Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 19,664	$ 19,543
Restricted cash	5	5
Investments in debt securities- short term	4,970	4,415
Trade accounts receivable, net of allowance for doubtful accounts	273	303
Inventory	0	12
Prepaid expenses and other current assets	293	322
Total current assets	25,205	24,600
Investments in debt securities- long term	5,533	7,074
Property and equipment, net	8,832	8,819
Patents and trademarks, net	218	239
Equipment held for sale	585	585
Other Assets	137	14
Total assets	40,510	41,331
Current liabilities:
Accounts payable	81	132
Accrued liabilities	712	775
Total current liabilities	793	907
Long-term liabilities
Other long-term liabilities	899	856
Total liabilities	1,692	1,763
Shareholders' equity:
Preferred Stock, $0.001 par value; 10,000,000 shares authorized; 0 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively
Common stock, $0.001 par value; 1,100,000,000 shares authorized; 914,449,957 and 914,449,957 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively	914	914
Warrants	18,179	18,179
Additional paid-in capital	286,924	286,832
Accumulated deficit	(267,030)	(266,284)
Accumulated other comprehensive income (loss)	(94)	2
Non-controlling interest in subsidiary	(75)	(75)
Total shareholders' equity	38,818	39,568
Total liabilities and shareholders' equity	$ 40,510	$ 41,331