Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue	$ 8,243	$ 5,584
Grant and other revenue	25	32
Total revenues	8,243	5,616
Cost of goods sold	10,583	9,408
Gross loss	(2,340)	(3,792)
Operating expenses
Research and development expense	789	1,217
Selling, general and administrative expense	1,870	2,173
Total operating expenses	2,659	3,390
Loss from operations	(4,999)	(7,182)
Other (expense) income
Interest expense	(825)	(714)
(Loss) on exchange of debt	(21)	(964)
(Loss) from change in fair value of the 2017 Notes		(339)
Gain from change in fair value of derivative warrant liability	477	3,259
Gain from change in fair value of 2020 Notes embedded derivative	2,858
Other income	8	6
Total other expense, net	2,497	1,248
Net loss	$ (2,502)	$ (5,934)
Net loss per share - basic and diluted (in dollars per share)	$ (0.11)	$ (0.51)
Weighted-average number of common shares outstanding - basic and diluted (in shares)	22,534,727	11,584,595
Ethanol Sales and Related Products [Member]
Revenue	$ 8,218	$ 5,494
Total revenues	8,218	5,494
Hydrocarbon [Member]
Revenue		90
Total revenues		$ 90