Clean Energy Fuels (CLNE) 10-Q 9 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Nov. 02, 2023
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Securities Act File Number	001-33480
Entity Registrant Name	CLEAN ENERGY FUELS CORP.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0968580
Entity Address, Address Line One	4675 MacArthur Court
Entity Address, Address Line Two	Suite 800
Entity Address, City or Town	Newport Beach
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92660
City Area Code	949
Local Phone Number	437-1000
Title of 12(b) Security	Common stock, $0.0001 par value per share
Trading Symbol	CLNE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		223,020,351
Entity Central Index Key	0001368265
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash, cash equivalents and current portion of restricted cash	$ 27,099	$ 125,950
Short-term investments	149,325	139,569
Accounts receivable, net of allowance of $1,375 and $1,471 as of December 31, 2022 and September 30, 2023, respectively	87,550	91,430
Other receivables	36,509	17,026
Inventory	40,472	37,144
Prepaid expenses and other current assets	52,082	60,601
Total current assets	393,037	471,720
Operating lease right-of-use assets	74,868	52,586
Land, property and equipment, net	305,988	264,068
Notes receivable and other long-term assets, net	26,560	30,467
Investments in other entities	193,807	193,273
Goodwill	64,328	64,328
Intangible assets, net	6,365	5,915
Total assets	1,064,953	1,082,357
Current liabilities:
Current portion of debt	38	93
Current portion of finance lease obligations	916	948
Current portion of operating lease obligations	5,712	4,206
Accounts payable	48,794	44,435
Accrued liabilities	83,141	90,079
Deferred revenue	3,523	5,970
Derivative liabilities, related party	3,723	2,415
Total current liabilities	145,847	148,146
Long-term portion of debt	144,913	145,471
Long-term portion of finance lease obligations	1,808	2,134
Long-term portion of operating lease obligations	71,341	48,911
Long-term portion of derivative liabilities, related party	0	1,430
Other long-term liabilities	9,432	8,794
Total liabilities	373,341	354,886
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.0001 par value. 1,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.0001 par value. 454,000,000 shares authorized; 222,437,429 shares and 222,987,248 shares issued and outstanding as of December 31, 2022 and September 30, 2023, respectively	22	22
Additional paid-in capital	1,598,634	1,553,668
Accumulated deficit	(910,785)	(829,975)
Accumulated other comprehensive loss	(3,280)	(3,722)
Total Clean Energy Fuels Corp. stockholders' equity	684,591	719,993
Noncontrolling interest in subsidiary	7,021	7,478
Total stockholders' equity	691,612	727,471
Total liabilities and stockholders' equity	$ 1,064,953	$ 1,082,357

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 1,471	$ 1,375
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	454,000,000	454,000,000
Common stock, issued (in shares)	222,987,248	222,437,429
Common stock, outstanding (in shares)	222,987,248	222,437,429

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue:
Total revenue	$ 95,571	$ 125,687	$ 318,302	$ 306,408
Cost of sales (exclusive of depreciation and amortization shown separately below):
Selling, general and administrative	29,117	26,501	87,314	80,909
Depreciation and amortization	13,389	20,539	34,960	42,485
Total operating expenses	116,935	134,315	388,133	346,966
Operating loss	(21,364)	(8,628)	(69,831)	(40,558)
Interest expense	(3,893)	(670)	(12,612)	(4,479)
Interest income	2,551	1,019	8,034	1,773
Other income, net	14	25	85	59
Loss from equity method investments	(3,304)	(728)	(7,109)	(3,598)
Loss before income taxes	(25,996)	(8,982)	(81,433)	(46,803)
Income tax (expense) benefit	47	(106)	166	(223)
Net loss	(25,949)	(9,088)	(81,267)	(47,026)
Loss attributable to noncontrolling interest	137	115	457	627
Net loss attributable to Clean Energy Fuels Corp.	$ (25,812)	$ (8,973)	$ (80,810)	$ (46,399)
Net loss attributable to Clean Energy Fuels Corp. per share:
Basic (in dollars per share)	$ (0.12)	$ (0.04)	$ (0.36)	$ (0.21)
Diluted (in dollars per share)	$ (0.12)	$ (0.04)	$ (0.36)	$ (0.21)
Weighted-average common shares outstanding:
Basic (in shares)	222,973,575	222,239,376	222,867,303	222,409,802
Diluted (in shares)	222,973,575	222,239,376	222,867,303	222,409,802
Product revenue
Revenue:
Total revenue	$ 81,279	$ 113,360	$ 276,635	$ 271,720
Cost of sales (exclusive of depreciation and amortization shown separately below):
Cost of sales	65,427	79,710	240,655	203,258
Service revenue
Revenue:
Total revenue	14,292	12,327	41,667	34,688
Cost of sales (exclusive of depreciation and amortization shown separately below):
Cost of sales	$ 9,002	$ 7,565	$ 25,204	$ 20,314

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net loss	$ (25,949)	$ (9,088)	$ (81,267)	$ (47,026)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2022 and 2023	(864)	(1,901)	182	(2,926)
Unrealized gain (loss) on available-for-sale securities, net of $0 tax in 2022 and 2023	(1,097)	(187)	260	(329)
Total other comprehensive income (loss)	(1,961)	(2,088)	442	(3,255)
Comprehensive loss	(27,910)	(11,176)	(80,825)	(50,281)
Clean Energy Fuels Corp.
Net loss	(25,812)	(8,973)	(80,810)	(46,399)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2022 and 2023	(864)	(1,901)	182	(2,926)
Unrealized gain (loss) on available-for-sale securities, net of $0 tax in 2022 and 2023	(1,097)	(187)	260	(329)
Total other comprehensive income (loss)	(1,961)	(2,088)	442	(3,255)
Comprehensive loss	(27,773)	(11,061)	(80,368)	(49,654)
Noncontrolling Interest
Net loss	(137)	(115)	(457)	(627)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2022 and 2023	0	0	0	0
Unrealized gain (loss) on available-for-sale securities, net of $0 tax in 2022 and 2023	0	0	0	0
Total other comprehensive income (loss)	0	0	0	0
Comprehensive loss	$ (137)	$ (115)	$ (457)	$ (627)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, tax	$ 0	$ 0	$ 0	$ 0
Unrealized gains on available-for sale securities, tax	$ 0	$ 0	$ 0	$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest in Subsidiary	Total
Beginning balance at Dec. 31, 2021	$ 22	$ 1,519,918	$ (771,242)	$ (1,622)	$ 8,335	$ 755,411
Beginning balance (in shares) at Dec. 31, 2021	222,684,923
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		273				273
Issuance of common stock (in shares)	585,775
Repurchase of common stock		(3,001)				(3,001)
Repurchase of common stock (in shares)	(511,010)
Stock-based compensation		8,253				8,253
Stock-based sales incentive charges		1,721				1,721
Net loss			(24,191)		(385)	(24,576)
Other comprehensive income (loss)				249		249
Ending balance at Mar. 31, 2022	$ 22	1,527,164	(795,433)	(1,373)	7,950	738,330
Ending balance (in shares) at Mar. 31, 2022	222,759,688
Beginning balance at Dec. 31, 2021	$ 22	1,519,918	(771,242)	(1,622)	8,335	755,411
Beginning balance (in shares) at Dec. 31, 2021	222,684,923
Increase (Decrease) in Stockholders' Equity
Net loss					(627)	(47,026)
Other comprehensive income (loss)					0	(3,255)
Ending balance at Sep. 30, 2022	$ 22	1,543,511	(817,641)	(4,877)	7,708	728,723
Ending balance (in shares) at Sep. 30, 2022	222,413,908
Beginning balance at Mar. 31, 2022	$ 22	1,527,164	(795,433)	(1,373)	7,950	738,330
Beginning balance (in shares) at Mar. 31, 2022	222,759,688
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		300				300
Issuance of common stock (in shares)	96,728
Repurchase of common stock		(3,121)				(3,121)
Repurchase of common stock (in shares)	(679,244)
Stock-based compensation		6,468				6,468
Stock-based sales incentive charges		2,307				2,307
Net loss			(13,235)		(127)	(13,362)
Other comprehensive income (loss)				(1,416)		(1,416)
Ending balance at Jun. 30, 2022	$ 22	1,533,118	(808,668)	(2,789)	7,823	729,506
Ending balance (in shares) at Jun. 30, 2022	222,177,172
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		744				744
Issuance of common stock (in shares)	236,736
Stock-based compensation		5,964				5,964
Stock-based sales incentive charges		3,685				3,685
Net loss			(8,973)		(115)	(9,088)
Other comprehensive income (loss)				(2,088)	0	(2,088)
Ending balance at Sep. 30, 2022	$ 22	1,543,511	(817,641)	(4,877)	7,708	728,723
Ending balance (in shares) at Sep. 30, 2022	222,413,908
Beginning balance at Dec. 31, 2022	$ 22	1,553,668	(829,975)	(3,722)	7,478	$ 727,471
Beginning balance (in shares) at Dec. 31, 2022	222,437,429					222,437,429
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		332				$ 332
Issuance of common stock (in shares)	470,351
Shares withheld related to net share settlement		(175)				(175)
Stock-based compensation		6,096				6,096
Stock-based sales incentive charges		8,172				8,172
Net loss			(38,697)		(135)	(38,832)
Other comprehensive income (loss)				705		705
Ending balance at Mar. 31, 2023	$ 22	1,568,093	(868,672)	(3,017)	7,343	703,769
Ending balance (in shares) at Mar. 31, 2023	222,907,780
Beginning balance at Dec. 31, 2022	$ 22	1,553,668	(829,975)	(3,722)	7,478	$ 727,471
Beginning balance (in shares) at Dec. 31, 2022	222,437,429					222,437,429
Increase (Decrease) in Stockholders' Equity
Net loss					(457)	$ (81,267)
Other comprehensive income (loss)					0	442
Ending balance at Sep. 30, 2023	$ 22	1,598,634	(910,785)	(3,280)	7,021	$ 691,612
Ending balance (in shares) at Sep. 30, 2023	222,987,248					222,987,248
Beginning balance at Mar. 31, 2023	$ 22	1,568,093	(868,672)	(3,017)	7,343	$ 703,769
Beginning balance (in shares) at Mar. 31, 2023	222,907,780
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		3				3
Issuance of common stock (in shares)	2,277
Stock-based compensation		6,093				6,093
Stock-based sales incentive charges		7,820				7,820
Net loss			(16,301)		(185)	(16,486)
Other comprehensive income (loss)				1,698		1,698
Ending balance at Jun. 30, 2023	$ 22	1,582,009	(884,973)	(1,319)	7,158	702,897
Ending balance (in shares) at Jun. 30, 2023	222,910,057
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		284				284
Issuance of common stock (in shares)	77,191
Stock-based compensation		6,091				6,091
Stock-based sales incentive charges		10,250				10,250
Net loss			(25,812)		(137)	(25,949)
Other comprehensive income (loss)				(1,961)	0	(1,961)
Ending balance at Sep. 30, 2023	$ 22	$ 1,598,634	$ (910,785)	$ (3,280)	$ 7,021	$ 691,612
Ending balance (in shares) at Sep. 30, 2023	222,987,248					222,987,248

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (81,267)	$ (47,026)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	34,960	42,485
Provision for credit losses and inventory	1,486	1,606
Stock-based compensation expense	18,280	20,685
Stock-based sales incentive charges	44,473	15,500
Change in fair value of derivative instruments	304	1,606
Amortization of discount and debt issuance cost	(3,475)	(862)
Gain on disposal of property and equipment	(134)	40
Loss on extinguishment of debt	0	2,268
Asset impairments and other charges	555	0
Loss from equity method investments	7,109	3,598
Non-cash lease expense	4,629	2,602
Deferred income taxes	(235)	143
Changes in operating assets and liabilities:
Accounts and other receivables	(7,046)	(19,139)
Inventory	(6,009)	(7,601)
Prepaid expenses and other assets	(3,918)	1,583
Operating lease liabilities	(2,975)	(2,589)
Accounts payable	4,204	5,937
Deferred revenue	(2,296)	(2,324)
Accrued liabilities and other	(7,862)	13,216
Net cash provided by (used in) operating activities	783	31,728
Cash flows from investing activities:
Purchases of short-term investments	(334,272)	(292,930)
Maturities and sales of short-term investments	329,403	312,239
Purchases of and deposits on property and equipment	(67,298)	(29,091)
Grant proceeds for capital projects	1,947	0
Disbursements for loans receivable	(3,500)	(810)
Proceeds from paydowns, maturities, and sales of loans receivables	1,835	480
Cash received from sale of certain assets of subsidiary, net	0	3,885
Investments in other entities	(5,500)	(89,700)
Payment and deposits on equipment and manure rights for RNG production projects	(17,709)	(4,915)
Proceeds received for joint development and construction of station projects	3,137	0
Advance to DR JV	(5,500)	0
Proceeds from settlement of insurance claims	495	0
Proceeds from disposal of property and equipment	230	129
Net cash (used in) investing activities	(96,732)	(100,713)
Cash flows from financing activities:
Issuance of common stock	175	1,317
Repurchase of common stock	0	(6,122)
Payments of tax withholdings on net settlement of equity awards	(175)	0
Fees paid for lender and debt issuance costs	(1,732)	(50)
Proceeds for Adopt-a-Port program	390	1,100
Repayment of proceeds for Adopt-a-Port program	(1,071)	(828)
Proceeds from debt instruments	255	14,000
Repayments of debt instruments and finance lease obligations	(870)	(21,167)
Payments of debt extinguishment costs	0	(2,186)
Net cash (used in) financing activities	(3,028)	(13,936)
Effect of exchange rates on cash, cash equivalents and restricted cash	126	(412)
Net (decrease) in cash, cash equivalents and restricted cash	(98,851)	(83,333)
Cash, cash equivalents and restricted cash, beginning of period	125,950	106,456
Cash, cash equivalents and restricted cash, end of period	27,099	23,123
Supplemental disclosure of cash flow information:
Income taxes paid	57	50
Interest paid, net of $0 and $581 capitalized, respectively	$ 11,927	$ 1,373

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Statement of Cash Flows [Abstract]
Capitalized interest paid, respectively	$ 1,673	$ 0

