Net Loss and Diluted Loss Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended													12 Months Ended
	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014		Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Net income (loss)	$ 9,537	$ (200)	$ (1,604)	[1]	$ (6,900)	$ (4,656)	$ (4,744)	$ (3,276)	$ 549	$ 1,356	$ (6,628)	$ (9,688)	$ (4,909)	$ 833	$ (12,127)	$ (19,869)
Basic EPS
Weighted average shares outstanding-basic														48,214	47,719	49,080
Basic EPS	$ 0.20	$ 0.00	$ (0.03)	[1]	$ (0.14)									$ 0.02	$ (0.25)	$ (0.40)
Diluted EPS
Weighted average shares outstanding-basic														48,214	47,719	49,080
Plus: impact of stock options and unvested restricted stock units														936
Weighted average shares outstanding-diluted														49,150	47,719	49,080
Diluted EPS	$ 0.19	$ 0.00	$ (0.03)	[1]	$ (0.14)									$ 0.02	$ (0.25)	$ (0.40)

[1] The results for the second quarter of 2014, as presented here, reflect the impact of retroactive accounting treatment for $2.6 million of bargain purchase gain, ($1.4) million of which was recorded in the third quarter of 2014 and $4 million of which was recorded in the fourth quarter of 2014.