Condensed Consolidated Balance Sheets - USD ($)	Jan. 31, 2019	Jul. 31, 2018
Current assets
Cash and cash equivalents	$ 335,000	$ 851,000
Accounts receivable	129,000	275,000
Inventories, net	205,000	197,000
Restricted cash	75,000	75,000
Prepaid expenses	49,000	58,000
Total current assets	793,000	1,456,000
Property, plant and equipment, net	416,000	461,000
Patents, net	568,000	658,000
Total assets	1,777,000	2,575,000
Current liabilities
Accounts payable	525,000	608,000
Accrued liabilities	125,000	170,000
Promissory note payable		503,000
Total current liabilities	650,000	1,281,000
Deferred rent	10,000	13,000
Total liabilities	660,000	1,294,000
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: 100,000,000 shares authorized, 71,713,372 shares issued and outstanding at January 31, 2019, and 68,248,158 shares issued and outstanding at July 31, 2018	717,000	683,000
Additional paid-in capital	121,186,000	117,522,000
Accumulated deficit	(120,786,000)	(116,924,000)
Total stockholders' equity	1,117,000	1,281,000
Total liabilities and stockholders' equity	$ 1,777,000	$ 2,575,000