Valuation Allowances and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Allowance for Doubtful Accounts & Returned Goods [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 282	$ 282	$ 330
Charges to Cost and Expenses	37	5	48
Charges to Other Accounts	0	0	0
Deduction from Reserves	0	(5)	(96)
Balance at End of Year	319	282	282
Allowance for Excess and Obsolete Inventory [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	82	38	39
Charges to Cost and Expenses	384	44	0
Charges to Other Accounts	0	0	0
Deduction from Reserves	0	0	(1)
Balance at End of Year	$ 466	$ 82	$ 38