Romeo Power (RMO) 10-Q 17 May 21 2021 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2021	May 14, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-38795
Entity Registrant Name	ROMEO POWER, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-2289787
Entity Address, Address Line One	4380 Ayers Avenue
Entity Address, City or Town	Vernon,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90058
City Area Code	833
Local Phone Number	467-2237
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	RMO
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		131,197,350
Entity Central Index Key	0001757932
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 41,278	$ 292,442
Investments	246,215	0
Accounts receivable, net of allowance for expected credit loss of $213 and $238 at March 31, 2021 and December 31, 2020, respectively	1,444	841
Inventories, net	5,689	4,937
Insurance receivable	6,000	6,000
Deferred costs	998	0
Prepaid expenses and other current assets	9,306	1,269
Total current assets	310,930	305,489
Restricted cash	1,500	1,500
Property, plant and equipment, net	6,321	5,484
Equity method investments	38,357	35,000
Operating lease right-of-use assets	5,411	5,469
Other noncurrent assets	2,893	3,100
TOTAL ASSETS	365,412	356,042
Current liabilities
Accounts payable	5,033	2,900
Accrued expenses	3,094	2,844
Contract liabilities	1,672	815
Current maturities of long-term debt	2,783	2,260
Operating lease liabilities, current	855	853
Legal settlement payable	6,000	6,000
Other current liabilities	248	384
Total current liabilities	19,685	16,056
Commitments and Contingencies
Long-term debt, net of current portion	559	1,082
Public and private placement warrants	11,921	138,466
Operating lease liabilities, net of current portion	4,661	4,723
Other noncurrent liabilities	0	17
Total liabilities	36,826	160,344
Stockholders’ equity
Preferred stock ($0.0001 par value, 10,000,000 shares authorized, no shares issued and outstanding at March 31, 2021 and December 31, 2020)	0	0
Common stock ($0.0001 par value, 250,000,000 shares authorized, 130,529,147 and 126,911,861 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively)	13	12
Additional paid-in capital	416,308	373,129
Accumulated other comprehensive loss	(304)	0
Accumulated deficit	(87,431)	(177,443)
Total stockholders’ equity	328,586	195,698
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 365,412	$ 356,042

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Accounts receivable-allowance for doubtful accounts	$ 213	$ 238
Preferred stock, par value (USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	130,529,147	126,911,861
Common stock, shares outstanding (in shares)	130,529,147	126,911,861

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
REVENUES:
Related party revenues	$ 713	$ 882
Total revenues	1,054	2,522
COST OF REVENUES:
Related party cost	589	750
Total cost of revenues	4,827	3,632
GROSS LOSS	(3,773)	(1,110)
OPERATING EXPENSES:
Research and development	3,771	1,802
Selling, general and administrative	17,999	2,907
Total operating expenses	21,770	4,709
OPERATING LOSS	(25,543)	(5,819)
Interest expense	(7)	(254)
Interest income	90	0
Change in fair value of public and private placement warrants	116,125	0
INCOME (LOSS) BEFORE INCOME TAXES AND LOSS IN EQUITY METHOD INVESTMENTS	90,665	(6,073)
Loss in equity method investments	(643)	(696)
Provision for income taxes	(10)	0
NET INCOME (LOSS)	90,012	(6,769)
OTHER COMPREHENSIVE LOSS
Change in net unrealized losses, net of income taxes	(342)	0
Net losses reclassified to earnings, net of income taxes	38	0
Total other comprehensive loss, net of income taxes	(304)	0
COMPREHENSIVE INCOME (LOSS)	$ 89,708	$ (6,769)
Net income (loss) per share
Basic (USD per share)	$ 0.70	$ (0.09)
Diluted (USD per share)	$ 0.66	$ (0.09)
Weighted average number of shares outstanding
Basic (in shares)	128,788,715	74,647,985
Diluted (in shares)	135,812,697	74,647,985
Product revenues
REVENUES:
Revenue	$ 341	$ 1,588
COST OF REVENUES:
Cost of revenues	4,238	2,729
Service revenues
REVENUES:
Revenue	0	52
COST OF REVENUES:
Cost of revenues	$ 0	$ 153

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	APIC	Notes Receivable from Stockholders	Accumulated Other Comprehensive Loss	Accumulated Deficit
Common stock beginning balance (in shares) at Dec. 31, 2019		74,449,847
Stockholders' equity beginning balance at Dec. 31, 2019	$ 2,573	$ 7	$ 181,567	$ (9,175)	$ 0	$ (169,826)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		531,764
Issuance of common stock	1,277		1,277
Stock based compensation	277		277
Net income	(6,769)					(6,769)
Common stock ending balance (in shares) at Mar. 31, 2020		74,981,611
Stockholders' equity ending balance at Mar. 31, 2020	(2,642)	$ 7	183,121	(9,175)	0	(176,595)
Common stock beginning balance (in shares) at Dec. 31, 2020		126,911,861
Stockholders' equity beginning balance at Dec. 31, 2020	195,698	$ 12	373,129	0	0	(177,443)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		3,617,286
Issuance of common stock	36,627	$ 1	36,626
Stock based compensation	6,553		6,553
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(304)				(304)
Net income	90,012					90,012
Common stock ending balance (in shares) at Mar. 31, 2021		130,529,147
Stockholders' equity ending balance at Mar. 31, 2021	$ 328,586	$ 13	$ 416,308	$ 0	$ (304)	$ (87,431)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 90,012	$ (6,769)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	505	482
Stock-based compensation	6,553	277
Inventory provision	392	0
Change in fair value of public and private placement warrants	(116,125)	0
Loss in equity method investment	643	696
Non-cash lease expense—operating leases	58	57
Non-cash lease expense—finance leases	71	71
Other	(113)	0
Changes in operating assets and liabilities:
Accounts receivable	(603)	26
Inventories	(1,144)	(961)
Prepaid expenses and other current assets	(7,023)	691
Accounts payable	2,630	853
Accrued expenses	250	441
Interest accrued on notes payable	0	239
Increase (Decrease) in Deferred Charges	(998)	0
Contract liabilities	857	367
Operating lease liabilities	(60)	(53)
Other, net	(77)	(48)
Net cash used in operating activities	(24,172)	(3,631)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of investments	(281,124)	0
Proceeds from maturities of investments	32,318	0
Proceeds from sales of investments	1,300	0
Equity method investment	(4,000)	0
Capital expenditures	(1,617)	(601)
Net cash used in investing activities	(253,123)	(601)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of convertible notes	0	4,924
Issuance of term notes	0	750
Issuance of common stock	0	1,277
Exercise of stock options	4,681	0
Exercise of stock warrants	21,526	0
Principal portion of finance lease liabilities	(76)	(69)
Net cash provided by financing activities	26,131	6,882
Net change in cash, cash equivalents and restricted cash	(251,164)	2,650
Cash, cash equivalents and restricted cash, beginning of period	293,942	1,929
Cash, cash equivalents and restricted cash, end of period	42,778	4,579
Reconciliation of cash, cash equivalents and restricted cash to the condensed consolidated balance sheets:
Total cash, cash equivalents and restricted cash	42,778	4,579
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	0	0
Cash paid for income taxes	10	0
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property, plant and equipment in accounts payable at the end of period	$ 86	$ 588

