Consolidated Balance Sheets - USD ($)	Jul. 31, 2022	Jul. 31, 2021
Current assets
Cash and cash equivalents	$ 3,391,000	$ 2,390,000
Accounts receivable	201,000	368,000
Inventories, net	179,000	332,000
Restricted cash	75,000	75,000
Prepaid expenses	18,000	32,000
Total current assets	3,864,000	3,197,000
Property, plant and equipment, net	620,000	740,000
Patents, net		366,000
Total assets	4,484,000	4,303,000
Current liabilities
Accounts payable	488,000	593,000
Accrued liabilities	87,000	138,000
Loan payable		239,000
Total current liabilities	575,000	970,000
Total liabilities	575,000	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, 111,356,473 shares issued and outstanding at July 31, 2022, and 87,223,141 shares issued and outstanding at July 31, 2021	1,114,000	873,000
Additional paid-in capital	132,079,000	128,253,000
Accumulated deficit	(129,284,000)	(125,793,000)
Total stockholders’ equity	3,909,000	3,333,000
Total liabilities and stockholders’ equity	$ 4,484,000	$ 4,303,000