Revenue and Net Income (Loss) of Discontinued Operation (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Oct. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total net revenue		$ 2,906	$ 8,784
Net income (loss)	$ 289	$ 289	$ (244)