DESCRIPTION OF BUSINESS AND BAS

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION Romeo Power, Inc. (f/k/a RMG Acquisition Corp.) was originally incorporated under the name RMG Acquisition Corp. (“RMG”) as a blank check company incorporated in Delaware on October 22, 2018 for the purpose of effecting a merger, capital stock-exchange, asset acquisition, share purchase, reorganization, or similar business combination. On October 5, 2020, RMG and RMG Merger Sub, Inc. a Delaware corporation and a wholly owned subsidiary of RMG (“Merger Sub”), entered into an Agreement and Plan of Merger (as amended, the “Merger Agreement”) with Romeo Systems, Inc., a Delaware corporation (“Legacy Romeo”). On December 29, 2020, pursuant to the terms of the Merger Agreement, the business combination with Legacy Romeo was effected through the merger of Merger Sub with and into Legacy Romeo, with Legacy Romeo continuing as the surviving company and as our wholly owned subsidiary (the “Merger” and, collectively with the other transactions described in the Merger Agreement, the “Business Combination”). Upon the closing of the Business Combination, we changed our name to Romeo Power, Inc. Romeo Power, Inc. designs, engineers, and manufactures lithium ion cylindrical battery packs for electric vehicles and energy storage solutions, with a focus on battery innovation, functionality, energy density, safety, and performance. We are headquartered in Vernon, California. Unless the context otherwise requires, “Romeo,” the “Company,” “we,” “us,” or “our” refers to the combined company and its subsidiaries following the Business Combination and “Legacy Romeo” refers to Romeo Systems, Inc. In 2019, Legacy Romeo and BorgWarner, Inc. (“BorgWarner”) formed BorgWarner Romeo Power LLC (the “Joint Venture”) of which we own 40%. The Joint Venture is intended to accelerate our reach into international regions in a capital efficient way. As a result, we manage our operations to focus on both this specific production and our core operations. Basis of Presentation —The Business Combination was accounted for as a reverse recapitalization (the “Recapitalization Transaction”) in accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 805, Business Combinations . For accounting and financial reporting purposes, Legacy Romeo was considered the acquirer based on facts and circumstances, including the following: • Legacy Romeo’s former stockholders hold a majority ownership interest in the combined company; • Legacy Romeo’s senior management team became the senior management of the combined company; • Legacy Romeo was the larger of the companies based on historical operating activity and employee base; and • Legacy Romeo’s operations comprise the ongoing operations of the combined company. Accordingly, all historical financial information presented in these condensed consolidated financial statements represents the accounts of Legacy Romeo and its wholly owned subsidiaries “as if” Legacy Romeo is the predecessor and legal successor. The historical operations of Legacy Romeo are deemed to be those of the Company. Thus, the financial statements included in this report reflect (i) the historical operating results of Legacy Romeo prior to the Business Combination; (ii) the combined results of RMG and Legacy Romeo following the Business Combination on December 29, 2020; and (iii) RMG’s equity structure for all periods presented. No step-up basis of RMG’s assets and liabilities and no intangible assets or goodwill were recorded in connection with the Business Combination transaction consistent with the treatment of the transaction as a reverse recapitalization. In connection with the Business Combination each share of Legacy Romeo common stock and preferred stock issued and outstanding immediately prior to the Business Combination (with each share of Legacy Romeo preferred stock being treated as if it were converted into Legacy Romeo common stock immediately prior to the Business Combination) converted into the right to receive 0.121730 shares (the “Exchange Ratio”) of common stock, par value $0.0001 (the “Common Stock”). The recapitalization of the number of shares of Common Stock attributable to Legacy Romeo is reflected retroactively to the earliest period presented based upon the Exchange Ratio and is utilized for calculating earnings per share in all prior periods presented. The accompanying condensed consolidated financial statements include the results of Romeo Power, Inc. and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated and the effect of variable interest entities have been considered in the consolidation. Unaudited Interim Financial Information —The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information, the instructions to Form 10-Q, and the rules and regulations of the Securities and Exchange Commission (“SEC”). The condensed consolidated financial statements presented herein have not been audited by an independent registered public accounting firm, but include all material adjustments (consisting of normal recurring adjustments) which are, in the opinion of management, necessary for a fair presentation of our financial position, results of operations and cash flows for the period. These results are not necessarily indicative of results for any other interim period or for the full fiscal year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been omitted pursuant to the rules of the SEC. The accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the SEC on April 15, 2021 (the “2020 Form 10-K”). Use of Estimates —The preparation of financial statements in conformity with GAAP requires us to make certain estimates and assumptions for the reporting periods covered by the financial statements. These estimates and assumptions affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent liabilities. Actual amounts could differ from these estimates. The condensed consolidated financial statements have been prepared under the assumption that Romeo will continue as a going concern.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Except as described below, no material changes have been made to our significant accounting policies disclosed in Note 2 of the notes to consolidated financial statements in Part II, Item 8 of the 2020 Form 10-K. Available-for-Sale Debt Investments — We classify our investments in fixed income debt securities as available-for-sale debt investments. Our available-for-sale debt investments primarily consist of U.S. government securities, municipal securities, corporate debt, commercial paper, and U.S. agency mortgage-backed securities. These available-for-sale debt investments are primarily held in the custody of a major financial institution. These investments are reported on the condensed consolidated balance sheets at fair value. Unrealized gains and losses on these investments, to the extent the investments are unhedged, are included as a separate component of accumulated other comprehensive loss, net of tax. A specific identification method is used to determine the cost basis of available-for-sale debt investments and any realized gains or losses when sold. We classify our investments as current based on the nature of the investments and their availability for use in current operations. Recently Adopted Accounting Pronouncements In January 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-01, ASC subtopic 825-10, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities , which revised an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. This accounting guidance also amended certain disclosure requirements associated with the fair value of financial instruments. Under ASU No. 2016-01, entities must measure certain equity investments at fair value and recognize any changes in fair value in net income, unless the investments qualify for a new practicality exception. ASU 2016-01 is effective for financial statements issued for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. We adopted the standard on January 1, 2021, when we began making significant investments in available-for-sale debt securities and formulating a company investment policy to support the use and management of the proceeds from the Business Combination. In December 2019, the FASB issued ASU No. 2019-12, ASC 740, Income Taxes (ASC 740): Simplifying the Accounting for Income Taxes , which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in ASC 740 and also clarifies and amends existing guidance to improve consistent application. The guidance is effective for all public business entities for fiscal years beginning after December 15, 2020, including interim periods therein. Early adoption is also permitted. We adopted the standard on January 1, 2021 and the adoption of the new guidance does not have a material impact on our financial position, operating results or cash flows.

