Renewable Energy (REGI) 10-Q 4 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Renewable Energy Group, Inc.
Entity Central Index Key	1,463,258
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		37,315,929

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 69,290	$ 77,627
Accounts receivable, net	466,509	90,648
Inventories	171,933	135,547
Prepaid expenses and other assets	42,225	51,880
Total current assets	749,957	355,702
Property, plant and equipment, net	594,722	587,397
Goodwill	16,080	16,080
Intangible assets, net	26,537	27,127
Investments	12,193	12,250
Other assets	7,565	7,040
TOTAL ASSETS	1,407,054	1,005,596
CURRENT LIABILITIES:
Lines of credit	105,535	65,525
Current maturities of long-term debt	14,207	13,397
Accounts payable	238,517	84,608
Accrued expenses and other liabilities	38,886	39,187
Deferred revenue	1,740	2,218
Total current liabilities	398,885	204,935
Unfavorable lease obligation	3,106	3,388
Deferred income taxes	6,913	8,192
Long-term contingent consideration for acquisitions	5,846	8,849
Long-term debt (net of debt issuance costs of $5,513 and $6,627, respectively)	213,078	208,536
Other liabilities	3,718	4,114
Total liabilities	631,546	438,014
COMMITMENTS AND CONTINGENCIES
EQUITY:
Common stock ($.0001 par value; 300,000,000 shares authorized; 38,342,069 and 38,837,749 shares outstanding, respectively)	5	5
Common stock—additional paid-in-capital	517,058	515,452
Retained earnings	349,317	134,928
Accumulated other comprehensive income	997	278
Treasury stock (10,086,459 and 9,363,166 shares outstanding, respectively)	(91,869)	(83,081)
Total equity	775,508	567,582
TOTAL LIABILITIES AND EQUITY	$ 1,407,054	$ 1,005,596

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Debt issuance costs	$ 5,513	$ 6,627
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares, outstanding (in shares)	38,342,069	38,837,749
Treasury stock, shares outstanding (in shares)	10,086,459	9,363,166

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
REVENUES:
Biomass-based diesel sales	$ 274,761	$ 343,737
Separated RIN sales	47,179	57,324
Biomass-based diesel government incentives	365,285	16,941
Total biomass-based diesel revenue	687,225	418,002
Other revenue	2,027	891
Total revenues	689,252	418,893
COSTS OF GOODS SOLD:
Biomass-based diesel	405,809	353,851
Separated RINs	32,737	46,629
Other costs of goods sold	1,138	1,130
Total cost of goods sold	439,684	401,610
GROSS PROFIT	249,568	17,283
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	31,654	22,907
RESEARCH AND DEVELOPMENT EXPENSE	6,598	3,598
INCOME (LOSS) FROM OPERATIONS	211,316	(9,222)
OTHER INCOME (EXPENSE), NET:
Change in fair value of contingent consideration	1,540	(589)
Change in fair value of convertible debt conversion liability	0	(172)
Loss on debt extinguishment	(232)	0
Gain on involuntary conversion	4,000	0
Other income (loss), net	1,213	(320)
Interest expense	(4,651)	(4,536)
Total other income (expense), net	1,870	(5,617)
INCOME (LOSS) BEFORE INCOME TAXES	213,186	(14,839)
INCOME TAX BENEFIT (EXPENSE)	1,203	(1,075)
NET INCOME (LOSS) ATTRIBUTABLE TO THE COMPANY	214,389	(15,914)
LESS—EFFECT OF PARTICIPATING SHARE-BASED AWARDS	5,151	0
NET INCOME (LOSS) ATTRIBUTABLE TO THE COMPANY’S COMMON STOCKHOLDERS	$ 209,238	$ (15,914)
NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS:
BASIC (in dollars per share)	$ 5.39	$ (0.41)
DILUTED (in dollars per share)	$ 5.30	$ (0.41)
WEIGHTED AVERAGE SHARES USED TO COMPUTE NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS:
BASIC (in shares)	38,819,443	38,599,048
DILUTED (in shares)	39,484,087	38,599,048

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 214,389	$ (15,914)
Foreign currency translation adjustments	719	551
Other comprehensive income	719	551
Comprehensive income (loss) attributable to the Company	$ 215,108	$ (15,363)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Common Stock - Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest
Beginning Balance (in shares) at Dec. 31, 2016		38,553,413
Beginning Balance at Dec. 31, 2016	$ 610,174	$ 5	$ 480,906	$ 214,007	$ (5,751)	$ (81,824)	$ 2,831
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased) (in shares)		40,853
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased)	(383)					(383)
Acquisition of noncontrolling interest	(3,102)		(271)				(2,831)
Stock compensation expense	1,308		1,308
Other comprehensive income	551				551		0
Net income (loss)	(15,914)			(15,914)			0
Ending Balance (in shares) at Mar. 31, 2017		38,594,266
Ending Balance at Mar. 31, 2017	592,634	$ 5	481,943	198,093	(5,200)	(82,207)	0
Beginning Balance (in shares) at Dec. 31, 2017		38,837,749
Beginning Balance at Dec. 31, 2017	567,582	$ 5	515,452	134,928	278	(83,081)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased) (in shares)		127,470
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased)	(621)					(621)
Settlement of stock appreciation rights in common stock (net of shares of treasury stock purchased) (in shares)		33,463
Settlement of stock appreciation rights in common stock (net of shares of treasury stock purchased)	(172)					(172)
Partial termination of capped call options (in shares)		(15,012)
Partial termination of capped call options	85		252			(167)
Convertible debt extinguishment impact (net of tax impact)	(440)		(440)
Treasury stock purchases (in shares)		(641,601)
Treasury stock purchases	(7,828)					(7,828)
Stock compensation expense	1,794		1,794
Other comprehensive income	719				719
Net income (loss)	214,389			214,389
Ending Balance (in shares) at Mar. 31, 2018		38,342,069
Ending Balance at Mar. 31, 2018	$ 775,508	$ 5	$ 517,058	$ 349,317	$ 997	$ (91,869)	$ 0

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Equity (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Convertible debt extinguishment impact, tax impact		$ 68
Treasury Stock | Restricted stock units
Conversion or settlement to common stock, net of treasury shares purchased (in shares)	51,995	24,494
Treasury Stock | Stock appreciation rights
Conversion or settlement to common stock, net of treasury shares purchased (in shares)	14,558

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 214,389	$ (15,914)
Adjustments to reconcile net income (loss) to net cash flows from operating activities:
Depreciation expense	8,859	8,423
Amortization expense of assets and liabilities, net	634	440
Gain on involuntary conversion	(4,000)	0
Accretion of convertible note discount	1,357	1,338
Change in fair value of contingent consideration	(1,540)	589
Change in fair value of convertible debt conversion liability	0	172
Gain on sale of assets	(990)	0
Loss on debt extinguishment	232	0
Provision for doubtful accounts	314	255
Stock compensation expense	1,794	1,308
Deferred tax expense	(1,487)	650
Other operating activities	10	222
Changes in assets and liabilities:
Accounts receivable, net	(376,072)	106,094
Inventories	(35,891)	(24,195)
Prepaid expenses and other assets	9,731	(13,022)
Accounts payable	153,449	(29,173)
Accrued expenses and other liabilities	1,042	(6,907)
Deferred revenue	(479)	(8,304)
Net cash flows provided by (used in) operating activities	(28,648)	21,976
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash receipts for involuntary conversion	4,000	0
Cash receipts of restricted cash	0	1,500
Cash paid for purchase of property, plant and equipment	(16,822)	(16,636)
Cash receipts for sale of assets	1,629	0
Cash paid for acquisitions and additional interests, net of cash acquired	0	(3,291)
Cash paid for investments	0	(816)
Net cash flows used in investing activities	(11,193)	(19,243)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings (repayments) on revolving line of credit	40,514	(31,853)
Borrowings on other lines of credit	12,358	2,671
Repayments on other lines of credit	(12,992)	(1,100)
Cash received from notes payable	10,890	0
Cash paid on notes payable	(8,018)	(2,254)
Cash paid for debt issuance costs	(78)	(434)
Cash paid for treasury stock	(7,828)	0
Cash paid for contingent consideration settlement	(2,813)	(3,980)
Cash received on partial termination of capped call options	85	0
Cash paid for conversion of restricted stock units and stock appreciation rights	(793)	0
Net cash flows provided by (used in) financing activities	31,325	(36,950)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(8,516)	(34,217)
CASH AND CASH EQUIVALENTS, Beginning of period	77,627	116,210
Effect of exchange rate changes on cash	179	242
CASH AND CASH EQUIVALENTS, End of period	69,290	82,235
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION:
Cash paid for income taxes	0	14
Cash paid for interest	1,154	715
Amounts included in period-end accounts payable for:
Purchases of property, plant and equipment	7,123	3,484
Debt issuance cost	$ 52	$ 45

