Summary of Significant Accounting Policies - Summary of Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance .	$ 72	$ 72	$ 72
Adjustment	(30)
Write off
Ending balance .	$ 42	$ 72	$ 72