REVENUES

REVENUES	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
REVENUES	REVENUES Contract Liabilities —Contract liabilities in the accompanying condensed consolidated balance sheets relate to payments received in advance of satisfying performance obligations under our contracts and are realized when the associated revenue is recognized under the contracts. During the three months ended March 31, 2021, changes in contract liabilities were as follows (in thousands): Three Months Ended March 31, 2021 Beginning balance $ 815 Revenues recognized (926) Increase due to billings 1,783 Ending balance $ 1,672 Contract liabilities are earned as services and prototypes are transferred to the customer. The remaining contract liability balance as of March 31, 2021 is expected to be earned and recognized as revenue within the next twelve months. As of March 31, 2021, we had executed certain contracts with customers to deliver specific battery packs, modules, and battery management system and software services. These contracts contain minimum quantity purchase requirements that are non-cancellable (other than for a breach by Romeo), and we have enforceable rights to pursue payments due under these contracts under make-whole provisions, or through customary remedies for breach of contract if the minimum quantities are not ordered. As of March 31, 2021, we had $555.1 million of unsatisfied performance obligations related to minimum quantity purchase commitments included in these contracts. For $311.9 million out of the $555.1 million of unsatisfied performance obligations related to minimum quantity purchase commitments, if the customers do not follow through on their minimum purchase commitments, we would receive a maximum of $292.5 million under certain make-whole provisions included in these contracts. For the remaining $243.2 million of unsatisfied performance obligations related to minimum quantity purchase commitments included in these contracts, if the customers do not follow through on their minimum purchase commitments, we would seek damages through customary remedies for breach of contract. Of the $555.1 million of unsatisfied performance obligations as of March 31, 2021, $23.4 million is expected to be satisfied during the fiscal year ending December 31, 2021, $442.4 million is expected to be satisfied during our fiscal years ending December 31, 2022 and 2023, and the remaining $89.3 million is expected to be satisfied thereafter. This backlog includes the total value of our existing customer contracts and includes products that are within the scope of the license granted to the Joint Venture, based on the types of customer vehicles in which the products will be used. To the extent that those product deliveries are fulfilled by the Joint Venture, or pursuant to an agreement with the Joint Venture, we may not recognize the full amount of such contracted backlog as revenue. The realization and timing of the recognition of our backlog is dependent, among other things, on our ability to obtain and secure a steady supply of battery cells from our suppliers as well as our ability to meet the acceptance requirements in contracts, such as design and quality tests. In addition, these amounts exclude any potential adjustments for variable consideration which could arise from provisions in our contracts where the price for a product or service can change based on future events. Based on practical expedient elections permitted by ASC 606, Revenue from Contracts with Customers , the Company does not disclose the value of unsatisfied performance obligations for variable consideration that is allocated entirely to a wholly unsatisfied performance obligation. Disaggregation of Revenues —We earn revenue through the sale of products and services. Product and service lines are the disaggregation of revenues primarily used by management, as this disaggregation allows for the evaluation of market trends, and certain product lines and services vary in recurring versus non-recurring nature. We do not have any material sales outside of North America. The following tables disaggregate revenues by type of products, services and segment for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 Romeo Power Joint Venture North America Support Total Product revenues: Modules $ 91 $ — $ 91 Packs 250 — 250 Total product revenues 341 — 341 Service revenues: Non-recurring engineering and prototype — — — Total service revenues — — — Related party revenues: Related party modules 256 — 256 Related party packs 15 — 15 Joint Venture support — 442 442 Total Related party revenues 271 442 713 Total revenues $ 612 $ 442 $ 1,054 Three Months Ended March 31, 2020 Romeo Power Joint Venture North America Support Total Products: revenues Modules $ 1,588 $ — $ 1,588 Packs — — — Total product revenues 1,588 — 1,588 Services: revenues Non-recurring engineering and prototype 52 — 52 Total service revenues 52 — 52 Related party revenues: Related Party Module — — — Related Party Packs — — — Joint Venture support — 882 882 Total related party revenues — 882 882 Total revenues $ 1,640 $ 882 $ 2,522 The following table disaggregates revenues by when control is transferred for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 2020 Point in time $ 612 $ 1,640 Over time 442 882 Total $ 1,054 $ 2,522

INVENTORY

INVENTORY	3 Months Ended
	Mar. 31, 2021
Inventory Disclosure [Abstract]
INVENTORY	INVENTORY As of March 31, 2021 and December 31, 2020, inventory consisted of the following (in thousands): March 31, 2021 December 31, 2020 Raw materials $ 3,780 $ 4,064 Work-in-process 1,204 531 Finished goods 705 342 Total inventories $ 5,689 $ 4,937 We write down inventory for obsolete inventory items and when the net realizable value of inventory items is less than their carrying value. During the three months ended March 31, 2021, we recorded a write-down of $0.4 million of inventory in cost of revenues. We did not record any write-downs of inventory in cost of revenues during the three months ended March 31, 2020 .