Basis of Presentation and Natur

Basis of Presentation and Nature of the Business	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Nature of the Business	BASIS OF PRESENTATION AND NATURE OF THE BUSINESS The condensed consolidated financial statements have been prepared by Renewable Energy Group, Inc. and its subsidiaries (the "Company" or "REG"), pursuant to the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"). Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted as permitted by such rules and regulations. All adjustments, consisting of normal recurring adjustments, have been included. Management believes that the disclosures are adequate to present fairly the financial position, results of operations and cash flows at the dates and for the periods presented. It is suggested that these interim financial statements be read in conjunction with the consolidated financial statements and the notes thereto appearing in the Company’s latest annual report on Form 10-K filed on March 9, 2018. Results for interim periods are not necessarily indicative of those to be expected for the fiscal year. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and related disclosures. Actual results could differ from those estimates. As of March 31, 2018 , the Company operates a network of fourteen biorefineries, with twelve locations in North America and two locations in Europe, which includes thirteen operating biomass-based diesel production facilities with aggregate nameplate production capacity of 520 million gallons per year ("mmgy") and one fermentation facility. REG also has one feedstock processing facility. Ten of these plants are “multi-feedstock capable” which allows them to use a broad range of lower-cost feedstocks, such as inedible corn oil, used cooking oil and inedible animal fats in addition to vegetable oils, such as soybean oil and canola oil. The biomass-based diesel industry and the Company’s business have benefited from the continuation of certain federal and state incentives. The federal biodiesel mixture excise tax credit (the "BTC") was reinstated for 2015, in effect throughout 2016, lapsed on January 1, 2017 and retroactively reinstated on February 9, 2018 for the fiscal year 2017, but was not reinstated for 2018 and accordingly we are currently operating without the benefit of the BTC. It is uncertain whether the BTC will be reinstated to apply to 2018. The expiration or modification of any one or more of those incentives, could adversely affect the financial results of the Company.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The following accounting policies should be read in conjunction with a summary of the significant accounting policies the Company has disclosed in its Annual Report on Form 10-K for the year ended December 31, 2017 . Accounts Receivable Accounts receivable are carried at invoiced amount less allowance for doubtful accounts. Management estimates the allowance for doubtful accounts based on existing economic conditions, the financial conditions of customers, and the amount and age of past due accounts. Receivables are considered past due if full payment is not received by the contractual due date. Past due accounts are generally written off against the allowance for doubtful accounts only after reasonable collection attempts have been exhausted. As of and for the three months ended March 31, 2018 , the Company has recognized $365,155 and $16,688 as receivables from the federal government and customers, respectively, related to the 2017 biodiesel mixture excise tax credit. Renewable Identification Numbers (RINs) When the Company produces and sells a gallon of biomass-based diesel, 1.5 to 1.7 RINs per gallon are generated. RINs are used to track compliance with Renewable Fuel Standards (RFS2). RFS2 allows the Company to attach between zero and 2.5 RINs to any gallon of biomass-based diesel. As a result, a portion of the selling price for a gallon of biomass-based diesel is generally attributable to RFS2 compliance. However, RINs that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the RIN when it is generated, regardless of whether the RIN is transferred with the biomass-based diesel produced or held by the Company pending attachment to other biomass-based diesel production sales. In addition, the Company also obtains RINs from third parties who have separated the RINs from gallons of biomass-based diesel. From time to time, the Company holds varying amounts of these separated RINs for resale. RINs obtained from third parties are initially recorded at their cost and are subsequently revalued at the lower of cost or net realizable value as of the last day of each accounting period. The resulting adjustments are reflected in costs of goods sold for the period. The value of these RINs is reflected in “Prepaid expenses and other assets” on the Condensed Consolidated Balance Sheets. The cost of goods sold related to the sale of these RINs is determined using the average cost method, while market prices are determined by RIN values, as reported by the Oil Price Information Service ("OPIS"). Low Carbon Fuel Standards The Company generates Low Carbon Fuel Standards ("LCFS") credits for its low carbon fuels or blendstocks when its qualified low carbon fuels are transported into an LCFS market. LCFS credits are used to track compliance with the LCFS. As a result, a portion of the selling price for a gallon of biomass-based diesel sold into an LCFS market is also attributable to LCFS compliance. However, LCFS credits that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the LCFS credit when it is generated, regardless of whether the LCFS credit is transferred with the biomass-based diesel produced or held by the Company pending attachment to other biomass-based diesel sales that do not transfer credits. In addition, the Company also obtains LCFS credits from third-party trading activities. From time to time, the Company holds varying amounts of these third-party LCFS credits for resale. LCFS credits obtained from third parties are initially recorded at their cost and are subsequently revalued at the lower of cost or net realizable value as of the last day of each accounting period, and the resulting adjustments are reflected in costs of goods sold for the period. The value of LCFS credits obtained from third parties is reflected in “Prepaid expenses and other assets” on the Condensed Consolidated Balance Sheet. The cost of goods sold related to the sale of these LCFS credits is determined using the average cost method, while market prices are determined by LCFS values, as reported by the OPIS. At March 31, 2018 and December 31, 2017 , the Company held no LCFS credits purchased from third parties. The Company records assets acquired and liabilities assumed through the exchange of non-monetary assets based on the fair value of the assets and liabilities acquired or the fair value of the consideration exchanged, whichever is more readily determinable. Property, Plant and Equipment Property, plant and equipment is recorded at cost less accumulated depreciation. Maintenance and repairs are expensed as incurred. Depreciation expense is computed on a straight-line method based upon estimated useful lives of the assets. In June 2017, the Company experienced a fire at its Madison facility, resulting in the shutdown of the facility. To date, the Company impaired fixed assets with a total net book value of approximately $2,671 as a result of the fire in June 2017 and received payments in the amounts of $12,000 and $3,620 to cover initial costs incurred for property losses and business interruption, respectively. Convertible Debt In June 2016, the Company issued $152,000 aggregate principal amount of 4% convertible senior notes due in 2036 (the "2036 Convertible Senior Notes"). The embedded conversion option was initially accounted for as an embedded derivative liability as the Company could not elect to issue shares of common stock upon conversion of the 2036 Convertible Notes to the extent such election would result in the issuance of more than 19.99% of the common stock outstanding immediately before the issuance of the 2036 Convertible Notes unless the Company received stockholder approval for such issuance. On December 8, 2017, at the special meeting of stockholders, the Company obtained approval from its stockholders to remove the common stock issuance restrictions in connection with conversions of the 2036 Convertible Notes. Accordingly, the embedded conversion option, valued at $45,933 and net of tax of $18,025 , was reclassified into Additional Paid-in Capital at December 8, 2017. See "Note 7 - Debt" for a further description of the transaction. Capped Call Transaction In connection with the issuance of the 2014 Convertible Senior Notes, the Company entered into capped call transactions. The purchased capped call transactions were recorded as a reduction to common stock-additional paid-in-capital. Because this was considered to be an equity transaction and qualifies for the derivative scope exception, no future changes in the fair value of the capped call will be recorded by the Company. During 2016, in connection with the issuance of the 2036 Convertible Notes, certain call options covered by the original capped call transaction were rebalanced and reset to cover 100% of the total number of shares of the Company's Common Stock underlying the remaining principal of the 2019 Convertible Notes. The impact of these transactions, net of tax, was reflected as an addition/reduction to common stock-additional paid-in capital as presented in the Consolidated Statements of Stockholders' Equity. Security Repurchase Programs In December 2017, the Company's board of directors approved a repurchase program of up to $75,000 of the Company's convertible notes and/or shares of common stock. Under the program, the Company may repurchase convertible notes or shares from time to time in open market transactions, privately negotiated transactions or by other means. The timing and amount of repurchase transactions are determined by the Company's management based on its evaluation of market conditions, share price, bond price, legal requirements and other factors. During the three months ended March 31, 2018 , the Company repurchased 641,601 shares of Common Stock for $7,828 under this program. In addition, the Company used approximately $6,689 to repurchase $6,311 principal amount of the 2019 Convertible Senior Notes. Research and Development Research and development ("R&D") costs are charged to expense as incurred. In process research and development ("IPR&D") assets acquired in connection with acquisitions are recorded on the Condensed Consolidated Balance Sheets as intangible assets. Revenue Recognition In the first quarter of 2018, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606). Under the ASU, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The Company applied the five-step method outlined in the ASU to all contracts with customers and elected the modified retrospective implementation method. The Company has generally a single performance obligation in its arrangements with customers. The Company believes for most of its contracts with customers, control is transferred at a point in time, typically upon delivery to the customers. When the Company performs shipping and handling activities after the transfer of control to the customers (e.g., when control transfers prior to delivery), they are considered as fulfillment activities, and accordingly, the costs are accrued for when the related revenue is recognized. Taxes collected from customers relating to product sales and remitted to governmental authorities are excluded from revenues. The Company generally expenses sales commissions when incurred because the amortization period would have been less than one year. The Company records these costs within selling, general and administrative expenses. The implementation of the new standard did not have any material impact on the measurement or recognition of revenue of prior periods, however additional disclosures have been added in accordance with the ASU. The following is a description of principal activities from which we generate revenue. Revenues from contracts with customers are recognized when control of the promised goods or services are transferred to our customers, in an amount that reflects the consideration that we expect to receive in exchange for those goods or services. • sales of biodiesel and renewable diesel produced at our facilities, including RINs and LCFS credits; • resale of finished biomass-based diesel, RINs and LCFS credits acquired from third parties, and raw material feedstocks acquired from others; • revenues from our sale of petroleum-based heating oil and ultra-low sulfur diesel, or ULSD, acquired from third parties, along with the sale of these petroleum-based products further blended with biodiesel produced at our wholly owned facilities; • sales of glycerin, other co-products of the biomass-based diesel production process; • incentive payments from federal and state governments, including the BTC, and from the USDA Advanced Biofuel Program; and • other revenue: • collaborative research and development and other service revenue for research and development activities to continue to build out the technology platform; and • sales of renewable chemical products. Disaggregation of revenue: All 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 Segment Three months ended March 31, 2018 Biomass-based Services Renewable Corporate Intersegment Consolidated Biomass-based diesel sales, net of BTC related amount due to customers of $144,944 $ 166,191 $ — $ — $ 3,579 $ (17,683 ) $ 152,087 Petroleum diesel sales — — — 70,964 — 70,964 Other biomass-based diesel revenue 51,710 — — — — 51,710 Separated RIN sales 47,179 — — — — 47,179 Other revenues — 35,215 1,860 — (35,048 ) 2,027 Total revenues from contracts with customers $ 265,080 $ 35,215 $ 1,860 $ 74,543 $ (52,731 ) $ 323,967 Biomass-based diesel government incentives 365,285 — — — — $ 365,285 Total revenues $ 630,365 $ 35,215 $ 1,860 $ 74,543 $ (52,731 ) $ 689,252 Contract balances: The following table provides information about receivables and contract liabilities from contracts with customers: March 31, Accounts receivable $ 98,593 Short-term contract liabilities (deferred revenue) $ 1,740 Short-term contract liabilities (accounts payable) $ 150,776 The Company receives payments from customers based upon contractual billing schedules; accounts receivable are recorded when the right to consideration becomes unconditional. Contract liabilities include payments received in advance of performance under the contract, and are realized with the associated revenue recognized under the contract. While in general the Company has not historically offered sales incentives to customers, the uncertainty around the reinstatement of the federal biodiesel tax credit led to the Company and other market participants acting as if the federal biodiesel tax credit would be reinstated throughout the year and entering into agreements with both customers and vendors throughout the year to capture the credit when or if reinstated. The impacts of the agreements with customers are recorded as contract liabilities in accounts payable and as adjustments to Biomass-based diesel sales, whereas agreements with vendors are recorded net as adjustments to Biomass-based diesel costs of goods sold on the Condensed Consolidated Statements of Operations. Significant changes to the contract liabilities during the quarter are as follows: January 1, 2018 Cash receipts Less: Impact on Other March 31, 2018 Deferred revenue $ 2,218 $ 10,507 $ 10,985 $ — $ 1,740 Payables to customers related to BTC — — (144,944 ) 5,832 150,776 $ 2,218 $ 10,507 $ (133,959 ) $ 5,832 $ 152,516 New Accounting Standards On February 25, 2016, the FASB issued ASU 2016-02, which introduces a lessee model that brings most leases on the balance sheet. The new standard also aligns many of the underlying principles of the new lessor model with those in ASC 606, the FASB’s new revenue recognition standard (e.g., those related to evaluating when profit can be recognized). Furthermore, the ASU addresses other concerns related to the current leases model. The ASU is effective for annual periods beginning after December 15, 2018 and interim periods therein. While the Company is continuing to assess all potential impacts of the standard, the Company currently believes the most significant impact relates to its accounting for office, railcar and terminal operating leases. The Company plans to apply a modified retrospective transition approach to each applicable lease that exists at January 1, 2017 as well as leases entered after this date. On January 25, 2018, the FASB issued ASU 2018-01, which amends the Board’s new leasing standard, ASU 2016-02 (codified in ASC 842), to provide a transition practical expedient for existing or expired land easements (i.e., rights to access, cross, or otherwise use someone else’s land for a specified purpose) that were not previously accounted for in accordance with ASC 840. The practical expedient would allow entities to elect not to assess whether those land easements are, or contain, leases in accordance with ASC 842 when transitioning to the new leasing standard. However, the ASU clarifies that land easements entered into (or existing land easements modified) on or after the effective date of the new leasing standard must be assessed under ASC 842. T he Company is evaluating the impact of this guidance on its consolidated financial statements as part of the lease standard adoption project, but does not expect the impact to be significant. On August 28, 2017, the FASB issued ASU 2017-12, which amends the hedge accounting recognition and presentation requirements in ASC 815 to (1) improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities by better aligning the entity’s financial reporting for hedging relationships with those risk management activities and (2) reduce the complexity of and simplify the application of hedge accounting by preparers. T he Company is evaluating the impact on its consolidated financial statements. On December 22, 2017, President Donald Trump signed into law “H.R. 1”, formerly known as the “Tax Cuts and Jobs Act” (the “Tax Legislation”). The Tax Legislation, which became effective on January 1, 2018, significantly revises the U.S. tax code by, among other things, lowering the corporate income tax rate from 35% to 21%, limiting deductibility of interest expense, implementing a hybrid-territorial tax system imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries (the “transition tax”), and enacted additional international tax provisions, including a minimum tax on global intangible low-taxed income (“GILTI”) and a new base erosion anti-abuse tax (“BEAT”). The Company recorded a provisional non-cash tax benefit of $13,712 in the fourth quarter of 2017. The Company finalized its accounting for the transition tax during the quarter ended March 31, 2018, but continue to evaluate the financial statement impact of the other provisions within the Tax Legislation as guidance is issued by the Internal Revenue Services and U.S. Department of Treasury. On February 28, 2018, the FASB issued ASU 2018-03, which makes technical corrections to certain aspects of ASU 2016-016 (on recognition of financial assets and financial liabilities), including equity securities without a readily determinable fair value (discontinuation and adjustments); forward contracts and purchased options; presentation requirements for certain fair value option liabilities; fair value option liabilities denominated in a foreign currency and transition guidance for equity securities without a readily determinable fair value. For public business entities, the amendments in ASU 2018-03 are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years beginning after June 15, 2018. Public business entities with fiscal years beginning between December 15, 2017, and June 15, 2018, are not required to adopt the amendments until the interim period beginning after June 15, 2018. T he Company is evaluating the impact of this guidance on its consolidated financial statements.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS Sanimax Energy, LLC On March 15, 2016, the Company acquired fixed assets and inventory from Sanimax Energy, including the 20 mmgy nameplate capacity biomass-based diesel refinery in DeForest, Wisconsin. The Company completed its initial accounting of this business combination as the valuation of the real and personal property was finalized as of September 30, 2016. The following table summarizes the consideration paid for the acquisition from Sanimax Energy: March 15, 2016 Consideration at fair value for acquisition from Sanimax: Cash $ 12,541 Common stock 4,050 Contingent consideration 4,500 Total $ 21,091 The fair value of the 500,000 shares of Common Stock issued was determined using the closing market price of the Company's common shares at the date of acquisition. REG Madison may pay contingent consideration of up to $5,000 ("Earnout Payments") over a seven -year period after the acquisition, subject to achievement of certain milestones related to the biomass-based diesel gallons produced and sold by REG Madison. The Earnout Payments are payable in cash and cannot exceed $1,700 in any one year period beginning March 15, 2016 through 2023 and up to $5,000 in aggregate. As of March 31, 2018 , the Company has recorded a contingent liability of $2,648 , approximately $1,595 of which has been classified as current on the Condensed Consolidated Balance Sheets. The following table summarizes the fair values of the assets acquired at the acquisition date: March 15, 2016 Assets acquired from Sanimax Energy: Inventory $ 1,591 Property, plant and equipment 19,500 Net identifiable assets acquired $ 21,091

