v2.4.0.6
Stock-based Compensation - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended 1 Months Ended 12 Months Ended
Jul. 28, 2012
Year
Jul. 30, 2011
Jul. 31, 2010
Sep. 23, 2010
2010 Stock Plan
Jul. 28, 2012
2010 Stock Plan
Jul. 28, 2012
Employee Stock Option
Jul. 28, 2012
Employee Stock Option
Minimum
Jul. 28, 2012
Employee Stock Option
Maximum
Jul. 28, 2012
Restricted Equity Awards
Jul. 28, 2012
Service-based Restricted Equity Awards
Year
Jul. 28, 2012
Performance-based Restricted Equity Awards
Year
Jul. 28, 2012
Market-based Restricted Equity Awards
Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Aggregate number of share that may be issued under Stock Incentive Plan       18,000,000                
Shares available for future grants under stock incentive plan         7,300,000              
Stock options vesting period             4 years 5 years   4 years 3 years 3 years
Stock options, maximum period of expiration           10 years            
Total unrecognized compensation costs related to non-vested option $ 23.8                 $ 12.6 $ 9.1 $ 2.0
Weighted-average recognition period for unrecognized compensation cost related to non-vested stock awards 2.4                 3.1 1.4 1.5
Total intrinsic value of options exercised 25.5 21.4 20.3                  
Total fair value of options vested $ 10.3 $ 8.4 $ 6.4                  
Share based award description                 The 2010 Stock Plan also allows for the issuance of shares of restricted stock and restricted stock units ("RSUs"). Any shares of restricted stock or RSUs are counted against the shares available for future grant limit as three shares for every one restricted share or unit granted. In general, if options are cancelled for any reason or expire, the shares covered by such options again become available for grant. If a share of restricted stock or an RSU unit is forfeited for any reason, three shares become available for grant.      
Number of shares issuable per vesting of one restricted stock or unit                 3      
Number of shares available for grant upon forfeiture of restricted stock or unit                 3