Leases - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Operating Leased Assets [Line Items]
Total future minimum rental payments	$ 1,726
Amounts due in fiscal year 2013	1,163
Amounts due in fiscal year 2014	360
Amounts due in fiscal year 2015	145
Amounts due in fiscal year 2016	37
Amounts due in fiscal year 2017	21
Rent expense	$ 1,874	$ 2,201	$ 2,139