General

General	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	Note 1—General Nature of Business Clean Energy Fuels Corp., together with its majority and wholly owned subsidiaries (hereinafter collectively referred to as the “Company,” unless the context or the use of the term indicates or requires otherwise) is engaged in the business of selling renewable and conventional natural gas as alternative fuels for vehicle fleets and related fueling solutions to its customers, primarily in the United States and Canada. The Company’s principal business is supplying renewable natural gas (“RNG”) and conventional natural gas, in the form of compressed natural gas (“CNG”) and liquefied natural gas (“LNG”), for medium and heavy-duty vehicles and providing operation and maintenance (“O&M”) services to public and private vehicle fleet customer stations. The Company is also focused on developing, owning, and operating dairy and other livestock waste RNG projects and supplying RNG (currently procured from third party sources and from the DR JV, one of the Company’s jointly owned RNG production facilities (see Note 3)) to its customers in the heavy and medium-duty commercial transportation sector. As a comprehensive clean energy solution provider, the Company also designs and builds, as well as operates and maintains, public and private vehicle fueling stations in the United States and Canada; sells and services compressors and other equipment used in RNG production and at fueling stations; transports and sells RNG and conventional natural gas, in the form of CNG and LNG, via “virtual” natural gas pipelines and interconnects; sells U.S. federal, state and local government credits it generates by selling RNG in the form of CNG and LNG as a vehicle fuel, including Renewable Identification Numbers (“RIN Credits” or “RINs”) under the federal Renewable Fuel Standard Phase 2 and credits under the California, Oregon, and Washington Low Carbon Fuel Standards (collectively, “LCFS Credits”); and obtains federal, state and local tax credits, grants and incentives. Basis of Presentation The accompanying interim unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to state fairly the Company’s consolidated financial position as of September 30, 2023, results of operations, comprehensive loss, and stockholders’ equity for the three and nine months ended September 30, 2022 and 2023, and cash flows for the nine months ended September 30, 2022 and 2023. All intercompany accounts and transactions have been eliminated in consolidation. The results of operations for the three and nine months ended September 30, 2022 and 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any other interim period or any future year. Certain information and disclosures normally included in the notes to consolidated financial statements have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), but the resultant disclosures contained herein are in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) as they apply to interim reporting. The accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2022 that are included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2023. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying condensed consolidated financial statements and these notes. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position. Significant estimates made in preparing the accompanying condensed consolidated financial statements include (but are not limited to) those related to revenue recognition, fair value measurements, goodwill and long-lived asset valuations and impairment assessments, income tax valuations, stock-based compensation expense and stock-based sales incentive charges. Amazon Warrant The Amazon Warrant (defined in Note 14) is accounted for as an equity instrument and measured in accordance with Accounting Standards Codification (“ASC”) 718, Compensation – Stock Compensation Revenue from Contracts with Customers Tourmaline Joint Development In April 2023, the Company and Tourmaline Oil Corp. (“Tourmaline”) announced a CAD $70 million Joint Development Agreement to build and operate a network of CNG stations along key highway corridors across Western Canada. Under a 50-50 shared investment, the Company and Tourmaline expect to construct and commission up to 20 CNG fueling stations over the next five years, allowing heavy-duty trucks and other commercial transportation fleets that operate in the area to transition to the use of CNG, a lower carbon alternative to gasoline and diesel. Costs associated with station construction and profit and loss arising from station operation are shared 50-50 between the Company and Tourmaline. This arrangement between the Company and Tourmaline to jointly develop, build and operate CNG fueling stations is accounted for in accordance with ASC 808, Collaborative Arrangements Revenue from Contracts with Customers The Company determined that it is the principal for the revenue generated from third parties under this collaborative arrangement with Tourmaline in accordance with ASC 606; as such, the associated revenue and cost of sales generated and incurred are recognized on a gross basis in the condensed consolidated statements of operations. Net participation of profit and loss owed to or from Tourmaline is recorded as an increase or decrease to cost of sales, respectively, as the transaction is not deemed to be with a customer within the scope of ASC 606. Capitalized station costs are presented at half of the total development and construction costs in the condensed consolidated balance sheets, corresponding to the Company’s 50% ownership in the shared assets. Recently Issued Accounting Pronouncements In March 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2023-01, Leases (Topic 842): Common Control Arrangements December 15, 2023, with early adoption allowed. The Company is currently evaluating the impact of adopting this new ASU and does not expect the adoption to have a material effect on the Company’s condensed consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Note 2—Revenue from Contracts with Customers Revenue Recognition Overview The Company recognizes revenue when control of the promised goods or services is transferred to its customers, in an amount that reflects the consideration to which it expects to be entitled in exchange for the goods or services. To achieve that core principle, a five-step approach is applied: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue allocated to each performance obligation when the Company satisfies the performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account for revenue recognition. The Company is generally the principal in its customer contracts because it has control over the goods and services prior to their transfer to the customer, and as such, revenue is recognized on a gross basis. Sales and usage-based taxes are excluded from revenue. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The table below presents the Company’s revenue disaggregated by revenue source (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2022 2023 2022 2023 Product revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Volume-related ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fuel sales (1) ​ $ 78,512 ​ $ 60,006 ​ $ 204,224 ​ $ 220,168 Change in fair value of derivative instruments (2) ​ ​ 508 ​ ​ (1,372) ​ ​ (1,606) ​ ​ (304) RIN Credits ​ ​ 9,270 ​ ​ 6,784 ​ ​ 26,997 ​ ​ 16,664 LCFS Credits ​ ​ 2,595 ​ ​ 2,846 ​ ​ 10,114 ​ ​ 7,618 AFTC (3) ​ 16,057 ​ 5,422 ​ 16,279 ​ 14,977 Total volume-related product revenue ​ ​ 106,942 ​ ​ 73,686 ​ ​ 256,008 ​ ​ 259,123 Station construction sales ​ ​ 6,418 ​ ​ 7,593 ​ ​ 15,712 ​ ​ 17,512 Total product revenue ​ 113,360 ​ 81,279 ​ 271,720 ​ 276,635 Service revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Volume-related, O&M services ​ ​ 11,982 ​ ​ 13,646 ​ ​ 33,727 ​ ​ 39,603 Other services ​ ​ 345 ​ ​ 646 ​ ​ 961 ​ ​ 2,064 Total service revenue ​ ​ 12,327 ​ ​ 14,292 ​ ​ 34,688 ​ ​ 41,667 Total revenue ​ $ 125,687 ​ $ 95,571 ​ $ 306,408 ​ $ 318,302 (1) Includes non-cash stock-based sales incentive contra-revenue charges associated with the Amazon Warrant. For the three and nine months ended September 30, 2022, contra-revenue charges recognized in fuel revenue were $7.0 million and $15.5 million, respectively. For the three and nine months ended September 30, 2023, contra-revenue charges recognized in fuel revenue were $16.8 million and $44.5 million, respectively. See Note 14 for more information. (2) Represents changes in fair value of derivative instruments related to the Company’s commodity swap and customer fueling contracts associated with the Company’s Zero Now truck financing program. The amounts are classified as revenue because the Company’s commodity swap contracts are used to economically offset the risk associated with the diesel-to-natural gas price spread resulting from customer fueling contracts under the Company’s Zero Now truck financing program. See Note 6 for more information about these derivative instruments. (3) Represents the federal alternative fuel excise tax credit (“AFTC”). See Note 19 for more information. Remaining Performance Obligations Remaining performance obligations represent the transaction price of customer orders for which the work has not been performed. As of September 30, 2023, the aggregate amount of the transaction price allocated to remaining performance obligations was $26.1 million, which related to the Company’s station construction sale contracts. The Company expects to recognize revenue on the remaining performance obligations under these contracts over the next 12 For volume-related revenue, the Company has elected to apply an optional exemption, which waives the requirement to disclose the remaining performance obligation for revenue recognized through the ‘ Contract Balances The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) in the accompanying condensed consolidated balance sheets. As of December 31, 2022 and September 30, 2023, the Company’s contract balances were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Accounts receivable, net ​ $ 91,430 ​ $ 87,550 ​ ​ ​ ​ ​ ​ Contract assets - current ​ $ 6,063 ​ $ 10,374 Contract assets - non-current ​ 2,976 ​ 2,563 Contract assets - total ​ $ 9,039 ​ $ 12,937 ​ ​ ​ ​ ​ ​ Contract liabilities - current ​ $ 5,477 ​ $ 2,586 Contract liabilities - non-current ​ — ​ 151 Contract liabilities - total ​ $ 5,477 ​ $ 2,737 ​ Accounts Receivable, Net “Accounts receivable, net” in the accompanying condensed consolidated balance sheets includes billed and accrued amounts that are currently due from customers. The amounts due are stated at their net estimated realizable value. The Company maintains an allowance to provide for the estimated amount of receivables that will not be collected. The allowance is based on an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables, and economic conditions that may affect a customer’s ability to pay. Contract Assets Contract assets include unbilled amounts typically resulting from the Company’s station construction sale contracts, when the cost-to-cost method of revenue recognition is utilized and revenue recognized exceeds the amount billed to the customer, and right to payment is not just subject to the passage of time. Amounts may not exceed their net realizable value. Contract assets are classified as current or noncurrent based on the timing of billings. The current portion is included in “Other receivables” and in “Prepaid expenses and other current assets” and the noncurrent portion is included in “Notes receivable and other long-term assets, net” in the accompanying condensed consolidated balance sheets. Contract Liabilities Contract liabilities primarily consist of billings in excess of revenue recognized from the Company’s station construction sale contracts and payments received primarily from customers of NG Advantage, LLC (“NG Advantage”) in advance of the satisfaction of performance obligations and are classified as current or noncurrent based on when the related revenue is expected to be recognized. The current portion and noncurrent portion of contract liabilities are included in “Deferred revenue” and in “Other long-term liabilities,” respectively, in the accompanying condensed consolidated balance sheets. Revenue recognized in the nine months ended September 30, 2022 relating to the Company’s contract liability balances as of December 31, 2021 was $2.5 million. The decrease in the contract liability balance in the nine months ended September 30, 2023 is mainly driven by $4.2 million of revenue recognized relating to the Company’s contract liability balances as of December 31, 2022, partially offset by billings in excess of revenue recognized in the nine months ended September 30, 2023.

Investments in Other Entities a

Investments in Other Entities and Noncontrolling Interest in a Subsidiary	9 Months Ended
	Sep. 30, 2023
Investments, All Other Investments [Abstract]
Investments in Other Entities and Noncontrolling Interest in a Subsidiary	Note 3— Investments in Other Entities and Noncontrolling Interest in a Subsidiary TotalEnergies Joint Venture On March 3, 2021, the Company entered into an agreement (the “TotalEnergies JV Agreement”) with TotalEnergies S.E. (“TotalEnergies”) to create 50/50 joint ventures to develop anaerobic digester gas (“ADG”) RNG production facilities in the United States. Pursuant to the TotalEnergies JV Agreement, each ADG RNG production facility project will be formed as a separate limited liability company (“LLC”) that is owned 50/50 by the Company and TotalEnergies, and contributions to such LLCs count toward the TotalEnergies JV Equity Obligations (as defined below). The TotalEnergies JV Agreement contemplates investing up to $400.0 million of equity in production projects, and TotalEnergies and the Company each committed to initially provide $50.0 million (the “TotalEnergies JV Equity Obligations”). In October 2021, TotalEnergies and the Company executed a LLC agreement (the “DR Development Agreement”) for an ADG RNG production facility project (the “DR JV”). Under the DR Development Agreement, TotalEnergies and the Company have each committed to contribute $7.0 million to the DR JV, and in November 2021, TotalEnergies and the Company each contributed an initial $4.8 million to the DR JV. On June 28, 2023, the DR JV issued a capital call for $11.0 million in additional funding, requiring TotalEnergies and the Company each to contribute $5.5 million. Funds from the capital call will be used to fund required loan reserves and to paydown outstanding liabilities of the DR JV. On June 30, 2023, the Company contributed $5.5 million and advanced $5.5 million to the DR JV. The $5.5 million advance is anticipated to be refunded to the Company by the DR JV before the end of 2023. The Company accounts for its interest in the LLC using the equity method of accounting because the Company does not control but has the ability to exercise significant influence over the LLC’s operations. The Company recorded a loss of $0.0 million and $0.5 million from the LLC’s operations in the three months ended September 30, 2022 and 2023, respectively, and a loss of $0.1 million and $1.9 million from the LLC’s operations in the nine months ended September 30, 2022 and 2023, respectively. The Company had an investment balance of $4.5 million and $8.1 million as of December 31, 2022 and September 30, 2023, respectively. bp Joint Venture On April 13, 2021, the Company entered into an agreement (the “bp JV Agreement”) with bp Products North America, Inc. (“bp”) that created a 50/50 joint venture (the “bpJV”) to develop, own and operate new ADG RNG production facilities in the United States. Pursuant to the bp JV Agreement, bp and the Company committed to provide $50.0 million and $30.0 million, respectively, with bp Pursuant to the bp JV Agreement, the Company had the option, exercisable prior to August 31, 2021 (the “bp Option”), to commit an additional $20.0 million to the bpJV upon which bp’s Class B Units would convert into Class A Units. On June 21, 2021, the Company contributed $50.2 million to the bpJV, which consisted of (i) its initial contribution commitment of $30.0 million, (ii) the $20.0 million additional contribution to effect the conversion of bp’s Class B Units into Class A Units pursuant to the Company’s exercise of the bp Option, and (iii) $0.2 million for interest in accordance with the bp JV Agreement to effect the conversion of bp’s Class B Units into Class A Units. In December 2021, the bpJV issued a capital call for $143.2 million in additional funding, requiring bp bp bpJV The Company accounts for its interest in the bpJV using the equity method of accounting because the Company does not control but has the ability to exercise significant influence over the bpJV’s operations. The Company recorded a loss of $0.2 million and $0.8 million from this investment in the three months ended September 30, 2022 and 2023, respectively, and a loss of $2.2 million and $1.4 million from this investment in the nine months ended September 30, 2022 and 2023, respectively. The Company had an investment balance in the bpJV of $156.8 million and $155.4 million as of December 31, 2022 and September 30, 2023, respectively. SAFE&CEC S.r.l. On November 26, 2017, the Company, through its former subsidiary, IMW Industries Ltd. (formerly known as Clean Energy Compression Corp.) (“CEC”), entered into an investment agreement with Landi Renzo S.p.A. (“LR”), an alternative fuels company based in Italy. Pursuant to the investment agreement, the Company and LR agreed to combine their respective natural gas compressor fueling systems manufacturing subsidiaries, CEC and SAFE S.p.A, into a new company, SAFE&CEC S.r.l. (such combination transaction is referred to as the “CEC Combination”). SAFE&CEC S.r.l. is focused on manufacturing, selling and servicing natural gas fueling compressors and related equipment for the global natural gas fueling market. At the closing of the CEC Combination on December 29, 2017, the Company owned 49% of SAFE&CEC S.r.l., and LR owned 51% of SAFE&CEC S.r.l. The Company accounts for its interest in SAFE&CEC S.r.l. using the equity method of accounting because the Company does not control but has the ability to exercise significant influence over SAFE&CEC S.r.l.’s operations. The Company recorded a loss of $0.3 million and $1.1 million in the three months ended September 30, 2022 and 2023, respectively, and a loss of $0.6 million and $1.3 million in the nine months ended September 30, 2022 and 2023, respectively. The Company had an investment balance in SAFE&CEC S.r.l. of $21.8 million and $20.5 million as of December 31, 2022 and September 30, 2023, respectively. NG Advantage On October 14, 2014, the Company entered into a Common Unit Purchase Agreement (“UPA”) with NG Advantage for a 53.3% controlling interest in NG Advantage. Subsequently, the Company’s controlling interest increased in connection with various equity and financing arrangements with NG Advantage. As of September 30, 2023, the Company’s controlling interest in NG Advantage was 93.3%. NG Advantage is engaged in the business of transporting CNG in high-capacity trailers to industrial and institutional energy users, such as hospitals, food processors, manufacturers and paper mills that do not have direct access to natural gas pipelines. The Company recorded a loss attributable to the noncontrolling interest in NG Advantage of $0.1 million in each of the three months ended September 30, 2022 and 2023, and a loss attributable to the noncontrolling interest in NG Advantage of $0.6 million and $0.5 million in the nine months ended September 30, 2022 and 2023, respectively. The carrying value of the noncontrolling interest was $7.5 million and $7.0 million as of December 31, 2022 and September 30, 2023, respectively. Investments in Equity Securities For investments in equity securities of privately held entities without readily determinable fair values, the Company measures such investments at cost, adjusted for impairment, if any, and observable price changes in orderly transactions for the identical or similar investment of the same issuer. As of December 31, 2022 and September 30, 2023, the Company had an investment balance recorded at cost of $8.0 million. The Company did not recognize any adjustments to the recorded cost basis in the three and nine months ended September 30, 2022 and 2023.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	9 Months Ended
	Sep. 30, 2023
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	Note 4—Cash, Cash Equivalents and Restricted Cash Cash, cash equivalents and restricted cash as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Current assets: ​ ​ Cash and cash equivalents ​ $ 123,950 ​ $ 25,080 Restricted cash - standby letter of credit ​ 2,000 ​ 2,019 Total cash, cash equivalents and current portion of restricted cash ​ $ 125,950 ​ $ 27,099 ​ ​ ​ ​ ​ ​ ​ Total cash, cash equivalents and restricted cash ​ $ 125,950 ​ $ 27,099 ​ The Company considers all highly liquid investments with maturities of three months or less on the date of acquisition to be cash equivalents. The Company places its cash and cash equivalents with high credit quality financial institutions. At times, such balances may be in excess of the Federal Deposit Insurance Corporation (“FDIC”) and Canadian Deposit Insurance Corporation (“CDIC”) limits. Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash deposits. The amounts in excess of FDIC and CDIC limits were approximately $124.8 million and $25.9 million as of December 31, 2022 and September 30, 2023, respectively. The Company classifies restricted cash as short-term and a current asset if the cash is expected to be used in operations within a year or to acquire a current asset. Otherwise, the restricted cash is classified as long-term. The Company deposited $2.0 million, in the form of a certificate of deposit, at PlainsCapital Bank as collateral for the standby letter of credit issued to Chevron Products Company, a division of Chevron U.S.A. Inc., in connection with the Company’s Adopt-A-Port program. The $2.0 million certificate of deposit is classified as short-term restricted cash and a current asset and is included in “Cash, cash equivalents and current portion of restricted cash” in the accompanying condensed consolidated balance sheets as of December 31, 2022 and September 30, 2023.

