CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 5,360,000	$ 5,990,000
Accounts receivable, net	15,000	424,000
Inventory, net	127,000	239,000
Prepaid expenses and other current assets	421,000	243,000
Total current assets	5,923,000	6,896,000
Operating lease - right of use asset, net	0	17,000
Other assets	12,000	12,000
Total assets	5,935,000	6,925,000
Current liabilities:
Accounts payable	351,000	211,000
Accrued expenses and other current liabilities	1,031,000	1,038,000
Current portion of deferred revenue	105,000	132,000
Operating lease liabilities	0	17,000
Total current liabilities	1,487,000	1,398,000
Long-term liabilities:
Deferred revenue, net of current portion	14,000	26,000
Total liabilities	1,501,000	1,424,000
Commitments and contingencies (see Note 9)
Stockholders’ equity:
Preferred stock Series F, convertible; $.0001 par value; $1,102,150 stated value; 42,000 shares authorized, 1,008 and 1,930 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	0	0
Common stock, $.0001 par value; 150,000,000 shares authorized; 20,294,228 shares issued and 20,285,675 outstanding at March 31, 2024 and 16,692,124 shares issued and 16,683,572 shares outstanding at December 31, 2023	2,000	2,000
Treasury stock, 8,000 shares of common stock	(181,000)	(181,000)
Additional paid-in capital	233,980,000	233,911,000
Accumulated deficit	(229,367,000)	(228,231,000)
Total stockholders' equity	4,434,000	5,501,000
Total liabilities and stockholders’ equity	$ 5,935,000	$ 6,925,000