Consolidated Statements Of Cash Flows (USD $)	9 Months Ended
	Apr. 30, 2012	Apr. 30, 2011
Consolidated Statements Of Cash Flows [Abstract]
Net loss	$ (6,383,000)	$ (6,318,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	841,000	807,000
Amortization of stock issued for services	59,000	0
Depreciation and amortization	299,000	352,000
Allowance for doubtful accounts	0	353,000
Changes in operating assets and liabilities:
Accounts receivable	(143,000)	(118,000)
Inventories	(40,000)	(161,000)
Prepaid expenses	47,000	(43,000)
Accounts payable and accrued liabilities	1,349,000	556,000
Deferred revenue	0	(10,000)
Deferred rent	(3,000)	(7,000)
Net cash used in operating activities	(3,974,000)	(4,589,000)
Investing activities
Investment in patents	(189,000)	(187,000)
Purchases of property, plant and equipment	(9,000)	(11,000)
Net cash used in investing activities	(198,000)	(198,000)
Financing activities
Net proceeds from the sale of common stock	2,667,000	2,367,000
Net proceeds from exercise of stock options and warrants	0	537,000
Net cash provided by financing activities	2,667,000	2,904,000
Net decrease in cash and cash equivalents	(1,505,000)	(1,883,000)
Cash and cash equivalents at beginning of period	1,794,000	2,193,000
Cash and cash equivalents at end of period	289,000	310,000
Supplemental disclosure of cash flow information
Cash paid for taxes	5,000	2,400
Supplemental disclosure of non-cash investing and financing activities
Common stock issued for prepaid services	142,000	0
Common stock issued under stock purchase agreement	$ 296,000	$ 0