Short-Term Investments

Short-Term Investments	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Short-Term Investments	Note 5—Short-Term Investments Short-term investments include available-for-sale debt securities, excluded from cash equivalents, that have maturities of one year or less on the date of acquisition and certificates of deposit. Available-for-sale debt securities are carried at fair value, inclusive of unrealized gains and losses. Unrealized gains and losses on available-for-sale debt securities are recognized in other comprehensive income (loss), net of applicable income taxes. Gains or losses on sales of available-for-sale debt securities are recognized on the specific identification basis. The Company reviews available-for-sale debt securities for declines in fair value below their cost basis each quarter and whenever events or changes in circumstances indicate that the cost basis of an asset may not be recoverable and evaluates the current expected credit loss. This evaluation is based on a number of factors, including historical experience, market data, issuer-specific factors, economic conditions, and any changes to the credit rating of the security. As of September 30, 2023, the Company has not recorded a credit loss related to available-for-sale debt securities and believes the carrying values of its available-for-sale debt securities are properly recorded. Short-term investments as of December 31, 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Estimated ​ Cost Gain (Loss) Fair Value Zero coupon bonds ​ $ 74,524 ​ $ (365) ​ $ 74,159 U.S. government securities ​ 64,861 ​ 19 ​ 64,880 Certificates of deposit ​ 530 ​ — ​ 530 Total short-term investments ​ $ 139,915 ​ $ (346) ​ $ 139,569 ​ Short-term investments as of September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Estimated ​ Cost Gain (Loss) Fair Value U.S. government securities ​ $ 148,767 ​ $ 28 ​ $ 148,795 Certificates of deposit ​ ​ 530 ​ ​ — ​ ​ 530 Total short-term investments ​ $ 149,297 ​ $ 28 ​ $ 149,325 ​

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Note 6—Derivative Instruments and Hedging Activities In October 2018, the Company executed two commodity swap contracts with TotalEnergies Gas & Power North America, an affiliate of TotalEnergies, for a total of 5.0 million diesel gallons annually from April 1, 2019 to June 30, 2024. These commodity swap contracts are used to manage diesel price fluctuation risks related to the natural gas fuel supply commitments the Company makes in its fueling agreements with fleet operators who participate in the Zero Now The Company has entered into fueling agreements with fleet operators under the Zero Now Commodity swaps and embedded derivatives as of December 31, 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Amounts ​ Gross Amounts ​ Net Amount ​ Recognized Offset Presented Assets: ​ ​ ​ Fueling agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets ​ $ 1,640 ​ $ — ​ $ 1,640 Notes receivable and other long-term assets, net ​ ​ 5,115 ​ ​ — ​ ​ 5,115 Total derivative assets ​ $ 6,755 ​ $ — ​ $ 6,755 Liabilities: ​ ​ ​ Commodity swaps: ​ ​ ​ ​ ​ ​ ​ ​ ​ Current portion of derivative liabilities, related party ​ $ 2,415 ​ $ — ​ $ 2,415 Long-term portion of derivative liabilities, related party ​ 1,430 ​ — ​ 1,430 Total derivative liabilities ​ $ 3,845 ​ $ — ​ $ 3,845 ​ Commodity swaps and embedded derivatives as of September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Amounts ​ Gross Amounts ​ Net Amount ​ Recognized Offset Presented Assets: ​ ​ ​ Fueling agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets ​ $ 3,594 ​ $ — ​ $ 3,594 Notes receivable and other long-term assets, net ​ ​ 2,735 ​ ​ — ​ ​ 2,735 Total derivative assets ​ $ 6,329 ​ $ — ​ $ 6,329 Liabilities: ​ ​ ​ Commodity swaps: ​ ​ ​ ​ ​ ​ ​ ​ ​ Current portion of derivative liabilities, related party ​ $ 3,723 ​ $ — ​ $ 3,723 Total derivative liabilities ​ $ 3,723 ​ $ — ​ $ 3,723 ​ As of December 31, 2022 and September 30, 2023, the Company had a total volume on open commodity swap contracts of 6.9 million and 3.1 million diesel gallons, respectively, at a weighted-average price of approximately $3.18 per gallon. The following table reflects the weighted-average price of open commodity swap contracts as of December 31, 2022 and September 30, 2023, by year with associated volumes: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 ​ ​ Volumes ​ Weighted-Average Price per ​ Volumes ​ Weighted-Average Price per Year (Diesel Gallons) Diesel Gallon (Diesel Gallons) Diesel Gallon 2023 5,000,000 ​ $ 3.18 1,250,000 ​ $ 3.18 2024 1,875,000 ​ $ 3.18 1,875,000 ​ $ 3.18 ​ ​

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 7—Fair Value Measurements The Company follows the authoritative guidance for fair value measurements with respect to assets and liabilities that are measured at fair value on a recurring basis and non-recurring basis. Under the standard, fair value is defined as the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as of the measurement date. The standard also establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs developed based on market data obtained from sources independent of the Company that market participants would use in valuing the asset or liability. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available in the circumstances. The hierarchy consists of the following three levels: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly; and Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Assets and Liabilities Measured at Fair Value on a Recurring Basis The Company’s U.S. government issued debt securities are classified within Level 1 because they are valued using the most recent quoted prices for identical assets in active markets. Certificate of deposits is classified within Level 2 because it is valued using the most recent quoted prices for identical assets in markets that are not active and quoted prices for similar assets in active markets. The Company used the income approach to value its outstanding commodity swap contracts and embedded derivatives in its fueling agreements under the Zero Now approach, the Company used a discounted cash flow (“DCF”) model in which cash flows anticipated over the term of the contracts are discounted to their present value using an expected discount rate. The discount rate used for cash flows reflects the specific risks in spot and forward rates and credit valuation adjustments. This valuation approach is considered a Level 3 fair value measurement. The significant unobservable inputs used in the fair value measurement of the Company’s derivative instruments are Ultra-Low Sulfur Diesel (“ULSD”) forward prices and differentials from ULSD to Petroleum Administration for Defense District (“PADD”) regions. Significant increases (decreases) in any of those inputs in isolation would result in a significantly lower (higher) fair value measurement. Generally, a change in the ULSD forward prices is accompanied by a directionally opposite but less extreme change in the ULSD-PADD differential. The Company estimated the fair value of its outstanding commodity swap contracts based on the following inputs as of December 31, 2022 and September 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 Significant Unobservable Inputs Input Range Weighted Average Input Range Weighted Average ULSD Gulf Coast Forward Curve ​ $2.35 - $2.59 ​ $ 2.48 ​ $2.30 - $2.57 ​ $ 2.41 Historical Differential to PADD 3 Diesel ​ $0.88 - $1.62 ​ $ 1.13 ​ $0.92 - $1.62 ​ $ 1.15 Historical Differential to PADD 5 Diesel ​ $1.89 - $3.00 ​ $ 2.30 ​ $1.89 - $3.10 ​ $ 2.41 ​ The Company estimated the fair value of embedded derivatives in its fueling agreements under the Zero Now ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 Significant Unobservable Inputs Input Range Weighted Average Input Range Weighted Average ULSD Gulf Coast Forward Curve ​ $2.35 - $2.59 ​ $ 2.48 ​ $2.30 - $2.57 ​ $ 2.41 Historical Differential to PADD 3 Diesel ​ $0.88 - $1.62 ​ $ 1.13 ​ $0.92 - $1.62 ​ $ 1.15 Historical Differential to PADD 5 Diesel ​ $1.91 - $3.05 ​ $ 2.31 ​ $1.89 - $3.10 ​ $ 2.41 ​ Convertible Promissory Note In connection with the Company’s loan commitment to a certain equity method investee, the Company was issued a convertible promissory note with a principal balance equal to the amount of drawdown on the loan commitment (see Note 17). The convertible promissory note bears interest at 7% per annum, compounded quarterly, with a maturity date the earlier of May 7, 2024 or upon the occurrence of a triggering event such as change of control or an event of default. The convertible promissory note is classified as available-for-sale and is carried at fair value, which is measured using the income approach. Under the income approach, the Company used a DCF model in which cash flows anticipated over the term of the note are discounted to their present value using an expected discount rate. The discount rate used reflects the interest rates offered on loans of similar terms and to borrowers of similar credit quality, which are Level 3 inputs. As such, this valuation approach is considered a Level 3 fair value measurement. The following table provides quantitative information about the significant inputs used to estimate the fair value of the convertible promissory note as of December 31, 2022 and September 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Significant Unobservable Inputs December 31, 2022 September 30, 2023 Risk-free interest rate ​ 4.57% ​ 5.52% Credit adjustment ​ 8.36% ​ 6.65% Credit adjusted discount rate ​ 12.93% ​ 12.17% ​ The above significant unobservable inputs are subject to change based on changes in economic and market conditions. The use of significant unobservable inputs creates uncertainty in the measurement of fair value as of the reporting date. Significant increase or decrease in any of the inputs in isolation would result in a significantly lower or higher fair value measurement. Generally, a change in market interest rates is accompanied by a directionally opposite change in the estimated fair value of fixed-rate debt securities. The Company records changes in the fair value of available- for-sale debt securities in “Unrealized gain (loss) on available-for-sale securities” within other comprehensive income (loss) in the accompanying condensed consolidated statements of comprehensive loss. There were no transfers of assets or liabilities between Level 1, Level 2, or Level 3 of the fair value hierarchy as of December 31, 2022 or September 30, 2023. The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2022 and September 30, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 Level 1 Level 2 Level 3 Assets: ​ ​ ​ ​ Available-for-sale securities: ​ ​ ​ ​ U.S. government securities (1) ​ $ 64,880 ​ $ 64,880 ​ $ — ​ $ — Zero coupon bonds (1) ​ 74,159 ​ — ​ 74,159 ​ — Convertible promissory note (4) ​ 1,880 ​ — ​ — ​ 1,880 Certificates of deposit (1) ​ 530 ​ — ​ 530 ​ — Embedded derivatives (3) ​ ​ 6,755 ​ ​ — ​ ​ — ​ ​ 6,755 Liabilities: ​ ​ ​ ​ ​ Commodity swap contracts (2) ​ $ 3,845 ​ $ — ​ $ — ​ $ 3,845 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2023 Level 1 Level 2 Level 3 Assets: ​ ​ ​ ​ Available-for-sale securities: ​ ​ ​ ​ U.S. government securities (1) ​ $ 148,795 ​ $ 148,795 ​ $ — ​ $ — Convertible promissory note (4) ​ 3,528 ​ — ​ — ​ 3,528 Certificates of deposit (1) ​ 530 ​ — ​ 530 ​ — Embedded derivatives (3) ​ ​ 6,329 ​ ​ — ​ ​ — ​ ​ 6,329 Liabilities: ​ ​ ​ ​ ​ Commodity swap contracts (2) ​ $ 3,723 ​ $ — ​ $ — ​ $ 3,723 ​ (1) Included in “Short-term investments” in the accompanying condensed consolidated balance sheets. See Note 5 for more information. (2) Included in “Derivative liabilities, related party” and “Long-term portion of derivative liabilities, related party” as of December 31, 2022 and in “Derivative liabilities, related party” as of September 30, 2023 in the accompanying condensed consolidated balance sheets. See Note 6 for more information. (3) Included in “Prepaid expenses and other current assets” and “Notes receivable and other long-term assets, net” as of December 31, 2022 and in “Prepaid expenses and other current assets,” and “Notes receivable and other long-term assets, net,” as of September 30, 2023 in the accompanying condensed consolidated balance sheets. See Note 6 for more information. (4) Included in “Notes receivable and other long-term assets, net” as of December 31, 2022 and in “Other receivables” as of September 30, 2023 in the accompanying condensed consolidated balance sheets. The following table provides a reconciliation of the beginning and ending balances of items measured at fair value on a recurring basis as shown in the tables above that used significant unobservable inputs (Level 3), as well as the change in unrealized gains or losses for the periods included in earnings or other comprehensive income (loss) (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ Assets: ​ Assets: ​ Liabilities: ​ Liabilities: ​ ​ Commodity ​ Embedded ​ Convertible ​ Commodity ​ Embedded ​ Swap Contracts Derivatives ​ Promissory Note ​ Swap Contracts ​ Derivatives Balance as of June 30, 2022 ​ $ — ​ $ 11,345 ​ $ — ​ $ (11,034) ​ $ (32) Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,942 ​ ​ — Total gain (loss) ​ — ​ ​ (4,899) ​ ​ — ​ ​ 3,486 ​ ​ (21) Balance as of September 30, 2022 ​ $ — ​ $ 6,446 ​ $ — ​ $ (5,606) ​ $ (53) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of June 30, 2023 ​ $ — ​ $ 6,837 ​ $ 4,295 ​ $ (2,779) ​ $ (80) Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,893 ​ ​ — Total gain (loss) ​ — ​ ​ (508) ​ ​ (1,084) ​ ​ (2,837) ​ ​ 80 Purchases ​ ​ — ​ ​ — ​ ​ 1,243 ​ ​ — ​ ​ — Equity method investment loss ​ ​ — ​ ​ — ​ ​ (926) ​ ​ — ​ ​ — Balance as of September 30, 2023 ​ $ — ​ $ 6,329 ​ $ 3,528 ​ $ (3,723) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in unrealized gain (loss) for the three months ended September 30, 2022 included in earnings ​ $ — ​ $ (4,899) ​ $ — ​ $ 5,428 ​ $ (21) Change in unrealized gain (loss) for the three months ended September 30, 2023 included in earnings ​ $ — ​ $ (508) ​ $ — ​ $ (944) ​ $ 80 Change in unrealized gain (loss) for the three months ended September 30, 2023 included in other comprehensive income (loss) ​ $ — ​ $ — ​ $ (1,084) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ Assets: ​ Assets: ​ Liabilities: ​ Liabilities: ​ ​ Commodity ​ Embedded ​ Convertible ​ Commodity ​ Embedded ​ Swap Contracts ​ Derivatives ​ Promissory Note ​ Swap Contracts ​ Derivatives Balance as of December 31, 2021 ​ $ — ​ $ 6,776 ​ $ — ​ $ (4,383) ​ $ — Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 5,843 ​ ​ — Total gain (loss) ​ ​ — ​ ​ (330) ​ ​ — ​ ​ (7,066) ​ ​ (53) Balance as of September 30, 2022 ​ $ — ​ $ 6,446 ​ $ — ​ $ (5,606) ​ $ (53) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of December 31, 2022 ​ $ — ​ $ 6,755 ​ $ 1,880 ​ $ (3,845) ​ $ — Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,926 ​ ​ — Total gain (loss) ​ — ​ ​ (426) ​ ​ 21 ​ ​ (2,804) ​ ​ — Purchases ​ ​ — ​ ​ — ​ ​ 3,721 ​ ​ — ​ ​ — Equity method investment loss ​ ​ — ​ ​ — ​ ​ (2,094) ​ ​ — ​ ​ — Balance as of September 30, 2023 ​ $ — ​ $ 6,329 ​ $ 3,528 ​ $ (3,723) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in unrealized gain (loss) for the nine months ended September 30, 2022 included in earnings ​ $ — ​ $ (330) ​ $ — ​ $ (1,223) ​ $ (53) Change in unrealized gain (loss) for the nine months ended September 30, 2023 included in earnings ​ $ — ​ $ (426) ​ $ — ​ $ 122 ​ $ — Change in unrealized gain (loss) for the nine months ended September 30, 2023 included in other comprehensive income (loss) ​ $ — ​ $ — ​ $ 21 ​ $ — ​ $ — ​ Other Financial Assets and Liabilities The carrying amounts of the Company’s cash, cash equivalents, receivables and payables approximate fair value due to the short-term nature of those instruments. The carrying amounts of the Company’s debt instruments approximated their respective fair values as of December 31, 2022 and September 30, 2023. The fair values of these debt instruments were estimated using a DCF analysis based on interest rates offered on loans with similar terms to borrowers of similar credit quality, which are Level 3 inputs. See Note 12 for more information about the Company’s debt instruments.

Other Receivables

Other Receivables	9 Months Ended
	Sep. 30, 2023
Receivables [Abstract]
Other Receivables	Note 8—Other Receivables Other receivables as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 2023 Loans to customers to finance vehicle purchases ​ $ 523 ​ $ 309 Accrued customer billings ​ 4,910 ​ 8,703 Fuel tax credits ​ 9,462 ​ 15,143 Other ​ 2,131 ​ 12,354 Total other receivables ​ $ 17,026 ​ $ 36,509 ​ ​

Inventory

Inventory	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Inventory	Note 9—Inventory Inventory consists of raw materials and spare parts, work in process and finished goods and is stated at the lower of cost (first-in, first-out) or net realizable value. The Company evaluates inventory balances for excess quantities and obsolescence by analyzing estimated demand, inventory on hand, sales levels and other information and reduces inventory balances to net realizable value for excess and obsolete inventory based on this analysis. Inventory as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Raw materials and spare parts ​ $ 37,144 ​ $ 40,472 Total inventory ​ $ 37,144 ​ $ 40,472 ​ ​

Land, Property and Equipment

Land, Property and Equipment	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Land, Property and Equipment	Note 10—Land, Property and Equipment Land, property and equipment, net as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ 2022 2023 Land ​ $ 3,476 ​ $ 3,620 LNG liquefaction plants ​ 94,790 ​ 96,786 Station equipment ​ 353,104 ​ 396,651 Trailers ​ 73,253 ​ 72,753 Other equipment ​ 106,184 ​ 98,703 Construction in progress ​ 91,105 ​ 125,010 ​ ​ 721,912 ​ 793,523 Less accumulated depreciation ​ (457,844) ​ (487,535) Total land, property and equipment, net ​ $ 264,068 ​ $ 305,988 ​ Included in “Land, property and equipment, net” are capitalized software costs of $35.3 million and $36.3 million as of December 31, 2022 and September 30, 2023, respectively. Accumulated amortization of the capitalized software costs are $32.1 million and $33.5 million as of December 31, 2022 and September 30, 2023, respectively. The Company recorded amortization expense related to capitalized software costs of $0.7 million and $0.5 million in the three months ended September 30, 2022 and 2023, respectively, and $1.3 million and $1.4 million in the nine months ended September 30, 2022 and 2023, respectively. As of December 31, 2022 and September 30, 2023, $12.9 million and $13.0 million, respectively, are included in “Accounts payable” and “Accrued liabilities” in the accompanying condensed consolidated balance sheets, representing amounts related to purchases of property and equipment. These amounts are excluded from the accompanying condensed consolidated statements of cash flows as they are non-cash investing activities. ​ Fueling Station Equipment Removal The Company was requested by Pilot Travel Centers LLC (“Pilot”) to remove LNG station equipment at select Pilot locations to accommodate Pilot making physical changes to the premises, which required the removal of the Company’s LNG station equipment. The premises where the affected fueling stations are located were secured by long-term lease agreements between Pilot and the Company pursuant to which the Company had contractual rights to operate its fueling stations until the expiration of the respective leases. However, in July 2022, the Company entered into an amendment (the “Amendment”) to the Liquefied Natural Gas Fueling Station and LNG Master Sales Agreement between Pilot and Clean Energy, dated August 2, 2010, to decommission and remove LNG station equipment from the premises where the affected fueling stations are located in accordance with a phased removal schedule beginning in the third quarter of 2022. In April 2023, Pilot and the Company agreed to extend the removal completion deadline to provide the Company additional time to obtain the required permits and to complete the decommissioning activities. All removal and decommissioning activities at these selected sites were completed by the end of the third quarter of 2023.