EQUITY METHOD INVESTMENTS

EQUITY METHOD INVESTMENTS	3 Months Ended
	Mar. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
EQUITY METHOD INVESTMENTS	EQUITY METHOD INVESTMENTS BorgWarner Romeo Power LLC Legacy Romeo and BorgWarner formed BorgWarner Romeo Power LLC on June 28, 2019. Legacy Romeo and BorgWarner received a 40% interest and 60% interest in the Joint Venture, respectively. Subsequently, Legacy Romeo and BorgWarner agreed to contribute an additional $10.0 million to the Joint Venture which represented funding for 2021 capital needs. In January 2021, we invested $4.0 million in the Joint Venture, which represented our pro rata share of the agreed upon funding. Heritage Battery Recycling, LLC On October 2, 2020, we entered into a Battery Recycling Agreement (the “Battery Recycling Arrangement”) with Heritage Battery Recycling, LLC (“HBR”), an affiliate of Heritage Environmental Services, Inc. (“HES”). Under the Battery Recycling Arrangement, HBR has agreed to design, build and operate a system for redeploying, recycling or disposing of lithium-ion batteries (the “System”) to be located at HES’s facility in Arizona. Immediately following the Business Combination on December 29, 2020, we contributed $35.0 million to HBR, a related party to an investor in Legacy Romeo and an investor of $25.0 million in the private placement of shares of Common Stock (the “PIPE Shares”) that were sold in connection with the Business Combination. While the arrangement is in effect, it establishes a strategic arrangement with HES for the collection of our battery packs for recycling, and it gives our customers priority at the recycling facility. We also have agreed to fund, in principal, up to $10.0 million for a pilot program that, if successful, could lead to the purchase of commercial vehicles containing Romeo batteries by HBR’s affiliate. The terms of the pilot program have not yet been finalized and reflected in an executed agreement.

PUBLIC AND PRIVATE PLACEMENT WA

PUBLIC AND PRIVATE PLACEMENT WARRANTS	3 Months Ended
	Mar. 31, 2021
PUBLIC AND PRIVATE PLACEMENT WARRANTS
PUBLIC AND PRIVATE PLACEMENT WARRANTS	PUBLIC AND PRIVATE PLACEMENT WARRANTSIn February 2019, in connection with the RMG initial public offering (the “RMG IPO”), RMG issued 7,666,648 warrants (the “Public Warrants”) to purchase shares of Common Stock at $11.50 per share. Simultaneously with the consummation of the RMG IPO, RMG issued 4,600,000 warrants (the “Private Placement Warrants” and, together with the Public Warrants, the “Public and Private Placement Warrants”) to purchase shares of Common Stock at $11.50 per share, to RMG Sponsor, LLC (the “Sponsor”), certain funds and accounts managed by subsidiaries of BlackRock, Inc., and certain funds and accounts managed by Alta Fundamental Advisers LLC (together, the “Anchor Investors”). On February 16, 2021, we announced the redemption of all of the outstanding Public Warrants to purchase shares of our Common Stock, that were issued under the Warrant Agreement. All Public Warrants could be exercised until April 5, 2021 to purchase shares of our Common Stock, at the exercise price of $11.50 per share, and any Public Warrants that remained unexercised were voided and no longer exercisable. On April 5, 2021, 7,223,683 Public Warrants were redeemed at the redemption price of $0.01 per Public Warrant. The Company paid Public Warrant holders a total of $72.2 thousand in connection with the redemption. The Public and Private Placement warrants are recorded as liabilities in our condensed consolidated balance sheets.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION We estimate the grant date fair value of stock options containing only a service condition using the Black-Scholes option-pricing model. The Black-Scholes option-pricing model requires inputs such as the fair value of our Common Stock, the risk-free interest rate, expected term, expected dividend yield and expected volatility. Prior to the Business Combination, when there was no public market for Legacy Romeo’s common stock, the fair value of our common stock was estimated with the assistance of an independent third-party valuation firm using a combination of a market and income approach. The risk-free interest rate assumption is determined by using the U.S. Treasury rates of the same period as the expected option term of each stock option. We use the simplified method to calculate the expected term. The dividend yield assumption is based on the dividends expected to be paid over the expected life of the stock option. Our volatility is derived from several publicly traded peer companies, due to our limited history as a publicly traded company. The grant date fair value of awards with market conditions is estimated using a Monte Carlo simulation or other appropriate fair value method with the assistance of an independent third-party valuation firm. Following the Business Combination, the outstanding stock options issued under the 2016 Stock Plan may be exercised (subject to their original vesting, exercise and other terms and conditions) to purchase a number of shares of Common Stock equal to the number of shares of Legacy Romeo common stock subject to such Legacy Romeo options multiplied by the Exchange Ratio (rounded down to the nearest whole share) at an exercise price per share divided by the Exchange Ratio (rounded up to the nearest whole cent). The information presented herein is as if the exchange of stock options and Common Stock occurred as of the earliest period presented. Time-based awards During the three months ended March 31, 2021 we did not grant any stock options to employees. During the three months ended March 31, 2021, our employees exercised stock options totaling 836,749 shares for total proceeds of $4.7 million. The fair value of the time-based stock options granted during the three months ended March 31, 2020 was determined using the following assumptions: Fair Value Assumptions: Three Months Ended March 31, 2020 Risk-free interest rate 0.92% Expected term (in years) 6.5 Expected volatility 60% Dividend yield 0% Grant date fair value per share 1.44 Performance and market-based award In August 2020, we awarded 4,633,978 stock options to our then Chairman and CEO at an exercise price of $6.69 per share. All of the shares covered by such award are subject to time-based, performance and market condition vesting requirements. As of December 29, 2020, the date of the Business Combination, the performance condition was satisfied, and we began recognizing stock-based compensation expense based upon the grant date fair value of the award. We recognize the stock-based compensation expense over the requisite service period, which is from December 29, 2020 through June 28, 2021. We estimated the grant date fair value of the award to be $9.6 million, which was determined using a Monte Carlo simulation with the assistance of an independent third-party valuation firm. The number of shares that will be exercisable, if any, is determined solely by the average of the closing price per share of our Common Stock on each of the five trading days immediately following the expiration of the six-month lockup period assigned to Legacy Romeo stockholders in connection with the Business Combination, which is June 27, 2021. The number of shares that may become exercisable is set forth in the table below: Average Closing Share Price Cumulative Number Of Shares $6.6869 - $8.9452 926,795 $8.9453 - $11.9272 1,853,591 $11.9273 - $14.9092 3,243,781 $14.9093 4,633,978 As of March 31, 2021, the performance and market-based award is not exercisable, and 4,633,978 stock options related to the performance and market-based award were outstanding. Stock-based compensation expense During the three months ended March 31, 2021 and 2020, we recognized a total of $6.6 million and $0.3 million, respectively, of stock-based compensation expense related to the vesting of stock options. The following table summarizes our stock-based compensation expense by line item in the condensed consolidated statements of operations and comprehensive income (loss) (in thousands): Three Months Ended March 31, 2021 2020 Cost of revenues $ 121 $ 33 Research and development 61 — Selling, general, and administrative 6,371 244 Total $ 6,553 $ 277

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXESOur income tax provision consists of federal and state income taxes. The tax provision for the three months ended March 31, 2021 and 2020 was based on the estimated effective tax rates applicable for the three months ended March 31, 2021 and 2020. The Company’s overall effective tax rate of zero percent is different than the federal statutory tax rate because the Company has established a full valuation allowance against its net deferred income tax assets. As of March 31, 2021, the Company continues to record a full valuation allowance against the deferred tax asset balance as realization was uncertain.

