Energy Vault (NRGV) 10-Q 8 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-39982
Entity Registrant Name	ENERGY VAULT HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3230987
Entity Address, Address Line One	4360 Park Terrace Drive
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Westlake Village
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91361
City Area Code	805
Local Phone Number	852-0000
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	NRGV
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		148,850,450
Entity Central Index Key	0001828536
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current Assets
Cash and cash equivalents	$ 135,773	$ 109,923
Restricted cash	1,011	35,632
Accounts receivable, net of allowance for credit losses of $23 and $69 as of March 31, 2024 and December 31, 2023, respectively	1,335	27,189
Contract assets, net of allowance for credit losses of $1,041 and $1,113 as of March 31, 2024 and December 31, 2023, respectively	51,328	84,873
Inventory	415	415
Customer financing receivable, current portion, net of allowance for credit losses of $375 and $375 as of March 31, 2024 and December 31, 2023, respectively	2,625	2,625
Advances to suppliers	5,307	8,294
Assets held for sale	6,281	6,111
Prepaid expenses and other current assets	3,618	4,520
Total current assets	207,693	279,582
Property and equipment, net	47,440	31,043
Intangible assets, net	2,491	1,786
Operating lease right-of-use assets	1,436	1,700
Customer financing receivable, long-term portion, net of allowance for credit losses of $986 and $957 as of March 31, 2024 and December 31, 2023, respectively	6,899	6,698
Investments	17,365	17,295
Other assets	2,541	2,649
Total Assets	285,865	340,753
Current Liabilities
Accounts payable	52,564	21,165
Accrued expenses	15,353	85,042
Contract liabilities, current portion	1,495	4,923
Lease liabilities, current portion	427	724
Total current liabilities	69,839	111,854
Deferred pension obligation	1,629	1,491
Contract liabilities, long-term portion	0	1,500
Other long-term liabilities	2,138	2,115
Total liabilities	73,606	116,960
Commitments and contingencies
Stockholders’ Equity
Preferred stock, $0.0001 par value; 5,000 shares authorized, none issued	0	0
Common stock, $0.0000 par value; 500,000 shares authorized, 147,868 and 146,577 issued and outstanding at March 31, 2024 and December 31, 2023, respectively	15	15
Additional paid-in capital	482,955	473,271
Accumulated deficit	(269,211)	(248,072)
Accumulated other comprehensive loss	(1,500)	(1,421)
Total stockholders’ equity	212,259	223,793
Total Liabilities and Stockholders’ Equity	$ 285,865	$ 340,753

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Accounts receivable allowance for credit loss	$ 23	$ 69
Contract assets allowance for credit loss	1,041	1,113
Customer financing receivable, current portion, allowance for credit loss	375	375
Customer financing receivable, long-term portion, allowance for credit loss	$ 986	$ 957
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock authorized (in shares)	500,000,000	500,000,000
Common stock issued (in shares)	147,868,000	146,577,000
Common stock outstanding (in shares)	147,868,000	146,577,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 7,759,000	$ 11,422,000
Cost of revenue	5,691,000	9,003,000
Gross profit	2,068,000	2,419,000
Operating expenses:
Sales and marketing	4,170,000	4,574,000
Research and development	6,966,000	11,178,000
General and administrative	15,264,000	19,400,000
Depreciation and amortization	295,000	209,000
Loss from operations	(24,627,000)	(32,942,000)
Other income (expense):
Interest expense	(8,000)	(1,000)
Interest income	1,826,000	1,935,000
Other income (expense), net	1,670,000	(159,000)
Loss before income taxes	(21,139,000)	(31,167,000)
Provision for income taxes	0	0
Net loss	$ (21,139,000)	$ (31,167,000)
Net loss per share — basic (in dollars per share)	$ (0.14)	$ (0.22)
Net loss per share — diluted (in dollars per share)	$ (0.14)	$ (0.22)
Weighted average shares of outstanding — basic (in shares)	147,019	139,669
Weighted average shares of outstanding — diluted (in shares)	147,019	139,669
Other comprehensive income (loss) — net of tax
Actuarial (loss) gain on pension	$ (231,000)	$ 164,000
Foreign currency translation gain	152,000	121,000
Total other comprehensive (loss) income	(79,000)	285,000
Total comprehensive loss	$ (21,218,000)	$ (30,882,000)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders’ Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2022			138,530
Beginning balance at Dec. 31, 2022	$ 287,713	$ (2,364)	$ 14	$ 435,852	$ (147,265)	$ (2,364)	$ (888)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)			43
Exercise of stock options	35			35
Stock based compensation	13,716			13,716
Vesting of restricted stock units (“RSUs”), net of shares withheld for payroll taxes (in shares)			2,819
Vesting of restricted stock units (“RSUs”), net of shares withheld for payroll taxes	(3,733)			(3,733)
Net loss	(31,167)				(31,167)
Actuarial (loss) gain on pension	164						164
Foreign currency translation gain	121						121
Ending balance (in shares) at Mar. 31, 2023			141,392
Ending balance at Mar. 31, 2023	$ 264,485		$ 14	445,870	(180,796)		(603)
Beginning balance (in shares) at Dec. 31, 2023	146,577		146,577
Beginning balance at Dec. 31, 2023	$ 223,793		$ 15	473,271	(248,072)		(1,421)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	0
Stock based compensation	$ 9,684			9,684
Vesting of restricted stock units (“RSUs”), net of shares withheld for payroll taxes (in shares)			1,291
Vesting of restricted stock units (“RSUs”), net of shares withheld for payroll taxes	0
Net loss	(21,139)				(21,139)
Actuarial (loss) gain on pension	(231)						(231)
Foreign currency translation gain	$ 152						152
Ending balance (in shares) at Mar. 31, 2024	147,868		147,868
Ending balance at Mar. 31, 2024	$ 212,259		$ 15	$ 482,955	$ (269,211)		$ (1,500)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash Flows From Operating Activities
Net loss	$ (21,139)	$ (31,167)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	295	209
Non-cash interest income	(375)	(334)
Stock based compensation	9,684	13,716
Benefit for credit losses	(89)	(14)
Foreign exchange losses	60	170
Change in operating assets	59,725	(35,504)
Change in operating liabilities	(47,214)	(17,848)
Net cash provided by (used in) operating activities	947	(70,772)
Cash Flows From Investing Activities
Purchase of property and equipment	(8,598)	(11,635)
Purchase of property and equipment held for sale	(170)	0
Purchase of equity securities	0	(6,000)
Net cash used in investing activities	(8,768)	(17,635)
Cash Flows From Financing Activities
Proceeds from exercise of stock options	0	35
Repayment of insurance premium financings	(358)	0
Payment of taxes related to net settlement of equity awards	(297)	(800)
Payment of finance lease obligations	(23)	(10)
Net cash used in financing activities	(678)	(775)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(272)	(27)
Net decrease in cash, cash equivalents, and restricted cash	(8,771)	(89,209)
Cash, cash equivalents, and restricted cash  –  beginning of the period	145,555	286,182
Cash, cash equivalents, and restricted cash –  end of the period	136,784	196,973
Less: Restricted cash at end of period	1,011	82,417
Cash and cash equivalents - end of period	135,773	114,556
Supplemental Disclosures of Cash Flow Information:
Income taxes paid	0	0
Cash paid for interest	8	1
Supplemental Disclosures of Non-Cash Investing and Financing Information:
Actuarial (loss) gain on pension	(231)	164
Property and equipment financed through accounts payable and accrued expenses	4,798	4,021
Assets acquired on finance lease	$ 60	$ 0

