Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 7,029	$ 11,553
Accounts receivable	1,288	1,054
Inventories	4,356	4,362
Prepaid expenses and other current assets	633	712
Total current assets	13,306	17,681
Property, plant and equipment, net	68,764	70,369
Deposits and other assets	803	803
Total assets	82,873	88,853
Current liabilities:
Accounts payable and accrued liabilities	3,467	4,011
2020 Notes embedded derivative liability	2,366	5,224
Derivative warrant liability	1,474	1,951
Total current liabilities	7,307	11,186
Other long-term liabilities	117	130
Total liabilities	21,317	25,322
Commitments and Contingencies (see Note 11)
Stockholders' Equity
Common Stock, $0.01 par value per share; 250,000,000 authorized, 22,696,112 and 21,811,059 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively.	227	218
Additional paid-in capital	465,181	464,663
Accumulated deficit	(403,852)	(401,350)
Total stockholders' equity	61,556	63,531
Total liabilities and stockholders' equity	82,873	88,853
Convertible 2020 Notes [Member]
Current liabilities:
2020 Notes, net	13,893	13,491
Convertible 2022 Notes [Member]
Current liabilities:
2020 Notes, net		$ 515