Inventories

Inventories	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following: March 31, 2018 December 31, 2017 Raw materials $ 43,085 $ 39,975 Work in process 4,007 3,523 Finished goods 124,841 92,049 Total $ 171,933 $ 135,547

Other Assets

Other Assets	3 Months Ended
	Mar. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	OTHER ASSETS Prepaid expense and other assets consist of the following: March 31, 2018 December 31, 2017 Commodity derivatives and related collateral, net $ 4,054 $ 1,610 Prepaid expenses 19,028 11,733 Deposits 1,902 2,899 RIN inventory 9,952 27,028 Taxes receivable 3,685 6,356 Other 3,604 2,254 Total $ 42,225 $ 51,880 RIN inventory values were adjusted in the amounts of $1,784 and $2,629 at March 31, 2018 and December 31, 2017 , respectively, to reflect the lower of cost or net realizable value. Other noncurrent assets consist of the following: March 31, 2018 December 31, 2017 Spare parts inventory $ 2,700 $ 2,764 Catalysts 2,686 2,962 Deposits 690 381 Other 1,489 933 Total $ 7,565 $ 7,040

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	INTANGIBLE ASSETS Intangible assets consist of the following: March 31, 2018 Cost Accumulated Amortization Net Weighted Average Remaining Life Raw material supply agreement $ 6,230 $ (2,518 ) $ 3,712 7.8 years Renewable diesel technology 8,300 (2,121 ) 6,179 11.3 years Ground lease 200 (144 ) 56 3.6 years Acquired customer relationships 2,900 (759 ) 2,141 7.3 years In-process research and development 15,956 (1,507 ) 14,449 13.6 years Total intangible assets $ 33,586 $ (7,049 ) $ 26,537 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 Ground lease 200 (141 ) 59 3.9 years Acquired customer relationships 2,900 (686 ) 2,214 7.6 years In-process research and development 15,956 (1,241 ) 14,715 13.8 years Total intangible assets $ 33,586 $ (6,459 ) $ 27,127 The Company recorded intangible amortization expense of $590 for the three months ended March 31, 2018 and $584 for the three months ended March 31, 2017 , respectively. The estimated intangible asset amortization expense for the remainder of 2018 through 2023 and thereafter is as follows: April 1, 2018 through December 31, 2018 $ 1,781 2019 2,382 2020 2,389 2021 2,395 2022 2,388 2023 2,395 2024 and thereafter 12,807 Total $ 26,537

Debt

Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Debt	DEBT The following table shows the Company’s term debt: March 31, 2018 December 31, 2017 4.00% Convertible Senior Notes, $152,000 face amount, due in June 2036 $ 116,968 $ 116,255 2.75% Convertible Senior Notes, $67,527 face amount, due in June 2019 64,497 69,859 REG Danville term loan, secured, variable interest rate of LIBOR plus 4%, due in July 2022 10,836 11,460 REG Newton term loan, secured, variable interest rate of LIBOR plus 4%, due in December 2018 7,405 8,189 REG Ralston term loan, variable interest rate of Prime Rate plus 0.5%, due in July 2025 17,074 6,183 REG Mason City term loan, fixed interest rate of 5%, due in July 2019 979 1,153 REG Grays Harbor term loan, variable interest of minimum of 3.5% or Prime Rate plus 0.25%, due in May 2022 7,523 7,882 REG Capital term loan, fixed interest rate of 3.99%, due in January 2028 7,368 7,400 Other 148 179 Total term debt before debt issuance costs 232,798 228,560 Less: Current portion of long-term debt 14,207 13,397 Less: Debt issuance costs (net of accumulated amortization of $3,442 and $3,510, respectively) 5,513 6,627 Total long-term debt $ 213,078 $ 208,536 Convertible Senior Notes On June 2, 2016, the Company issued $152,000 aggregate principal amount of the 2036 Convertible Senior Notes in a private offering to qualified institutional buyers. The 2036 Convertible Senior Notes bear interest at a rate of 4.00% per year payable semi-annually in arrears on June 15 and December 15 of each year, beginning December 15, 2016. The notes will mature on June 15, 2036, unless repurchased, redeemed or converted in accordance with their terms prior to such date. Prior to December 15, 2035, the 2036 Convertible Senior Notes will be convertible only upon satisfaction of certain conditions and during certain periods as stipulated in the indenture. On or after December 15, 2035 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders of the 2036 Convertible Senior Notes may convert their notes at any time. The 2036 Convertible Senior Notes may be settled in cash, the Company’s common shares or a combination of cash and the Company’s common shares, at the Company’s election. The Company may not redeem the 2036 Convertible Notes prior to June 15, 2021. Holders of the 2036 Convertible Senior Notes will have the right to require the Company to repurchase for cash all or some of their notes at 100% of their principal, plus any accrued and unpaid interest on each of June 15, 2021, June 15, 2026 and June 15, 2031. Holders of the 2036 Convertible Senior Notes will have the right to require the Company to repurchase for cash all or some of their notes at 100% of their principal, plus any accrued and unpaid interest upon the occurrence of certain fundamental changes. The initial conversion rate is 92.8074 common shares per $1,000 (one thousand) principal amount of 2036 Convertible Senior Notes (equivalent to an initial conversion price of approximately $10.78 per common share). The net proceeds from the offering of the 2036 Convertible Senior Notes were approximately $147,118 , after deducting fees and offering expenses of $4,882 , which was capitalized as debt issuance costs and is being amortized through June 2036. The Company evaluated the terms of the conversion features under the applicable accounting literature, including Derivatives and Hedging, ASC 815, and determined that a certain feature required separate accounting as a derivative. This derivative was initially recorded as a long-term liability, "Convertible Debt Conversion Liability", on the Condensed Consolidated Balance Sheets and was adjusted to reflect fair value each reporting date. The fair value of the convertible debt conversion liability at issuance was $40,145 . On December 8, 2017, at the Company's Special Meeting of Stockholders, the Company obtained the approval from its stockholders to remove the common stock issuance restrictions in connection with conversions of the 2036 Convertible Notes. Accordingly, on December 8, 2017, the Convertible Debt Conversion Liability was remeasured at fair value at $45,933 and was then reclassified into equity. The debt liability component of 2036 Convertible Senior Notes was determined to be $111,855 at issuance, reflecting a debt discount of $40,145 . The debt discount is to be amortized through June 2036. The effective interest rate on the debt liability component was 2.45% . REG Ralston In April 2017, REG Ralston, LLC ("REG Ralston") entered into a construction loan agreement ("Construction Loan Agreement") with First Midwest Bank. The Construction Loan Agreement allows REG Ralston to borrow up to $20.0 million during the construction period at REG Ralston and convert it into an amortizing term debt thereafter. The loan has a maturity date of July 15, 2025. The loan requires monthly principal payments and interest to be charged using prime rate plus 0.5% per annum. The loan agreement contains various loan covenants. At March 31, 2018 , the effective interest rate on the amount borrowed under this Construction Loan Agreement was 5.25% per annum. REG Danville In July 2017, REG Danville, LLC ("REG Danville") entered into an amended loan agreement ("Loan Agreement") with Fifth Third Bank. The Loan Agreement allowed REG Danville to borrow $12,500 maturing in July 2022. The loan requires monthly principal payments and bears LIBOR-based variable interest rates. The loan agreement contains various loan covenants. At March 31, 2018 , the effective interest rate on the amount borrowed under this Loan Agreement was 5.75% per annum. REG Capital In December 2017, REG Capital, LLC ("REG Capital") entered into a mortgage refinancing loan agreement ("Mortgage Refinancing Loan Agreement") with First National Bank to refinance existing mortgages on our office buildings in Ames, IA. The outstanding principal under the Mortgage Refinancing Loan Agreement is $7,368 with a maturity date of January 3, 2028. The loan requires monthly principal payments and bears a fixed interest rate of 3.99% per annum. Lines of Credit The following table shows the Company's lines of credit: March 31, 2018 December 31, 2017 Amount outstanding under lines of credit $ 105,535 $ 65,525 Maximum available to be borrowed under lines of credit $ 56,615 $ 60,839 The Company's wholly-owned subsidiaries, REG Services Group, LLC and REG Marketing & Logistics Group, LLC, are borrowers under a Credit Agreement dated December 23, 2011 with the lenders party thereto (“Lenders”) and Wells Fargo Capital Finance, LLC, as the agent, (as amended, the “M&L and Services Revolver”). The maximum commitment of the Lenders under the M&L and Services Revolver to make revolving loans is $150,000 , subject to an accordion feature, which allows the borrowers to request commitments for additional revolving loans in an aggregate amount not to exceed to $50,000 , the making of which is subject to customary conditions, including the consent of Lenders providing such additional commitments. The maturity date of the M&L and Services Revolver is September 30, 2021. Loans advanced under the M&L and Services Revolver bear interest based on a one-month LIBOR rate (which shall not be less than zero ), plus a margin based on Quarterly Average Excess Availability (as defined in the Revolving Credit Agreement), which may range from 1.75% per annum to 2.25% per annum. The M&L and Services Revolver contains various loan covenants that restrict each subsidiary borrower’s ability to take certain actions, including restrictions on incurrence of indebtedness, creation of liens, mergers or consolidations, dispositions of assets, repurchase or redemption of capital stock, making certain investments, making distributions to the Company unless certain conditions are satisfied, entering into certain transactions with affiliates or changing the nature of the subsidiary’s business. In addition, the subsidiary borrowers are required to maintain a fixed charge coverage ratio of at least 1.0 to 1.0 if excess availability under the M&L and Services Revolver is less than 10% of the total $150,000 of current revolving loan commitments, or $15,000 currently. The M&L and Services Revolver is secured by the subsidiary borrowers’ membership interests and substantially all of their assets. In addition, the M&L and Services Revolver is secured by the accounts receivable and inventory of REG Albert Lea, LLC, REG Houston, LLC, REG New Boston, LLC, and REG Geismar, LLC (collectively, the "Plant Loan Parties") subject to a $40,000 limitation with respect to each of the Plant Loan Parties. In March 2018, REG Energy Services, LLC ("REG Energy Services") amended its operating and revolving line of credit agreement with Bankers Trust Company (“Bankers Trust”) that was entered in March 2016. As amended, this operating and revolving line of credit ("the Line of Credit") was decreased to $15,000 , subject to customary borrowing base limitations and the maturity was extended to September 2018. Amounts outstanding under the Line of Credit bear variable interest as stipulated in the agreement. The Line of Credit contains various loan covenants that restrict REG Energy Services’ ability to take certain actions, including prohibiting it in certain circumstances from making payments to the Company. In addition, the Line of Credit is secured by substantially all of REG Energy Services’ accounts receivable and inventory. REG Germany has a trade finance facility agreement ("Uncommitted Credit Facility Agreement") with BNP Paribas in Europe, which allows it to borrow up to $25,000 for funding the purchase of goods and services. Amounts outstanding under the Uncommitted Credit Facility Agreement bear variable interest and are payable as stipulated in the agreement. The amount that can be borrowed under the agreement can be amended, cancelled or restricted at BNP Paribas's sole discretion and therefore is not included in the maximum available to be borrowed under lines of credit above. The Uncommitted Credit Facility Agreement contains various loan covenants that require REG Germany to maintain certain financial measures. At March 31, 2018 , the nominal interest rates ranged from 1.50% to 2.00% per annum.

