Net Income (Loss) Per Common Share - Computation of Net Loss Per Share (Detail) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 6 Months Ended
Jan. 31, 2015
Jan. 31, 2014
Jan. 31, 2015
Jan. 31, 2014
Earnings Per Share [Abstract]        
Net income (loss) $ 5,683 $ (10,701) $ 8,426 $ (18,528)
Weighted-average shares outstanding - basic 107,891 107,153 108,132 109,608
Dilutive effect of potential shares 5,502 0 6,579 0
Weighted-average shares outstanding - diluted 113,393 107,153 114,711 109,608
Net income (loss) per share - basic (in dollars per share) $ 0.05 $ (0.10) $ 0.08 $ (0.17)
Net income (loss) per share - diluted (in dollars per share) $ 0.05 $ (0.10) $ 0.07 $ (0.17)