Aggregate Cash and Cash Equivalents (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 25, 2014	Jul. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 17,475	$ 21,041
Gross Unrealized Gains
Gross Unrealized Losses
Fair Market Value	17,475	21,041
Cash and cash equivalents
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,475	21,041
Gross Unrealized Gains
Gross Unrealized Losses
Fair Market Value	$ 17,475	$ 21,041