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS The Company enters into New York Mercantile Exchange NY Harbor ULSD ("NY Harbor ULSD" or previously referred to as heating oil) and CBOT Soybean Oil (previously referred to as soybean oil) futures, swaps and options ("commodity contract derivatives") to reduce the risk of price volatility related to anticipated purchases of feedstock raw materials and to protect cash margins from potentially adverse effects of price volatility on biomass-based diesel sales where prices are set at a future date. All of the Company’s commodity contract derivatives are designated as non-hedge derivatives and recorded at fair value on the Condensed Consolidated Balance Sheets. Unrealized gains and losses are recognized as a component of biomass-based diesel costs of goods sold reflected in current results of operations. As of March 31, 2018 , the net notional volumes of NY Harbor ULSD and CBOT Soybean Oil covered under the open commodity derivative contracts were approximately 107 million gallons and 2 million pounds, respectively. The Company offsets the fair value amounts recognized for its commodity contract derivatives with cash collateral with the same counterparty under a master netting agreement. The net position is presented within prepaid and other assets in the Condensed Consolidated Balance Sheets. The following table sets forth the fair value of the Company's commodity contract derivatives and amounts that offset within the Condensed Consolidated Balance Sheets: March 31, 2018 December 31, 2017 Assets Liabilities Assets Liabilities Gross amounts of derivatives recognized at fair value $ 1,472 $ 7,074 $ 812 $ 8,001 Cash collateral 9,656 — 8,799 — Total gross amount recognized 11,128 7,074 9,611 8,001 Gross amounts offset (7,074 ) (7,074 ) (8,001 ) (8,001 ) Net amount reported in the condensed consolidated balance sheets $ 4,054 $ — $ 1,610 $ — The following table sets forth the commodity contract derivatives gains and (losses) included in the Condensed Consolidated Statements of Operations: Location of Gain (Loss) Three Months Three Months Commodity derivatives Cost of goods sold – Biomass-based diesel $ (2,438 ) $ 8,289

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement	FAIR VALUE MEASUREMENT The fair value hierarchy prioritizes the inputs used in measuring fair value as follows: • Level 1 — Quoted prices for identical instruments in active markets. • Level 2 — Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-derived valuations, in which all significant inputs are observable in active markets. • Level 3 — Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. A summary of assets (liabilities) measured at fair value is as follows: As of March 31, 2018 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (5,602 ) $ (2,657 ) $ (2,945 ) $ — Contingent considerations for acquisitions (30,040 ) — — (30,040 ) $ (35,642 ) $ (2,657 ) $ (2,945 ) $ (30,040 ) As of December 31, 2017 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (7,189 ) $ (3,742 ) $ (3,447 ) $ — Contingent considerations for acquisitions (34,393 ) — — (34,393 ) $ (41,582 ) $ (3,742 ) $ (3,447 ) $ (34,393 ) The following is a reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3): Contingent Consideration for Acquisitions 2018 2017 Balance at beginning of period, January 1 $ 34,393 $ 46,568 Change in estimates included in earnings (1,540 ) 589 Settlements (2,813 ) (3,980 ) Balance at end of period, March 31 30,040 43,177 The estimated fair values of the Company’s financial instruments, which are not recorded at fair value, are as follows: As of March 31, 2018 As of December 31, 2017 Asset (Liability) Fair Value Asset (Liability) Fair Value Financial liabilities: Debt and lines of credit $ (338,333 ) $ (427,838 ) $ (294,085 ) $ (273,983 ) The carrying amounts reported in the Condensed Consolidated Balance Sheets for cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate their fair values. Money market funds are included in cash and cash equivalents on the Condensed Consolidated Balance Sheets. The Company used the following methods and assumptions to estimate fair value of its financial instruments: Commodity derivatives: The instruments held by the Company consist primarily of futures contracts, swap agreements, purchased put options and written call options. The fair value of contracts based on quoted prices of identical assets in an active exchange-traded market is reflected in Level 1. Contract fair value that is determined based on quoted prices of similar contracts in over-the-counter markets is reflected in Level 2. Contingent consideration for acquisitions : The fair value of the contingent consideration regarding REG Life Sciences, LLC ("REG Life Sciences") is determined using an expected present value technique. Expected cash flows are determined using the probability weighted-average of possible outcomes that would occur should achievement of certain milestones related to the development and commercialization of products from REG Life Sciences' technology occur. There is no observable market data available to use in valuing the contingent consideration; therefore, the Company developed its own assumptions related to the expected future delivery of product enhancements to estimate the fair value of these liabilities. An 8.0% discount rate is used to estimate the fair value of the expected payments. During November 2016, the Company's Board of Directors authorized a review of strategic alternatives for the Life Sciences business. The course of action chosen as a result of this strategic review might affect the timeline and assumptions used to estimate the fair value of REG Life Sciences contingent consideration. The fair value of all other contingent consideration is determined using an expected present value technique. Expected cash flows are determined using the probability weighted-average of possible outcomes that would occur should the achievement of certain milestones related to the production and/or sale of biomass-based diesel at the specific production facility. A discount rate ranging from 5.8% to 10.0% is used to estimate the fair value of the expected payments. Convertible debt conversion liability: The fair value of the convertible debt conversion liability is estimated using the Black-Scholes model incorporating the terms and conditions of the 2036 Convertible Notes and considering changes in the prices of the Company's common stock, Company stock price volatility, risk-free rates and changes in market rates. The valuations are, among other things, subject to changes in the Company's credit worthiness as well as change in general market conditions. As the majority of the assumptions used in the calculations are based on market sources, the fair value of the convertible conversion liability is reflected in Level 2. Debt and lines of credit: The fair value of long-term debt and lines of credit was established using discounted cash flow calculations and current market rates reflecting Level 2 inputs.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	NET INCOME (LOSS) PER SHARE Basic net income (loss) per share is presented in conformity with the two-class method required for participating securities. Participating securities include restricted stock units ("RSUs"). Under the two-class method, net income is reduced for distributed and undistributed dividends earned in the current period. The remaining earnings are then allocated to Common Stock and the participating securities. The Company calculates the effects of participating securities on diluted earnings per share ("EPS") using both the “if-converted or treasury stock” and "two-class" methods and discloses the method which results in a more dilutive effect. The effects of Common Stock options, warrants, stock appreciation rights and convertible notes on diluted EPS are calculated using the treasury stock method unless the effects are anti-dilutive to EPS. For the convertible senior notes, the Company’s current intent and policy is to settle conversions using cash for the principal amount of convertible senior notes converted, with the remaining value satisfied at the Company’s option in cash, stock or a combination of cash and stock. Therefore, the dilutive effect of the convertible senior notes is limited to the conversion premium. The following potentially dilutive weighted average securities were excluded from the calculation of diluted net income (loss) per share attributable to common stockholders during the periods presented, as the effect was anti-dilutive: Three Months Three Months Stock appreciation rights 1,006,849 2,291,803 2019 Convertible Senior Notes 5,377,690 5,567,112 2036 Convertible Senior Notes 13,545,060 14,106,725 Total 19,929,599 21,965,640 The following table presents the calculation of diluted net loss per share: Three Months Three Months Net income (loss) attributable to the Company’s common stockholders - Basic $ 209,238 $ (15,914 ) Less: effect of participating securities — — Net income (loss) attributable to common stockholders - Dilutive $ 209,238 $ (15,914 ) Shares: Weighted-average shares used to compute basic net income per share 38,819,443 38,599,048 Adjustment to reflect conversion of convertible notes 561,665 — Adjustment to reflect stock appreciation right conversions 102,979 — Weighted-average shares used to compute diluted net income per share 39,484,087 38,599,048 Net income (loss) per share attributable to common stockholders: Diluted $ 5.30 $ (0.41 )