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Accrued Liabilities	Note 11—Accrued Liabilities Accrued liabilities as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ September 30, ​ 2022 2023 Accrued alternative fuels incentives (1) ​ $ 34,239 ​ $ 34,261 Accrued employee benefits ​ 5,128 ​ 5,091 Accrued gas and equipment purchases ​ 22,008 ​ 16,914 Accrued interest ​ 1,827 ​ 1,471 Accrued property and other taxes ​ 3,782 ​ 3,898 Accrued salaries and wages ​ 6,857 ​ 8,016 Other (2) ​ 16,238 ​ 13,490 Total accrued liabilities ​ $ 90,079 ​ $ 83,141 (1) Includes amount for RINs, LCFS Credits, and AFTC payable to third parties. (2) No individual item in “Other” exceeds 5% of total current liabilities .

Debt

Debt	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt	Note 12—Debt Debt obligations as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ Unamortized Debt Balance, Net of ​ ​ Principal Balance ​ Financing Costs ​ Financing Costs Riverstone term loan ​ $ 150,000 $ 4,529 ​ $ 145,471 Other debt ​ 93 ​ — ​ 93 Total debt ​ 150,093 ​ 4,529 ​ 145,564 Less amounts due within one year ​ (93) ​ — ​ (93) Total long-term debt ​ $ 150,000 ​ $ 4,529 ​ $ 145,471 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2023 ​ ​ ​ Unamortized Debt Balance, Net of ​ ​ Principal Balance ​ Financing Costs ​ Financing Costs Riverstone term loan ​ $ 150,000 ​ $ 5,304 ​ $ 144,696 Other debt ​ 255 ​ ​ — ​ ​ 255 Total debt ​ 150,255 ​ 5,304 ​ 144,951 Less amounts due within one year ​ (38) ​ ​ — ​ ​ (38) Total long-term debt ​ $ 150,217 ​ $ 5,304 ​ $ 144,913 ​ Riverstone Credit Agreement On December 22, 2022 (the “Closing Date”), the Company entered into a Senior Secured First Lien Term Loan Credit Agreement (the “Riverstone Credit Agreement”) with a syndicate of lenders. Pursuant to the Riverstone Credit Agreement, the lenders made a $150,000,000 sustainability-linked senior secured term loan (the “Sustainability-Linked Term Loan”) to the Company, a transaction aligned with the five pillars of the Loan Syndications and Trading Association’s sustainability-linked loan principles. Payments for the Sustainability-Linked Term Loan are interest only with a balloon principal payment due on the maturity date, which is December 22, 2026. The Sustainability-Linked Term Loan bears interest, at the option of the Company, at (a) Adjusted Term SOFR or (b) the Alternate Base Rate (“ABR”), which is defined as the greater of (i) the Prime Rate, (ii) the Federal Funds Effective Rate plus 0.50%, and (iii) one-month Adjusted Term SOFR plus 1.00%, plus an applicable margin of 6.50% for interest rate based on SOFR or 5.50% for election under the ABR through the second anniversary of the Closing Date. After the second anniversary of the Closing Date, the applicable margin increases to 7.25% for election under SOFR or 6.25% for election under the ABR. The applicable margin is subject to a sustainability rate adjustment feature, which may increase the applicable margin by 25 basis points if certain KPI metric is not met for fiscal years beginning after December 31, 2024. The sustainability rate adjustment feature shall be applied retroactively to commence as of December 31, 2025. Interest rate for the Sustainability-Linked Term Loan has an interest rate floor of 1.50% for election under SOFR and 2.50% for election under the ABR. Proceeds from the Sustainability-Linked Term Loan were or will be used to repay certain existing indebtedness of the Company, to finance permitted investments from time to time, to pay transaction costs related to the Riverstone Credit Agreement and for other general corporate purposes. In connection with the Sustainability-Linked Term Loan, the Company is obligated to pay other facility fees customary for credit facilities of similar size and type. The Company has the option to prepay all or any portion of the amounts owed prior to the maturity date and is subject to customary mandatory prepayments clauses. All prepayments and all other payments of the Sustainability-Linked Term Loan principal are subject to a call premium (2.0% from the one-year anniversary of the Closing Date to the date that is eighteen months after the Closing Date, 2.5% after the date that is eighteen months after the Closing Date to the date that is twenty-four months after the Closing Date, and 3% at any time thereafter). No call premium applies to any prepayment of the Sustainability-Linked Term Loan made prior to the first anniversary of the Closing Date. In conjunction with the Riverstone Credit Agreement, the Company and certain of its subsidiaries entered into a Guarantee and Collateral Agreement (the “Security Agreement”) in favor of the lenders. Under the Security Agreement, the Company and certain of its subsidiaries granted the lenders a security interest in substantially all of their personal property, rights and assets as collateral for the Sustainability-Linked Term Loan under the Riverstone Credit Agreement. The Company and certain of its subsidiaries also agreed to grant a security interest in certain of their material real property interests. The Riverstone Credit Agreement contains customary representations, warranties, and affirmative and negative covenants, including compliance with certain financial ratios and liquidity test and limitation on the Company’s ability to incur additional indebtedness, make certain payments, and enter into certain transactions. Additionally, the Riverstone Credit Agreement includes a number of events of default clauses. If any event of default occurs (subject, in certain instances, to specified grace periods), the then outstanding principal, premium, if any, interest and any other monetary obligations under the Riverstone Credit Agreement may become due and payable immediately. Other Debt In May 2023, the Company entered into a sale and leaseback arrangement and received $0.3 million pursuant to the arrangement. The transaction did not qualify for sale and leaseback accounting due to a fixed price repurchase option that is not at fair value. As a result, the transaction was recorded under the financing method in which the assets remained on the accompanying condensed consolidated balance sheets, and the proceeds from the transaction were recorded as a financing liability. The sale and leaseback arrangement has a term of five years with interest and principal payable in 60 monthly installments at an annual effective rate of 13.38%. As of December 31, 2022 and September 30, 2023, the Company had other outstanding debt bearing interest at 4.75% and 13.38%, respectively.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Note 13—Net Income (Loss) Per Share Basic net income (loss) per share is computed by dividing the net income (loss) attributable to Clean Energy Fuels Corp. by the weighted-average number of common shares outstanding and common shares issuable for little or no cash consideration during the period. Diluted net income (loss) per share is computed by dividing the net income (loss) attributable to Clean Energy Fuels Corp. by the weighted-average number of common shares outstanding and common shares issuable for little or no cash consideration during the period and potentially dilutive securities outstanding during the period, and therefore reflects the dilution from common shares that may be issued upon exercise or conversion of these potentially dilutive securities, such as stock options, warrants, convertible notes and restricted stock units. The dilutive effect of stock options and warrants is computed under the treasury stock method. The dilutive effect of convertible notes and restricted stock units is computed under the if-converted method. Potentially dilutive securities are excluded from the computations of diluted net income (loss) per share if their effect would be antidilutive. The following table sets forth the computations of basic and diluted earnings (loss) per share for the three and nine months ended September 30, 2022 and 2023 (in thousands except share and per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ September 30, ​ September 30, ​ ​ 2022 2023 2022 2023 Net loss attributable to Clean Energy Fuels Corp. ​ $ (8,973) ​ $ (25,812) ​ $ (46,399) ​ $ (80,810) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding ​ 222,239,376 ​ 222,973,575 ​ 222,409,802 ​ 222,867,303 Dilutive effect of potential common shares from restricted stock units, stock options and stock warrants ​ — ​ — ​ — ​ — Weighted-average common shares outstanding - diluted ​ 222,239,376 ​ 222,973,575 ​ 222,409,802 ​ 222,867,303 Basic and diluted loss per share ​ $ (0.04) ​ $ (0.12) ​ $ (0.21) ​ $ (0.36) ​ The following potentially dilutive securities have been excluded from the diluted net loss per share calculations because their effect would have been antidilutive. Although these securities were antidilutive for these periods, they could be dilutive in future periods. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2022 2023 2022 2023 Stock options ​ 16,170,384 ​ ​ 17,955,617 ​ ​ 16,170,384 ​ ​ 17,955,617 Restricted stock units ​ 680,191 ​ ​ 367,145 ​ ​ 680,191 ​ ​ 367,145 Amazon warrant shares ​ ​ 58,767,714 ​ ​ 58,767,714 ​ ​ 58,767,714 ​ ​ 58,767,714 Total ​ ​ 75,618,289 ​ ​ 77,090,476 ​ ​ 75,618,289 ​ ​ 77,090,476 ​

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2023
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Note 14—Stock-Based Compensation The following table summarizes the compensation expense and related income tax benefit related to the Company’s stock-based compensation arrangements recognized in the accompanying condensed consolidated statements of operations during the three and nine months ended September 30, 2022 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2022 2023 2022 2023 Stock-based compensation expense, net of $0 tax in 2022 and 2023 ​ $ 5,964 ​ $ 6,091 ​ $ 20,685 ​ $ 18,280 ​ As of September 30, 2023, there was $16.9 million of total unrecognized compensation costs related to unvested shares subject to outstanding service-based and market-based stock options and service-based restricted stock units. Unrecognized compensation costs associated with these stock-based awards are expected to be expensed over a weighted-average period of approximately 1.3 years. As of September 30, 2023, total unrecognized compensation costs related to unvested shares subject to outstanding performance-based stock options were $4.1 million. Amazon Warrant On April 16, 2021, the Company entered into a Project Addendum to Fuel Pricing Agreement (the “Fuel Agreement”) with Amazon Logistics, Inc., a subsidiary of Amazon.com, Inc. (“Amazon”), and a Transaction Agreement with Amazon (the “Transaction Agreement”), pursuant to which, among other things, the Company issued to Amazon.com NV Investment Holdings LLC, a subsidiary of Amazon (“Amazon Holdings”), a warrant to purchase up to an aggregate of 53,141,755 shares (the “Warrant Shares”) of the Company’s common stock at an exercise price of $13.49 per share. As a result of the issuance of additional shares of common stock under the Company’s at-the-market offering programs in 2021 and in accordance with the terms of the warrant, on June 14, 2021, the number of shares of the Company’s common stock that may be purchased pursuant to the warrant, at an exercise price of $13.49 per share, increased by an aggregate of 5,625,959 shares (the “Additional Warrant Shares”). The Warrant Shares and the Additional Warrant Shares shall vest in multiple tranches, certain of which vested immediately upon execution of the Fuel Agreement. Subsequent tranches will vest over time based on fuel purchases by Amazon and its affiliates, up to a total of $500.0 million, excluding any payments attributable to “Pass Through Costs,” which consist of all costs associated with the delivered cost of gas and applicable taxes determined by reference to the selling price of gallons or gas sold. The right to exercise the warrants and to receive the Warrant Shares and Additional Warrant Shares (the “Amazon Warrant”) that have vested expires on April 16, 2031. Non-cash stock-based sales incentive contra-revenue charges (“Amazon Warrant Charges”) associated with the Amazon Warrant are recognized as Amazon and its affiliates purchase fuel and vesting conditions become probable of being achieved, based on the grant date fair value of the Amazon Warrant. The following table summarizes the Amazon Warrant activity for the nine months ended September 30, 2023: ​ ​ ​ ​ ​ Warrant ​ Shares Outstanding and unvested as of December 31, 2022 42,314,667 Granted — Vested (2,938,520) Outstanding and unvested as of September 30, 2023 39,376,147 ​ 2,938,520 shares of the Amazon Warrant vested in the nine months ended September 30, 2023 based on fuel purchases made by Amazon and its affiliates. The Company recognized Amazon Warrant Charges of $7.0 million and $16.8 million in the three months ended September 30, 2022 and 2023, respectively, and $15.5 million and $44.5 million in the nine months ended September 30, 2022 and 2023, respectively, relating to customer fuel purchases. As of December 31, 2022 and September 30, 2023, the Company had a customer incentive asset of $22.2 million and $4.0 million, respectively, classified in “Prepaid expenses and other current assets” in the accompanying condensed consolidated balance sheets.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Note 15—Stockholders’ Equity Authorized Shares Share Repurchase Program On March 12, 2020, the Company’s Board of Directors approved a share repurchase program of up to $30.0 million (exclusive of fees and commissions) of the Company’s outstanding common stock (the “Repurchase Program”). On December 7, 2021, the Company’s Board of Directors approved an increase in the aggregate purchase amount under the Repurchase Program from $30.0 million to $50.0 million (exclusive of fees and commissions). The Repurchase Program does not have an expiration date, and it may be suspended or discontinued at any time. As of September 30, 2023, the Company has utilized a total of $23.5 million under the Repurchase Program from its inception to repurchase 9,387,340 shares of common stock, and a total of $26.5 million of authorized funds remain available for common stock repurchase under the Repurchase Program. The Repurchase Program does not obligate the Company to acquire any specific number of shares. Repurchases under the Repurchase Program may be effected from time to time through open market purchases, privately negotiated transactions, structured or derivative transactions, including accelerated share repurchase transactions, or other methods of acquiring shares, in each case subject to market conditions, applicable securities laws and other relevant factors. Repurchases may also be made under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Note 16—Income Taxes The provision for income taxes for interim periods is determined using an estimate of the Company’s annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter, the Company updates the estimate of the annual effective tax rate, and if the estimated tax rate changes, a cumulative adjustment is recorded. The Company recorded an income tax expense of $0.1 million in the three months ended September 30, 2022 and an income tax benefit of $0.1 The Company increased its unrecognized tax benefits in the nine months ended September 30, 2023 by $3.4 million. This increase is primarily attributable to the portion of AFTC revenue recognized in the period attributed to the federal fuel tax the Company collected from its customers and deductions attributed to the unvested Amazon Warrant during the nine months ended September 30, 2023. The net interest incurred was immaterial for the three and nine months ended September 30, 2022 and 2023. On August 16, 2022, the Inflation Reduction Act of 2022 (the "IRA”) was signed into law. ● Beginning after December 31, 2022, there will be a 1% excise tax on certain share repurchases with certain exceptions. The Company will be subject to the 1% excise tax if it repurchases shares after December 31, 2022. The Company did not repurchase any shares in the current quarter. In addition, the IRA offers significant tax incentives targeting energy transaction and renewables: ● Alternative Fuel Excise Tax Credit (“AFTC”) is reinstated to apply retroactively to fuel sales transactions from January 1, 2022 to December 31, 2024. ● The investment tax credit under Section 48 of the Internal Revenue Code is expanded to include Qualified Biogas Property placed in service after December 31, 2022. The rate of this credit is 6% at base level and increased to 30% if the prevailing wages and apprenticeship requirements are met. Further, this credit is transferrable to an unrelated party. The Company expects the credit to bring significant cash flow for the Renewable Natural Gas projects that it has invested and will invest from year 2024. ● A new tax credit under Section 45Z of the Internal Revenue Code is introduced to apply to transportation fuel produced and sold by the taxpayer from January 1, 2025 through December 31, 2027. The credit is calculated as 20 cents per gallon ($1 per gallon if the prevailing wages and apprenticeship requirements are met) multiplied by an emissions factor which is determined relative to how low the carbon intensity (“CI”) score is against a baseline level, defined as 50 CI (kg CO2e/mmbtu) in statute, under the Argonne Greenhouse gases, Regulated Emissions, and Energy use in Transportation (“GREET”) model for non-aviation fuel. The lower the CI score is, the higher the emissions factor will be. Given the negative CI score for the renewable natural gas, the Company expects that the Renewable Natural Gas projects will be eligible for this credit at a rate over $1 per gallon of fuel sold. ● The alternative fuel refueling property credit under Section 30C of the Internal Revenue Code is reinstated for 2022 and extended an additional 10 years to apply to any property placed in service before January 1, 2033. For business property, the credit amount decreases to 6% (from 30%) with a maximum amount of $100,000 per item (previously $30,000 per location per year). Business property meeting prevailing wage and registered apprenticeship requirements may be eligible for a credit amount of 30% ($100,000 maximum). The Internal Revenue Service and Department of the Treasury have been issuing regulations or other guidance that clarify how these credits will be eligible and calculated. The Company will continue to evaluate the impact of the IRA as additional information becomes available.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 17—Commitments and Contingencies Environmental Matters The Company is subject to federal, state, local and foreign environmental laws and regulations. The Company does not anticipate any expenditures to comply with such laws and regulations that would have a material effect on the Company’s consolidated financial position, results of operations or liquidity. The Company believes that its operations comply, in all material respects, with applicable federal, state, local and foreign environmental laws and regulations. Litigation, Claims and Contingencies The Company may become party to various legal actions that arise in the ordinary course of its business. The Company is also subject to audit by tax and other authorities for varying periods in various federal, state, local and foreign jurisdictions, and disputes may arise during the course of these audits. It is impossible to determine the ultimate liabilities that the Company may incur resulting from any of these lawsuits, claims, proceedings, audits, commitments, contingencies and related matters or the timing of these liabilities, if any. If these matters were to ultimately be resolved unfavorably, it is possible that such an outcome could have a material adverse effect upon the Company’s consolidated financial position, results of operations, or liquidity. The Company does not, however, anticipate such an outcome and believes the ultimate resolution of these matters will not have a material adverse effect on the Company’s consolidated financial position, results of operations, or liquidity. Long-Term Take-or-Pay Natural Gas Purchase Contracts The Company has entered into quarterly fixed price natural gas purchase contracts with take-or-pay commitments extending through September 2024. As of September 30, 2023, the fixed commitments under these contracts totaled approximately $7.0 million for the remainder of the year ending December 31, 2023 and $13.2 million for the year ending December 31, 2024. Loan Commitment to an Equity Method Investee In November 2022, the Company entered into a note purchase agreement with a certain equity method investee (the “Note Purchase Agreement”). Pursuant to the Note Purchase Agreement, the Company irrevocably committed to make available up to $5.5 million in delayed draw loans to fund the investee’s working capital requirements. In exchange, the Company received a convertible promissory note with a principal balance equal to the total amount of drawdown on the loan commitment. The convertible promissory note carries an interest rate equal to 7% per annum, compounded quarterly, and is due and payable in May 2024, subject to certain, specified prepayment clauses.