ORGANIZATION AND DESCRIPTION OF

ORGANIZATION AND DESCRIPTION OF BUSINESS	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND DESCRIPTION OF BUSINESS	ORGANIZATION AND DESCRIPTION OF BUSINESS Energy Vault Holdings, Inc., which together with its subsidiaries is referred to herein as “Energy Vault” or the “Company”, develops and deploys utility-scale energy storage solutions designed to aid in the global transition to a clean energy future. The Company’s mission is to provide energy storage solutions to accelerate the global transition to renewable energy.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared on an accrual basis of accounting in accordance with United States Generally Accepted Accounting Principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain information and disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes for the year ended December 31, 2023. The condensed consolidated balance sheet as of December 31, 2023, included herein, was derived from the consolidated financial statements of the Company as of that date. These unaudited interim condensed consolidated financial statements, in the opinion of management, reflect all adjustments necessary to present fairly the Company’s financial position as of March 31, 2024 and the Company’s results of operations and comprehensive loss, stockholders’ equity activities, and the cash flows for the three months ended March 31, 2024 and 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any interim period or for any other future year. Principles of Consolidation These unaudited interim condensed consolidated financial statements include Energy Vault Holdings, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Emerging Growth Company Section 102(b)(1) of the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”) exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that an emerging growth company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth companies but any such election to opt out is irrevocable. The Company has elected not to opt out of such extended transition period, which means that when a standard is issued or revised, and it has different application dates for public or private companies, the Company, as an emerging growth company, can adopt the new or revised standard at the time private companies adopt the new or revised standard. This may make comparison of the Company’s consolidated financial statement with another public company that is neither an emerging growth company nor an emerging growth company that has opted out of using the extended transition period difficult or impossible because of the potential differences in accounting standards used. Use of Estimates The preparation of the condensed consolidated financial statements, in conformity with GAAP requires management to make estimates an d assumptions that affect the amounts reported in the unaudited interim condensed consolidated financial statements and accompanying notes. The Company evaluates its assumptions on an ongoing basis. The Company’s management believes that the estimates, judgment, and assumptions used are reasonable based upon information available at the time they are made. Significant estimates made by management include, among others, revenue recognition and stock-based compensation. Due to the inherent uncertainty invol ved in making assumptions and estimates, changes in circumstances could result in actual results differing from those estimates, and such differences could be material to the Company’s consolidated financial condition and results of operations. Segment Reporting The Company reports its operating results and financial information in one operating and reportable segment. Our chief operating decision maker, which is our chief executive officer, reviews our operating results on a consolidated basis and uses that consolidated financial information to make operating decisions, assess financial performance, and allocate resources. Concentration of Credit and Other Risks Financial instruments that subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash, accounts receivable, and customer financings receivable. Risks associated with cash and cash equivalents and restricted cash are mitigated by banking with creditworthy institutions. Such balances with any one institution may, at times, be in excess of federally insured amounts. As of March 31, 2024, one customer accounted for 87% of accounts receivable and as of December 31, 2023, one customer accounted for 92% of accounts receivable. As of March 31, 2024 and December 31, 2023 , one custo mer accounted for 100% of the customer financing receivable. Revenue from two customers accounted for 80% and 14% of total revenue, respectively, for the three months ended March 31, 2024 and re venue from three customers accounted for 43%, 39%, and 16% of total revenue, respectively, for the three months ended March 31, 2023. Summary of Significant Accounting Policies The Company’s significant accounting policies are discussed in Note 2 of the notes to the consolidated financial statements included in the Company’s 2023 Annual Report on Form 10-K filed with the SE C on March 13, 2024. The re have not been any significant changes to these policies during the three months ended March 31, 2024.

REVENUE RECOGNITION

REVENUE RECOGNITION	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITION The Company recognized revenue for the product and service categories as follows for the three months ended March 31, 2024 and 2023 (amounts in thousands). Three Months Ended March 31, 2024 2023 Build and transfer energy storage products $ 7,386 $ 11,273 Other 373 149 Total revenue $ 7,759 $ 11,422 Remaining Performance Obligations Remaining performance obligations represent the amount of unearned transaction prices under contracts for which work is wholly or partially unperformed. As of March 31, 2024, the amount of the Company’s remaining performance obligations was $137.5 million. The Company generally expects to recognize approximately 3% of the remaining performance obligations as revenue over the next 12 months and the remainder more than 12 months from March 31, 2024. Contract Balances The following table provides information about contract assets and contract liabilities from contracts with customers. March 31, December 31, Refundable contribution $ 25,000 $ 25,000 Unbilled receivables 21,624 55,241 Retainage 5,745 5,745 Less allowance for credit losses (1,041) (1,113) Contract assets, net of allowance for credit losses $ 51,328 $ 84,873 Contract liabilities, current portion $ 1,495 $ 4,923 Contract liabilities, long-term portion — 1,500 Total contract liabilities $ 1,495 $ 6,423 Contract assets consist of a refundable contribution, unbilled receivables, and retainage. Refundable contribution represents the contribution the Company made to a customer to be used during the construction of its first gravity energy storage system (“GESS”), which will be refunded to the Company upon the customer’s first GESS obtaining substantial completion, subject to adjustment for potential liquidated damages if certain performance metrics are not met. Unbilled receivables represent the estimated value of unbilled work for projects with performance obligations recognized over time. Retainage represents a portion of the contract amount that has been billed, but for which the contract allows the customer to retain a portion of the billed amount until final contract settlement. Retainage is not considered to be a significant financing component because the intent is to protect the customer.

ALLOWANCE FOR CREDIT LOSSES

ALLOWANCE FOR CREDIT LOSSES	3 Months Ended
	Mar. 31, 2024
Credit Loss [Abstract]
ALLOWANCE FOR CREDIT LOSSES	ALLOWANCE FOR CREDIT LOSSES Activity in the allowance for credit losses was as follows for the three months ended March 31, 2024 and 2023 (amounts in thousands): Three Months Ended March 31, 2024 Accounts Receivable Contract Assets Customer Financing Receivable Total Allowance for credit losses, beginning of period $ 69 $ 1,113 $ 1,332 $ 2,514 Provision (benefit) for credit losses (46) (72) 29 (89) Allowance for credit losses, end of period $ 23 $ 1,041 $ 1,361 $ 2,425 Three Months Ended March 31, 2023 Accounts Receivable Contract Assets Customer Financing Receivable Total Allowance for credit losses, beginning of period $ — $ — $ — $ — Addition due to adoption of ASU 2016-13 81 1,063 1,220 2,364 Provision (benefit) for credit losses (71) 31 26 (14) Allowance for credit losses, end of period $ 10 $ 1,094 $ 1,246 $ 2,350 The Company utilizes a probability-of-default (“PD”) and loss-given-default (“LGD”) methodology to calculate the allowance for expected credit losses for each customer by type of financial asset. Due to the Company’s limited operating history and lack of loss history, the Company derived its PD and LGD rates using average historical rates for corporate bonds as published by Moody’s. The Company uses PD and LGD rates that correspond to the customer’s credit rating and period of time in which the financial asset is expected to remain outstanding.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Carrying amounts of certain financial instruments, including cash, accounts payable, and accrued expenses approximate their fair value due to their relatively short maturities and market interest rates, if applicable. The Company categorizes assets and liabilities recorded or disclosed at fair value on the consolidated balance sheet based upon the level of judgment associated with inputs used to measure their fair value. The categories are as follows: • Level 1 —Inputs which included quoted prices in active markets for identical assets and liabilities. • Level 2 —Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3 —Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The Company’s financial assets and liabilities measured at fair value on a recurring basis were as follows as of March 31, 2024 and December 31, 2023, respectively (amounts in thousands): Level 1 Level 2 Level 3 Total Assets (Liabilities): Derivative asset —  conversion option (1) $ — $ — $ 1,025 $ 1,025 Warrant liability — — (2) (2) __________________ (1) Refer to Note 7 - Investments for further information.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS In May 2019, the Company received a $1.5 million deposit for a gravity-based system from a customer that was owned by one of its primary shareholders. The deposit and order were received before the owner of the customer became one of the Company’s primary shareholders and the deposit was recognized in the line item, contract liabilities, long-term portion, in the condensed consolidated balance sheet as of December 31, 2023. During the three months ended March 31, 2024, the Company concluded it was no longer obligated to provide a gravity-based system to the customer and that the deposit was nonrefundable. As a result, the Company derecognized the $1.5 million liability and recognized it as a gain within the line item, other income (expense), net, in the condensed consolidated statements of operations during the three months ended March 31, 2024. During the three months ended March 31, 2024 and 2023, the Company paid contracted engineering, design, and civil tolerance code calculation support fees of $0.1 million and $0.1 million, res pectively, to an immediate family member of an executive officer. The Company retains all intellectual property as part of these services.