Reportable Segments and Geograp

Reportable Segments and Geographic Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Reportable Segments and Geographic Information	REPORTABLE SEGMENTS AND GEOGRAPHIC INFORMATION The Company reports its reportable segments based on products and services provided to customers. The Company re-assesses its reportable segments on an annual basis. The Company has three reportable segments, which generally align the Company's external financial reporting segments with its internal operating segments, which are based on its internal organizational structure, operating decisions and performance assessment. The Company's reportable segments at March 31, 2018 and for the year ended December 31, 2017 are composed of Biomass-based Diesel, Services, Renewable Chemicals and Corporate and other activities. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. The Biomass-based Diesel segment processes waste vegetable oils, animal fats, virgin vegetable oils and other feedstocks and methanol into biomass-based diesel. The Biomass-based Diesel segment also includes the Company’s purchases and resale of biomass-based diesel produced by third parties. Revenue is derived from the purchases and sales of biomass-based diesel, RINs and raw material feedstocks acquired from third parties, sales of biomass-based diesel produced under toll manufacturing arrangements with third party facilities, sales of processed biomass-based diesel from Company facilities, related by-products and renewable energy government incentive payments, in the U.S. and internationally. The Services segment offers services for managing the construction of biomass-based diesel production facilities and managing ongoing operations of third-party plants and collects fees related to the services provided. The Company does not allocate items that are of a non-operating nature or corporate expenses to the business segments. Revenues from services provided to other segments are recorded by the Services segment at cost. The Renewable Chemicals segment consists of research and development activities involving the production of renewable chemicals, additional advanced biofuels and other products from the Company's proprietary microbial fermentation process and the operations of a demonstration scale facility located in Okeechobee, Florida. The Corporate and Other segment includes trading activities related to petroleum-based heating oil and diesel fuel as well as corporate activities, which consist of corporate office expenses such as compensation, benefits, occupancy and other administrative costs, including management service expenses. Corporate and Other also includes income/(expense) not associated with the reportable segments, such as corporate general and administrative expenses, shared service expenses, interest expense and interest income, all reflected on an accrual basis of accounting. In addition, Corporate and Other includes cash and other assets not associated with the reportable segments, including investments. Intersegment revenues are reported by the Services and Corporate and Other segments. The following table represents the significant items by reportable segment: Three Months Three Months Net revenues: Biomass-based Diesel (includes REG Germany's net sales of $46,356 and $53,551, respectively) $ 630,365 $ 390,105 Services 35,215 22,833 Renewable Chemicals 1,860 828 Corporate and Other 74,543 37,773 Intersegment revenues (52,731 ) (32,646 ) $ 689,252 $ 418,893 Income (loss) before income taxes: Biomass-based Diesel (includes REG Germany's income (loss) of ($4,654) and $760, respectively) $ 215,529 $ (10,716 ) Services 5,024 (110 ) Renewable Chemicals (7,484 ) (5,007 ) Corporate and Other 117 994 $ 213,186 $ (14,839 ) Depreciation and amortization expense, net: Biomass-based Diesel (includes REG Germany's amounts of $798 and $686, respectively) $ 8,303 $ 7,740 Services 329 231 Renewable Chemicals 394 384 Corporate and Other 467 508 $ 9,493 $ 8,863 Cash paid for purchases of property, plant and equipment: Biomass-based Diesel (includes REG Germany's amounts of $413 and $1,168, respectively) $ 15,603 $ 15,882 Services 851 582 Renewable Chemicals 335 7 Corporate and Other 33 165 $ 16,822 $ 16,636 March 31, 2018 December 31, 2017 Goodwill: Services $ 16,080 $ 16,080 Assets: Biomass-based Diesel (including REG Germany's assets of $46,462 and $55,761, respectively) $ 1,306,370 $ 898,180 Services 60,043 55,581 Renewable Chemicals 20,783 21,168 Corporate and Other 388,454 386,590 Intersegment eliminations (368,596 ) (355,923 ) $ 1,407,054 $ 1,005,596 Geographic Information: The following geographic data include net sales attributed to the countries based on the location of the subsidiary making the sale and long-lived assets based on physical location. Long-lived assets represent the net book value of property, plant and equipment. Three Months Three Months Net revenues: United States $ 640,924 $ 365,342 Germany 46,356 53,551 Other Foreign 1,972 — Non-United States 48,328 53,551 $ 689,252 $ 418,893 March 31, 2018 December 31, 2017 Long-lived assets: United States $ 573,866 $ 566,028 Germany 20,211 20,689 Other Foreign 645 680 $ 594,722 $ 587,397

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES The Company is involved in legal proceedings in the normal course of business. The Company currently believes that any ultimate liability arising out of such proceedings will not have a material adverse effect on the Company’s financial position, results of operations or cash flows.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable are carried at invoiced amount less allowance for doubtful accounts. Management estimates the allowance for doubtful accounts based on existing economic conditions, the financial conditions of customers, and the amount and age of past due accounts. Receivables are considered past due if full payment is not received by the contractual due date. Past due accounts are generally written off against the allowance for doubtful accounts only after reasonable collection attempts have been exhausted.
Renewable Identification Numbers (RINs)	Renewable Identification Numbers (RINs) When the Company produces and sells a gallon of biomass-based diesel, 1.5 to 1.7 RINs per gallon are generated. RINs are used to track compliance with Renewable Fuel Standards (RFS2). RFS2 allows the Company to attach between zero and 2.5 RINs to any gallon of biomass-based diesel. As a result, a portion of the selling price for a gallon of biomass-based diesel is generally attributable to RFS2 compliance. However, RINs that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the RIN when it is generated, regardless of whether the RIN is transferred with the biomass-based diesel produced or held by the Company pending attachment to other biomass-based diesel production sales. In addition, the Company also obtains RINs from third parties who have separated the RINs from gallons of biomass-based diesel. From time to time, the Company holds varying amounts of these separated RINs for resale. RINs obtained from third parties are initially recorded at their cost and are subsequently revalued at the lower of cost or net realizable value as of the last day of each accounting period. The resulting adjustments are reflected in costs of goods sold for the period. The value of these RINs is reflected in “Prepaid expenses and other assets” on the Condensed Consolidated Balance Sheets. The cost of goods sold related to the sale of these RINs is determined using the average cost method, while market prices are determined by RIN values, as reported by the Oil Price Information Service ("OPIS").
Low Carbon Fuel Standards	Low Carbon Fuel Standards The Company generates Low Carbon Fuel Standards ("LCFS") credits for its low carbon fuels or blendstocks when its qualified low carbon fuels are transported into an LCFS market. LCFS credits are used to track compliance with the LCFS. As a result, a portion of the selling price for a gallon of biomass-based diesel sold into an LCFS market is also attributable to LCFS compliance. However, LCFS credits that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the LCFS credit when it is generated, regardless of whether the LCFS credit is transferred with the biomass-based diesel produced or held by the Company pending attachment to other biomass-based diesel sales that do not transfer credits. In addition, the Company also obtains LCFS credits from third-party trading activities. From time to time, the Company holds varying amounts of these third-party LCFS credits for resale. LCFS credits obtained from third parties are initially recorded at their cost and are subsequently revalued at the lower of cost or net realizable value as of the last day of each accounting period, and the resulting adjustments are reflected in costs of goods sold for the period. The value of LCFS credits obtained from third parties is reflected in “Prepaid expenses and other assets” on the Condensed Consolidated Balance Sheet. The cost of goods sold related to the sale of these LCFS credits is determined using the average cost method, while market prices are determined by LCFS values, as reported by the OPIS. At March 31, 2018 and December 31, 2017 , the Company held no LCFS credits purchased from third parties. The Company records assets acquired and liabilities assumed through the exchange of non-monetary assets based on the fair value of the assets and liabilities acquired or the fair value of the consideration exchanged, whichever is more readily determinable.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment is recorded at cost less accumulated depreciation. Maintenance and repairs are expensed as incurred. Depreciation expense is computed on a straight-line method based upon estimated useful lives of the assets.
Convertible Debt	Convertible Debt In June 2016, the Company issued $152,000 aggregate principal amount of 4% convertible senior notes due in 2036 (the "2036 Convertible Senior Notes"). The embedded conversion option was initially accounted for as an embedded derivative liability as the Company could not elect to issue shares of common stock upon conversion of the 2036 Convertible Notes to the extent such election would result in the issuance of more than 19.99% of the common stock outstanding immediately before the issuance of the 2036 Convertible Notes unless the Company received stockholder approval for such issuance. On December 8, 2017, at the special meeting of stockholders, the Company obtained approval from its stockholders to remove the common stock issuance restrictions in connection with conversions of the 2036 Convertible Notes. Accordingly, the embedded conversion option, valued at $45,933 and net of tax of $18,025 , was reclassified into Additional Paid-in Capital at December 8, 2017. See "Note 7 - Debt" for a further description of the transaction.
Capped Call Transaction	Capped Call Transaction In connection with the issuance of the 2014 Convertible Senior Notes, the Company entered into capped call transactions. The purchased capped call transactions were recorded as a reduction to common stock-additional paid-in-capital. Because this was considered to be an equity transaction and qualifies for the derivative scope exception, no future changes in the fair value of the capped call will be recorded by the Company. During 2016, in connection with the issuance of the 2036 Convertible Notes, certain call options covered by the original capped call transaction were rebalanced and reset to cover 100% of the total number of shares of the Company's Common Stock underlying the remaining principal of the 2019 Convertible Notes. The impact of these transactions, net of tax, was reflected as an addition/reduction to common stock-additional paid-in capital as presented in the Consolidated Statements of Stockholders' Equity.
Security Repurchase Programs	Security Repurchase Programs In December 2017, the Company's board of directors approved a repurchase program of up to $75,000 of the Company's convertible notes and/or shares of common stock. Under the program, the Company may repurchase convertible notes or shares from time to time in open market transactions, privately negotiated transactions or by other means. The timing and amount of repurchase transactions are determined by the Company's management based on its evaluation of market conditions, share price, bond price, legal requirements and other factors.
Research and Development	Research and Development Research and development ("R&D") costs are charged to expense as incurred. In process research and development ("IPR&D") assets acquired in connection with acquisitions are recorded on the Condensed Consolidated Balance Sheets as intangible assets.
Revenue Recognition	The Company receives payments from customers based upon contractual billing schedules; accounts receivable are recorded when the right to consideration becomes unconditional. Contract liabilities include payments received in advance of performance under the contract, and are realized with the associated revenue recognized under the contract. While in general the Company has not historically offered sales incentives to customers, the uncertainty around the reinstatement of the federal biodiesel tax credit led to the Company and other market participants acting as if the federal biodiesel tax credit would be reinstated throughout the year and entering into agreements with both customers and vendors throughout the year to capture the credit when or if reinstated. The impacts of the agreements with customers are recorded as contract liabilities in accounts payable and as adjustments to Biomass-based diesel sales, whereas agreements with vendors are recorded net as adjustments to Biomass-based diesel costs of goods sold on the Condensed Consolidated Statements of Operations. Revenue Recognition In the first quarter of 2018, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606). Under the ASU, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The Company applied the five-step method outlined in the ASU to all contracts with customers and elected the modified retrospective implementation method. The Company has generally a single performance obligation in its arrangements with customers. The Company believes for most of its contracts with customers, control is transferred at a point in time, typically upon delivery to the customers. When the Company performs shipping and handling activities after the transfer of control to the customers (e.g., when control transfers prior to delivery), they are considered as fulfillment activities, and accordingly, the costs are accrued for when the related revenue is recognized. Taxes collected from customers relating to product sales and remitted to governmental authorities are excluded from revenues. The Company generally expenses sales commissions when incurred because the amortization period would have been less than one year. The Company records these costs within selling, general and administrative expenses. The implementation of the new standard did not have any material impact on the measurement or recognition of revenue of prior periods, however additional disclosures have been added in accordance with the ASU. The following is a description of principal activities from which we generate revenue. Revenues from contracts with customers are recognized when control of the promised goods or services are transferred to our customers, in an amount that reflects the consideration that we expect to receive in exchange for those goods or services. • sales of biodiesel and renewable diesel produced at our facilities, including RINs and LCFS credits; • resale of finished biomass-based diesel, RINs and LCFS credits acquired from third parties, and raw material feedstocks acquired from others; • revenues from our sale of petroleum-based heating oil and ultra-low sulfur diesel, or ULSD, acquired from third parties, along with the sale of these petroleum-based products further blended with biodiesel produced at our wholly owned facilities; • sales of glycerin, other co-products of the biomass-based diesel production process; • incentive payments from federal and state governments, including the BTC, and from the USDA Advanced Biofuel Program; and • other revenue: • collaborative research and development and other service revenue for research and development activities to continue to build out the technology platform; and • sales of renewable chemical products. Disaggregation of revenue: All revenue recognized in the income statement, except for Biomass-based diesel Government Incentives, is considered to be revenue from contracts with customers.
New Accounting Standards	New Accounting Standards On February 25, 2016, the FASB issued ASU 2016-02, which introduces a lessee model that brings most leases on the balance sheet. The new standard also aligns many of the underlying principles of the new lessor model with those in ASC 606, the FASB’s new revenue recognition standard (e.g., those related to evaluating when profit can be recognized). Furthermore, the ASU addresses other concerns related to the current leases model. The ASU is effective for annual periods beginning after December 15, 2018 and interim periods therein. While the Company is continuing to assess all potential impacts of the standard, the Company currently believes the most significant impact relates to its accounting for office, railcar and terminal operating leases. The Company plans to apply a modified retrospective transition approach to each applicable lease that exists at January 1, 2017 as well as leases entered after this date. On January 25, 2018, the FASB issued ASU 2018-01, which amends the Board’s new leasing standard, ASU 2016-02 (codified in ASC 842), to provide a transition practical expedient for existing or expired land easements (i.e., rights to access, cross, or otherwise use someone else’s land for a specified purpose) that were not previously accounted for in accordance with ASC 840. The practical expedient would allow entities to elect not to assess whether those land easements are, or contain, leases in accordance with ASC 842 when transitioning to the new leasing standard. However, the ASU clarifies that land easements entered into (or existing land easements modified) on or after the effective date of the new leasing standard must be assessed under ASC 842. T he Company is evaluating the impact of this guidance on its consolidated financial statements as part of the lease standard adoption project, but does not expect the impact to be significant. On August 28, 2017, the FASB issued ASU 2017-12, which amends the hedge accounting recognition and presentation requirements in ASC 815 to (1) improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities by better aligning the entity’s financial reporting for hedging relationships with those risk management activities and (2) reduce the complexity of and simplify the application of hedge accounting by preparers. T he Company is evaluating the impact on its consolidated financial statements. On December 22, 2017, President Donald Trump signed into law “H.R. 1”, formerly known as the “Tax Cuts and Jobs Act” (the “Tax Legislation”). The Tax Legislation, which became effective on January 1, 2018, significantly revises the U.S. tax code by, among other things, lowering the corporate income tax rate from 35% to 21%, limiting deductibility of interest expense, implementing a hybrid-territorial tax system imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries (the “transition tax”), and enacted additional international tax provisions, including a minimum tax on global intangible low-taxed income (“GILTI”) and a new base erosion anti-abuse tax (“BEAT”). The Company recorded a provisional non-cash tax benefit of $13,712 in the fourth quarter of 2017. The Company finalized its accounting for the transition tax during the quarter ended March 31, 2018, but continue to evaluate the financial statement impact of the other provisions within the Tax Legislation as guidance is issued by the Internal Revenue Services and U.S. Department of Treasury. On February 28, 2018, the FASB issued ASU 2018-03, which makes technical corrections to certain aspects of ASU 2016-016 (on recognition of financial assets and financial liabilities), including equity securities without a readily determinable fair value (discontinuation and adjustments); forward contracts and purchased options; presentation requirements for certain fair value option liabilities; fair value option liabilities denominated in a foreign currency and transition guidance for equity securities without a readily determinable fair value. For public business entities, the amendments in ASU 2018-03 are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years beginning after June 15, 2018. Public business entities with fiscal years beginning between December 15, 2017, and June 15, 2018, are not required to adopt the amendments until the interim period beginning after June 15, 2018. T he Company is evaluating the impact of this guidance on its consolidated financial statements.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Disaggregation of Revenue	The following table depicts the disaggregation of revenue according to product line and segment: Reportable Segment Three months ended March 31, 2018 Biomass-based Services Renewable Corporate Intersegment Consolidated Biomass-based diesel sales, net of BTC related amount due to customers of $144,944 $ 166,191 $ — $ — $ 3,579 $ (17,683 ) $ 152,087 Petroleum diesel sales — — — 70,964 — 70,964 Other biomass-based diesel revenue 51,710 — — — — 51,710 Separated RIN sales 47,179 — — — — 47,179 Other revenues — 35,215 1,860 — (35,048 ) 2,027 Total revenues from contracts with customers $ 265,080 $ 35,215 $ 1,860 $ 74,543 $ (52,731 ) $ 323,967 Biomass-based diesel government incentives 365,285 — — — — $ 365,285 Total revenues $ 630,365 $ 35,215 $ 1,860 $ 74,543 $ (52,731 ) $ 689,252
Contract Balances	Significant changes to the contract liabilities during the quarter are as follows: January 1, 2018 Cash receipts Less: Impact on Other March 31, 2018 Deferred revenue $ 2,218 $ 10,507 $ 10,985 $ — $ 1,740 Payables to customers related to BTC — — (144,944 ) 5,832 150,776 $ 2,218 $ 10,507 $ (133,959 ) $ 5,832 $ 152,516 The following table provides information about receivables and contract liabilities from contracts with customers: March 31, Accounts receivable $ 98,593 Short-term contract liabilities (deferred revenue) $ 1,740 Short-term contract liabilities (accounts payable) $ 150,776

