Net Income (Loss) Per Common Share - Summary of Outstanding Stock Options and Awards (Detail)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jan. 31, 2015
Jan. 31, 2014
Jan. 31, 2015
Jan. 31, 2014
Options to purchase common stock [Member]        
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive shares excluded from calculation of diluted net income (loss) per share 1,013 1,102 1,023 1,201
Restricted stock awards [Member]        
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive shares excluded from calculation of diluted net income (loss) per share 1,833 1,345 1,357 1,295
Market stock units [Member]        
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive shares excluded from calculation of diluted net income (loss) per share 580 0 429 0