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS Available-for-sale debt investments The following table summarizes our available-for-sale debt investment holdings at March 31, 2021 (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized and Credit Losses Fair Value U.S. government securities $ 52,018 $ 4 $ (9) $ 52,013 Municipal securities 59,160 25 (87) 59,098 Corporate debt securities 69,783 15 (222) 69,576 Asset-backed securities 18,196 1 (12) 18,185 U.S. agency mortgage-backed securities 18,140 — (31) 18,109 Commercial paper 24,222 13 — 24,235 Certificates of deposit 5,000 — (1) 4,999 Total (1) $ 246,519 $ 58 $ (362) $ 246,215 (1) There were no unsettled sales of available-for-sale debt investments at March 31, 2021. The following table presents the gross realized gains and gross realized losses related to available-for-sale debt investments (in thousands): Three Months Ended Gross realized gains $ 34 Gross realized losses (72) Gross realized loss, net $ (38) The following tables present the breakdown of the available-for-sale debt investments with gross unrealized losses and the duration that those losses had been unrealized at March 31, 2021 (in thousands): Unrealized Losses Unrealized Losses Total Fair Value Gross Fair Value Gross Fair Value Gross U.S. government securities $ 20,998 $ (9) $ — $ — $ 20,998 $ (9) Municipal securities 37,691 (87) — — 37,691 (87) Corporate debt securities 66,561 (222) — — 66,561 (222) Asset-backed securities 14,934 (12) — — 14,934 (12) U.S. agency mortgage-backed securities 18,109 (31) — — 18,109 (31) Certificates of deposit 4,999 (1) — — 4,999 (1) Total $ 163,292 $ (362) $ — $ — $ 163,292 $ (362) The following table summarizes the maturities of our available-for-sale debt investments at March 31, 2021 (in thousands): Amortized Cost Fair Value Less than 1 year $ 94,989 $ 94,998 1 year through 5 years 133,390 133,108 Mortgage-backed securities with no single maturity 18,140 18,109 Total $ 246,519 $ 246,215

FAIR VALUE

FAIR VALUE	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
FAIR VALUE	FAIR VALUE Fair Value of Financial Instruments — The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value, and establishes the disclosure requirements regarding fair value measurements. Fair value is defined as the price that would be received in the sale of an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1 Inputs —Unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date. Level 2 Inputs —Inputs, other than quoted prices included within Level 1, that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs). Level 3 Inputs —Unobservable inputs reflecting our assessment of assumptions that market participants would use in pricing the asset or liability. We develop these inputs based on the best information available. Our available-for-sale debt investments are measured at fair value on a recurring basis, consisting of investment grade high quality fixed income assets, which are priced using quoted market prices for similar instruments or unbinding market prices that are corroborated by observable market data. The Public and Private Placement Warrants are measured at fair value on a recurring basis. We will continue to adjust these liabilities for changes in the fair value of the Public and Private Placement Warrants until the warrants are exercised, redeemed or cancelled. Prior to the redemption of the Public Warrants on April 5, 2021, the Public Warrants were traded on the NYSE and were recorded at fair value using the closing stock price as of the measurement date, which represents a Level 1 fair value measurement. The fair value of the Private Placement Warrants is established using both Level 1 and Level 2 inputs and determined using the Black-Scholes option-pricing model. The Black-Scholes option-pricing model requires inputs such as the fair value of our Common Stock, the risk-free interest rate, expected term, expected dividend yield and expected volatility. The fair value of our Common Stock is considered a Level 1 input as our Common Stock is freely traded on the NYSE. The risk-free interest rate assumption is determined by using the U.S. Treasury rates of the same period as the expected term of the Private Placement Warrants, which is 4.75 years. The dividend yield assumption is based on the dividends expected to be paid over the expected life of the warrant. Our volatility is derived from several publicly traded peer companies. As of March 31, 2021 and December 31, 2020, assets and liabilities measured at fair value on a recurring basis were as follows (in thousands): March 31, 2021 Total (Level 1) (Level 2) (Level 3) Assets: Cash equivalents: Money market funds $ 19,000 $ 19,000 $ — $ — Available-for-sale debt investments: U.S. government securities 52,013 — 52,013 — Municipal securities 59,098 — 59,098 — Corporate debt securities 69,576 — 69,576 — Asset-backed securities 18,185 — 18,185 — U.S. agency mortgage-backed securities 18,109 — 18,109 — Commercial paper 24,235 — 24,235 — Certificates of deposit 4,999 — 4,999 — Total $ 265,215 $ 19,000 $ 246,215 $ — Financial Liabilities: Public Warrants $ 1,337 $ 1,337 $ — $ — Private Placement Warrants 10,584 — 10,584 — Total $ 11,921 $ 1,337 $ 10,584 $ — December 31, 2020 Total (Level 1) (Level 2) (Level 3) Assets: Cash equivalents: U.S. Treasury Bills $ 16,000 $ 16,000 $ — $ — Total $ 16,000 $ 16,000 $ — $ — Financial liabilities: Public Warrants $ 71,453 $ 71,453 $ — $ — Private Placement Warrants 67,013 — 67,013 — Total $ 138,466 $ 71,453 $ 67,013 $ — The key assumptions used to determine the fair value of the Private Placement Warrants as of March 31, 2021 and December 31, 2020 using the Black-Scholes model were as follows: Fair Value Assumptions March 31, 2021 December 31, 2020 Risk-free interest rate 0.85% 0.17% Expected term (in years) 4.75 5 Expected volatility 58% 57% Dividend yield — — Fair value of common stock $8.33 $22.49

NET INCOME (LOSS) PER SHARE

NET INCOME (LOSS) PER SHARE	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
NET INCOME (LOSS) PER SHARE	NET INCOME (LOSS) PER SHARE The basic and diluted net income (loss) per share is computed by dividing our net income or net loss by the weighted average shares outstanding during the period. The calculation of basic and diluted net income (loss) per share for the three months ended March 31, 2021 and 2020 is presented below (in thousands, except share and per share data): Three Months Ended March 31, 2021 2020 Net income (loss) $ 90,012 $ (6,769) Weighted average common shares outstanding – basic 128,788,715 74,647,985 Dilutive effect of potentially issuable shares 7,023,982 — Weighted average common shares outstanding – diluted 135,812,697 74,647,985 Basic net income (loss) per share $ 0.70 $ (0.09) Diluted net income (loss) per share $ 0.66 $ (0.09) Potentially dilutive shares that were considered in the determination of diluted net income (loss) per share include stock options and warrants to purchase our Common Stock. Antidilutive shares excluded from the calculation of diluted net income (loss) per share were 11,277,997 and 22,196,804 as of March 31, 2021 and 2020, respectively. As the inclusion of common stock share equivalents in the calculation of diluted loss per share would be anti-dilutive for the three months ended March 31, 2020, diluted net loss per share was the same as basic net loss per share.