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2018
Sanimax Energy, LLC
Business Acquisition [Line Items]
Schedule of Business Acquisitions	The following table summarizes the consideration paid for the acquisition from Sanimax Energy: March 15, 2016 Consideration at fair value for acquisition from Sanimax: Cash $ 12,541 Common stock 4,050 Contingent consideration 4,500 Total $ 21,091 The following table summarizes the fair values of the assets acquired at the acquisition date: March 15, 2016 Assets acquired from Sanimax Energy: Inventory $ 1,591 Property, plant and equipment 19,500 Net identifiable assets acquired $ 21,091

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following: March 31, 2018 December 31, 2017 Raw materials $ 43,085 $ 39,975 Work in process 4,007 3,523 Finished goods 124,841 92,049 Total $ 171,933 $ 135,547

Other Assets (Tables)

Other Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Prepaid Expense and Other Assets	Prepaid expense and other assets consist of the following: March 31, 2018 December 31, 2017 Commodity derivatives and related collateral, net $ 4,054 $ 1,610 Prepaid expenses 19,028 11,733 Deposits 1,902 2,899 RIN inventory 9,952 27,028 Taxes receivable 3,685 6,356 Other 3,604 2,254 Total $ 42,225 $ 51,880
Summary of Other Noncurrent Assets	Other noncurrent assets consist of the following: March 31, 2018 December 31, 2017 Spare parts inventory $ 2,700 $ 2,764 Catalysts 2,686 2,962 Deposits 690 381 Other 1,489 933 Total $ 7,565 $ 7,040

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Components of Intangible assets	Intangible assets consist of the following: March 31, 2018 Cost Accumulated Amortization Net Weighted Average Remaining Life Raw material supply agreement $ 6,230 $ (2,518 ) $ 3,712 7.8 years Renewable diesel technology 8,300 (2,121 ) 6,179 11.3 years Ground lease 200 (144 ) 56 3.6 years Acquired customer relationships 2,900 (759 ) 2,141 7.3 years In-process research and development 15,956 (1,507 ) 14,449 13.6 years Total intangible assets $ 33,586 $ (7,049 ) $ 26,537 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 Ground lease 200 (141 ) 59 3.9 years Acquired customer relationships 2,900 (686 ) 2,214 7.6 years In-process research and development 15,956 (1,241 ) 14,715 13.8 years Total intangible assets $ 33,586 $ (6,459 ) $ 27,127
Estimated Amortization Expense	The estimated intangible asset amortization expense for the remainder of 2018 through 2023 and thereafter is as follows: April 1, 2018 through December 31, 2018 $ 1,781 2019 2,382 2020 2,389 2021 2,395 2022 2,388 2023 2,395 2024 and thereafter 12,807 Total $ 26,537

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Company's Borrowings	The following table shows the Company’s term debt: March 31, 2018 December 31, 2017 4.00% Convertible Senior Notes, $152,000 face amount, due in June 2036 $ 116,968 $ 116,255 2.75% Convertible Senior Notes, $67,527 face amount, due in June 2019 64,497 69,859 REG Danville term loan, secured, variable interest rate of LIBOR plus 4%, due in July 2022 10,836 11,460 REG Newton term loan, secured, variable interest rate of LIBOR plus 4%, due in December 2018 7,405 8,189 REG Ralston term loan, variable interest rate of Prime Rate plus 0.5%, due in July 2025 17,074 6,183 REG Mason City term loan, fixed interest rate of 5%, due in July 2019 979 1,153 REG Grays Harbor term loan, variable interest of minimum of 3.5% or Prime Rate plus 0.25%, due in May 2022 7,523 7,882 REG Capital term loan, fixed interest rate of 3.99%, due in January 2028 7,368 7,400 Other 148 179 Total term debt before debt issuance costs 232,798 228,560 Less: Current portion of long-term debt 14,207 13,397 Less: Debt issuance costs (net of accumulated amortization of $3,442 and $3,510, respectively) 5,513 6,627 Total long-term debt $ 213,078 $ 208,536
Revolving Line of Credit	The following table shows the Company's lines of credit: March 31, 2018 December 31, 2017 Amount outstanding under lines of credit $ 105,535 $ 65,525 Maximum available to be borrowed under lines of credit $ 56,615 $ 60,839

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Derivative Financial Instruments by Balance Sheet Location	The following table sets forth the fair value of the Company's commodity contract derivatives and amounts that offset within the Condensed Consolidated Balance Sheets: March 31, 2018 December 31, 2017 Assets Liabilities Assets Liabilities Gross amounts of derivatives recognized at fair value $ 1,472 $ 7,074 $ 812 $ 8,001 Cash collateral 9,656 — 8,799 — Total gross amount recognized 11,128 7,074 9,611 8,001 Gross amounts offset (7,074 ) (7,074 ) (8,001 ) (8,001 ) Net amount reported in the condensed consolidated balance sheets $ 4,054 $ — $ 1,610 $ —
Summary of Derivative Financial Instruments by Location of Gain (Loss)	The following table sets forth the commodity contract derivatives gains and (losses) included in the Condensed Consolidated Statements of Operations: Location of Gain (Loss) Three Months Three Months Commodity derivatives Cost of goods sold – Biomass-based diesel $ (2,438 ) $ 8,289

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Assets (Liabilities) Measured at Fair Value	A summary of assets (liabilities) measured at fair value is as follows: As of March 31, 2018 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (5,602 ) $ (2,657 ) $ (2,945 ) $ — Contingent considerations for acquisitions (30,040 ) — — (30,040 ) $ (35,642 ) $ (2,657 ) $ (2,945 ) $ (30,040 ) As of December 31, 2017 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (7,189 ) $ (3,742 ) $ (3,447 ) $ — Contingent considerations for acquisitions (34,393 ) — — (34,393 ) $ (41,582 ) $ (3,742 ) $ (3,447 ) $ (34,393 )
Liabilities Measured at Fair Value on a Recurring Basis	The following is a reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3): Contingent Consideration for Acquisitions 2018 2017 Balance at beginning of period, January 1 $ 34,393 $ 46,568 Change in estimates included in earnings (1,540 ) 589 Settlements (2,813 ) (3,980 ) Balance at end of period, March 31 30,040 43,177
Estimated Fair Values of the Company's Financial Instruments	The estimated fair values of the Company’s financial instruments, which are not recorded at fair value, are as follows: As of March 31, 2018 As of December 31, 2017 Asset (Liability) Fair Value Asset (Liability) Fair Value Financial liabilities: Debt and lines of credit $ (338,333 ) $ (427,838 ) $ (294,085 ) $ (273,983 )

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Potentially Dilutive Weighted Average Securities Excluded From the Calculation of Diluted Net Income (Loss) Per Share Attributable to Common Stockholders	The following potentially dilutive weighted average securities were excluded from the calculation of diluted net income (loss) per share attributable to common stockholders during the periods presented, as the effect was anti-dilutive: Three Months Three Months Stock appreciation rights 1,006,849 2,291,803 2019 Convertible Senior Notes 5,377,690 5,567,112 2036 Convertible Senior Notes 13,545,060 14,106,725 Total 19,929,599 21,965,640
Calculation of Diluted Net Income (Loss) Per Share	The following table presents the calculation of diluted net loss per share: Three Months Three Months Net income (loss) attributable to the Company’s common stockholders - Basic $ 209,238 $ (15,914 ) Less: effect of participating securities — — Net income (loss) attributable to common stockholders - Dilutive $ 209,238 $ (15,914 ) Shares: Weighted-average shares used to compute basic net income per share 38,819,443 38,599,048 Adjustment to reflect conversion of convertible notes 561,665 — Adjustment to reflect stock appreciation right conversions 102,979 — Weighted-average shares used to compute diluted net income per share 39,484,087 38,599,048 Net income (loss) per share attributable to common stockholders: Diluted $ 5.30 $ (0.41 )