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
INVESTMENTS	INVESTMENTS The following table provides a reconciliation of investments to the Company’s condensed consolidated balance sheets (amounts in thousands): March 31, December 31, Investment in equity securities $ 15,000 $ 15,000 Convertible note receivable 2,365 2,295 $ 17,365 $ 17,295 Investment in Equity Securities In November 2022, the Company purchased $9.0 million of equity securities in KORE Power, Inc. (“KORE”), a U.S. manufacturer of battery cells and modules. In February 2023, the Company purchased an additional $6.0 million of equity securities, increasing the Company’s total investment in KORE to $15.0 million. These equity securities do not have a readily determinable fair value and are recorded at cost, less any impairment, plus or minus adjustments related to observable transactions for the same or similar securities, with unrealized gains and losses included in earnings. As of March 31, 2024 and December 31, 2023, the carrying value of these equity securities was equal to its cost basis. Convertible Note Receivable In October 2021, the Company entered into a convertible promissory note purchase agreement with DG Fuels, LLC (“DG Fuels”) and purchased a promissory note with a principal balance of $1.0 million (“DG Fuels Tranche 1 Note”). In April 2022, the Company purchased an additional promissory note from DG Fuels with a principal balance of $2.0 million. (“DG Fuels Tranche 2 Note”) (collectively, the “DG Fuels Note”). The convertible promissory note is recorded in other assets in the condensed consolidated balance sheets. The maturity date of the DG Fuels Note is the earlier of (i) 30 days after a demand for payment is made by the Company at any time after the two year anniversary of the date of issuance of the note; (ii) the four year anniversary of the date of issuance of the note; (iii) five days following a Financial Close (“Financial Close” means a project finance style closing by DG Fuels or its subsidiary of debt and equity capital to finance the construction of that certain biofuel facility currently under development by DG Fuels), or (iv) upon an event of default determined at the discretion of the Company. The DG Fuels Note has an annual interest rate of 10.0%. The Company intends to hold and convert the DG Fuels Note into the equity securities issued by DG Fuels in its next equity financing round that is greater than $20.0 million at a 20% discount to the issuance price. The principal balance and unpaid accrued interest on the DG Fuels Note will, at the option of the Company, convert into equity securities upon the closing of such next equity financing round. The discounted conversion rate in the DG Fuels Note is considered a redemption feature that is an embedded derivative, which requires bifurcation and separate accounting at its estimated fair value under ASC 815 – Derivative and Hedging . The embedded derivative upon the purchase of the DG Fuels Tranche 1 Note was an asset of $0.4 million and the embedded derivative upon the purchase of the DG Fuels Tranche 2 note was an asset of $0.7 million. The estimated fair value of the derivative instruments was recognized as a derivative asset on the condensed consolidated balance sheets, with an offsetting discount to the DG Fuels Note. The Company amortizes the discount on the Note into interest income using the effective interest method. The Company recognized interest income from the DG Fuels Note of $0.1 million for the three months ended March 31, 2024 and $0.1 million for the three months ended March 31, 2023. Interest income related to the amortization of the debt discount was $0.1 million for the three months ended March 31, 2024 and $44 thousand for the three months ended March 31, 2023. The derivative financial instrument is recorded in other assets in the condensed consolidated balance sheets. At each reporting period, the Company remeasures this derivative financial instrument to its estimated fair value. The change in the estimated fair value is recorded in other income (expense), net in the consolidated statement of operations and comprehensive loss. For the three and three months ended March 31, 2024 and 2023, ther e was no change in the fair value of th e embedded derivative. A reconciliation of the beginning and ending asset balance for the embedded derivative in the DG Fuels Note is as follows (amounts in thousands): Three Months Ended March 31, 2024 2023 Beginning of period $ 1,025 $ 1,025 Additions — — Change in fair value — — End of period $ 1,025 $ 1,025

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT, NET	PROPERTY AND EQUIPMENT, NET As of March 31, 2024 and December 31, 2023, property and equipment, net consisted of the following (amounts in thousands): March 31, December 31, Land $ 226 $ 226 Buildings 774 774 Machinery and equipment 11,707 9,330 Finance lease right-of-use assets – vehicles 187 187 Furniture and IT equipment 1,454 1,474 Leasehold improvements 700 702 Construction in progress 34,641 20,095 Total property and equipment 49,689 32,788 Less: accumulated depreciation and amortization (2,249) (1,745) Property and equipment, net $ 47,440 $ 31,043 For the three months ended March 31, 2024 and 2023, depreciation and amortization related to property and equipment was $0.2 million and $0.2 million , respe ctively. The increases in machinery and equipment and construction in progress primarily relate to the energy storage systems being constructed in Snyder, Texas and Calistoga, California.

INTANGIBLE ASSETS, NET

INTANGIBLE ASSETS, NET	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS, NET	INTANGIBLE ASSETS, NET Intangible assets are stated at amortized cost and consist of the following (amounts in thousands): March 31, 2024 December 31, 2023 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Capitalized software to be sold $ 2,573 $ (82) $ 2,491 $ 1,786 $ — $ 1,786 Once a software application is available for general release and is placed in service, the Company amortizes the capitalized costs on a product basis by the greater of the straight-line method over the estimated economic life of the product, or the ratio that current gross revenues for a product bear to the total current and anticipated future gross revenues for that product. The useful life for our external-use software development costs is five years. Amortization expense for the three months ended March 31, 2024 and 2023 was $0.1 million and $—, respectively. Future amortization expense for intangible assets is estimated as follows (amounts in thousands): Amount Remainder of 2024 $ 247 2025 329 2026 329 2027 329 2028 329 Subtotal 1,563 Software projects in process 928 Total $ 2,491

DEBT

DEBT	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
DEBT	DEBT In July 2023, the Company entered into a financing agreement related to premiums under certain insurance policies. The Company is obligated to repay the lender an aggregate sum of $1.1 million through nine equal monthly payments, at an annual interest rate of 7.0%, commencing on July 15, 2023. In September 2023, the Company entered into a financing agreement related to premiums under certain insurance policies. The Company is obligated to repay the lender an aggregate sum of $0.2 million through four equal monthly payments, at an annual interest rate of 7.0%, commencing on September 15, 2023.

