Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Reconciliation of cash and cash equivalents and restricted cash

See the table below for reconciliation of Cash and cash equivalents and restricted cash in regard to the Consolidated Statements of Cash Flows:

	December 31, 2019		December 31, 2018		December 31, 2017
Cash and cash equivalents	$	50,436	$	123,575	$	77,627
Restricted cash	3,000		3,000		—
Total cash, cash equivalents and restricted cash shown in the statement of cash flow	$	53,436	$	126,575	$	77,627

Estimated useful lives

Depreciation expense is computed on a straight-line method based upon estimated useful lives of the assets. Estimated useful lives are as follows:

Automobiles and trucks	5 years
Computers and office equipment	5 years
Office furniture and fixtures	7 years
Machinery and equipment	5-30 years
Leasehold improvements	the lesser of the lease term or 30 years
Buildings and improvements	30-40 years

Activity Under Repurchase Agreements

The table below sets out the information regarding the activities under the 2017 Program, the 2018 Program and 2019 Program during 2018 and 2019:

	For the year ended December 31, 2019								For the year ended December 31, 2018
	Number of shares/Principal amount in $'000		June 2018 Program		January 2019 Program		Both Programs		Number of shares/Principal amount in $'000		December 2017 Program		June 2018 Program		Both Programs
Repurchases of shares of common stock	—		$	—	$	—	$	—	1,937,844		$	25,048	$	—	$	25,048
2019 Convertible Senior Notes Repurchases	$	—	$	—	$	—	$	—	$	6,311	$	6,689	$	—	$	6,689
2036 Convertible Senior Notes Repurchases	$	6,673	$	7,435	$	7,203	$	14,638	$	55,700	$	43,263	$	67,565	$	110,828

Disaggregation of Revenue

recognized in the income statement, except for Biomass-based diesel Government Incentives, is considered to be revenue from contracts with customers. The following table depicts the disaggregation of revenue according to product line and segment:

	Reportable Segments
Year ended December 31, 2019	Biomass-based Diesel		Services		Corporate and other		Intersegment Revenues			Consolidated Total
Biomass-based diesel sales, net of BTC related amount due to customers of $157,896	$	1,400,973	$	—	$	—	$	(11,309	)	$	1,389,664
Petroleum and blended petroleum diesel sales	—		—		270,326		—			270,326
Other biomass-based diesel revenue	215,086		—		—		—			215,086
Separated RIN sales	98,285		—		—		—			98,285
Other revenues	—		99,086		—		(97,446		)	1,640
Total revenues from contracts with customers	$	1,714,344	$	99,086	$	270,326	$	(108,755	)	$	1,975,001
Biomass-based diesel government incentives	666,392		—		—		—			666,392
Total revenues	$	2,380,736	$	99,086	$	270,326	$	(108,755	)	$	2,641,393

	Reportable Segments
Year ended December 31, 2018	Biomass-based Diesel		Services		Corporate and other		Intersegment Revenues			Consolidated Total
Biomass-based diesel sales, net of BTC related amount due to customers of $144,944	$	1,474,459	$	—	$	9,682	$	(26,348	)	$	1,457,793
Petroleum and blended petroleum diesel sales	—		—		239,470		—			239,470
Other biomass-based diesel revenue	178,053		—		—		—			178,053
Separated RIN sales	137,895		—		—		—			137,895
Other revenues	—		93,347		—		(91,061		)	2,286
Total revenues from contracts with customers	$	1,790,407	$	93,347	$	249,152	$	(117,409	)	$	2,015,497
Biomass-based diesel government incentives	367,490		—		—		—			367,490
Total revenues	$	2,157,897	$	93,347	$	249,152	$	(117,409	)	$	2,382,987

Contract Balances

Significant changes to the contract liabilities during the year are as follows:

	January 1, 2019		Cash receipts (Payments)		Less: Impact on Revenue			Other		December 31, 2019
Deferred revenue	$	300	$	55,477	$	55,146		$	—	$	631
Payables to customers related to BTC	—		—		(255,193		)	—		255,193
	$	300	$	55,477	$	(200,047	)	$	—	$	255,824

	January 1, 2018		Cash receipts (Payments)			Less: Impact on Revenue			Other			December 31, 2018
Deferred revenue	$	2,218	$	27,264		$	29,179		$	(3	)	$	300
Payables to customers related to BTC	—		(150,776		)	(144,944		)	5,832			—
	$	2,218	$	(123,512	)	$	(115,765	)	$	5,829		$	300

The following table provides information about receivables and contract liabilities from contracts with customers:

	December 31, 2019			December 31, 2018
Trade accounts receivable	$	185,156		$	74,551
Short-term contract liabilities (deferred revenue)	$	(631	)	$	(300	)
Short-term contract liabilities (accounts payable)	$	(255,193	)	$	—