Share-Based Compensation (Schedule Of Share-Based Compensation Expense Related To Stock Options And Restricted Stock Awards) (Details) (Imported) (USD $)	3 Months Ended
	Oct. 31, 2012	Oct. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 188,000	$ 377,000
Employees And Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	187,000	385,000
Employees And Directors [Member] | Selling, General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	141,000	322,000
Employees And Directors [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	46,000	63,000
Consultants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	1,000	(8,000)
Consultants [Member] | Selling, General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	0	(8,000)
Consultants [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 1,000	$ 0