SUPPLEMENTAL BALANCE SHEETS DET

SUPPLEMENTAL BALANCE SHEETS DETAIL	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
SUPPLEMENTAL BALANCE SHEETS DETAIL	SUPPLEMENTAL BALANCE SHEETS DETAIL (amounts in thousands) March 31, December 31, Prepaid and other current assets: Prepaid expenses $ 2,223 $ 3,131 Tax refund receivable 1,341 1,359 Other 54 30 Total $ 3,618 $ 4,520 Other assets: Derivative asset —  conversion option $ 1,025 $ 1,025 Other 1,516 1,624 Total $ 2,541 $ 2,649 Accrued expenses: Professional fees $ 4,635 $ 4,522 Accrued purchases 7,338 71,932 Employee costs 1,664 5,985 Taxes payable 106 733 Accrued project loss 614 591 Insurance premium financings — 358 Warranty accrual 983 894 Other 13 27 Total $ 15,353 $ 85,042 Lease liabilities, current portion: Operating leases $ 391 $ 697 Finance leases 36 27 Total $ 427 $ 724 Other long-term liabilities: Operating leases $ 984 $ 1,044 Asset retirement obligation 17 52 Warranty accrual 1,022 924 Finance leases 113 93 Warrant liability 2 2 Total $ 2,138 $ 2,115

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION 2017 Stock Incentive Plan In 2017, the Company adopted its 2017 Stock Incentive Plan (the “2017 Plan”) which provided for the granting of stock options, restricted stock, and RSUs to employees, directors, and consultants of the Company. Options granted under the 2017 Plan were either Incentive Stock Options (“ISOs”) or Nonqualified Stock Options (“NSOs”). Awards under the 2017 Plan were granted for periods of up to ten years. Under the terms of the 2017 Plan, awards were granted at an exercise price not less than the estimated fair value of the shares on the date of grant, as determined by the Company’s Board of Directors. For employees holding more than 10% of the voting rights of all classes of stock, the exercise price of ISOs and NSOs was not less than 110% of the estimated fair value of the shares on the date of grant, as determined by the board of directors. Awards generally vested over one 2020 Stock Incentive Plan In 2020, the Company adopted its 2020 Stock Incentive Plan (the “2020 Plan”). The 2020 Plan provided for the granting of stock options, restricted stock, and RSUs to employees, directors, and consultants of the Company. Options granted under the 2020 Plan were either ISOs or NSOs. Awards under the 2020 Plan were granted for periods of up to ten years. Under the terms of the 2020 Plan, awards were granted at an exercise price not less than the estimated fair value of the shares on the date of grant, as determined by the Company’s Board of Directors. For employees holding more than 10% of the voting rights of all classes of stock, the exercise price of ISOs and NSOs was not less than 110% of the estimated fair value of the shares on the date of grant, as determined by the board of directors. Awards generally vested over one 2022 Equity Incentive Plan In 2022, the Company adopted its 2022 Equity Incentive Plan (the “2022 Incentive Plan”). The 2022 Incentive Plan provides for the granting of stock options, stock appreciation rights (“SARs”), restricted stock, and RSUs to employees, non-employee directors, and consultants of the Company. Shares of common stock underlying awards that expire or are forfeited or canceled will again be available for issuance under the 2022 Incentive Plan. The initial number of shares of the Company’s common stock reserved for issuance under the 2022 Incentive Plan was approximately 15.5 million, plus up to approximately 8.3 million shares subject to awards granted under the 2017 and 2020 Plans. Beginning on March 1, 2022 and ending on (and including) March 31, 2031, the number of shares of the Company’s common stock that may be issued under the 2022 Incentive Plan increases by a number of shares equal to the lesser of (i) 4.0% of the outstanding shares on the last day of the immediately preceding month or (ii) such lesser number of shares (including zero) that the Company’s Board determines for the purposes of the annual increase for that fiscal year. 2022 Inducement Plan In 2022, the Company adopted its 2022 Inducement Plan, which provides for the granting of stock options, SARs, restricted stock, and RSUs to individuals who were not previously employees of Energy Vault, or following a bona fide period of non-employment, as inducement material to such individuals entering into employment with Energy Vault. Shares of common stock underlying awards that expire or are forfeited or canceled will again be available for issuance under the 2022 Inducement Plan. 8.0 million shares of the Company’s common stock are reserved for issuance under the 2022 Inducement Plan. Stock Option Activity Stock option activity for the three months ended March 31, 2024 was as follows (in thousands, except per share data): Options Outstanding Number of Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance as of December 31, 2023 5,807 $ 1.71 6.37 $ 3,605 Stock options granted — — — — Stock options exercised — — — — Stock options forfeited, canceled, or expired (4) 0.80 — — Balance as of March 31, 2024 5,803 1.71 6.15 815 Options exercisable as of March 31, 2024 689 0.71 6.32 744 Options vested and expected to vest as of March 31, 2024 5,803 1.71 6.15 815 As of March 31, 2024, total unrecognized stock-based compensation expense related to unvested awards that are expected to vest was $5.1 million. The weighted-average period over which such stock-based compensation expense will be recognized is approximately 2.07 years. The aggregate intrinsic values of options outstanding, exercisable, vested and expected to vest were calculated as the difference between the exercise price of the options and the closing stock price of the Company’s common stock on the NYSE as of March 31, 2024. Restricted Stock Units RSU activity for the three months ended March 31, 2024 was as follows (in thousands, except per share data): Number of RSUs Weighted Average Grant Date Fair Value per Share Nonvested balance as of December 31, 2023 19,029 $ 4.55 RSUs granted 7,409 1.73 RSUs forfeited (307) 3.24 RSUs vested (2,110) 4.45 Nonvested balance as of March 31, 2024 24,021 $ 3.71 As of March 31, 2024, unrecognized stock-based compensation expense related to these RSUs w as $74.3 million which is expected to be recognized over the remaining weighted-average vesting period of approximately 2.10 years. Stock-Based Compensation Expense Total stock-based compensation expense for the three months ended March 31, 2024 and 2023 is as follows (in thousands): Three Months Ended March 31, 2024 2023 Sales and marketing $ 1,715 $ 1,949 Research and development 2,227 3,149 General and administrative 5,742 8,618 Total stock-based compensation expense $ 9,684 $ 13,716

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company did not recog nize any tax provision for the three months ended March 31, 2024 and 2023. The Company has recorded a valuation allowance against substantially all of the Company’s net deferred tax assets. The Company provides for a valuation allowance when it is more likely than not that some portion of, or all of the Company’s deferred tax assets will not be realized. Due to the Company’s history of losses, the Company determined that it is not more likely than not to realize its deferred tax assets.

