Employee benefit plan (Details) - Schedule of contrubutions plan (USD $) In Thousands, unless otherwise specified	12 Months Ended
Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Schedule of contrubutions plan [Abstract]
Contributions	$ 467	$ 521	$ 483

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration