Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Cost, finite-lived	$ 17,630	$ 17,630
Accumulated Amortization, finite-lived	(2,962)	(2,645)
Total	14,668	14,985
Cost, indefinite lived	33,586	33,586
Accumulated Amortization, indefinite-lived	(2,962)	(2,645)
Net, indefinite-lived	30,624	30,941
In-process research and development, indefinite lives
Finite-Lived Intangible Assets [Line Items]
Cost, indefinite lived	15,956	15,956
Accumulated Amortization, indefinite-lived	0	0
Net, indefinite-lived	15,956	15,956
Raw material supply agreement
Finite-Lived Intangible Assets [Line Items]
Cost, finite-lived	6,230	6,230
Accumulated Amortization, finite-lived	(1,653)	(1,551)
Total	$ 4,577	$ 4,679
Weighted Average Remaining Life	9 years 9 months	10 years
Renewable hydrocarbon diesel technology
Finite-Lived Intangible Assets [Line Items]
Cost, finite-lived	$ 8,300	$ 8,300
Accumulated Amortization, finite-lived	(1,014)	(876)
Total	$ 7,286	$ 7,424
Weighted Average Remaining Life	13 years 3 months	13 years 6 months
Ground lease
Finite-Lived Intangible Assets [Line Items]
Cost, finite-lived	$ 200	$ 200
Accumulated Amortization, finite-lived	(116)	(112)
Total	$ 84	$ 88
Weighted Average Remaining Life	5 years 6 months 24 days	5 years 10 months 24 days
Acquired customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost, finite-lived	$ 2,900	$ 2,900
Accumulated Amortization, finite-lived	(179)	(106)
Total	$ 2,721	$ 2,794
Weighted Average Remaining Life	9 years 4 months	9 years 7 months