $ 0.2 0.1 $ 0.1
Product Development and Engineering [Abstract]      
Recoveries from nonrecurring engineering services $ 21.1 $ 29.3 $ 17.6
Cash Equivalents [Member] | Maximum      
Investment maturity period 90 days