NET LOSS PER SHARE OF COMMON ST

NET LOSS PER SHARE OF COMMON STOCK	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
NET LOSS PER SHARE OF COMMON STOCK	NET LOSS PER SHARE OF COMMON STOCK Basic and diluted net loss per share attributable to common stockholders are calculated as follows (amounts in thousands, except per share amounts): Three Months Ended March 31, 2024 2023 Net loss $ (21,139) $ (31,167) Weighted-average shares outstanding – basic and diluted 147,019 139,669 Net loss per share – basic and diluted $ (0.14) $ (0.22) There were no common share equivalents that were dilutive for th e three mo nths ended March 31, 2024 and 2023. Due to net losses during those periods, basic and diluted net loss per common share were the same, as the effect of potentially dilutive securities would have been anti-dilutive. The following outstanding balances of common share equivalent securities have been excluded from the calculation of diluted weighted-average common shares outstanding because the effect is anti-dilutive for the for th e three mo nths ended March 31, 2024 and 2023 (amounts in thousands): Three Months Ended March 31, 2024 2023 Private warrants 5,167 5,167 Stock options 5,803 1,050 RSUs 24,021 22,128 Total 34,991 28,345 In connection with the reverse recapitalization in 2022, eligible Energy Vault stockholders immediately prior to the closing of the transaction obtained a contingent right to receive 9.0 million shares of the Company’s common stock (“Earn-Out Shares”) upon the Company’s common stock quoted on the NYSE equaling or exceeding certain specified prices for any 20 trading days within a 30 consecutive day trading period (“Earn-Out Triggering Event”). 9.0 million of common stock equivalents subject to the Earn-Out Shares are excluded from the anti-dilutive table above as of March 31, 2024, as the underlying shares remain contingently issuable as the Earn-Out Triggering Events have not been satisfied.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Our principal commitments as of March 31, 2024 consisted primarily of obligations under operating leases, finance leases, deferred pensions, warranty obligations, and issued purchase orders. Our non-cancelable purchase obligations as of March 31, 2024 totaled approximately $0.4 million. In connection with one of the Company’s licensing agreements, the Company agreed to make a refundable contribution to a customer in the amount up to $25.0 million during the period in which the customer constructs its first GESS. As of March 31, 2024, t he Company has contributed all $25.0 million, which is included within the line item, contract assets, in the condensed consolidated balance sheets. The refundable contribution will be returned to the Company upon the customer’s first GESS reaching substantial completion, subject to adjustment for potential liquidated damages if certain performance metrics are not met. Loss Contingencies: In the ordinary course of business, the Company is regularly subject to various legal proceedings. The Company has identified certain legal matters where the Company believes an unfavorable outcome is not probable and, therefore, no reserve has been established. Although the Company currently believes that resolving claims against the Company, including claims where an unfavorable outcome is reasonably possible, will not have a material impact on the Company’s business, financial position, results of operations, or cash flows, these matters are subject to inherent uncertainties and the Company’s view of these matters may change in the future. Assurance Warranty Obligations: The Company provides a limited warranty to its battery energy storage system (“BESS”) customers assuring that the BESSs are free from defects. The Company’s limited warranties are generally for a period of two years after the substantial completion date of a project. These warranties are considered assurance-type warranties which provide a guarantee of quality of the products. For assurance-type warranties, the Company records an estimate of future warranty costs over the period of construction. Warranty costs are recorded as a component of cost of revenue in the Company’s consolidated statements of operations. As of March 31, 2024 and 2023, the Company accrued the below estimated warranty liabilities, respectively (amounts in thousands): Three Months Ended March 31, 2024 2023 Warranty balance, beginning of period $ 1,818 $ — Accruals for warranties issued — — Change in estimates 243 — Settlements (56) — Warranty balance, end of period $ 2,005 $ — The key inputs and assumptions used in calculating the estimated warranty liability are reviewed by management each reporting period. The Company may make additional adjustments to the estimated warranty liability based on a comparison of actual warranty results to expected results for significant differences or based on performance trends or other qualitative factors. If actual failure rates or replacement costs differ from our estimates in future periods, changes to these estimates may be required, resulting in increases or decreases in the estimated warranty liability, which may be material. Letters of Credit: In the ordinary course of business and under certain contracts, the Company is required to post letters of credit for its customers, insurance carriers, and surety bond providers for project performance, and for its vendors for payment guarantees. Such letters of credit are generally issued by a bank or a similar financial institution. The letter of credit commits the issuer to pay specified amounts to the holder of the letter of credit under certain conditions. As of March 31, 2024, there was $22.7 million of letters of credit issued through the Company’s credit relationships. The Company is not aware of any material claims relating to its outstanding letters of credit. The Company’s restricted cash balance of $1.0 million as of March 31, 2024 primarily consists of cash held by banks as collateral for the Company’s letters of credit. Performance and Payment Bonds: In the ordinary course of business, Energy Vault is required by certain customers to provide performance and payment bonds for contractual commitments related to its projects. These bonds provide a guarantee that the Company will perform under the terms of a contract and that the Company will pay its subcontractors and vendors. If the Company fails to perform under a contract or to pay its subcontractors and vendors, the customer may demand that the surety make payments or provide services under the bond. The Company must reimburse the surety for expenses or outlays it incurs. As of March 31, 2024, there were $28.6 million outstanding performance and payment bonds. Other Bonds : In the ordinary course of business, Energy Vault is required to obtain other bonds, such as for insurance and government payments. These bonds provide a guarantee that the Company will post the necessary reserves as required by banks and tax or licensing authorities. Additionally, bonds are issued to banks as support for letters of credit provided by those banks. As of March 31, 2024, there were $28.8 million of outstanding other bonds.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net loss	$ (21,139)	$ (31,167)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared on an accrual basis of accounting in accordance with United States Generally Accepted Accounting Principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain information and disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes for the year ended December 31, 2023. The condensed consolidated balance sheet as of December 31, 2023, included herein, was derived from the consolidated financial statements of the Company as of that date. These unaudited interim condensed consolidated financial statements, in the opinion of management, reflect all adjustments necessary to present fairly the Company’s financial position as of March 31, 2024 and the Company’s results of operations and comprehensive loss, stockholders’ equity activities, and the cash flows for the three months ended March 31, 2024 and 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any interim period or for any other future year.
Principles of Consolidation	Principles of Consolidation These unaudited interim condensed consolidated financial statements include Energy Vault Holdings, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements, in conformity with GAAP requires management to make estimates an d assumptions that affect the amounts reported in the unaudited interim condensed consolidated financial statements and accompanying notes. The Company evaluates its assumptions on an ongoing basis. The Company’s management believes that the estimates, judgment, and assumptions used are reasonable based upon information available at the time they are made. Significant estimates made by management include, among others, revenue recognition and stock-based compensation. Due to the inherent uncertainty invol ved in making assumptions and estimates, changes in circumstances could result in actual results differing from those estimates, and such differences could be material to the Company’s consolidated financial condition and results of operations.
Segment Reporting	Segment Reporting
Concentration of Credit and Other Risks	Concentration of Credit and Other Risks Financial instruments that subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash, accounts receivable, and customer financings receivable.
Fair Value Measurements	Carrying amounts of certain financial instruments, including cash, accounts payable, and accrued expenses approximate their fair value due to their relatively short maturities and market interest rates, if applicable. The Company categorizes assets and liabilities recorded or disclosed at fair value on the consolidated balance sheet based upon the level of judgment associated with inputs used to measure their fair value. The categories are as follows: • Level 1 —Inputs which included quoted prices in active markets for identical assets and liabilities. • Level 2 —Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The Company recognized revenue for the product and service categories as follows for the three months ended March 31, 2024 and 2023 (amounts in thousands). Three Months Ended March 31, 2024 2023 Build and transfer energy storage products $ 7,386 $ 11,273 Other 373 149 Total revenue $ 7,759 $ 11,422
Schedule of Contract Assets and Contract Liabilities	The following table provides information about contract assets and contract liabilities from contracts with customers. March 31, December 31, Refundable contribution $ 25,000 $ 25,000 Unbilled receivables 21,624 55,241 Retainage 5,745 5,745 Less allowance for credit losses (1,041) (1,113) Contract assets, net of allowance for credit losses $ 51,328 $ 84,873 Contract liabilities, current portion $ 1,495 $ 4,923 Contract liabilities, long-term portion — 1,500 Total contract liabilities $ 1,495 $ 6,423

