Share-Based Compensation (Schedule Of Share-Based Compensation Expense Related To Stock Options And Restricted Stock Awards) (Details) (USD $)	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 720,000	$ 1,077,000
Employees And Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	718,000	1,082,000
Employees And Directors [Member] | Selling, General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	564,000	825,000
Employees And Directors [Member] | Research And Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	154,000	257,000
Consultants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	2,000	(5,000)
Consultants [Member] | Selling, General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	0	(5,000)
Consultants [Member] | Research And Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 2,000	$ 0