Reportable Segments and Geogr31

Reportable Segments and Geographic Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of Significant Items by Reportable Segment	The following table represents the significant items by reportable segment: Three Months Three Months Net revenues: Biomass-based Diesel (includes REG Germany's net sales of $46,356 and $53,551, respectively) $ 630,365 $ 390,105 Services 35,215 22,833 Renewable Chemicals 1,860 828 Corporate and Other 74,543 37,773 Intersegment revenues (52,731 ) (32,646 ) $ 689,252 $ 418,893 Income (loss) before income taxes: Biomass-based Diesel (includes REG Germany's income (loss) of ($4,654) and $760, respectively) $ 215,529 $ (10,716 ) Services 5,024 (110 ) Renewable Chemicals (7,484 ) (5,007 ) Corporate and Other 117 994 $ 213,186 $ (14,839 ) Depreciation and amortization expense, net: Biomass-based Diesel (includes REG Germany's amounts of $798 and $686, respectively) $ 8,303 $ 7,740 Services 329 231 Renewable Chemicals 394 384 Corporate and Other 467 508 $ 9,493 $ 8,863 Cash paid for purchases of property, plant and equipment: Biomass-based Diesel (includes REG Germany's amounts of $413 and $1,168, respectively) $ 15,603 $ 15,882 Services 851 582 Renewable Chemicals 335 7 Corporate and Other 33 165 $ 16,822 $ 16,636 March 31, 2018 December 31, 2017 Goodwill: Services $ 16,080 $ 16,080 Assets: Biomass-based Diesel (including REG Germany's assets of $46,462 and $55,761, respectively) $ 1,306,370 $ 898,180 Services 60,043 55,581 Renewable Chemicals 20,783 21,168 Corporate and Other 388,454 386,590 Intersegment eliminations (368,596 ) (355,923 ) $ 1,407,054 $ 1,005,596
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	The following geographic data include net sales attributed to the countries based on the location of the subsidiary making the sale and long-lived assets based on physical location. Long-lived assets represent the net book value of property, plant and equipment. Three Months Three Months Net revenues: United States $ 640,924 $ 365,342 Germany 46,356 53,551 Other Foreign 1,972 — Non-United States 48,328 53,551 $ 689,252 $ 418,893 March 31, 2018 December 31, 2017 Long-lived assets: United States $ 573,866 $ 566,028 Germany 20,211 20,689 Other Foreign 645 680 $ 594,722 $ 587,397

Basis of Presentation and Nat32

Basis of Presentation and Nature of the Business (Details) gal in Millions	3 Months Ended
	Mar. 31, 2018facilitygal
Class of Stock [Line Items]
Number of biorefineries	14
Number of operating biomass-based diesel production facilities	13
Production capacity per year | gal	520
Number of fermentation facilities	1
Number of feedstock processing facilities	1
Number of multi-feedstock capable plants	10
North America
Class of Stock [Line Items]
Number of biorefineries	12
Europe
Class of Stock [Line Items]
Number of biorefineries	2

Summary of Significant Accoun33

Summary of Significant Accounting Policies (Details Textual)	3 Months Ended			10 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)renewable_identification_numbershares	Dec. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 02, 2016USD ($)
Business Acquisition [Line Items]
Biomass-based diesel government incentives	$ 365,285,000		$ 16,941,000
Estimated impaired fixed assets				$ 2,671,000
Estimated insurance recoveries				12,000,000
Payment of business interruption				3,620,000
Shares covered by rebalancing call options					100.00%
Security repurchase program, amount authorized to be repurchased		$ 75,000,000			$ 75,000,000
Security repurchase program, shares repurchased (in shares) | shares	641,601
Security repurchase program, value of shares repurchased	$ 7,828,000
Non-cash tax benefit due to Tax Cuts and Jobs Act		$ 13,712,000
2036 Convertible Notes | Convertible Notes
Business Acquisition [Line Items]
Face amount						$ 152,000,000	$ 152,000,000
Interest rate						4.00%	4.00%
Fair value of embedded conversion option					45,933,000
Tax impact of convertible conversion liability reclassification					$ 18,025,000
Cash paid for debt buyback							$ 147,118,000
2019 Convertible Notes | Convertible Notes
Business Acquisition [Line Items]
Cash paid for debt buyback	6,689,000			$ 6,689,000
Principal amount of debt repurchased	$ 6,311,000
Minimum
Business Acquisition [Line Items]
RINs per gallon | renewable_identification_number	1.5
Allowed RINs per gallon | renewable_identification_number	0
Maximum
Business Acquisition [Line Items]
RINs per gallon | renewable_identification_number	1.7
Allowed RINs per gallon | renewable_identification_number	2.5
Federal goverment | Biodiesel Mixture Excise Tax Credit
Business Acquisition [Line Items]
Biomass-based diesel government incentives	$ 365,155,000
Customers | Biodiesel Mixture Excise Tax Credit
Business Acquisition [Line Items]
Biomass-based diesel government incentives	$ 16,688,000

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 323,967
Biomass-based diesel government incentives	365,285	$ 16,941
Total revenues	689,252	$ 418,893
Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	265,080
Biomass-based diesel government incentives	365,285
Total revenues	630,365
Services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	35,215
Biomass-based diesel government incentives	0
Total revenues	35,215
Renewable Chemicals
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,860
Biomass-based diesel government incentives	0
Total revenues	1,860
Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	74,543
Biomass-based diesel government incentives	0
Total revenues	74,543
Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(52,731)
Biomass-based diesel government incentives	0
Total revenues	(52,731)
Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	152,087
Biomass-based Diesel | Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	166,191
Biomass-based Diesel | Services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Biomass-based Diesel | Renewable Chemicals
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Biomass-based Diesel | Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	3,579
Biomass-based Diesel | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(17,683)
Petroleum diesel sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	70,964
Petroleum diesel sales | Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Petroleum diesel sales | Services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Petroleum diesel sales | Renewable Chemicals
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Petroleum diesel sales | Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	70,964
Petroleum diesel sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other biomass-based diesel revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	51,710
Other biomass-based diesel revenue | Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	51,710
Other biomass-based diesel revenue | Services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other biomass-based diesel revenue | Renewable Chemicals
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other biomass-based diesel revenue | Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other biomass-based diesel revenue | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Separated RIN sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	47,179
Separated RIN sales | Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	47,179
Separated RIN sales | Services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Separated RIN sales | Renewable Chemicals
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Separated RIN sales | Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Separated RIN sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,027
Other revenues | Biomass-based Diesel
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other revenues | Services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	35,215
Other revenues | Renewable Chemicals
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,860
Other revenues | Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0
Other revenues | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ (35,048)

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Contract Balances) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Accounts receivable	$ 98,593
Short-term contract liabilities (deferred revenue)	1,740	$ 2,218
Short-term contract liabilities (accounts payable)	$ 150,776

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Significant Changes in Contract Liabilities) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Deferred revenue
January 1, 2018	$ 2,218
Cash receipts (Payments)	10,507
Less: Impact on Revenue	10,985
Other	0
March 31, 2018	1,740
Payables to customers related to BTC
January 1, 2018	0
Cash receipts (Payments)	0
Less: Impact on Revenue	(144,944)
Other	5,832
March 31, 2018	150,776
Total
January 1, 2018	2,218
Cash receipts (Payments)	10,507
Less: Impact on Revenue	(133,959)
Other	5,832
March 31, 2018	$ 152,516

Acquisitions (Details Textual)

Acquisitions (Details Textual) $ in Thousands, gal in Millions	Mar. 15, 2016USD ($)sharesgal	Mar. 31, 2018USD ($)gal	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Production capacity per year | gal		520
Long-term contingent consideration for acquisitions		$ 5,846	$ 8,849
Sanimax Energy, LLC
Business Acquisition [Line Items]
Production capacity per year | gal	20
Shares of common stock issued (in shares) | shares	500,000
Long-term contingent consideration for acquisitions	$ 5,000	2,648
Earnout payment period	7 years
Maximum Earnout Payment per year	$ 1,700
Current contingent liability		$ 1,595

Acquisitions (Details)

Acquisitions (Details) - Sanimax Energy, LLC $ in Thousands	Mar. 15, 2016USD ($)
Business Acquisition [Line Items]
Cash	$ 12,541
Common stock	4,050
Contingent consideration	4,500
Total	21,091
Assets acquired from Sanimax Energy:
Inventory	1,591
Property, plant and equipment	19,500
Net identifiable assets acquired	$ 21,091

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Inventories
Raw materials	$ 43,085	$ 39,975
Work in process	4,007	3,523
Finished goods	124,841	92,049
Total	$ 171,933	$ 135,547

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Summary of prepaid expense and other assets
Commodity derivatives and related collateral, net	$ 4,054	$ 1,610
Prepaid expenses	19,028	11,733
Deposits	1,902	2,899
RIN inventory	9,952	27,028
Taxes receivable	3,685	6,356
Other	3,604	2,254
Total	$ 42,225	$ 51,880

Other Assets (Details Textual)

Other Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Other Assets [Abstract]
Inventory adjustments to reflect lower of cost or net realizable value	$ 1,784	$ 2,629

Other Assets (Details 1)

Other Assets (Details 1) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Spare parts inventory	$ 2,700	$ 2,764
Catalysts	2,686	2,962
Deposits	690	381
Other	1,489	933
Total	$ 7,565	$ 7,040

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Cost	$ 33,586	$ 33,586
Accumulated Amortization	(7,049)	(6,459)
Net	26,537	27,127
Raw material supply agreement
Finite-Lived Intangible Assets [Line Items]
Cost	6,230	6,230
Accumulated Amortization	(2,518)	(2,408)
Net	$ 3,712	$ 3,822
Weighted Average Remaining Life	7 years 9 months	8 years
Renewable diesel technology
Finite-Lived Intangible Assets [Line Items]
Cost	$ 8,300	$ 8,300
Accumulated Amortization	(2,121)	(1,983)
Net	$ 6,179	$ 6,317
Weighted Average Remaining Life	11 years 3 months	11 years 6 months
Ground lease
Finite-Lived Intangible Assets [Line Items]
Cost	$ 200	$ 200
Accumulated Amortization	(144)	(141)
Net	$ 56	$ 59
Weighted Average Remaining Life	3 years 7 months 24 days	3 years 10 months 24 days
Acquired customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	$ 2,900	$ 2,900
Accumulated Amortization	(759)	(686)
Net	$ 2,141	$ 2,214
Weighted Average Remaining Life	7 years 4 months	7 years 7 months
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Cost	$ 15,956	$ 15,956
Accumulated Amortization	(1,507)	(1,241)
Net	$ 14,449	$ 14,715
Weighted Average Remaining Life	13 years 7 months	13 years 10 months

Intangible Assets (Details Text

Intangible Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expense	$ 590	$ 584

Intangible Assets (Details 1)

Intangible Assets (Details 1) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Estimated amortization expense
April 1, 2018 through December 31, 2018	$ 1,781
2,019	2,382
2,020	2,389
2,021	2,395
2,022	2,388
2,023	2,395
2024 and thereafter	12,807
Net	$ 26,537	$ 27,127

Debt (Details)