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Leases
Leases	Note 18—Leases Lessor Accounting The Company leases fueling station equipment to customers pursuant to agreements that contain an option to extend and an end-of-term purchase option. Receivables from these leases are accounted for as finance leases, specifically sales-type leases, and are included in “Other receivables” and “Notes receivable and other long-term assets, net” in the accompanying condensed consolidated balance sheets. The Company recognizes the net investment in the lease as the sum of the lease receivable and the unguaranteed residual value, both of which are measured at the present value using the interest rate implicit in the lease. During each of the three months ended September 30, 2022 and 2023, the Company recognized $0.1 million in “Interest income” on its lease receivables. During each of the nine months ended September 30, 2022 and 2023, the Company recognized $0.3 million in “Interest income” on its lease receivables. The following schedule represents the Company’s maturities of lease receivables as of September 30, 2023 (in thousands): ​ ​ ​ ​ ​ Fiscal year: ​ Remainder of 2023 ​ $ 240 2024 ​ 962 2025 ​ 962 2026 ​ 985 2027 ​ 1,105 Thereafter ​ 1,218 Total minimum lease payments ​ 5,472 Less amount representing interest ​ (1,165) Present value of lease receivables ​ $ 4,307 ​ ​

Alternative Fuels Excise Tax Cr

Alternative Fuels Excise Tax Credit	9 Months Ended
	Sep. 30, 2023
Alternative Fuel Excise Tax Credit
Alternative Fuels Excise Tax Credit	Note 19—Alternative Fuel Excise Tax Credit Under separate pieces of U.S. federal legislation, the Company was eligible to receive AFTC for its natural gas vehicle fuel sales made between October 1, 2006 and December 31, 2021. In August 2022, the IRA was enacted, extending AFTC for an additional three years through December 31, 2024, beginning retroactively to January 1, 2022. The AFTC incentive in the extension period under the IRA is equal to $0.50 per gasoline gallon equivalent of CNG and $0.50 per diesel gallon of LNG that the Company sells as vehicle fuel. Based on the service relationship with its customers, either the Company or its customers claim the credit. The Company records its AFTC, if any, as revenue in its condensed consolidated statements of operations because the credits are fully payable to the Company and do not offset income tax liabilities. As such, the credits are not deemed income tax credits under the accounting guidance applicable to income taxes.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Note 20—Related Party Transactions TotalEnergies S.E. In the three and nine months ended September 30, 2022, the Company recognized revenue of $2.8 million and $5.7 million, respectively, relating to equipment lease revenue and LNG sold to TotalEnergies and its affiliates in the ordinary course of business. In the nine months ended September 30, 2023, the Company recognized revenue of $1.4 million relating to RINs and LNG sold to TotalEnergies and its affiliates in the ordinary course of business, equipment lease revenue, AFTCs, and settlements on commodity swap contracts (Note 6). Revenue recognized in the three months ended September 30, 2023 was immaterial. As of December 31, 2022, the Company had receivables from TotalEnergies of $2.5 million. Outstanding receivables due from TotalEnergies were immaterial as of September 30, 2023. In the three and nine months ended September 30, 2022, the Company paid TotalEnergies $2.5 million and $6.1 million, respectively, for expenses incurred in the ordinary course of business, settlements on commodity swap contracts (Note 6), and the guaranty fee under the Credit Support Agreement with TotalEnergies Holdings USA Inc., a wholly owned subsidiary of TotalEnergies. In the three and nine months ended September 30, 2023, the Company paid TotalEnergies $1.2 million and $3.7 million, respectively, for settlements on commodity swap contracts (Note 6) and for expenses incurred in the ordinary course of business. As of December 31, 2022 and September 30, 2023, outstanding payables due to TotalEnergies were $0.2 million and $0.7 million, respectively. SAFE&CEC S.r.l. In each of the three months ended September 30, 2022 and September 30, 2023, cash receipts from SAFE&CEC S.r.l were immaterial. In the nine months ended September 30, 2022 and September 30, 2023, the Company received $0.2 million and $0.3 million, respectively, from SAFE&CEC S.r.l. in the ordinary course of business. As of December 31, 2022 and September 30, 2023, the Company had receivables due from SAFE&CEC S.r.l. of $0.3 million and $0.2 million, respectively. In the three and nine months ended September 30, 2022, the Company paid SAFE&CEC S.r.l. $2.8 million and $8.5 million, respectively, for parts and equipment in the ordinary course of business. In the three and nine months ended September 30, 2023, the Company paid SAFE&CEC S.r.l. $1.8 million and $11.1 million, respectively, for parts and equipment in the ordinary course of business. As of December 31, 2022 and September 30, 2023, the Company had payables due to SAFE&CEC S.r.l. of $3.3 million and $5.9 million, respectively. TotalEnergies Joint Venture(s) and bpJV Pursuant to various contractual agreements of the TotalEnergies joint venture(s) and bpJV, the Company manages day-to-day operations of RNG projects in the joint ventures in exchange for an O&M fee and management fee. In the three and nine months ended September 30, 2022, the Company recognized management fee revenue of $0.3 million and $0.9 million, respectively. In the three and nine months ended September 30, 2023, the Company recognized total management and O&M fee revenue of $1.1 million and $2.2 million, respectively. As of December 31, 2022 and September 30, 2023, the Company had management and O&M fee receivables due from the joint ventures with TotalEnergies and bp of $0.5 million and $0.3 million, respectively. In the three and nine months ended September 30, 2022, the Company paid $0.2 million and $0.3 million, respectively, on behalf of the joint ventures for expenses incurred in the ordinary course of business. In the nine months ended September 30, 2023, the Company paid $1.2 million on behalf of the joint ventures for expenses incurred in the ordinary course of business. No amount was paid on behalf of the joint ventures in the three months ended September 30, 2023. As of December 31, 2022 and September 30, 2023, outstanding receivables due from the joint ventures with TotalEnergies and bp were $0.6 million and $0.7 million, respectively, representing outstanding unreimbursed expenses that the Company paid on behalf of the joint ventures. In the three and nine months ended September 30, 2022, the Company received $0.2 million and $1.1 million, respectively, from the joint ventures with TotalEnergies and bp for management fees and reimbursement of expenses incurred in the ordinary course of business. In the three and nine months ended September 30, 2023, the Company received $0.6 million and $3.5 million, respectively, from the joint ventures for management fees and reimbursement of expenses incurred in the ordinary course of business. No amounts were paid to the joint ventures in the three and nine months ended September 30, 2022 and 2023 in the ordinary course of business. In connection with the capital call issued by the DR JV on June 28, 2023, the Company advanced $5.5 million to the DR JV. Proceeds from the advance were used to fund required loan reserves and to paydown outstanding liabilities of the DR JV (see Note 3). As of September 30, 2023, the Company had a receivable due from the DR JV of $5.5 million, which is anticipated to be paid by the DR JV before the end of 2023. As of September 30, 2023, the Company had payables due to the joint ventures with TotalEnergies and bp of $0.4 million relating to sharing of environmental credits pursuant to the various contractual agreements of the TotalEnergies joint venture(s) and bpJV. As of December 31, 2022, no payables were outstanding relating to sharing of environmental credits. Other Equity Method Investees Pursuant to the Note Purchase Agreement, in the three and nine months ended September 30, 2023, the Company provided $1.2 million and $3.5 million, respectively, to a certain equity method investee in connection with the loan commitment (see Note 17). As of December 31, 2022 and September 30, 2023, the carrying amount of the Company’s convertible promissory note measured at fair value was $1.9 million and $3.5 million, respectively, and is included in “Notes receivable and other long-term assets, net” as of December 31, 2022 and in “Other receivables” as of September 30, 2023 in the accompanying condensed consolidated balance sheets. In the three and nine months ended September 30, 2023, the Company recognized management fee revenue of $0.2 million and $0.5 million, respectively, relating to other equity method investees. No management fee revenue was recognized in the three and nine months ended September 30, 2022. As of December 31, 2022 and September 30, 2023, the Company had management fee receivables due from other equity method investees of $0.1 million and $0.5 million, respectively.

General (Policies)

General (Policies)	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying interim unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to state fairly the Company’s consolidated financial position as of September 30, 2023, results of operations, comprehensive loss, and stockholders’ equity for the three and nine months ended September 30, 2022 and 2023, and cash flows for the nine months ended September 30, 2022 and 2023. All intercompany accounts and transactions have been eliminated in consolidation. The results of operations for the three and nine months ended September 30, 2022 and 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any other interim period or any future year. Certain information and disclosures normally included in the notes to consolidated financial statements have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), but the resultant disclosures contained herein are in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) as they apply to interim reporting. The accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2022 that are included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2023.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying condensed consolidated financial statements and these notes. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position. Significant estimates made in preparing the accompanying condensed consolidated financial statements include (but are not limited to) those related to revenue recognition, fair value measurements, goodwill and long-lived asset valuations and impairment assessments, income tax valuations, stock-based compensation expense and stock-based sales incentive charges.
Amazon Warrant	Amazon Warrant The Amazon Warrant (defined in Note 14) is accounted for as an equity instrument and measured in accordance with Accounting Standards Codification (“ASC”) 718, Compensation – Stock Compensation Revenue from Contracts with Customers
Tourmaline Joint Development	Tourmaline Joint Development In April 2023, the Company and Tourmaline Oil Corp. (“Tourmaline”) announced a CAD $70 million Joint Development Agreement to build and operate a network of CNG stations along key highway corridors across Western Canada. Under a 50-50 shared investment, the Company and Tourmaline expect to construct and commission up to 20 CNG fueling stations over the next five years, allowing heavy-duty trucks and other commercial transportation fleets that operate in the area to transition to the use of CNG, a lower carbon alternative to gasoline and diesel. Costs associated with station construction and profit and loss arising from station operation are shared 50-50 between the Company and Tourmaline. This arrangement between the Company and Tourmaline to jointly develop, build and operate CNG fueling stations is accounted for in accordance with ASC 808, Collaborative Arrangements Revenue from Contracts with Customers The Company determined that it is the principal for the revenue generated from third parties under this collaborative arrangement with Tourmaline in accordance with ASC 606; as such, the associated revenue and cost of sales generated and incurred are recognized on a gross basis in the condensed consolidated statements of operations. Net participation of profit and loss owed to or from Tourmaline is recorded as an increase or decrease to cost of sales, respectively, as the transaction is not deemed to be with a customer within the scope of ASC 606. Capitalized station costs are presented at half of the total development and construction costs in the condensed consolidated balance sheets, corresponding to the Company’s 50% ownership in the shared assets.
Recently Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In March 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2023-01, Leases (Topic 842): Common Control Arrangements December 15, 2023, with early adoption allowed. The Company is currently evaluating the impact of adopting this new ASU and does not expect the adoption to have a material effect on the Company’s condensed consolidated financial statements.
Revenue Recognition	Revenue Recognition Overview The Company recognizes revenue when control of the promised goods or services is transferred to its customers, in an amount that reflects the consideration to which it expects to be entitled in exchange for the goods or services. To achieve that core principle, a five-step approach is applied: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue allocated to each performance obligation when the Company satisfies the performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account for revenue recognition.
Basis of Presentation	Basis of Presentation The accompanying interim unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to state fairly the Company’s consolidated financial position as of September 30, 2023, results of operations, comprehensive loss, and stockholders’ equity for the three and nine months ended September 30, 2022 and 2023, and cash flows for the nine months ended September 30, 2022 and 2023. All intercompany accounts and transactions have been eliminated in consolidation. The results of operations for the three and nine months ended September 30, 2022 and 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any other interim period or any future year. Certain information and disclosures normally included in the notes to consolidated financial statements have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), but the resultant disclosures contained herein are in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) as they apply to interim reporting. The accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2022 that are included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2023.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying condensed consolidated financial statements and these notes. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position. Significant estimates made in preparing the accompanying condensed consolidated financial statements include (but are not limited to) those related to revenue recognition, fair value measurements, goodwill and long-lived asset valuations and impairment assessments, income tax valuations, stock-based compensation expense and stock-based sales incentive charges.
Revenue Recognition	Revenue Recognition Overview The Company recognizes revenue when control of the promised goods or services is transferred to its customers, in an amount that reflects the consideration to which it expects to be entitled in exchange for the goods or services. To achieve that core principle, a five-step approach is applied: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue allocated to each performance obligation when the Company satisfies the performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account for revenue recognition.
Amazon Warrant	Amazon Warrant The Amazon Warrant (defined in Note 14) is accounted for as an equity instrument and measured in accordance with Accounting Standards Codification (“ASC”) 718, Compensation – Stock Compensation Revenue from Contracts with Customers
Recently Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In March 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2023-01, Leases (Topic 842): Common Control Arrangements December 15, 2023, with early adoption allowed. The Company is currently evaluating the impact of adopting this new ASU and does not expect the adoption to have a material effect on the Company’s condensed consolidated financial statements.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Disaggregation of revenue	The Company is generally the principal in its customer contracts because it has control over the goods and services prior to their transfer to the customer, and as such, revenue is recognized on a gross basis. Sales and usage-based taxes are excluded from revenue. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The table below presents the Company’s revenue disaggregated by revenue source (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2022 2023 2022 2023 Product revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Volume-related ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fuel sales (1) ​ $ 78,512 ​ $ 60,006 ​ $ 204,224 ​ $ 220,168 Change in fair value of derivative instruments (2) ​ ​ 508 ​ ​ (1,372) ​ ​ (1,606) ​ ​ (304) RIN Credits ​ ​ 9,270 ​ ​ 6,784 ​ ​ 26,997 ​ ​ 16,664 LCFS Credits ​ ​ 2,595 ​ ​ 2,846 ​ ​ 10,114 ​ ​ 7,618 AFTC (3) ​ 16,057 ​ 5,422 ​ 16,279 ​ 14,977 Total volume-related product revenue ​ ​ 106,942 ​ ​ 73,686 ​ ​ 256,008 ​ ​ 259,123 Station construction sales ​ ​ 6,418 ​ ​ 7,593 ​ ​ 15,712 ​ ​ 17,512 Total product revenue ​ 113,360 ​ 81,279 ​ 271,720 ​ 276,635 Service revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Volume-related, O&M services ​ ​ 11,982 ​ ​ 13,646 ​ ​ 33,727 ​ ​ 39,603 Other services ​ ​ 345 ​ ​ 646 ​ ​ 961 ​ ​ 2,064 Total service revenue ​ ​ 12,327 ​ ​ 14,292 ​ ​ 34,688 ​ ​ 41,667 Total revenue ​ $ 125,687 ​ $ 95,571 ​ $ 306,408 ​ $ 318,302 (1) Includes non-cash stock-based sales incentive contra-revenue charges associated with the Amazon Warrant. For the three and nine months ended September 30, 2022, contra-revenue charges recognized in fuel revenue were $7.0 million and $15.5 million, respectively. For the three and nine months ended September 30, 2023, contra-revenue charges recognized in fuel revenue were $16.8 million and $44.5 million, respectively. See Note 14 for more information. (2) Represents changes in fair value of derivative instruments related to the Company’s commodity swap and customer fueling contracts associated with the Company’s Zero Now truck financing program. The amounts are classified as revenue because the Company’s commodity swap contracts are used to economically offset the risk associated with the diesel-to-natural gas price spread resulting from customer fueling contracts under the Company’s Zero Now truck financing program. See Note 6 for more information about these derivative instruments. (3) Represents the federal alternative fuel excise tax credit (“AFTC”). See Note 19 for more information.
Summary of contract balances	As of December 31, 2022 and September 30, 2023, the Company’s contract balances were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Accounts receivable, net ​ $ 91,430 ​ $ 87,550 ​ ​ ​ ​ ​ ​ Contract assets - current ​ $ 6,063 ​ $ 10,374 Contract assets - non-current ​ 2,976 ​ 2,563 Contract assets - total ​ $ 9,039 ​ $ 12,937 ​ ​ ​ ​ ​ ​ Contract liabilities - current ​ $ 5,477 ​ $ 2,586 Contract liabilities - non-current ​ — ​ 151 Contract liabilities - total ​ $ 5,477 ​ $ 2,737

