Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue and cost of goods sold
Revenue from contract with Customer	$ 988	$ 5,058	$ 4,813	$ 11,461
Other revenue	46	28	46	28
Total revenues	988	5,086	4,813	11,489
Cost of goods sold	2,644	8,452	10,783	17,413
Gross loss	(1,656)	(3,366)	(5,970)	(5,924)
Operating expenses:
Research and development expense	677	945	1,257	1,923
Selling, general and administrative expense	2,919	2,182	5,702	4,274
Restructuring expenses	5		304
Total operating expenses	3,601	3,127	7,263	6,197
Loss from operations	(5,257)	(6,493)	(13,233)	(12,121)
Other income (expense):
Interest expense	(541)	(767)	(1,086)	(1,522)
(Loss) on modification of 2020 Notes	(57)		(726)
Gain from change in fair value of derivative warrant liability	1	2	8	3
(Loss) gain from change in fair value of 2020/21 Notes and 2020 Notes embedded derivative liability	(176)	148	(276)	394
Other income (expense)	(13)	20	17	20
Total other income (expense), net	(786)	(597)	(2,063)	(1,105)
Net loss	$ (6,043)	$ (7,090)	$ (15,296)	$ (13,226)
Net loss per share - basic and diluted (in dollars per share)	$ (0.40)	$ (0.60)	$ (1.04)	$ (1.20)
Weighted-average number of common shares outstanding - basic and diluted (in shares)	15,071,105	11,885,524	14,771,952	11,024,482
Ethanol Sales and Related Products [Member]
Revenue and cost of goods sold
Revenue from contract with Customer	$ 83	$ 4,966	$ 3,783	$ 10,630
Total revenues	83	4,996	3,783	10,630
Hydrocarbon [Member]
Revenue and cost of goods sold
Revenue from contract with Customer	859	92	984	831
Total revenues	$ 859	$ 92	$ 984	$ 831