Condensed Consolidated Balance Sheets - USD ($)	Oct. 31, 2021	Jul. 31, 2021
Current assets
Cash and cash equivalents	$ 1,760,000	$ 2,390,000
Accounts receivable	238,000	368,000
Inventories, net	312,000	332,000
Restricted cash	75,000	75,000
Prepaid expenses	68,000	32,000
Total current assets	2,453,000	3,197,000
Property, plant and equipment, net	769,000	740,000
Patents, net	333,000	366,000
Total assets	3,555,000	4,303,000
Current liabilities
Accounts payable	465,000	593,000
Accrued liabilities	124,000	138,000
Loan payable	239,000	239,000
Total current liabilities	828,000	970,000
Commitments and contingencies
Stockholders’ equity
Preferred stock, $0.01 par value: 5,000,000 shares authorized, no shares issued and outstanding
Common stock, $0.01 par value: 150,000,000 shares authorized, 87,873,141 shares issued and outstanding at October 31, 2021, and 87,223,141shares issued and outstanding at July 31, 2021	879,000	873,000
Additional paid-in capital	128,437,000	128,253,000
Accumulated deficit	(126,589,000)	(125,793,000)
Total stockholders’ equity	2,727,000	3,333,000
Total liabilities and stockholders’ equity	$ 3,555,000	$ 4,303,000