SEGMENTS

SEGMENTS	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
SEGMENTS	SEGMENTS We have two operating segments, which are also reportable segments. Our reportable segments are determined and presented based on how information is used by our Chief Operating Decision Maker (“CODM”), which is collectively a senior leadership team consisting of two individuals, to measure performance and allocate resources. These reportable segments are Romeo Power North America and Joint Venture Support. The activities of our Romeo Power North America reportable segment include the research, design, development, and manufacture of electrical power systems for commercial vehicles (Class 6-8: trucks and buses) in the North American market. Our Joint Venture Support reportable segment provides design, research and development, and other engineering related services exclusively to the Joint Venture. The CODM evaluates and monitors segment performance primarily based upon segment sales and gross profit. Asset information has not been separately disclosed for the segments, as this information is not regularly reported to CODM for purposes of the allocation of resources to our segments or assessing segment performance. Net revenues and gross profit (loss) from each of our reportable segments are as follows (in thousands): Three Months Ended March 31, 2021 2020 Net revenues: Romeo Power North America $ 612 $ 1,640 Joint Venture Support 442 882 Total net revenues $ 1,054 $ 2,522 Gross loss: Romeo Power North America $ (3,826) $ (1,242) Joint Venture Support 53 132 Total gross loss $ (3,773) $ (1,110)

TRANSACTIONS WITH RELATED PARTI

TRANSACTIONS WITH RELATED PARTIES	3 Months Ended
	Mar. 31, 2021
Related Party Transactions [Abstract]
TRANSACTIONS WITH RELATED PARTIES	TRANSACTIONS WITH RELATED PARTIES Transactions with BorgWarner and the Joint Venture — In connection with Legacy Romeo’s investment in the Joint Venture formed on June 28, 2019 (Note 5), Legacy Romeo entered into a services agreement to provide various professional services to the Joint Venture. We have also sold certain products directly to a subsidiary of BorgWarner. Revenue earned for services rendered to the Joint Venture and products sold to BorgWarner during the three months ended March 31, 2021 and 2020 was $0.7 million and $0.9 million, respectively. Transactions with Heritage Environmental Services and its related parties — On October 2, 2020, we entered into the Battery Recycling Arrangement with HBR, an affiliate of HES, a related party to an investor in Legacy Romeo and an investor of $25.0 million in the PIPE Shares. Immediately following the Business Combination on December 29, 2020, we contributed $35.0 million to HBR. See Note 5, Equity Method Investments for additional information relating to our contribution to HBR. In connection with the Battery Recycling Arrangement, we also agreed to fund up to $10.0 million to purchase ten battery electric vehicle (“BEV”) trucks and the charging infrastructure for a one-year pilot program to determine the feasibility of transitioning HES’s or its affiliates’ fleet of trucks from diesel powered vehicles to BEVs. If such pilot program is successful, the parties would enter into an agreement for the procurement through us of at least 500 BEVs on terms acceptable to HBR, HES and us. The participants in the pilot program have been selected, and the parties are beginning to work towards an agreement to fund and support the pilot program.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Litigation — We are subject to certain claims and legal matters that arise in the normal course of business. Management does not expect any such claims and legal actions to have a material adverse effect on our financial position, results of operations or liquidity, except the following: A police officer was injured as a result of an automobile accident resulting from an intoxicated Legacy Romeo employee driving following his departure from a 2017 company holiday party that occurred after hours and not on our premises. We terminated the employee’s employment shortly after the incident occurred. This matter resulted in a personal injury lawsuit ( Chelico et al. v. Romeo Systems, Inc., et al. , Case # 18STCV04589, Los Angeles County), for which we are a named defendant. In July 2020, we settled this matter in principle and agreed to pay a settlement of $6.0 million. Our business and umbrella insurance carriers have agreed to cover the cost of damages owed. As a result, we accrued $6.0 million as a legal settlement payable with a corresponding insurance receivable for $6.0 million as of March 31, 2021 and December 31, 2020. In October 2020, a wage-and-hour class action was filed in Los Angeles Superior Court on behalf of all current and former non-exempt employees in California from October 2016 to present. The allegations include meal and rest period violations and various related claims. The case is currently stayed pending mediation, which was continued to July 2021. We intend to defend ourselves against these claims and the possible range of loss, if any, cannot currently be estimated. On April 16, 2021, plaintiff Travis Nichols filed a class action complaint (the “Nichols Complaint”) against Romeo, in the U.S. District Court for the Southern District of New York. The Nichols Complaint alleges that defendants made false and misleading statements regarding the supply of battery cells, which are components of Romeo’s products, and the Company’s ability to meet customer demand and achieve its revenue forecast for 2021. The relief sought includes money damages, reimbursement of expenses, and equitable relief. The court has scheduled a hearing for July 15, 2021 to consider motions for

