Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 9,489	$ 11,241
Restricted cash	172	169
Short-term investments	16,210	14,356
Accounts receivable, net	613	733
Inventories	2,100	2,130
Other inventory supplies	140	183
Prepaid expenses and other current assets	216	109
Assets held for sale	4,145	4,145
Total current assets	33,085	33,066
Property and equipment, net	2,709	2,728
Total assets	35,794	35,794
Liabilities and stockholders' equity
Accounts payable	347	400
Accrued payroll	111	28
Accrued and other current liabilities	287	345
Corporate income and franchise taxes	283	286
Accrued real estate taxes	133	96
Advance payments	16	39
Total current liabilities	1,177	1,194
Total liabilities	1,177	1,194
Commitments and contingencies (Note 7)
Stockholders' equity
Preferred stock, $.001 par value, 1,000,000 undesignated shares authorized, no shares issued or outstanding
Common stock, $.001 par value, 8,200,000 shares authorized; 2,921,488 and 2,919,542 shares issued; 2,731,548 and 2,733,601 shares outstanding	29	29
Additional paid-in capital	375,990	375,979
Treasury stock, at cost, 189,940 and 185,941 shares	(12,244)	(12,213)
Accumulated other comprehensive loss	(21)	(2)
Accumulated deficit	(329,137)	(329,193)
Total stockholders' equity	34,617	34,600
Total liabilities and stockholders' equity	$ 35,794	$ 35,794