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2023
Cash and Cash Equivalents [Abstract]
Schedule of cash and cash equivalents	Cash, cash equivalents and restricted cash as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Current assets: ​ ​ Cash and cash equivalents ​ $ 123,950 ​ $ 25,080 Restricted cash - standby letter of credit ​ 2,000 ​ 2,019 Total cash, cash equivalents and current portion of restricted cash ​ $ 125,950 ​ $ 27,099 ​ ​ ​ ​ ​ ​ ​ Total cash, cash equivalents and restricted cash ​ $ 125,950 ​ $ 27,099
Schedule of components of restricted cash	Cash, cash equivalents and restricted cash as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Current assets: ​ ​ Cash and cash equivalents ​ $ 123,950 ​ $ 25,080 Restricted cash - standby letter of credit ​ 2,000 ​ 2,019 Total cash, cash equivalents and current portion of restricted cash ​ $ 125,950 ​ $ 27,099 ​ ​ ​ ​ ​ ​ ​ Total cash, cash equivalents and restricted cash ​ $ 125,950 ​ $ 27,099

Short-Term Investments (Tables)

Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of short-term investments	Short-term investments as of December 31, 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Estimated ​ Cost Gain (Loss) Fair Value Zero coupon bonds ​ $ 74,524 ​ $ (365) ​ $ 74,159 U.S. government securities ​ 64,861 ​ 19 ​ 64,880 Certificates of deposit ​ 530 ​ — ​ 530 Total short-term investments ​ $ 139,915 ​ $ (346) ​ $ 139,569 ​ Short-term investments as of September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Estimated ​ Cost Gain (Loss) Fair Value U.S. government securities ​ $ 148,767 ​ $ 28 ​ $ 148,795 Certificates of deposit ​ ​ 530 ​ ​ — ​ ​ 530 Total short-term investments ​ $ 149,297 ​ $ 28 ​ $ 149,325 ​

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of commodity derivative activity	Commodity swaps and embedded derivatives as of December 31, 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Amounts ​ Gross Amounts ​ Net Amount ​ Recognized Offset Presented Assets: ​ ​ ​ Fueling agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets ​ $ 1,640 ​ $ — ​ $ 1,640 Notes receivable and other long-term assets, net ​ ​ 5,115 ​ ​ — ​ ​ 5,115 Total derivative assets ​ $ 6,755 ​ $ — ​ $ 6,755 Liabilities: ​ ​ ​ Commodity swaps: ​ ​ ​ ​ ​ ​ ​ ​ ​ Current portion of derivative liabilities, related party ​ $ 2,415 ​ $ — ​ $ 2,415 Long-term portion of derivative liabilities, related party ​ 1,430 ​ — ​ 1,430 Total derivative liabilities ​ $ 3,845 ​ $ — ​ $ 3,845 ​ Commodity swaps and embedded derivatives as of September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Amounts ​ Gross Amounts ​ Net Amount ​ Recognized Offset Presented Assets: ​ ​ ​ Fueling agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets ​ $ 3,594 ​ $ — ​ $ 3,594 Notes receivable and other long-term assets, net ​ ​ 2,735 ​ ​ — ​ ​ 2,735 Total derivative assets ​ $ 6,329 ​ $ — ​ $ 6,329 Liabilities: ​ ​ ​ Commodity swaps: ​ ​ ​ ​ ​ ​ ​ ​ ​ Current portion of derivative liabilities, related party ​ $ 3,723 ​ $ — ​ $ 3,723 Total derivative liabilities ​ $ 3,723 ​ $ — ​ $ 3,723
Schedule of weighted-average price of open commodity swap contract	The following table reflects the weighted-average price of open commodity swap contracts as of December 31, 2022 and September 30, 2023, by year with associated volumes: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 ​ ​ Volumes ​ Weighted-Average Price per ​ Volumes ​ Weighted-Average Price per Year (Diesel Gallons) Diesel Gallon (Diesel Gallons) Diesel Gallon 2023 5,000,000 ​ $ 3.18 1,250,000 ​ $ 3.18 2024 1,875,000 ​ $ 3.18 1,875,000 ​ $ 3.18

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of fair value inputs	The Company estimated the fair value of its outstanding commodity swap contracts based on the following inputs as of December 31, 2022 and September 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 Significant Unobservable Inputs Input Range Weighted Average Input Range Weighted Average ULSD Gulf Coast Forward Curve ​ $2.35 - $2.59 ​ $ 2.48 ​ $2.30 - $2.57 ​ $ 2.41 Historical Differential to PADD 3 Diesel ​ $0.88 - $1.62 ​ $ 1.13 ​ $0.92 - $1.62 ​ $ 1.15 Historical Differential to PADD 5 Diesel ​ $1.89 - $3.00 ​ $ 2.30 ​ $1.89 - $3.10 ​ $ 2.41 ​ The Company estimated the fair value of embedded derivatives in its fueling agreements under the Zero Now ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 Significant Unobservable Inputs Input Range Weighted Average Input Range Weighted Average ULSD Gulf Coast Forward Curve ​ $2.35 - $2.59 ​ $ 2.48 ​ $2.30 - $2.57 ​ $ 2.41 Historical Differential to PADD 3 Diesel ​ $0.88 - $1.62 ​ $ 1.13 ​ $0.92 - $1.62 ​ $ 1.15 Historical Differential to PADD 5 Diesel ​ $1.91 - $3.05 ​ $ 2.31 ​ $1.89 - $3.10 ​ $ 2.41
Schedule of information by level for assets and liabilities that are measured at fair value on a recurring basis	The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2022 and September 30, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 Level 1 Level 2 Level 3 Assets: ​ ​ ​ ​ Available-for-sale securities: ​ ​ ​ ​ U.S. government securities (1) ​ $ 64,880 ​ $ 64,880 ​ $ — ​ $ — Zero coupon bonds (1) ​ 74,159 ​ — ​ 74,159 ​ — Convertible promissory note (4) ​ 1,880 ​ — ​ — ​ 1,880 Certificates of deposit (1) ​ 530 ​ — ​ 530 ​ — Embedded derivatives (3) ​ ​ 6,755 ​ ​ — ​ ​ — ​ ​ 6,755 Liabilities: ​ ​ ​ ​ ​ Commodity swap contracts (2) ​ $ 3,845 ​ $ — ​ $ — ​ $ 3,845 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2023 Level 1 Level 2 Level 3 Assets: ​ ​ ​ ​ Available-for-sale securities: ​ ​ ​ ​ U.S. government securities (1) ​ $ 148,795 ​ $ 148,795 ​ $ — ​ $ — Convertible promissory note (4) ​ 3,528 ​ — ​ — ​ 3,528 Certificates of deposit (1) ​ 530 ​ — ​ 530 ​ — Embedded derivatives (3) ​ ​ 6,329 ​ ​ — ​ ​ — ​ ​ 6,329 Liabilities: ​ ​ ​ ​ ​ Commodity swap contracts (2) ​ $ 3,723 ​ $ — ​ $ — ​ $ 3,723 ​ (1) Included in “Short-term investments” in the accompanying condensed consolidated balance sheets. See Note 5 for more information. (2) Included in “Derivative liabilities, related party” and “Long-term portion of derivative liabilities, related party” as of December 31, 2022 and in “Derivative liabilities, related party” as of September 30, 2023 in the accompanying condensed consolidated balance sheets. See Note 6 for more information. (3) Included in “Prepaid expenses and other current assets” and “Notes receivable and other long-term assets, net” as of December 31, 2022 and in “Prepaid expenses and other current assets,” and “Notes receivable and other long-term assets, net,” as of September 30, 2023 in the accompanying condensed consolidated balance sheets. See Note 6 for more information. (4) Included in “Notes receivable and other long-term assets, net” as of December 31, 2022 and in “Other receivables” as of September 30, 2023 in the accompanying condensed consolidated balance sheets.
Schedule of reconciliation of the beginning and ending balances of items measured at fair value on a recurring basis that used significant unobservable inputs (Level 3)	The following table provides a reconciliation of the beginning and ending balances of items measured at fair value on a recurring basis as shown in the tables above that used significant unobservable inputs (Level 3), as well as the change in unrealized gains or losses for the periods included in earnings or other comprehensive income (loss) (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ Assets: ​ Assets: ​ Liabilities: ​ Liabilities: ​ ​ Commodity ​ Embedded ​ Convertible ​ Commodity ​ Embedded ​ Swap Contracts Derivatives ​ Promissory Note ​ Swap Contracts ​ Derivatives Balance as of June 30, 2022 ​ $ — ​ $ 11,345 ​ $ — ​ $ (11,034) ​ $ (32) Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,942 ​ ​ — Total gain (loss) ​ — ​ ​ (4,899) ​ ​ — ​ ​ 3,486 ​ ​ (21) Balance as of September 30, 2022 ​ $ — ​ $ 6,446 ​ $ — ​ $ (5,606) ​ $ (53) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of June 30, 2023 ​ $ — ​ $ 6,837 ​ $ 4,295 ​ $ (2,779) ​ $ (80) Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,893 ​ ​ — Total gain (loss) ​ — ​ ​ (508) ​ ​ (1,084) ​ ​ (2,837) ​ ​ 80 Purchases ​ ​ — ​ ​ — ​ ​ 1,243 ​ ​ — ​ ​ — Equity method investment loss ​ ​ — ​ ​ — ​ ​ (926) ​ ​ — ​ ​ — Balance as of September 30, 2023 ​ $ — ​ $ 6,329 ​ $ 3,528 ​ $ (3,723) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in unrealized gain (loss) for the three months ended September 30, 2022 included in earnings ​ $ — ​ $ (4,899) ​ $ — ​ $ 5,428 ​ $ (21) Change in unrealized gain (loss) for the three months ended September 30, 2023 included in earnings ​ $ — ​ $ (508) ​ $ — ​ $ (944) ​ $ 80 Change in unrealized gain (loss) for the three months ended September 30, 2023 included in other comprehensive income (loss) ​ $ — ​ $ — ​ $ (1,084) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ Assets: ​ Assets: ​ Liabilities: ​ Liabilities: ​ ​ Commodity ​ Embedded ​ Convertible ​ Commodity ​ Embedded ​ Swap Contracts ​ Derivatives ​ Promissory Note ​ Swap Contracts ​ Derivatives Balance as of December 31, 2021 ​ $ — ​ $ 6,776 ​ $ — ​ $ (4,383) ​ $ — Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 5,843 ​ ​ — Total gain (loss) ​ ​ — ​ ​ (330) ​ ​ — ​ ​ (7,066) ​ ​ (53) Balance as of September 30, 2022 ​ $ — ​ $ 6,446 ​ $ — ​ $ (5,606) ​ $ (53) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of December 31, 2022 ​ $ — ​ $ 6,755 ​ $ 1,880 ​ $ (3,845) ​ $ — Settlements, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,926 ​ ​ — Total gain (loss) ​ — ​ ​ (426) ​ ​ 21 ​ ​ (2,804) ​ ​ — Purchases ​ ​ — ​ ​ — ​ ​ 3,721 ​ ​ — ​ ​ — Equity method investment loss ​ ​ — ​ ​ — ​ ​ (2,094) ​ ​ — ​ ​ — Balance as of September 30, 2023 ​ $ — ​ $ 6,329 ​ $ 3,528 ​ $ (3,723) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in unrealized gain (loss) for the nine months ended September 30, 2022 included in earnings ​ $ — ​ $ (330) ​ $ — ​ $ (1,223) ​ $ (53) Change in unrealized gain (loss) for the nine months ended September 30, 2023 included in earnings ​ $ — ​ $ (426) ​ $ — ​ $ 122 ​ $ — Change in unrealized gain (loss) for the nine months ended September 30, 2023 included in other comprehensive income (loss) ​ $ — ​ $ — ​ $ 21 ​ $ — ​ $ — ​
Convertible promissory note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of fair value inputs	The following table provides quantitative information about the significant inputs used to estimate the fair value of the convertible promissory note as of December 31, 2022 and September 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Significant Unobservable Inputs December 31, 2022 September 30, 2023 Risk-free interest rate ​ 4.57% ​ 5.52% Credit adjustment ​ 8.36% ​ 6.65% Credit adjusted discount rate ​ 12.93% ​ 12.17%

Other Receivables (Tables)

Other Receivables (Tables)	9 Months Ended
	Sep. 30, 2023
Receivables [Abstract]
Schedule of other receivables	Other receivables as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 2023 Loans to customers to finance vehicle purchases ​ $ 523 ​ $ 309 Accrued customer billings ​ 4,910 ​ 8,703 Fuel tax credits ​ 9,462 ​ 15,143 Other ​ 2,131 ​ 12,354 Total other receivables ​ $ 17,026 ​ $ 36,509

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Schedule of inventories	Inventory as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ ​ 2022 ​ 2023 Raw materials and spare parts ​ $ 37,144 ​ $ 40,472 Total inventory ​ $ 37,144 ​ $ 40,472

Land, Property and Equipment (T

Land, Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Summary of land, property and equipment	Land, property and equipment, net as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, September 30, ​ 2022 2023 Land ​ $ 3,476 ​ $ 3,620 LNG liquefaction plants ​ 94,790 ​ 96,786 Station equipment ​ 353,104 ​ 396,651 Trailers ​ 73,253 ​ 72,753 Other equipment ​ 106,184 ​ 98,703 Construction in progress ​ 91,105 ​ 125,010 ​ ​ 721,912 ​ 793,523 Less accumulated depreciation ​ (457,844) ​ (487,535) Total land, property and equipment, net ​ $ 264,068 ​ $ 305,988

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Schedule of accrued liabilities	Accrued liabilities as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ September 30, ​ 2022 2023 Accrued alternative fuels incentives (1) ​ $ 34,239 ​ $ 34,261 Accrued employee benefits ​ 5,128 ​ 5,091 Accrued gas and equipment purchases ​ 22,008 ​ 16,914 Accrued interest ​ 1,827 ​ 1,471 Accrued property and other taxes ​ 3,782 ​ 3,898 Accrued salaries and wages ​ 6,857 ​ 8,016 Other (2) ​ 16,238 ​ 13,490 Total accrued liabilities ​ $ 90,079 ​ $ 83,141 (1) Includes amount for RINs, LCFS Credits, and AFTC payable to third parties. (2) No individual item in “Other” exceeds 5% of total current liabilities .

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule of long-term debt	Debt obligations as of December 31, 2022 and September 30, 2023 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ Unamortized Debt Balance, Net of ​ ​ Principal Balance ​ Financing Costs ​ Financing Costs Riverstone term loan ​ $ 150,000 $ 4,529 ​ $ 145,471 Other debt ​ 93 ​ — ​ 93 Total debt ​ 150,093 ​ 4,529 ​ 145,564 Less amounts due within one year ​ (93) ​ — ​ (93) Total long-term debt ​ $ 150,000 ​ $ 4,529 ​ $ 145,471 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2023 ​ ​ ​ Unamortized Debt Balance, Net of ​ ​ Principal Balance ​ Financing Costs ​ Financing Costs Riverstone term loan ​ $ 150,000 ​ $ 5,304 ​ $ 144,696 Other debt ​ 255 ​ ​ — ​ ​ 255 Total debt ​ 150,255 ​ 5,304 ​ 144,951 Less amounts due within one year ​ (38) ​ ​ — ​ ​ (38) Total long-term debt ​ $ 150,217 ​ $ 5,304 ​ $ 144,913 ​

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Schedule of information required to compute basic and diluted net loss per share	The following table sets forth the computations of basic and diluted earnings (loss) per share for the three and nine months ended September 30, 2022 and 2023 (in thousands except share and per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ September 30, ​ September 30, ​ ​ 2022 2023 2022 2023 Net loss attributable to Clean Energy Fuels Corp. ​ $ (8,973) ​ $ (25,812) ​ $ (46,399) ​ $ (80,810) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding ​ 222,239,376 ​ 222,973,575 ​ 222,409,802 ​ 222,867,303 Dilutive effect of potential common shares from restricted stock units, stock options and stock warrants ​ — ​ — ​ — ​ — Weighted-average common shares outstanding - diluted ​ 222,239,376 ​ 222,973,575 ​ 222,409,802 ​ 222,867,303 Basic and diluted loss per share ​ $ (0.04) ​ $ (0.12) ​ $ (0.21) ​ $ (0.36)
Schedule of potentially dilutive securities that have been excluded from the diluted net loss per share calculations because their effect would have been antidilutive	The following potentially dilutive securities have been excluded from the diluted net loss per share calculations because their effect would have been antidilutive. Although these securities were antidilutive for these periods, they could be dilutive in future periods. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2022 2023 2022 2023 Stock options ​ 16,170,384 ​ ​ 17,955,617 ​ ​ 16,170,384 ​ ​ 17,955,617 Restricted stock units ​ 680,191 ​ ​ 367,145 ​ ​ 680,191 ​ ​ 367,145 Amazon warrant shares ​ ​ 58,767,714 ​ ​ 58,767,714 ​ ​ 58,767,714 ​ ​ 58,767,714 Total ​ ​ 75,618,289 ​ ​ 77,090,476 ​ ​ 75,618,289 ​ ​ 77,090,476 ​

