Share-Based Compensation (Schedule Of Share-Based Compensation Expense Related To Stock Options And Restricted Stock Awards) (Details) (USD $)	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 153,000	$ 218,000	$ 583,000	$ 841,000
Employees And Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	144,000	218,000	572,000	848,000
Employees And Directors [Member] | Selling, General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	132,000	155,000	457,000	658,000
Employees And Directors [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	12,000	63,000	115,000	190,000
Consultants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	9,000	0	11,000	(7,000)
Consultants [Member] | Selling, General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	0	0	0	(7,000)
Consultants [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 9,000	$ 0	$ 11,000	$ 0