CONCENTRATION OF RISK

CONCENTRATION OF RISK	3 Months Ended
	Mar. 31, 2021
CONCENTRATION OF RISK
CONCENTRATION OF RISK	CONCENTRATION OF RISK Customer Concentration and Accounts Receivable We had certain customers whose revenue individually represented 10% or more of our total revenue, or whose accounts receivable balances individually represented 10% or more of our total accounts receivable, as follows: For the three months ended March 31, 2021, total revenue recognized included 26% from one major customer, 22% from a second major customer, and 42% from the Joint Venture engineering services, representing 90% of our total revenue. For the three months ended March 31, 2020, total revenue recognized included 62% from one major customer, and 35% from the Joint Venture engineering services, representing 97% of our total revenue. As of December 31, 2020, our total reported accounts receivable balance included 13% from one major customer, 13% from another major customer and 44% from the Joint Venture engineering services account, representing 70% of our total accounts receivable. The Joint Venture engineering services account is included in the Joint Venture Support operating segment. The remaining major customers identified are customers of the Romeo Power North America operating segment. Supplier Concentration We rely on third-party suppliers for the provision and development of many of the key components and materials used in our battery modules and packs, such as battery cells, electrical components, electromechanical components, mechanical components and enclosure materials. Some of the components used in our battery modules and packs are purchased by us from single sources. While we believe that we may be able to establish alternative supply relationships and can obtain or engineer replacement components for our single-sourced components, we may be unable to do so in the short term (or at all) at prices or quality levels that are favorable to us, which could have a material adverse effect on our business, financial condition, operating results, and future prospects. Furthermore, in certain cases, the establishment of an alternative supply relationship could require us to visit a new supplier’s facilities in order to qualify the supplier and perform supplier quality audits, and, over the past 12 months, our ability to travel and qualify new suppliers has been directly impacted by COVID-19. During the three months ended March 31, 2021, three third-party suppliers of key single-sourced components and materials used in our battery modules and packs represented 21% of our total purchases during the period. One of these third-party suppliers represented 17% of our total purchases during the period.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTSOn February 16, 2021, we announced the redemption of all the outstanding Public Warrants to purchase shares of our Common Stock, that were issued under the Warrant Agreement, dated February 7, 2019, by and between RMG and American Stock Transfer & Trust Company, LLC, as warrant agent, as part of the units sold in the initial public offering of RMG. All Public Warrants could be exercised until April 5, 2021 to purchase shares of our Common Stock, at the exercise price of $11.50 per share and any Public Warrants that remained unexercised were voided and no longer exercisable. On April 5, 2021, 7,223,683 Public Warrants were redeemed at the redemption price of $0.01 per Public Warrant. The Company paid Public Warrant holders a total of $72.2 thousand in connection with the redemption.On April 6, 2021, we announced a long-term supply agreement with Paccar, Inc. (“PACCAR”). Under the agreement we will be a battery supplier for Peterbilt 579 and 520 BEVs in the United States and Canada through 2025. The start of production is anticipated to begin after 2021. In connection with the long-term supply agreement, we agreed to issue PACCAR 650,000 shares of our Common Stock.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation —The Business Combination was accounted for as a reverse recapitalization (the “Recapitalization Transaction”) in accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 805, Business Combinations . For accounting and financial reporting purposes, Legacy Romeo was considered the acquirer based on facts and circumstances, including the following: • Legacy Romeo’s former stockholders hold a majority ownership interest in the combined company; • Legacy Romeo’s senior management team became the senior management of the combined company; • Legacy Romeo was the larger of the companies based on historical operating activity and employee base; and • Legacy Romeo’s operations comprise the ongoing operations of the combined company. Accordingly, all historical financial information presented in these condensed consolidated financial statements represents the accounts of Legacy Romeo and its wholly owned subsidiaries “as if” Legacy Romeo is the predecessor and legal successor. The historical operations of Legacy Romeo are deemed to be those of the Company. Thus, the financial statements included in this report reflect (i) the historical operating results of Legacy Romeo prior to the Business Combination; (ii) the combined results of RMG and Legacy Romeo following the Business Combination on December 29, 2020; and (iii) RMG’s equity structure for all periods presented. No step-up basis of RMG’s assets and liabilities and no intangible assets or goodwill were recorded in connection with the Business Combination transaction consistent with the treatment of the transaction as a reverse recapitalization. In connection with the Business Combination each share of Legacy Romeo common stock and preferred stock issued and outstanding immediately prior to the Business Combination (with each share of Legacy Romeo preferred stock being treated as if it were converted into Legacy Romeo common stock immediately prior to the Business Combination) converted into the right to receive 0.121730 shares (the “Exchange Ratio”) of common stock, par value $0.0001 (the “Common Stock”). The recapitalization of the number of shares of Common Stock attributable to Legacy Romeo is reflected retroactively to the earliest period presented based upon the Exchange Ratio and is utilized for calculating earnings per share in all prior periods presented. The accompanying condensed consolidated financial statements include the results of Romeo Power, Inc. and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated and the effect of variable interest entities have been considered in the consolidation. Unaudited Interim Financial Information —The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information, the instructions to Form 10-Q, and the rules and regulations of the Securities and Exchange Commission (“SEC”). The condensed consolidated financial statements presented herein have not been audited by an independent registered public accounting firm, but include all material adjustments (consisting of normal recurring adjustments) which are, in the opinion of management, necessary for a fair presentation of our financial position, results of operations and cash flows for the period. These results are not necessarily indicative of results for any other interim period or for the full fiscal year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been omitted pursuant to the rules of the SEC. The accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the SEC on April 15, 2021 (the “2020 Form 10-K”).
Use of Estimates	Use of Estimates —The preparation of financial statements in conformity with GAAP requires us to make certain estimates and assumptions for the reporting periods covered by the financial statements. These estimates and assumptions affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent liabilities. Actual amounts could differ from these estimates. The condensed consolidated financial statements have been prepared under the assumption that Romeo will continue as a going concern.
Available-for-Sale Debt Investments	Available-for-Sale Debt Investments — We classify our investments in fixed income debt securities as available-for-sale debt investments. Our available-for-sale debt investments primarily consist of U.S. government securities, municipal securities, corporate debt, commercial paper, and U.S. agency mortgage-backed securities. These available-for-sale debt investments are primarily held in the custody of a major financial institution. These investments are reported on the condensed consolidated balance sheets at fair value. Unrealized gains and losses on these investments, to the extent the investments are unhedged, are included as a separate component of accumulated other comprehensive loss, net of tax. A specific identification method is used to determine the cost basis of available-for-sale debt investments and any realized gains or losses when sold. We classify our investments as current based on the nature of the investments and their availability for use in current operations.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In January 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-01, ASC subtopic 825-10, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities , which revised an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. This accounting guidance also amended certain disclosure requirements associated with the fair value of financial instruments. Under ASU No. 2016-01, entities must measure certain equity investments at fair value and recognize any changes in fair value in net income, unless the investments qualify for a new practicality exception. ASU 2016-01 is effective for financial statements issued for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. We adopted the standard on January 1, 2021, when we began making significant investments in available-for-sale debt securities and formulating a company investment policy to support the use and management of the proceeds from the Business Combination. In December 2019, the FASB issued ASU No. 2019-12, ASC 740, Income Taxes (ASC 740): Simplifying the Accounting for Income Taxes , which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in ASC 740 and also clarifies and amends existing guidance to improve consistent application. The guidance is effective for all public business entities for fiscal years beginning after December 15, 2020, including interim periods therein. Early adoption is also permitted. We adopted the standard on January 1, 2021 and the adoption of the new guidance does not have a material impact on our financial position, operating results or cash flows.

