Consolidated Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue and cost of goods sold
Hydrocarbon revenue	$ 192	$ 778	$ 1,449	$ 3,426
Grant and other revenue	274	166	787	620
Total revenues	8,017	10,141	22,840	18,765
Cost of goods sold	10,629	11,760	29,761	24,709
Gross loss	(2,612)	(1,619)	(6,921)	(5,944)
Operating expenses
Research and development expense	1,527	3,723	5,014	11,414
Selling, general and administrative expense	5,135	3,570	13,406	13,508
Total operating expenses	6,662	7,293	18,420	24,922
Loss from operations	(9,274)	(8,912)	(25,341)	(30,866)
Other (expense) income
Interest expense	(2,121)	(2,017)	(6,186)	(6,227)
Interest expense - debt issue costs		(581)		(3,766)
Gain on conversion of debt			285
Gain on extinguishment of warrant liability			1,775
Gain from change in fair value of embedded derivatives of the 2022 Notes		726		3,470
Gain from change in fair value of the 2017 Notes	157	5,673	3,582	544
Gain (loss) from change in fair value of derivative warrant liability	4,719	4,173	(2,361)	6,772
Other income			14	7
Total other income (expense)	2,755	7,974	(2,891)	800
Net loss	$ (6,519)	$ (938)	$ (28,232)	$ (30,066)
Net loss per share - basic and diluted	$ (0.39)	$ (0.16)	$ (2.22)	$ (6.07)
Weighted-average number of common shares outstanding - basic and diluted	16,688,632	5,808,079	12,700,844	4,956,994
Ethanol
Revenue and cost of goods sold
Sales	$ 7,551	$ 9,197	$ 20,604	$ 14,719