Tax Benefits Relating to Valuation Allowance for Deferred Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Income Taxes [Line Items]
Income tax benefit recognized in the consolidated statement of operations	$ 528	$ (403)	$ (220)
Valuation Allowance of Deferred Tax Assets
Income Taxes [Line Items]
Income tax benefit recognized in the consolidated statement of operations	(750,897)
Additional paid in capital	(15,461)
Deferred Tax Assets Valuation Allowance Additions	$ (766,358)