Leases and Other Commitments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Oct. 31, 2013	Oct. 31, 2012
Lease and Rental Expense [Line Items]
Rent expense associated with the Company's operating leases	$ 0.6	$ 0.3
Outstanding non-cancelable purchase orders	$ 42.8

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

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