ALLOWANCE FOR CREDIT LOSSES (Ta

ALLOWANCE FOR CREDIT LOSSES (Tables)	3 Months Ended
	Mar. 31, 2024
Credit Loss [Abstract]
Schedule of Activity in the Allowance for Credit Losses	Activity in the allowance for credit losses was as follows for the three months ended March 31, 2024 and 2023 (amounts in thousands): Three Months Ended March 31, 2024 Accounts Receivable Contract Assets Customer Financing Receivable Total Allowance for credit losses, beginning of period $ 69 $ 1,113 $ 1,332 $ 2,514 Provision (benefit) for credit losses (46) (72) 29 (89) Allowance for credit losses, end of period $ 23 $ 1,041 $ 1,361 $ 2,425 Three Months Ended March 31, 2023 Accounts Receivable Contract Assets Customer Financing Receivable Total Allowance for credit losses, beginning of period $ — $ — $ — $ — Addition due to adoption of ASU 2016-13 81 1,063 1,220 2,364 Provision (benefit) for credit losses (71) 31 26 (14) Allowance for credit losses, end of period $ 10 $ 1,094 $ 1,246 $ 2,350

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities at Fair Value on a Recurring Basis	The Company’s financial assets and liabilities measured at fair value on a recurring basis were as follows as of March 31, 2024 and December 31, 2023, respectively (amounts in thousands): Level 1 Level 2 Level 3 Total Assets (Liabilities): Derivative asset —  conversion option (1) $ — $ — $ 1,025 $ 1,025 Warrant liability — — (2) (2) __________________ (1) Refer to Note 7 - Investments for further information.

INVESTMENTS (Tables)

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
Schedule of Investments	The following table provides a reconciliation of investments to the Company’s condensed consolidated balance sheets (amounts in thousands): March 31, December 31, Investment in equity securities $ 15,000 $ 15,000 Convertible note receivable 2,365 2,295 $ 17,365 $ 17,295
Schedule of Reconciliation of Asset Balance for the Embedded Derivative	A reconciliation of the beginning and ending asset balance for the embedded derivative in the DG Fuels Note is as follows (amounts in thousands): Three Months Ended March 31, 2024 2023 Beginning of period $ 1,025 $ 1,025 Additions — — Change in fair value — — End of period $ 1,025 $ 1,025

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	As of March 31, 2024 and December 31, 2023, property and equipment, net consisted of the following (amounts in thousands): March 31, December 31, Land $ 226 $ 226 Buildings 774 774 Machinery and equipment 11,707 9,330 Finance lease right-of-use assets – vehicles 187 187 Furniture and IT equipment 1,454 1,474 Leasehold improvements 700 702 Construction in progress 34,641 20,095 Total property and equipment 49,689 32,788 Less: accumulated depreciation and amortization (2,249) (1,745) Property and equipment, net $ 47,440 $ 31,043

INTANGIBLE ASSETS, NET (Tables)

INTANGIBLE ASSETS, NET (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets are stated at amortized cost and consist of the following (amounts in thousands): March 31, 2024 December 31, 2023 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Capitalized software to be sold $ 2,573 $ (82) $ 2,491 $ 1,786 $ — $ 1,786
Schedule of Future Amortization Expense for Intangible Assets	Future amortization expense for intangible assets is estimated as follows (amounts in thousands): Amount Remainder of 2024 $ 247 2025 329 2026 329 2027 329 2028 329 Subtotal 1,563 Software projects in process 928 Total $ 2,491

SUPPLEMENTAL BALANCE SHEETS D_2

SUPPLEMENTAL BALANCE SHEETS DETAIL (Tables)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Supplemental Balance Sheet Detail	(amounts in thousands) March 31, December 31, Prepaid and other current assets: Prepaid expenses $ 2,223 $ 3,131 Tax refund receivable 1,341 1,359 Other 54 30 Total $ 3,618 $ 4,520 Other assets: Derivative asset —  conversion option $ 1,025 $ 1,025 Other 1,516 1,624 Total $ 2,541 $ 2,649 Accrued expenses: Professional fees $ 4,635 $ 4,522 Accrued purchases 7,338 71,932 Employee costs 1,664 5,985 Taxes payable 106 733 Accrued project loss 614 591 Insurance premium financings — 358 Warranty accrual 983 894 Other 13 27 Total $ 15,353 $ 85,042 Lease liabilities, current portion: Operating leases $ 391 $ 697 Finance leases 36 27 Total $ 427 $ 724 Other long-term liabilities: Operating leases $ 984 $ 1,044 Asset retirement obligation 17 52 Warranty accrual 1,022 924 Finance leases 113 93 Warrant liability 2 2 Total $ 2,138 $ 2,115

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Option Activity	Stock option activity for the three months ended March 31, 2024 was as follows (in thousands, except per share data): Options Outstanding Number of Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance as of December 31, 2023 5,807 $ 1.71 6.37 $ 3,605 Stock options granted — — — — Stock options exercised — — — — Stock options forfeited, canceled, or expired (4) 0.80 — — Balance as of March 31, 2024 5,803 1.71 6.15 815 Options exercisable as of March 31, 2024 689 0.71 6.32 744 Options vested and expected to vest as of March 31, 2024 5,803 1.71 6.15 815
Schedule of Restricted Stock Units Activity	RSU activity for the three months ended March 31, 2024 was as follows (in thousands, except per share data): Number of RSUs Weighted Average Grant Date Fair Value per Share Nonvested balance as of December 31, 2023 19,029 $ 4.55 RSUs granted 7,409 1.73 RSUs forfeited (307) 3.24 RSUs vested (2,110) 4.45 Nonvested balance as of March 31, 2024 24,021 $ 3.71
Schedule of Stock-Based Compensation Expense	Total stock-based compensation expense for the three months ended March 31, 2024 and 2023 is as follows (in thousands): Three Months Ended March 31, 2024 2023 Sales and marketing $ 1,715 $ 1,949 Research and development 2,227 3,149 General and administrative 5,742 8,618 Total stock-based compensation expense $ 9,684 $ 13,716

NET LOSS PER SHARE OF COMMON _2

NET LOSS PER SHARE OF COMMON STOCK (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	Basic and diluted net loss per share attributable to common stockholders are calculated as follows (amounts in thousands, except per share amounts): Three Months Ended March 31, 2024 2023 Net loss $ (21,139) $ (31,167) Weighted-average shares outstanding – basic and diluted 147,019 139,669 Net loss per share – basic and diluted $ (0.14) $ (0.22)
Schedule of Equivalent Securities Excluded from Computation of Diluted Weighted-Average Common Shares Outstanding	The following outstanding balances of common share equivalent securities have been excluded from the calculation of diluted weighted-average common shares outstanding because the effect is anti-dilutive for the for th e three mo nths ended March 31, 2024 and 2023 (amounts in thousands): Three Months Ended March 31, 2024 2023 Private warrants 5,167 5,167 Stock options 5,803 1,050 RSUs 24,021 22,128 Total 34,991 28,345

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Warranty Liability	As of March 31, 2024 and 2023, the Company accrued the below estimated warranty liabilities, respectively (amounts in thousands): Three Months Ended March 31, 2024 2023 Warranty balance, beginning of period $ 1,818 $ — Accruals for warranties issued — — Change in estimates 243 — Settlements (56) — Warranty balance, end of period $ 2,005 $ —

