Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 8,709	$ 11,241
Restricted cash	171	169
Short-term investments	15,458	14,356
Accounts receivable, net	1,053	733
Inventories	1,710	2,130
Other inventory supplies	140	183
Prepaid expenses and other current assets	488	109
Assets held for sale	3,957	4,145
Total current assets	31,686	33,066
Inventories, non-current	468
Property and equipment, net	2,647	2,728
Total assets	34,801	35,794
Liabilities and stockholders' equity
Accounts payable	733	400
Accrued payroll	53	28
Accrued and other current liabilities	344	345
Corporate income and franchise taxes	296	286
Accrued real estate taxes	114	96
Advance payments	16	39
Total current liabilities	1,556	1,194
Commitments and contingencies
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; 2,955,253 and 2,919,542 shares issued; 2,702,171 and 2,733,601 shares outstanding	29	29
Additional paid-in capital	376,306	375,979
Treasury stock, at cost, 253,082 and 185,941 shares	(12,749)	(12,213)
Accumulated other comprehensive loss	(1)	(2)
Accumulated deficit	(330,340)	(329,193)
Total stockholders' equity	33,245	34,600
Total liabilities and stockholders' equity	$ 34,801	$ 35,794