Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 11,130	$ 8,709
Restricted cash		171
Short-term investments	14,748	15,458
Accounts receivable, net	386	1,053
Inventories	1,073	1,710
Other inventory supplies	140	140
Prepaid expenses and other current assets	284	488
Assets held for sale	529	3,957
Total current assets	28,290	31,686
Inventories, non-current	468	468
Property and equipment, net	2,482	2,647
Total assets	31,240	34,801
Liabilities and stockholders’ equity
Accounts payable	497	733
Accrued payroll	211	53
Accrued and other current liabilities	201	344
Corporate income and franchise taxes	307	296
Accrued real estate taxes	71	114
Advance payments	18	16
Total current liabilities	1,305	1,556
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; 2,971,283 and 2,955,253 shares issued; 2,422,255 and 2,702,171 shares outstanding	29	29
Additional paid-in capital	376,456	376,306
Treasury stock, at cost, 549,028 and 253,082 shares	(15,147)	(12,749)
Accumulated other comprehensive loss		(1)
Accumulated deficit	(331,403)	(330,340)
Total stockholders’ equity	29,935	33,245
Total liabilities and stockholders’ equity	$ 31,240	$ 34,801