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of compensation expense and related income tax benefit related to the stock-based compensation expense recognized	The following table summarizes the compensation expense and related income tax benefit related to the Company’s stock-based compensation arrangements recognized in the accompanying condensed consolidated statements of operations during the three and nine months ended September 30, 2022 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2022 2023 2022 2023 Stock-based compensation expense, net of $0 tax in 2022 and 2023 ​ $ 5,964 ​ $ 6,091 ​ $ 20,685 ​ $ 18,280
Schedule of warrant activity	The following table summarizes the Amazon Warrant activity for the nine months ended September 30, 2023: ​ ​ ​ ​ ​ Warrant ​ Shares Outstanding and unvested as of December 31, 2022 42,314,667 Granted — Vested (2,938,520) Outstanding and unvested as of September 30, 2023 39,376,147

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
Summary of compensation expense and related income tax benefit related to the stock-based compensation expense recognized	The following table summarizes the compensation expense and related income tax benefit related to the Company’s stock-based compensation arrangements recognized in the accompanying condensed consolidated statements of operations during the three and nine months ended September 30, 2022 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2022 2023 2022 2023 Stock-based compensation expense, net of $0 tax in 2022 and 2023 ​ $ 5,964 ​ $ 6,091 ​ $ 20,685 ​ $ 18,280
Schedule of fair value measurement of warrants	The Company estimated the fair value of its outstanding commodity swap contracts based on the following inputs as of December 31, 2022 and September 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 Significant Unobservable Inputs Input Range Weighted Average Input Range Weighted Average ULSD Gulf Coast Forward Curve ​ $2.35 - $2.59 ​ $ 2.48 ​ $2.30 - $2.57 ​ $ 2.41 Historical Differential to PADD 3 Diesel ​ $0.88 - $1.62 ​ $ 1.13 ​ $0.92 - $1.62 ​ $ 1.15 Historical Differential to PADD 5 Diesel ​ $1.89 - $3.00 ​ $ 2.30 ​ $1.89 - $3.10 ​ $ 2.41 ​ The Company estimated the fair value of embedded derivatives in its fueling agreements under the Zero Now ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ September 30, 2023 Significant Unobservable Inputs Input Range Weighted Average Input Range Weighted Average ULSD Gulf Coast Forward Curve ​ $2.35 - $2.59 ​ $ 2.48 ​ $2.30 - $2.57 ​ $ 2.41 Historical Differential to PADD 3 Diesel ​ $0.88 - $1.62 ​ $ 1.13 ​ $0.92 - $1.62 ​ $ 1.15 Historical Differential to PADD 5 Diesel ​ $1.91 - $3.05 ​ $ 2.31 ​ $1.89 - $3.10 ​ $ 2.41
Schedule of warrant activity	The following table summarizes the Amazon Warrant activity for the nine months ended September 30, 2023: ​ ​ ​ ​ ​ Warrant ​ Shares Outstanding and unvested as of December 31, 2022 42,314,667 Granted — Vested (2,938,520) Outstanding and unvested as of September 30, 2023 39,376,147

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases
Schedule of maturities of lease receivables	The following schedule represents the Company’s maturities of lease receivables as of September 30, 2023 (in thousands): ​ ​ ​ ​ ​ Fiscal year: ​ Remainder of 2023 ​ $ 240 2024 ​ 962 2025 ​ 962 2026 ​ 985 2027 ​ 1,105 Thereafter ​ 1,218 Total minimum lease payments ​ 5,472 Less amount representing interest ​ (1,165) Present value of lease receivables ​ $ 4,307

General (Details)

General (Details) - Tourmaline Joint Development - Tourmaline Oil Corp. $ in Millions	1 Months Ended
	Apr. 30, 2023 CAD ($) item
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Agreement amount | $	$ 70
Ownership interest (as a percent)	50%
Maximum number of CNG fueling stations expect to construct and commission | item	20
Period for construction and commission of CNG fueling stations	5 years

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contracts with Customers
Revenue	$ 95,571	$ 125,687	$ 318,302	$ 306,408
Contra revenue charge			44,473	15,500
Fuel Sales
Revenue from Contracts with Customers
Revenue	60,006	78,512	220,168	204,224
RIN Credits
Revenue from Contracts with Customers
Revenue	6,784	9,270	16,664	26,997
LCFS Credits
Revenue from Contracts with Customers
Revenue	2,846	2,595	7,618	10,114
AFTC
Revenue from Contracts with Customers
Revenue	5,422	16,057	14,977	16,279
Total volume-related product revenue
Revenue from Contracts with Customers
Revenue	73,686	106,942	259,123	256,008
Station construction sales
Revenue from Contracts with Customers
Revenue	7,593	6,418	17,512	15,712
Product revenue
Revenue from Contracts with Customers
Revenue	81,279	113,360	276,635	271,720
Volume-related, O&M services
Revenue from Contracts with Customers
Revenue	13,646	11,982	39,603	33,727
Other services
Revenue from Contracts with Customers
Revenue	646	345	2,064	961
Service revenue
Revenue from Contracts with Customers
Revenue	14,292	12,327	41,667	34,688
Volume-Related
Revenue from Contracts with Customers
Gain (loss) due to changes in fair value	(1,372)	508	(304)	(1,606)
Contra revenue charge	$ 16,800	$ 7,000	$ 44,500	$ 15,500

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Remaining Performance Obligations (Details) $ in Millions	Sep. 30, 2023 USD ($)
Remaining Performance Obligations
Revenue, remaining performance obligation, amount	$ 26.1
Minimum
Remaining Performance Obligations
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Maximum
Remaining Performance Obligations
Revenue, remaining performance obligation, expected timing of satisfaction, period	24 months

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 87,550	$ 91,430
Contract assets - current	10,374	6,063
Contract assets - non-current	2,563	2,976
Contract assets - total	12,937	9,039
Contract liabilities - current	2,586	5,477
Contract liabilities - non-current	151	0
Contract liabilities - total	$ 2,737	$ 5,477

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Contract Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Contract with customer, liability, revenue recognized	$ 4.2	$ 2.5

Investments in Other Entities_2

Investments in Other Entities and Noncontrolling Interest in a Subsidiary - TotalEnergies Joint Venture (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Nov. 30, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 28, 2023	Dec. 31, 2022	Oct. 12, 2021	Mar. 03, 2021
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments			$ (3,304)	$ (728)	$ (7,109)	$ (3,598)
Advance to DR JV					5,500	0
TotalEnergies
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments			(500)	$ 0	(1,900)	$ (100)
Investment balance			$ 8,100		$ 8,100			$ 4,500
TotalEnergies | ADG RNG Production Facilities
Schedule of Equity Method Investments [Line Items]
Investment commitment of equity in production projects										$ 400,000
Investment commitment in joint venture										50,000
TotalEnergies | ADG RNG Production Facilities | TotalEnergies S.E.
Schedule of Equity Method Investments [Line Items]
Investment commitment in joint venture										$ 50,000
TotalEnergies | DR Development Agreement
Schedule of Equity Method Investments [Line Items]
Investment commitment in joint venture							$ 5,500		$ 7,000
Initial contribution commitment		$ 4,800
Capital call contribution amount							$ 11,000
Contribution to joint venture	$ 5,500
Advance to DR JV	5,500
Advance amount expected to refund	$ 5,500
TotalEnergies | DR Development Agreement | TotalEnergies S.E.
Schedule of Equity Method Investments [Line Items]
Investment commitment in joint venture									$ 7,000
Initial contribution commitment		$ 4,800

Investments in Other Entities_3

Investments in Other Entities and Noncontrolling Interest in a Subsidiary - bp Joint Venture (Details) - USD ($) $ in Thousands, shares in Millions

1 Months Ended

3 Months Ended

9 Months Ended

Jun. 21, 2021

Apr. 13, 2021

Sep. 30, 2022

Jun. 30, 2022

Dec. 31, 2021

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Sep. 30, 2022

Dec. 31, 2022

Mar. 31, 2022

Dec. 18, 2020

Schedule of Equity Method Investments [Line Items]

Income (loss) from equity method investments

$ (3,304)

$ (728)

$ (7,109)

$ (3,598)

BP Products North America | bp Loan

Schedule of Equity Method Investments [Line Items]

Debt issuance amount

$ 50,000

bpJV | ADG RNG Production Facilities

Schedule of Equity Method Investments [Line Items]

Investment commitment in joint venture

$ 50,200

$ 30,000

Additional commitment in joint venture

$ 20,000

Initial contribution commitment

30,000

Ownership interest (as a percent)

50%

50%

Income (loss) from equity method investments

$ (800)

$ (200)

$ (1,400)

$ (2,200)

Investment balance

$ 155,400

$ 155,400

$ 156,800

bpJV | ADG RNG Production Facilities | bpJV Capital Call

Schedule of Equity Method Investments [Line Items]

Investment commitment in joint venture

$ 71,600

Initial contribution commitment

$ 38,100

$ 51,600

20,000

Capital call contribution amount

143,200

bpJV | ADG RNG Production Facilities | bpJV Capital Call 2

Schedule of Equity Method Investments [Line Items]

Investment commitment in joint venture

$ 38,100

Capital call contribution amount

76,200

bpJV | ADG RNG Production Facilities | Class A Units

Schedule of Equity Method Investments [Line Items]

Number of units received

30

Payments to acquire units in joint venture

20,000

Priority Return to acquire additional units

$ 200

bpJV | ADG RNG Production Facilities | bp

Schedule of Equity Method Investments [Line Items]

Investment commitment in joint venture

$ 50,000

bpJV | ADG RNG Production Facilities | bp | bpJV Capital Call

Schedule of Equity Method Investments [Line Items]

Investment commitment in joint venture

$ 71,600

bpJV | ADG RNG Production Facilities | bp | bpJV Capital Call 2

Schedule of Equity Method Investments [Line Items]

Investment commitment in joint venture

$ 38,100

bpJV | ADG RNG Production Facilities | bp | Class A Units

Schedule of Equity Method Investments [Line Items]

Number of units received

30

bpJV | ADG RNG Production Facilities | bp | Class B Units

Schedule of Equity Method Investments [Line Items]

Number of units received

20

Investments in Other Entities_4

Investments in Other Entities and Noncontrolling Interest in a Subsidiary - SAFE&CEC S.r.l (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 29, 2017
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	$ (3,304)	$ (728)	$ (7,109)	$ (3,598)
SAFE&CEC S.r.l.
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)						49%
Income (loss) from equity method investments	1,100	$ (300)	(1,300)	$ (600)
Investment balance	$ 20,500		$ 20,500		$ 21,800
SAFE&CEC S.r.l. | Landi Renzo S.p.A.
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)						51%

Investments in Other Entities_5

Investments in Other Entities and Noncontrolling Interest in a Subsidiary - NG Advantage (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Oct. 14, 2014
Schedule of Equity Method Investments [Line Items]
Loss from noncontrolling interest	$ (137)	$ (115)	$ (457)	$ (627)
Investments carried at cost	8,000		8,000
NG Advantage | NG Advantage
Schedule of Equity Method Investments [Line Items]
Noncontrolling interest, fair value	$ 7,000		7,000		$ 7,500
NG Advantage | NG Advantage
Schedule of Equity Method Investments [Line Items]
Loss from noncontrolling interest			$ 500	$ 600
NG Advantage | NG Advantage | NG Advantage
Schedule of Equity Method Investments [Line Items]
Loss from noncontrolling interest		$ 100
NG Advantage | Common unit purchase agreement
Schedule of Equity Method Investments [Line Items]
Ownership interest acquired						53.30%
Ownership interest after transaction (as a percent)			93.30%

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Restricted Cash
Cash and cash equivalents	$ 25,080	$ 123,950
Restricted cash	2,000
Total cash, cash equivalents and restricted cash	27,099	125,950	$ 23,123	$ 106,456
Amount in excess of FDIC and CDIC limits	25,900	124,800
Standby letters of credit
Restricted Cash
Restricted cash	2,019	2,000
Held as collateral
Restricted Cash
Restricted cash	$ 2,000	$ 2,000

Short-Term Investments (Details

Short-Term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 149,297	$ 139,915
Gross Unrealized Gain (Loss)	28
Gross Unrealized Gain (Loss)		(346)
Estimated Fair Value	149,325	139,569
Zero coupon bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		74,524
Gross Unrealized Gain (Loss)		(365)
Estimated Fair Value		74,159
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	148,767	64,861
Gross Unrealized Gain (Loss)	28	19
Estimated Fair Value	148,795	64,880
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	530	530
Gross Unrealized Gain (Loss)	0
Gross Unrealized Gain (Loss)		0
Estimated Fair Value	$ 530	$ 530

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Narrative (Details) - Not Designated as Hedging Instrument - Commodity swaps gal in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	Oct. 31, 2018 contract gal	Sep. 30, 2023 $ / gal gal	Dec. 31, 2022 $ / gal gal
Derivative [Line Items]
Derivative asset, number of instruments held | contract	2
Volumes (Diesel Gallons) | gal	5	3.1	6.9
Weighted-average price per diesel gallon (in usd per gallon) | $ / gal		3.18	3.18

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities - Summary of Commodity Derivative Activity (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Derivative Assets
Gross Amounts Recognized	$ 6,329	$ 6,755
Gross Amounts Offset	0	0
Net Amount Presented	6,329	6,755
Derivative Liability
Gross Amounts Recognized	3,723	3,845
Gross Amounts Offset	0	0
Net Amount Presented	3,723	3,845
Commodity swaps
Derivative Liability
Gross Amounts Recognized	3,723
Gross Amounts Offset	0
Net Amount Presented	$ 3,723
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Derivative Liability Current, Related Party
Notes receivable and other long-term assets, net | Fueling agreements
Derivative Assets
Gross Amounts Recognized	$ 2,735	5,115
Gross Amounts Offset	0	0
Net Amount Presented	2,735	5,115
Prepaid expenses and other current assets | Fueling agreements
Derivative Assets
Gross Amounts Recognized	3,594	1,640
Gross Amounts Offset	0	0
Net Amount Presented	$ 3,594	1,640
Current portion of derivative liabilities, related party | Commodity swaps
Derivative Assets
Gross Amounts Offset		0
Derivative Liability
Gross Amounts Recognized		2,415
Net Amount Presented		2,415
Long-term portion of derivative liabilities, related party | Commodity swaps
Derivative Assets
Gross Amounts Offset		0
Derivative Liability
Gross Amounts Recognized		1,430
Net Amount Presented		$ 1,430

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities - Schedule of Weighted-Average Price of Open Commodity Swap Contracts (Details) - Not Designated as Hedging Instrument	9 Months Ended	12 Months Ended
	Sep. 30, 2023 $ / gal gal	Dec. 31, 2022 $ / gal gal
Commodity Swap 2023
Derivative [Line Items]
Volumes (Diesel Gallons) | gal	1,250,000	5,000,000
Weighted-Average Price per Diesel Gallon (in usd per gallon) | $ / gal	3.18	3.18
Commodity Swap 2024
Derivative [Line Items]
Volumes (Diesel Gallons) | gal	1,875,000	1,875,000
Weighted-Average Price per Diesel Gallon (in usd per gallon) | $ / gal	3.18	3.18

Fair Value Measurements - Commo

Fair Value Measurements - Commodity Swap Contracts (Details) - Not Designated as Hedging Instrument - Valuation Technique, Discounted Cash Flow - Level 3	Sep. 30, 2023	Dec. 31, 2022
Commodity swaps | Minimum | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.30	2.35
Commodity swaps | Minimum | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.92	0.88
Commodity swaps | Minimum | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.89	1.89
Commodity swaps | Maximum | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.57	2.59
Commodity swaps | Maximum | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.62	1.62
Commodity swaps | Maximum | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	3.10	3
Commodity swaps | Weighted Average | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.41	2.48
Commodity swaps | Weighted Average | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.15	1.13
Commodity swaps | Weighted Average | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.41	2.30
Fueling agreements | Minimum | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.30	2.35
Fueling agreements | Minimum | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.92	0.88
Fueling agreements | Minimum | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.89	1.91
Fueling agreements | Maximum | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.57	2.59
Fueling agreements | Maximum | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.62	1.62
Fueling agreements | Maximum | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	3.10	3.05
Fueling agreements | Weighted Average | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.41	2.48
Fueling agreements | Weighted Average | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.15	1.13
Fueling agreements | Weighted Average | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.41	2.31

Fair Value Measurements - Conve

Fair Value Measurements - Convertible Promissory Note (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022	Nov. 07, 2022
Fair Value Measurements
Interest rate			7%
Convertible promissory note
Fair Value Measurements
Interest rate	7%
Convertible promissory note | Risk-free interest rate
Fair Value Measurements
Debt instrument, measurement input	$ 5.52	$ 4.57
Convertible promissory note | Credit adjustment
Fair Value Measurements
Debt instrument, measurement input	6.65	8.36
Convertible promissory note | Credit adjusted discount rate
Fair Value Measurements
Debt instrument, measurement input	$ 12.17	$ 12.93

Fair Value Measurements - Trans

Fair Value Measurements - Transfers (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Asset transferred level 3 net	$ 0	$ 0
Liabilities transferred level 3 net	$ 0	$ 0