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - segment	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Business Acquisition [Line Items]
Number of operating segments	1
Number of reportable segments	1
Customer One | Accounts Receivable | Customer Concentration Risk
Business Acquisition [Line Items]
Concentration risk percentage	87%		92%
Customer One | Contract With Customer Asset After Allowance For Credit Loss Member | Customer Concentration Risk
Business Acquisition [Line Items]
Concentration risk percentage	100%		100%
Customer One | Revenue Benchmark | Customer Concentration Risk
Business Acquisition [Line Items]
Concentration risk percentage	80%	43%
Customer Two | Revenue Benchmark | Customer Concentration Risk
Business Acquisition [Line Items]
Concentration risk percentage	14%	39%
Customer Three | Revenue Benchmark | Customer Concentration Risk
Business Acquisition [Line Items]
Concentration risk percentage		16%

REVENUE RECOGNITION - Recognize

REVENUE RECOGNITION - Recognized Revenue for Product and Service Categories (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 7,759	$ 11,422
Build and transfer energy storage products
Disaggregation of Revenue [Line Items]
Revenue	7,386	11,273
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 373	$ 149

REVENUE RECOGNITION - Narrative

REVENUE RECOGNITION - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Performance obligation and deferred transaction price	$ 137.5
Deferred revenue recognized in period	$ 0.5	$ 11.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, percentage	3%
Revenue, remaining performance obligation, period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, period	12 months

REVENUE RECOGNITION - Contract

REVENUE RECOGNITION - Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Refundable contribution	$ 25,000	$ 25,000
Unbilled receivables	21,624	55,241
Retainage	5,745	5,745
Less allowance for credit losses	(1,041)	(1,113)
Contract assets, net of allowance for credit losses	51,328	84,873
Contract with Customer, Liability [Abstract]
Contract liabilities, current portion	1,495	4,923
Contract liabilities, long-term portion	0	1,500
Total contract liabilities	$ 1,495	$ 6,423

ALLOWANCE FOR CREDIT LOSSES - S

ALLOWANCE FOR CREDIT LOSSES - Schedule of Activity in the Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period	$ 69	$ 0
Provision (benefit) for credit losses	(46)	(71)
Allowance for credit losses, end of period	23	10	$ 0
Allowance for credit losses, beginning of period	1,113	0
Provision (benefit) for credit losses	(72)	31
Allowance for credit losses, end of period	1,041	1,094	0
Allowance for credit losses, beginning of period	1,332	0
Provision (benefit) for credit losses	29	26
Allowance for credit losses, end of period	1,361	1,246	0
Allowance for credit losses, beginning of period	2,514	0
Provision (benefit) for credit losses	(89)	(14)
Allowance for credit losses, end of period	2,425	2,350	0
Allowance For credit loss	$ 2,425	2,350	$ 0
Accounting Standards Update [Extensible Enumeration]			Accounting Standards Update 2016-13
Accounting Standards Update 2016-13
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period		81
Allowance for credit losses, end of period			$ 81
Allowance for credit losses, beginning of period		1,063
Allowance for credit losses, end of period			1,063
Allowance for credit losses, beginning of period		1,220
Allowance for credit losses, end of period			1,220
Allowance for credit losses, beginning of period		$ 2,364
Allowance for credit losses, end of period			2,364
Allowance For credit loss			$ 2,364

ALLOWANCE FOR CREDIT LOSSES - N

ALLOWANCE FOR CREDIT LOSSES - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Credit Loss [Abstract]
Financing receivable amortized cost	$ 10.9	$ 10.7

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - Recurring Basis $ in Thousands	Mar. 31, 2024 USD ($)
Derivative asset —  conversion Option
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets	$ 1,025
Warrant liability
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities	(2)
Level 1 | Derivative asset —  conversion Option
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets	0
Level 1 | Warrant liability
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities	0
Level 2 | Derivative asset —  conversion Option
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets	0
Level 2 | Warrant liability
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities	0
Level 3 | Derivative asset —  conversion Option
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets	1,025
Level 3 | Warrant liability
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities	$ (2)

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Contract liabilities, long-term portion	$ 0		$ 1,500
Other income	1,670	$ (159)
Shareholder Lender
Related Party Transaction [Line Items]
Other income	1,500
Note Payable Agreement | Shareholder Lender
Related Party Transaction [Line Items]
Contract liabilities, long-term portion	1,500
Related Party Engineering Design and Civil Tolerance Code Calculation Support | Executive Officer's Family Member
Related Party Transaction [Line Items]
Transaction amount	100	100
Related Party Marketing and Sales Costs | Director
Related Party Transaction [Line Items]
Transaction amount	$ 200	$ 400

INVESTMENTS - Schedule of Inves

INVESTMENTS - Schedule of Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Investment in equity securities	$ 15,000	$ 15,000
Convertible note receivable	2,365	2,295
Investments	$ 17,365	$ 17,295

INVESTMENTS - Narrative (Detail

INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Feb. 28, 2023	Nov. 30, 2022	Oct. 31, 2021	Mar. 31, 2024	Mar. 31, 2023	Apr. 30, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase of equity securities				$ 0	$ 6,000
Interest income				1,826	1,935
Convertible Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal balance of promissory note			$ 1,000			$ 2,000
Maturity date description			The maturity date of the DG Fuels Note is the earlier of (i) 30 days after a demand for payment is made by the Company at any time after the two year anniversary of the date of issuance of the note; (ii) the four year anniversary of the date of issuance of the note; (iii) five days following a Financial Close (“Financial Close” means a project finance style closing by DG Fuels or its subsidiary of debt and equity capital to finance the construction of that certain biofuel facility currently under development by DG Fuels), or (iv) upon an event of default determined at the discretion of the Company.
Maturity date, number of days after demand for payment following two year anniversary			30 days
Maturity date, four years after issuance			4 years
Maturity date, number of days after a Financial Close			5 days
Annual interest rate (in percent)			10%
Note converted into equity securities				$ 20,000
Note converted into equity securities at discount price				20%
Interest income				$ 100	100
Amortization of debt discount				$ 100	$ 44
Convertible Notes Receivable | DG Fuels Tranche 1 Note
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value of embedded derivative asset			$ 400
Convertible Notes Receivable | DG Fuels Tranche 2 Note
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value of embedded derivative asset			$ 700
KORE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase of equity securities	$ 6,000	$ 9,000
Equity securities	$ 15,000

INVESTMENTS - Reconciliation of

INVESTMENTS - Reconciliation of Embedded Derivative Beginning and Ending Asset Balance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at the beginning	$ 1,025	$ 1,025
Additions	0	0
Change in fair value	0	0
Balance at the end	$ 1,025	$ 1,025

PROPERTY AND EQUIPMENT, NET- Sc

PROPERTY AND EQUIPMENT, NET- Schedule of Property and Equipment, net (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Finance lease right-of-use assets – vehicles	$ 187	$ 187
Total property and equipment	49,689	32,788
Less: accumulated depreciation and amortization	(2,249)	(1,745)
Property and equipment, net	47,440	31,043
Land
Property, Plant and Equipment [Line Items]
Property and equipment	226	226
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment	774	774
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment	11,707	9,330
Furniture and IT equipment
Property, Plant and Equipment [Line Items]
Property and equipment	1,454	1,474
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	700	702
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment	$ 34,641	$ 20,095

PROPERTY AND EQUIPMENT, NET- Na

PROPERTY AND EQUIPMENT, NET- Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation	$ 0.2	$ 0.2

INTANGIBLE ASSETS, NET - Schedu

INTANGIBLE ASSETS, NET - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Gross Carrying Amount	$ 2,573	$ 1,786
Accumulated Amortization	(82)	0
Net Carrying Amount	$ 2,491	$ 1,786

