Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
	Oct. 31, 2011	Oct. 31, 2010
Consolidated Statements Of Cash Flows [Abstract]
Net loss	$ (2,361,000)	$ (2,022,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	377,000	308,000
Depreciation and amortization	117,000	118,000
Changes in operating assets and liabilities:
Accounts receivable	(69,000)	(110,000)
Inventories	11,000	(122,000)
Prepaid expenses	8,000	70,000
Accounts payable and accrued liabilities	438,000	190,000
Deferred revenue	0	345,000
Deferred rent	(4,000)	(2,000)
Net cash used in operating activities	(1,483,000)	(1,225,000)
Investing activities
Investment in patents	(39,000)	(40,000)
Net cash used in investing activities	(39,000)	(40,000)
Financing activities
Net proceeds from the sale of common stock	720,000	2,367,000
Net proceeds from exercise of stock options and warrants	0	385,000
Net cash provided by financing activities	720,000	2,752,000
Net increase (decrease) in cash and cash equivalents	(802,000)	1,487,000
Cash and cash equivalents at beginning of period	1,794,000	2,193,000
Cash and cash equivalents at end of period	992,000	3,680,000
Supplemental disclosure of cash flow information
Cash paid for taxes	1,000	0
Supplemental disclosure of non-cash investing and financing activities
Common stock issued for prepaid services	$ 97,000	$ 0