Consolidated Balance Sheets - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash and cash equivalents	$ 11,260,000	$ 11,130,000
Short-term investments	14,751,000	14,748,000
Accounts receivable, net	719,000	386,000
Inventories	658,000	1,073,000
Other inventory supplies	133,000	140,000
Prepaid expenses and other current assets	167,000	284,000
Assets held for sale	529,000	529,000
Total current assets	28,217,000	28,290,000
Inventories, non-current	468,000	468,000
Property and equipment, net	2,301,000	2,482,000
Total assets	30,986,000	31,240,000
Liabilities and stockholders’ equity
Accounts payable	545,000	497,000
Accrued payroll	426,000	211,000
Accrued and other current liabilities	220,000	201,000
Corporate income and franchise taxes	327,000	307,000
Accrued real estate taxes	78,000	71,000
Advance payments	2,000	18,000
Total current liabilities	1,598,000	1,305,000
Commitments and contingencies (see Note 10)
Stockholders’ equity
Preferred stock, $0.001 par value, 1,000,000 undesignated shares authorized, no shares issued or outstanding
Common stock, $0.001 par value 8,200,000 shares authorized; 2,995,680 and 2,971,283 shares issued; 2,446,652 and 2,422,255 shares outstanding	29,000	29,000
Additional paid-in capital	376,640,000	376,456,000
Treasury stock, at cost, 549,028 and 549,028 shares	(15,147,000)	(15,147,000)
Accumulated other comprehensive loss	(1,000)
Accumulated deficit	(332,133,000)	(331,403,000)
Total stockholders’ equity	29,388,000	29,935,000
Total liabilities and stockholders’ equity	$ 30,986,000	$ 31,240,000