Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Components of Intangible assets

Amortizing intangible assets consist of the following at December 31:

	December 31, 2017
	Cost		Accumulated Amortization			Net		Weighted Average Remaining Life
Raw material supply agreement	$	6,230	$	(2,408	)	$	3,822	8.0 years
Renewable diesel technology	8,300		(1,983		)	6,317		11.5 years
Acquired customer relationships	2,900		(686		)	2,214		7.6 years
Ground lease	200		(141		)	59		3.9 years
In-process research and development	15,956		(1,241		)	14,715		13.8 years
Total intangible assets	$	33,586	$	(6,459	)	$	27,127

	December 31, 2016
	Cost		Accumulated Amortization			Net		Weighted Average Remaining Life
Raw material supply agreement	$	6,230	$	(1,987	)	$	4,243	9.0 years
Renewable diesel technology	8,300		(1,429		)	6,871		12.5 years
Acquired customer relationships	2,900		(396		)	2,504		8.6 years
Ground lease	200		(127		)	73		4.9 years
In-process research and development	15,956		(177		)	15,779		14.8 years
Total intangible assets	$	33,586	$	(4,116	)	$	29,470

Estimated amortization expense

Estimated amortization expense for fiscal years ended December 31 is as follows:

2018	$	2,425
2019	2,433
2020	2,440
2021	2,447
2022	2,441
Thereafter	14,941
Total	$	27,127