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Stock Option And Benefit Plans (Grant Date Fair Value For Awards Estimated Using Option Valuation Method With Weighted Average Assumptions) (Detail)
3 Months Ended 6 Months Ended 12 Months Ended
Oct. 21, 2010
Jan. 26, 2012
Jul. 27, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected dividend yield 0.00% 0.00% 0.00%
Risk - free interest rate 0.73% 0.52% 1.16%
Expected volatility 68.30% 64.90% 65.50%
Expected life 3 years 6 months 22 days 4 years 4 years