Equity Incentive Plans and Benefit Plans - Shares Available for Grant and Outstanding Stock Option Activity (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
 6 Months Ended 12 Months Ended
Jan. 31, 2015
Jul. 31, 2014
Jul. 31, 2013
Shares Available for Grant:      
Beginning balance 3,247,237 557,585  
Shares reserved for issuance 5,377,830 5,670,469  
Options cancelled 15,547 131,142  
Ending balance 6,650,687 3,247,237 557,585
Options Outstanding, Number of shares:      
Beginning balance 7,138,115 10,047,569  
Options exercised (1,996,705) (2,778,312)  
Options cancelled (15,547) (131,142)  
Ending balance 5,125,863 7,138,115 10,047,569
Options Outstanding, Weighted Average Exercise Price Per Share (in dollars per share):      
Beginning balance $ 7.03 $ 6.29  
Options exercised $ 3.89 $ 3.73  
Options cancelled $ 21.82 $ 19.98  
Ending balance $ 8.21 $ 7.03 $ 6.29
Weighted average remaining contractual term (in years) 1 year 7 months 6 days 2 years 2 years 11 months 5 days
Aggregate Intrinsic Value:      
Beginning balance $ 82,533 $ 121,227  
Options exercised 32,147 42,871  
Ending balance $ 49,331 $ 82,533 $ 121,227
Restricted stock awards [Member]      
Shares Available for Grant:      
Awards granted (2,441,672) (4,350,155)  
Awards forfeited 1,016,745 1,238,196  
Market stock units [Member]      
Shares Available for Grant:      
Awards granted (595,000)    
Awards forfeited 30,000