INTANGIBLE ASSETS, NET - Narrat

INTANGIBLE ASSETS, NET - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
External-use software development costs, useful life (in years)	5 years
Amortization expense	$ 0.1	$ 0

INTANGIBLE ASSETS, NET - Future

INTANGIBLE ASSETS, NET - Future Amortization Expense for Intangible Assets (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2024	$ 247
2025	329
2026	329
2027	329
2028	329
Subtotal	1,563
Software projects in process	928
Total	$ 2,491

DEBT (Details)

DEBT (Details) - Premiums Financing Agreement - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Jul. 31, 2023
Short-Term Debt [Line Items]
Debt instrument, face amount		$ 0.2	$ 1.1
Annual interest rate (in percent)		7%	7%
Insurance premium financings	$ 0.4

SUPPLEMENTAL BALANCE SHEETS D_3

SUPPLEMENTAL BALANCE SHEETS DETAIL (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Prepaid and other current assets:
Prepaid expenses	$ 2,223	$ 3,131
Tax refund receivable	1,341	1,359
Other	54	30
Total	3,618	4,520
Other assets:
Derivative asset —  conversion option	1,025	1,025
Other	1,516	1,624
Total	2,541	2,649
Accrued expenses:
Professional fees	4,635	4,522
Accrued purchases	7,338	71,932
Employee costs	1,664	5,985
Taxes payable	106	733
Accrued project loss	614	591
Insurance premium financings	0	358
Warranty accrual	983	894
Other	13	27
Total	15,353	85,042
Lease liabilities, current portion:
Operating leases	391	697
Finance leases	36	27
Total	$ 427	$ 724
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total	Total
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total	Total
Other long-term liabilities:
Operating leases	$ 984	$ 1,044
Asset retirement obligation	17	52
Warranty accrual	1,022	924
Finance leases	113	93
Warrant liability	2	2
Total	$ 2,138	$ 2,115
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Total	Total
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Total	Total

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2020	Dec. 31, 2017	Dec. 31, 2022
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense related to unvested	$ 5.1
Stock-based compensation expense expected recognized period	2 years 25 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense expected recognized period	2 years 1 month 6 days
Unrecognized stock-based compensation expense related to RSUs	$ 74.3
2017 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award grant period			10 years
Voting rights in percentage			10%
Minimum percentage of exercise price for options granted for employees who hold more than 10%			110%
2017 Stock Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			1 year
2017 Stock Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
2020 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award grant period		10 years
Voting rights in percentage		10%
Minimum percentage of exercise price for options granted for employees who hold more than 10%		110%
2020 Stock Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		1 year
2020 Stock Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
2022 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				15,500,000
Annual shares authorized increase, percent of outstanding shares				4%
2022 Equity Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual shares authorized increase, board of directors decision (in shares)				0
2022 Equity Incentive Plan, Shares From Prior Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				8,300,000
Twenty Twenty Two Equity Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved (in shares)				8,000,000

STOCK-BASED COMPENSATION - Stoc

STOCK-BASED COMPENSATION - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Options
Number of options, beginning balance (in shares)	5,807
Number of options, stock options granted (in shares)	0
Number of options, stock options exercised (in shares)	0
Number of options, stock options forfeited, canceled, or expired (in shares)	(4)
Number of options, ending balance (in shares)	5,803	5,807
Number of options, options exercisable (in shares)	689
Number of options, options vested and expected to vest (in shares)	5,803
Weighted Average Exercise Price Per Share
Weighted average exercise price per share, beginning balance (in dollars per share)	$ 1.71
Weighted average exercise price per share, stock options granted (in dollars per share)	0
Weighted average exercise price per share, stock options exercised (in dollars per share)	0
Weighted average exercise price per share, stock options forfeited, canceled, or expired (in dollars per share)	0.80
Weighted average exercise price per share, ending balance (in dollars per share)	1.71	$ 1.71
Weighted average exercise price per share, options exercisable (in dollars per share)	0.71
Weighted average exercise price per share, options vested and expected to vest (in dollars per share)	$ 1.71
Weighted Average Remaining Contractual Term (in years)
Weighted average remaining contractual term (in years)	6 years 1 month 24 days	6 years 4 months 13 days
Weighted average remaining contractual term (in years), options exercisable	6 years 3 months 25 days
Weighted average remaining contractual term (in years), options vested and expected to vest	6 years 1 month 24 days
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance	$ 3,605
Aggregate intrinsic value, stock options exercised	0
Aggregate intrinsic value, ending balance	815	$ 3,605
Aggregate intrinsic value, options exercisable	744
Aggregate intrinsic value, options vested and expected to vest	$ 815

STOCK-BASED COMPENSATION - Rest

STOCK-BASED COMPENSATION - Restricted Stock Units Activity (Details) - Restricted stock units shares in Thousands	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of RSUs
Beginning balance (in shares) | shares	19,029
RSUs granted (in shares) | shares	7,409
RSUs forfeited (in shares) | shares	(307)
RSUs vested (in shares) | shares	(2,110)
Ending balance (in shares) | shares	24,021
Weighted Average Grant Date Fair Value per Share
Beginning balance (in dollars per share) | $ / shares	$ 4.55
RSUs granted (in dollars per share) | $ / shares	1.73
RSUs forfeited (in dollars per share) | $ / shares	3.24
RSUs vested (in dollars per share) | $ / shares	4.45
Ending balance (in dollars per share) | $ / shares	$ 3.71

STOCK-BASED COMPENSATION - St_2

STOCK-BASED COMPENSATION - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 9,684	$ 13,716
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	1,715	1,949
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	2,227	3,149
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 5,742	$ 8,618

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0

NET LOSS PER SHARE OF COMMON _3

NET LOSS PER SHARE OF COMMON STOCK - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net loss	$ (21,139)	$ (31,167)
Net loss	$ (21,139)	$ (31,167)
Weighted-average shares outstanding – basic (in shares)	147,019	139,669
Weighted average shares of outstanding — diluted (in shares)	147,019	139,669
Net loss per share — basic (in dollars per share)	$ (0.14)	$ (0.22)
Net loss per share — diluted (in dollars per share)	$ (0.14)	$ (0.22)

NET LOSS PER SHARE OF COMMON _4

NET LOSS PER SHARE OF COMMON STOCK - Narrative (Details) - shares	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2022
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Number of dilutive shares (in shares)		0
Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Number of dilutive shares (in shares)	0
Number of earn-out shares (in shares)	9,000,000		9,000,000
Contingent right, Earn-Out Shares, threshold trading days			20 days
Contingent right, Earn-Out Shares, threshold consecutive trading days			30 days

NET LOSS PER SHARE OF COMMON _5

NET LOSS PER SHARE OF COMMON STOCK - Common Share Equivalent Securities Excluded From Computation of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	34,991	28,345
Private warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	5,167	5,167
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	5,803	1,050
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	24,021	22,128

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Purchase obligation	$ 400
Total refundable contributions to be made	25,000
Refundable contribution	25,000	$ 25,000
Letters of credit issued	22,700
Restricted cash	1,011	$ 35,632
Outstanding performance and payment bonds	28,600
Bonds outstanding, other	$ 28,800

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Warranty Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Movement in Standard Product Warranty Accrual [Roll Forward]
Warranty balance, beginning of period	$ 1,818	$ 0
Accruals for warranties issued	0	0
Change in estimates	243	0
Settlements	(56)	0
Warranty balance, end of period	$ 2,005	$ 0