Debt (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Jul. 28, 2017	Apr. 19, 2017
Line of Credit Facility [Line Items]
Accumulated amortization on debt issuance costs	$ 0	$ 3,510,000
Company's borrowings
Total term debt before debt issuance costs	232,798,000	228,560,000
Less: Current portion of long-term debt	14,207,000	13,397,000
Less: Debt issuance costs (net of accumulated amortization of $3,442 and $3,510, respectively)	5,513,000	6,627,000
Total long-term debt	$ 213,078,000	208,536,000
4.00% Convertible Senior Notes
Line of Credit Facility [Line Items]
Interest rate	4.00%
Face amount	$ 152,000,000
Company's borrowings
Total term debt before debt issuance costs	$ 116,968,000	116,255,000
2.75% Convertible Senior Notes
Line of Credit Facility [Line Items]
Interest rate	2.75%
Face amount	$ 67,257,000
Company's borrowings
Total term debt before debt issuance costs	$ 64,497,000	69,859,000
REG Danville term loan
Line of Credit Facility [Line Items]
Face amount			$ 12,500,000
Description of variable rate basis	LIBOR plus 4% per annum
Company's borrowings
Total term debt before debt issuance costs	$ 10,836,000	11,460,000
REG Danville term loan | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	4.00%
REG Newton term loan
Line of Credit Facility [Line Items]
Description of variable rate basis	LIBOR plus 4% per annum
Company's borrowings
Total term debt before debt issuance costs	$ 7,405,000	8,189,000
REG Newton term loan | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	4.00%
REG Ralston term loan
Line of Credit Facility [Line Items]
Face amount				$ 20,000,000
Description of variable rate basis	Prime Rate plus 0.5%
Company's borrowings
Total term debt before debt issuance costs	$ 17,074,000	6,183,000
REG Ralston term loan | Prime Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
REG Mason City term loan
Line of Credit Facility [Line Items]
Interest rate	5.00%
Company's borrowings
Total term debt before debt issuance costs	$ 979,000	1,153,000
REG Grays Harbor term loan
Line of Credit Facility [Line Items]
Description of variable rate basis	Prime Rate plus 0.25%
Basis spread on variable rate	3.50%
Company's borrowings
Total term debt before debt issuance costs	$ 7,523,000	7,882,000
REG Grays Harbor term loan | Prime Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.25%
REG Capital term loan
Line of Credit Facility [Line Items]
Interest rate	3.99%
Company's borrowings
Total term debt before debt issuance costs	$ 7,368,000	7,400,000
Other
Company's borrowings
Total term debt before debt issuance costs	$ 148,000	$ 179,000

Debt (Details Textual)

Debt (Details Textual)	Jun. 02, 2016USD ($)$ / shares	Mar. 31, 2018USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 08, 2017USD ($)	Jul. 28, 2017USD ($)	Apr. 19, 2017USD ($)	Jun. 30, 2016USD ($)	Mar. 16, 2016USD ($)
Debt Instrument [Line Items]
Debt liability component		$ 232,798,000		$ 228,560,000
Convertible Notes | 2036 Convertible Notes
Debt Instrument [Line Items]
Face amount	$ 152,000,000							$ 152,000,000
Interest rate	4.00%							4.00%
Percentage of convertible senior notes principal required for repurchase	100.00%
Initial conversion rate	92.8074
Initial conversion price (in dollars per share) | $ / shares	$ 10.78
Net proceeds from debt issuance	$ 147,118,000
Fees and offering expenses	4,882,000
Convertible debt conversion liability	40,145,000				$ 45,933,000
Debt liability component	111,855,000
Debt discount	$ 40,145,000
Effective interest rate	2.45%
Convertible Notes
Debt Instrument [Line Items]
Face amount		$ 67,257,000
Interest rate		2.75%
Debt liability component		$ 64,497,000		69,859,000
REG Ralston term loan
Debt Instrument [Line Items]
Face amount							$ 20,000,000
Debt liability component		$ 17,074,000		6,183,000
Effective interest rate		5.25%
REG Ralston term loan | Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%
REG Danville
Debt Instrument [Line Items]
Face amount						$ 12,500,000
Debt liability component		$ 10,836,000		11,460,000
Effective interest rate		5.75%
REG Capital term loan
Debt Instrument [Line Items]
Interest rate		3.99%
Debt liability component		$ 7,368,000		7,400,000
Bankers Trust Company
Debt Instrument [Line Items]
Line of credit									$ 15,000,000
BNP Master Banking Facility Agreement
Debt Instrument [Line Items]
Line of credit		$ 25,000,000
BNP Master Banking Facility Agreement | Minimum
Debt Instrument [Line Items]
Effective interest rate		1.50%
BNP Master Banking Facility Agreement | Maximum
Debt Instrument [Line Items]
Effective interest rate		2.00%
Wells Fargo Revolver
Debt Instrument [Line Items]
Additional Increase in maximum borrowing capacity		$ 150,000,000	$ 150,000,000
Line of credit facility limitation amount		$ 50,000,000		$ 40,000,000
Debt instrument, variable rate minimum		0.00%
Percentage required of total current revolving loan commitments		10.00%
Amount required of total current revolving loan commitments		$ 15,000,000
Wells Fargo Revolver | Minimum
Debt Instrument [Line Items]
LIBOR rate margin		1.75%
Fixed charge coverate ratio		1
Wells Fargo Revolver | Maximum
Debt Instrument [Line Items]
LIBOR rate margin		2.25%
Fixed charge coverate ratio		1

Debt (Details 1)

Debt (Details 1) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Amount outstanding under lines of credit	$ 105,535	$ 65,525
Maximum available to be borrowed under lines of credit	$ 56,615	$ 60,839

Derivative Instruments (Details

Derivative Instruments (Details Textual) lb in Millions, gal in Millions	3 Months Ended
	Mar. 31, 2018lbgal
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Heating oil covered under the open commodity derivative contracts (in gallons) | gal	107
Soybean oil covered under the open commodity derivative contracts (in pounds) | lb	2

Derivative Instruments (Detai50

Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets
Gross amounts of derivatives recognized at fair value	$ 1,472	$ 812
Cash collateral	9,656	8,799
Total gross amount recognized	11,128	9,611
Gross amounts offset	(7,074)	(8,001)
Net amount reported in the condensed consolidated balance sheets	4,054	1,610
Liabilities
Gross amounts of derivatives recognized at fair value	7,074	8,001
Cash collateral	0	0
Total gross amount recognized	7,074	8,001
Gross amounts offset	(7,074)	(8,001)
Net amount reported in the condensed consolidated balance sheets	$ 0	$ 0

Derivative Instruments (Detai51

Derivative Instruments (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cost of goods sold – Biomass-based diesel | Commodity derivatives
Derivative Instruments Gain Loss [Line Items]
Gains (losses) included in the condensed consolidated statement of operations	$ (2,438)	$ 8,289

Fair Value Measurement (Details

Fair Value Measurement (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	$ (35,642)	$ (41,582)
Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(2,657)	(3,742)
Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(2,945)	(3,447)
Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(30,040)	(34,393)
Commodity contract derivatives
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(5,602)	(7,189)
Commodity contract derivatives | Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(2,657)	(3,742)
Commodity contract derivatives | Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(2,945)	(3,447)
Commodity contract derivatives | Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	0	0
Contingent considerations for acquisitions
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(30,040)	(34,393)
Contingent considerations for acquisitions | Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	0	0
Contingent considerations for acquisitions | Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	0	0
Contingent considerations for acquisitions | Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	$ (30,040)	$ (34,393)

Fair Value Measurement (Detai53

Fair Value Measurement (Details 1) - Contingent Consideration for Acquisitions - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 34,393	$ 46,568
Change in estimates included in earnings	(1,540)	589
Settlements	(2,813)	(3,980)
Ending balance	$ 30,040	$ 43,177

Fair Value Measurement (Detai54

Fair Value Measurement (Details 2) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Asset (Liability) Carrying Amount
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt and lines of credit	$ (338,333)	$ (294,085)
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt and lines of credit	$ (427,838)	$ (273,983)

Fair Value Measurement (Detai55

Fair Value Measurement (Details Textual)	3 Months Ended
	Mar. 31, 2018
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, discount rate	5.80%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, discount rate	10.00%
REG Life Sciences
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, discount rate	8.00%

Net Income (Loss) Per Share (De

Net Income (Loss) Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	19,929,599	21,965,640
Stock appreciation rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	1,006,849	2,291,803
2019 Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	5,377,690	5,567,112
2036 Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	13,545,060	14,106,725

Net Income (Loss) Per Share (57

Net Income (Loss) Per Share (Details 1) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
NET INCOME (LOSS) ATTRIBUTABLE TO THE COMPANY’S COMMON STOCKHOLDERS	$ 209,238	$ (15,914)
Less: effect of participating securities	0	0
Net income (loss) attributable to common stockholders - Dilutive	$ 209,238	$ (15,914)
Shares:
Weighted-average shares used to compute basic net income per share (in shares)	38,819,443	38,599,048
Adjustment to reflect conversion of convertible notes (in shares)	561,665	0
Adjustment to reflect stock appreciation right conversions (in shares)	102,979	0
Weighted-average shares used to compute diluted net income per share (in shares)	39,484,087	38,599,048
Net income (loss) per share attributable to common stockholders:
Diluted (in dollars per share)	$ 5.30	$ (0.41)

Reportable Segments and Geogr58

Reportable Segments and Geographic Information (Details Textual)	3 Months Ended
	Mar. 31, 2018segment
Segment Reporting [Abstract]
Number of reportable segments	3

Reportable Segments and Geogr59

Reportable Segments and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 689,252	$ 418,893
Income (loss) before income taxes	213,186	(14,839)
Depreciation and amortization expense, net	9,493	8,863
Cash paid for purchases of property, plant and equipment	16,822	16,636
Goodwill	16,080		$ 16,080
Assets	1,407,054		1,005,596
Intersegment Revenues
Segment Reporting Information [Line Items]
Net revenues	(52,731)	(32,646)
Assets	(368,596)		(355,923)
Biomass-based Diesel | Segments
Segment Reporting Information [Line Items]
Net revenues	630,365	390,105
Income (loss) before income taxes	215,529	(10,716)
Depreciation and amortization expense, net	8,303	7,740
Cash paid for purchases of property, plant and equipment	15,603	15,882
Assets	1,306,370		898,180
Biomass-based Diesel | Segments | REG Germany
Segment Reporting Information [Line Items]
Net revenues	46,356	53,551
Income (loss) before income taxes	(4,654)	760
Depreciation and amortization expense, net	798	686
Cash paid for purchases of property, plant and equipment	413	1,168
Assets	46,462		55,761
Services
Segment Reporting Information [Line Items]
Goodwill	16,080		16,080
Services | Segments
Segment Reporting Information [Line Items]
Net revenues	35,215	22,833
Income (loss) before income taxes	5,024	(110)
Depreciation and amortization expense, net	329	231
Cash paid for purchases of property, plant and equipment	851	582
Assets	60,043		55,581
Renewable Chemicals | Segments
Segment Reporting Information [Line Items]
Net revenues	1,860	828
Income (loss) before income taxes	(7,484)	(5,007)
Depreciation and amortization expense, net	394	384
Cash paid for purchases of property, plant and equipment	335	7
Assets	20,783		21,168
Corporate and Other
Segment Reporting Information [Line Items]
Net revenues	74,543	37,773
Income (loss) before income taxes	117	994
Depreciation and amortization expense, net	467	508
Cash paid for purchases of property, plant and equipment	33	$ 165
Assets	$ 388,454		$ 386,590

Reportable Segments and Geogr60

Reportable Segments and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 689,252	$ 418,893
Long-lived assets	594,722		$ 587,397
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	640,924	365,342
Long-lived assets	573,866		566,028
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	46,356	53,551
Long-lived assets	20,211		20,689
Other Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	1,972	0
Long-lived assets	645		$ 680
Non-United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 48,328	$ 53,551