Employee Benefit Plan - Additional Information (Detail) - USD ($)	12 Months Ended
Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Company's contribution to defined-contribution retirement plan ("401(k) Plan")	$ 0	$ 0	$ 0

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