Quarterly report pursuant to Section 13 or 15(d)

Share-based compensation (Detail)

v2.4.0.6
Share-based compensation (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
6 Months Ended
Jan. 17, 2013
Jan. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures 336,817  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 2.88 336,817
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term 3 years 109 days  
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate 60.80%  
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate 0.45%  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options (in Dollars)   $ 0.4
Employee Service Share-based Compensation, Unrecognized Compensation Costs on Nonvested Awards, Weighted Average Period of Recognition (Deprecated 2011-01-31)   2.2
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in Dollars)   $ 0.4
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   2,320,000
Vests Over Two Years [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures 247,672  
Vests Over Three Years [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures 89,145