Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 29,933	$ 15,736
Investment securities	0	62,207
Prepaid expenses and other current assets	800	859
Total current assets	30,733	78,802
Property, plant and equipment, net	158,363	134,591
Operating lease right-of-use assets, net	675	1,054
Other non-current assets, net	15,096	6,748
Total assets	204,867	221,195
Current liabilities
Accounts payable	561	11,912
Share-based compensation liability	182	182
Accrued liabilities and other current liabilities	1,374	8,751
Current common stock warrant liabilities	4,655	0
Current operating lease liabilities	596	698
Total current liabilities	7,368	21,543
Non-current common stock warrant liabilities	1,233	12,034
Non-current operating lease liabilities	0	3
Other non-current liabilities	21,670	0
Total liabilities	30,271	33,580
Commitments and contingencies (Note 13)
Stockholders’ equity
Common stock, $0.0001 par value Authorized: 480.0 million shares at September 30, 2020 and December 31, 2019 Issued and outstanding: 117.7 million shares and 117.3 million shares at September 30, 2020 and December 31, 2019, respectively	12	12
Treasury stock: 281,036 shares and 137,860 shares at September 30, 2020 and December 31, 2019, respectively, at cost	(1,007)	(685)
Preferred stock, $0.0001 par value Authorized: 0.9 million, after designation of the Series A and Series B Convertible Preferred Stock Issued and outstanding: none at September 30, 2020 and December 31, 2019	0	0
Additional paid-in-capital	212,807	224,091
Accumulated deficit	(145,751)	(133,701)
Total stockholders’ equity	66,061	89,717
Total liabilities, Series A and Series B Convertible Preferred Stock and stockholders’ equity	204,867	221,195
Series A Convertible Preferred Stock [Member]
Current liabilities
Convertible Preferred Stock	53,586	48,084
Series B Convertible Preferred Stock [Member]
Current liabilities
Convertible Preferred Stock	$ 54,949	$ 49,814