Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Reserve for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period			$ 39		$ 40
Charged to expense	268				2
Deductions	(129)	[1]	(39)	[1]	(3)	[1]
Balance at end of period	139				39
Reserve for excess and obsolete inventory
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	41,817	[2]	42,392	[2]	42,978	[2]
Charged to expense	3,727	[2]	1,822	[2]	2,360	[2]
Transfers, Net	2,370	[2],[3]	359	[2],[3]	304	[2],[3]
Deductions	(2,656)	[1],[2]	(2,756)	[1],[2]	(3,250)	[1],[2]
Balance at end of period	$ 45,258	[2]	$ 41,817	[2]	$ 42,392	[2]

[1] Represents amounts written off or utilization of reserve or recovery of previously written off amounts.

[2] Amounts charged to expense and recorded in cost of sales are costs relating to product deemed defective or unusable during the normal manufacturing process which total $3.7 million, $1.8 million and $2.4 million for fiscal years 2014, 2013, and 2012, respectively. Deductions, which totaled $2.7 million, $2.8 million and $3.3 million for the fiscal years 2014, 2013 and 2012, respectively, are also recorded to cost of sales and primarily represent scrapping of inventory no longer in use, with some release of reserves related to sales of previously reserved inventory,

[3] Represents transfers from fully reserved vendor liability obligations and internal capital equipment and transfers to fixed assets.