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets:
Available-for-sale securities	$ 149,325	$ 139,569
Short-term investments	149,325	139,569
U.S. government securities
Assets:
Available-for-sale securities	148,795	64,880
Zero coupon bonds
Assets:
Available-for-sale securities		74,159
Certificates of deposit
Assets:
Available-for-sale securities	530	530
Fair value measured on recurring basis | U.S. government securities
Assets:
Available-for-sale securities	148,795	64,880
Fair value measured on recurring basis | Zero coupon bonds
Assets:
Available-for-sale securities		74,159
Fair value measured on recurring basis | Convertible promissory note
Assets:
Available-for-sale securities		1,880
Short-term investments	3,528
Fair value measured on recurring basis | Certificates of deposit
Assets:
Short-term investments		530
Derivative assets	530
Fair value measured on recurring basis | Embedded derivatives
Assets:
Derivative assets	6,329	6,755
Fair value measured on recurring basis | Commodity swap contracts
Liabilities:
Derivative liabilities	3,723	3,845
Fair value measured on recurring basis | Level 1 | U.S. government securities
Assets:
Available-for-sale securities	148,795	64,880
Fair value measured on recurring basis | Level 1 | Zero coupon bonds
Assets:
Available-for-sale securities		0
Fair value measured on recurring basis | Level 1 | Convertible promissory note
Assets:
Available-for-sale securities		0
Short-term investments	0
Fair value measured on recurring basis | Level 1 | Certificates of deposit
Assets:
Short-term investments		0
Derivative assets	0
Fair value measured on recurring basis | Level 1 | Embedded derivatives
Assets:
Derivative assets		0
Fair value measured on recurring basis | Level 1 | Commodity swap contracts
Liabilities:
Derivative liabilities	0	0
Fair value measured on recurring basis | Level 2 | U.S. government securities
Assets:
Available-for-sale securities	0	0
Fair value measured on recurring basis | Level 2 | Zero coupon bonds
Assets:
Available-for-sale securities		74,159
Fair value measured on recurring basis | Level 2 | Convertible promissory note
Assets:
Available-for-sale securities		0
Short-term investments	0
Fair value measured on recurring basis | Level 2 | Certificates of deposit
Assets:
Short-term investments		530
Derivative assets	530
Fair value measured on recurring basis | Level 2 | Embedded derivatives
Assets:
Derivative assets		0
Fair value measured on recurring basis | Level 2 | Commodity swap contracts
Liabilities:
Derivative liabilities	0	0
Fair value measured on recurring basis | Level 3 | U.S. government securities
Assets:
Available-for-sale securities	0	0
Fair value measured on recurring basis | Level 3 | Zero coupon bonds
Assets:
Available-for-sale securities		0
Fair value measured on recurring basis | Level 3 | Convertible promissory note
Assets:
Available-for-sale securities		1,880
Short-term investments	3,528
Fair value measured on recurring basis | Level 3 | Certificates of deposit
Assets:
Short-term investments		0
Derivative assets	0
Fair value measured on recurring basis | Level 3 | Embedded derivatives
Assets:
Derivative assets	6,329	6,755
Fair value measured on recurring basis | Level 3 | Commodity swap contracts
Liabilities:
Derivative liabilities	$ 3,723	$ 3,845

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Recognition - Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reconciliation of the beginning and ending balances of assets measured at fair value using significant unobservable inputs (Level 3)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenue from Contract with Customer, Excluding Assessed Tax	Revenue from Contract with Customer, Excluding Assessed Tax
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income [Extensible List]		Revenue from Contract with Customer, Excluding Assessed Tax		Revenue from Contract with Customer, Excluding Assessed Tax
Embedded derivatives
Reconciliation of the beginning and ending balances of assets measured at fair value using significant unobservable inputs (Level 3)
Beginning balance	$ 6,837	$ 11,345	$ 6,755	$ 6,776
Total gain (loss)	(508)	(4,899)	(426)	(330)
Ending balance	6,329	6,446	6,329	6,446
Change in unrealized gain (loss) included in earnings	(508)	$ (4,899)	(426)	$ (330)
Convertible promissory note
Reconciliation of the beginning and ending balances of assets measured at fair value using significant unobservable inputs (Level 3)
Beginning balance	4,295		1,880
Total gain (loss)	(1,084)		21
Purchases	1,243		3,721
Ending balance	3,528		3,528
Change in unrealized gain (loss) included in earnings	(1,084)		21
Equity method investment loss	$ (926)		$ (2,094)

Fair Value Measurements - Fai_2

Fair Value Measurements - Fair Value Recognition - Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income [Extensible List]	Revenue from Contract with Customer, Excluding Assessed Tax		Revenue from Contract with Customer, Excluding Assessed Tax
Commodity swap contracts
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Beginning Balance	$ (2,779)	$ (11,034)	$ (3,845)	$ (4,383)
Settlements, net	1,893	1,942	2,926	5,843
Total gain (loss)	(2,837)	3,486	$ (2,804)	$ (7,066)
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]			Revenue from Contract with Customer, Excluding Assessed Tax	Revenue from Contract with Customer, Excluding Assessed Tax
Ending Balance	(3,723)	(5,606)	$ (3,723)	$ (5,606)
Change in unrealized gain (loss) included in earnings	(944)	5,428	$ 122	(1,223)
Embedded derivatives
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Beginning Balance	(80)	(32)
Total gain (loss)	80	(21)		(53)
Ending Balance		(53)		(53)
Change in unrealized gain (loss) included in earnings	$ 80	$ (21)		$ (53)

Other Receivables (Details)

Other Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Other Receivables
Other receivables	$ 36,509	$ 17,026
Loans to customers to finance vehicle purchases
Other Receivables
Other receivables	309	523
Accrued customer billings
Other Receivables
Other receivables	8,703	4,910
Fuel tax credits
Other Receivables
Other receivables	15,143	9,462
Other
Other Receivables
Other receivables	$ 12,354	$ 2,131

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials and spare parts	$ 40,472	$ 37,144
Total inventory	$ 40,472	$ 37,144

Land, Property and Equipment (D

Land, Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Land, Property and Equipment
Land, property and equipment, gross	$ 793,523		$ 793,523		$ 721,912
Less accumulated depreciation	(487,535)		(487,535)		(457,844)
Total land, property and equipment, net	305,988		305,988		264,068
Capitalized software costs, net	36,300		36,300		35,300
Accumulated amortization on the capitalized software costs	33,500		33,500		32,100
Amortization expense related to the capitalized software costs	500	$ 700	1,400	$ 1,300
Amount included in accounts payable balances			13,000		12,900
Land
Land, Property and Equipment
Land, property and equipment, gross	3,620		3,620		3,476
LNG liquefaction plants
Land, Property and Equipment
Land, property and equipment, gross	96,786		96,786		94,790
Station equipment
Land, Property and Equipment
Land, property and equipment, gross	396,651		396,651		353,104
Trailers
Land, Property and Equipment
Land, property and equipment, gross	72,753		72,753		73,253
Other equipment
Land, Property and Equipment
Land, property and equipment, gross	98,703		98,703		106,184
Construction in progress
Land, Property and Equipment
Land, property and equipment, gross	$ 125,010		$ 125,010		$ 91,105

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued alternative fuels incentives	$ 34,261	$ 34,239
Accrued employee benefits	5,091	5,128
Accrued gas and equipment purchases	16,914	22,008
Accrued interest	1,471	1,827
Accrued property and other taxes	3,898	3,782
Accrued salaries and wages	8,016	6,857
Other	13,490	16,238
Total accrued liabilities	$ 83,141	$ 90,079

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Principal Balances
Total debt	$ 150,255	$ 150,093
Less amounts due within one year	(38)	(93)
Total long-term debt	150,217	150,000
Unamortized Debt Financing Costs
Total debt	5,304	4,529
Less amounts due within one year	0	0
Total long-term debt	5,304	4,529
Balance, Net of Financing Costs
Total debt	144,951	145,564
Less amounts due within one year	(38)	(93)
Total long-term debt	144,913	145,471
Riverstone Term Loan
Principal Balances
Total debt	150,000	150,000
Unamortized Debt Financing Costs
Total debt	5,304	4,529
Balance, Net of Financing Costs
Total debt	144,696	145,471
Other debt
Principal Balances
Total debt	255	93
Unamortized Debt Financing Costs
Total debt	0	0
Balance, Net of Financing Costs
Total debt	$ 255	$ 93

Debt - Riverstone Credit Agreem

Debt - Riverstone Credit Agreement (Details) - Riverstone Credit Agreement	Dec. 22, 2022 USD ($)
Debt Instrument [Line Items]
Proceeds from loan	$ 150,000,000
Elected under SOFR
Debt Instrument [Line Items]
Applicable margin (as a percent)	7.25%
Floor rate (as a percent)	1.50%
Elected under ABR
Debt Instrument [Line Items]
Applicable margin (as a percent)	6.25%
Floor rate (as a percent)	2.50%
1 year to 18 months
Debt Instrument [Line Items]
Call premium (as a percent)	2%
18 months to 24 months
Debt Instrument [Line Items]
Call premium (as a percent)	2.50%
Thereafter
Debt Instrument [Line Items]
Call premium (as a percent)	3%
Federal Funds
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Applicable margin (as a percent)	6.50%
ABR
Debt Instrument [Line Items]
Interest rate (as a percent)	5.50%

Debt - Other Debt (Details)

Debt - Other Debt (Details) $ in Millions	1 Months Ended
	May 31, 2023 USD ($) installment	Sep. 30, 2023	Dec. 31, 2022	Nov. 07, 2022
Long-term debt [Line Items]
Interest rate				7%
Other debt
Long-term debt [Line Items]
Interest rate		13.38%	4.75%
Other debt | Sale and leaseback arrangement
Long-term debt [Line Items]
Proceeds from sale of equipment in sale-leaseback agreement | $	$ 0.3
Number of equal monthly installments | installment	60
Sale leaseback transaction, term	5 years
Annual rate (as a percent)	13.38%

Net Loss Per Share (Details)

Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Net loss attributable to Clean Energy Fuels Corp.	$ (25,812)	$ (8,973)	$ (80,810)	$ (46,399)
Weighted-average common shares outstanding	222,973,575	222,239,376	222,867,303	222,409,802
Dilutive effect of potential common shares from restricted stock units and stock options	0	0	0	0
Weighted-average common shares outstanding - diluted	222,973,575	222,239,376	222,867,303	222,409,802
Basic loss per share (in dollars per share)	$ (0.12)	$ (0.04)	$ (0.36)	$ (0.21)
Diluted loss per share (in dollars per share)	$ (0.12)	$ (0.04)	$ (0.36)	$ (0.21)

Net Loss Per Share - Anti-dilut

Net Loss Per Share - Anti-dilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net Loss Per Share
Anti-dilutive securities (in shares)	77,090,476	75,618,289	77,090,476	75,618,289
Stock options
Net Loss Per Share
Anti-dilutive securities (in shares)	17,955,617	16,170,384	17,955,617	16,170,384
Restricted stock units
Net Loss Per Share
Anti-dilutive securities (in shares)	367,145	680,191	367,145	680,191
Amazon warrant shares
Net Loss Per Share
Anti-dilutive securities (in shares)	58,767,714	58,767,714	58,767,714	58,767,714

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense, net of $0 tax in 2022 and 2023	$ 6,091	$ 5,964	$ 18,280	$ 20,685
Stock-based compensation expense, tax	0	$ 0	0	$ 0
Unrecognized compensation cost	16,900		$ 16,900
Unrecognized compensation cost, weighted-average period			1 year 3 months 18 days
Total unrecognized compensation cost related to non-vested shares	$ 4,100		$ 4,100

Stock-Based Compensation - Amaz

Stock-Based Compensation - Amazon Warrant (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jun. 14, 2021	Apr. 16, 2021
Subsidiary, Sale of Stock [Line Items]
Contra revenue charge			$ 44,473	$ 15,500
Amazon Warrant | Transaction Agreement With Amazon
Subsidiary, Sale of Stock [Line Items]
Aggregate number of warrant shares (in shares)						5,625,959	53,141,755
Total discretionary fuel purchases							$ 500,000
Exercise price of the warrant (in dollars per share)						$ 13.49	$ 13.49
Amazon Warrant | Prepaid expenses and other current assets
Subsidiary, Sale of Stock [Line Items]
Customer incentive assets	$ 4,000		4,000		$ 22,200
Amazon Warrant | Vesting over the second year | Transaction Agreement With Amazon
Subsidiary, Sale of Stock [Line Items]
Contra revenue charge	$ 16,800	$ 7,000	$ 44,500	$ 15,500

Stock-Based Compensation - Am_2

Stock-Based Compensation - Amazon Warrant Activity (Details) - Amazon Warrant	9 Months Ended
	Sep. 30, 2023 USD ($) shares
Class of Warrant or Right [Line Items]
Outstanding and unvested Beginning Balance | $	$ 42,314,667
Granted	0
Vested	(2,938,520)
Outstanding and unvested as of Ending Balance | $	$ 39,376,147
Number of warrants vested	2,938,520

Stockholders' Equity - Authoriz

Stockholders' Equity - Authorized Shares (Details) - shares	Sep. 30, 2023	Dec. 31, 2022	Jun. 14, 2021	Jun. 13, 2021
Stockholders' Equity Note [Abstract]
Authorized shares (in shares)	455,000,000		454,000,000	304,000,000
Common stock, authorized (in shares)	454,000,000	454,000,000
Preferred stock, authorized (in shares)	1,000,000	1,000,000

Stockholders' Equity - Share Re

Stockholders' Equity - Share Repurchase Program (Details) - USD ($) $ in Thousands	3 Months Ended		43 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Dec. 07, 2021	Dec. 06, 2021	Mar. 12, 2020
Stockholders' Equity Note [Abstract]
Approved share repurchase program				$ 50,000	$ 30,000	$ 30,000
Cost to repurchase common stock	$ 3,121	$ 3,001
Stock repurchase program total stock repurchased			9,387,340
Amount utilized under the repurchase plan			$ 23,500
Authorized funds remaining under the Repurchase Program			$ 26,500

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income tax expense	$ (47)	$ 106	$ (166)	$ 223
Income tax benefit	$ 47	$ (106)	166	$ (223)
Unrecognized tax benefits, increase from portion of AFTC revenue offset by the fuel tax			$ 3,400

Commitments and Contingencies -

Commitments and Contingencies - Long-Term Take-or-Pay Natural Gas Purchase Contracts (Details) - USD ($) $ in Millions	Sep. 30, 2023	Nov. 07, 2022
Fixed commitments under the contract payable in future
Interest rate		7%
Loan Commitment to an Equity Method Investee
Fixed commitments under the contract payable in future
Irrevocably committed amount		$ 5.5
Convertible promissory note
Fixed commitments under the contract payable in future
Interest rate	7%
Natural Gas Supply Agreement | DGS
Fixed commitments under the contract payable in future
2023	$ 7
2024	$ 13.2

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Leases
Sales-type lease, interest income	$ 0.1	$ 0.1	$ 0.3	$ 0.3

Leases - Maturities of Lease Re

Leases - Maturities of Lease Receivables (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Fiscal year:
Remainder of 2023	$ 240
2024	962
2025	962
2026	985
2027	1,105
Thereafter	1,218
Total minimum lease payments	5,472
Less amount representing interest	(1,165)
Present value of lease receivables	$ 4,307

Alternative Fuel Excise Tax Cre

Alternative Fuel Excise Tax Credit (Details)	Jan. 01, 2022 $ / gal
Alternative Fuel Excise Tax Credit
Federal alternative fuels tax credit - CNG (in dollars per gasoline gallon equivalent)	0.50
Federal alternative fuels tax credit - LNG (in dollars per liquid gallon)	0.50

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jun. 28, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Advance given				$ 5,500	$ 0
Amount provided for funding in certain equity method investee		$ 1,200		3,500
Outstanding balance		144,951		144,951		$ 145,564
Convertible promissory note
Related Party Transaction [Line Items]
Outstanding balance		3,500		3,500		1,900
Related Party | TOTALEnergies S.E.
Related Party Transaction [Line Items]
Proceeds from related party			$ 2,800	1,400	5,700
Receivables from related party						2,500
Related party expense		1,200	2,500	3,700	6,100
Payable to related parties		700		700		200
Related Party | SAFE&CEC S.r.l.
Related Party Transaction [Line Items]
Proceeds from related party				300	200
Receivables from related party		200		200		300
Related party expense		1,800	2,800	11,100	8,500
Payable to related parties		5,900		5,900		3,300
Related Party | TotalEnergies JV and bpJV
Related Party Transaction [Line Items]
Proceeds from related party		600	200	3,500	1,100
Related party expense			200		300
Related Party | DR JV
Related Party Transaction [Line Items]
Advance given	$ 5,500
Receivables from related party		5,500		5,500
Related Party | Management Fee for Services | TotalEnergies JV and bpJV
Related Party Transaction [Line Items]
Proceeds from related party		1,100	300	2,200	900
Receivables from related party		300		300		500
Related Party | Business Expenses Reimbursement | TotalEnergies JV and bpJV
Related Party Transaction [Line Items]
Receivables from related party		700		700		600
Related party expense		0		1,200	0
Related Party | Sharing of Environmental Credits | TotalEnergies JV and bpJV
Related Party Transaction [Line Items]
Payable to related parties		400		400		0
Other Equity Method Investees
Related Party Transaction [Line Items]
Proceeds from related party		200	$ 0	500	$ 0
Receivables from related party		$ 500		$ 500		$ 100

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (25,812)	$ (8,973)	$ (80,810)	$ (46,399)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2023
Andrew Littlefair Trading Plan | Andrew J. Littlefair
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	None.