REVENUES (Tables)

REVENUES (Tables)	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Summary of Changes in Contract Liabilities	During the three months ended March 31, 2021, changes in contract liabilities were as follows (in thousands): Three Months Ended March 31, 2021 Beginning balance $ 815 Revenues recognized (926) Increase due to billings 1,783 Ending balance $ 1,672
Schedule of Disaggregation of Revenue	The following tables disaggregate revenues by type of products, services and segment for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 Romeo Power Joint Venture North America Support Total Product revenues: Modules $ 91 $ — $ 91 Packs 250 — 250 Total product revenues 341 — 341 Service revenues: Non-recurring engineering and prototype — — — Total service revenues — — — Related party revenues: Related party modules 256 — 256 Related party packs 15 — 15 Joint Venture support — 442 442 Total Related party revenues 271 442 713 Total revenues $ 612 $ 442 $ 1,054 Three Months Ended March 31, 2020 Romeo Power Joint Venture North America Support Total Products: revenues Modules $ 1,588 $ — $ 1,588 Packs — — — Total product revenues 1,588 — 1,588 Services: revenues Non-recurring engineering and prototype 52 — 52 Total service revenues 52 — 52 Related party revenues: Related Party Module — — — Related Party Packs — — — Joint Venture support — 882 882 Total related party revenues — 882 882 Total revenues $ 1,640 $ 882 $ 2,522 The following table disaggregates revenues by when control is transferred for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 2020 Point in time $ 612 $ 1,640 Over time 442 882 Total $ 1,054 $ 2,522

INVENTORY (Tables)

INVENTORY (Tables)	3 Months Ended
	Mar. 31, 2021
Inventory Disclosure [Abstract]
Schedule of Inventory	As of March 31, 2021 and December 31, 2020, inventory consisted of the following (in thousands): March 31, 2021 December 31, 2020 Raw materials $ 3,780 $ 4,064 Work-in-process 1,204 531 Finished goods 705 342 Total inventories $ 5,689 $ 4,937

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Assumptions Used in Estimating the Fair Value of Stock Options	The fair value of the time-based stock options granted during the three months ended March 31, 2020 was determined using the following assumptions: Fair Value Assumptions: Three Months Ended March 31, 2020 Risk-free interest rate 0.92% Expected term (in years) 6.5 Expected volatility 60% Dividend yield 0% Grant date fair value per share 1.44
Schedule of Number of Shares that may Become Exercisable Based on Share Price	The number of shares that may become exercisable is set forth in the table below: Average Closing Share Price Cumulative Number Of Shares $6.6869 - $8.9452 926,795 $8.9453 - $11.9272 1,853,591 $11.9273 - $14.9092 3,243,781 $14.9093 4,633,978
Schedule of Company's Stock-based Compensation Expense by Line Item	The following table summarizes our stock-based compensation expense by line item in the condensed consolidated statements of operations and comprehensive income (loss) (in thousands): Three Months Ended March 31, 2021 2020 Cost of revenues $ 121 $ 33 Research and development 61 — Selling, general, and administrative 6,371 244 Total $ 6,553 $ 277

INVESTMENTS (Tables)

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Debt Investments and Maturities	The following table summarizes our available-for-sale debt investment holdings at March 31, 2021 (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized and Credit Losses Fair Value U.S. government securities $ 52,018 $ 4 $ (9) $ 52,013 Municipal securities 59,160 25 (87) 59,098 Corporate debt securities 69,783 15 (222) 69,576 Asset-backed securities 18,196 1 (12) 18,185 U.S. agency mortgage-backed securities 18,140 — (31) 18,109 Commercial paper 24,222 13 — 24,235 Certificates of deposit 5,000 — (1) 4,999 Total (1) $ 246,519 $ 58 $ (362) $ 246,215 (1) There were no unsettled sales of available-for-sale debt investments at March 31, 2021. The following table summarizes the maturities of our available-for-sale debt investments at March 31, 2021 (in thousands): Amortized Cost Fair Value Less than 1 year $ 94,989 $ 94,998 1 year through 5 years 133,390 133,108 Mortgage-backed securities with no single maturity 18,140 18,109 Total $ 246,519 $ 246,215
Schedule of Realized Gain (Loss) on Available-for-Sale Debt Investments	The following table presents the gross realized gains and gross realized losses related to available-for-sale debt investments (in thousands): Three Months Ended Gross realized gains $ 34 Gross realized losses (72) Gross realized loss, net $ (38)
Schedule of Unrealized Loss on Investments	The following tables present the breakdown of the available-for-sale debt investments with gross unrealized losses and the duration that those losses had been unrealized at March 31, 2021 (in thousands): Unrealized Losses Unrealized Losses Total Fair Value Gross Fair Value Gross Fair Value Gross U.S. government securities $ 20,998 $ (9) $ — $ — $ 20,998 $ (9) Municipal securities 37,691 (87) — — 37,691 (87) Corporate debt securities 66,561 (222) — — 66,561 (222) Asset-backed securities 14,934 (12) — — 14,934 (12) U.S. agency mortgage-backed securities 18,109 (31) — — 18,109 (31) Certificates of deposit 4,999 (1) — — 4,999 (1) Total $ 163,292 $ (362) $ — $ — $ 163,292 $ (362)

FAIR VALUE (Tables)

FAIR VALUE (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	As of March 31, 2021 and December 31, 2020, assets and liabilities measured at fair value on a recurring basis were as follows (in thousands): March 31, 2021 Total (Level 1) (Level 2) (Level 3) Assets: Cash equivalents: Money market funds $ 19,000 $ 19,000 $ — $ — Available-for-sale debt investments: U.S. government securities 52,013 — 52,013 — Municipal securities 59,098 — 59,098 — Corporate debt securities 69,576 — 69,576 — Asset-backed securities 18,185 — 18,185 — U.S. agency mortgage-backed securities 18,109 — 18,109 — Commercial paper 24,235 — 24,235 — Certificates of deposit 4,999 — 4,999 — Total $ 265,215 $ 19,000 $ 246,215 $ — Financial Liabilities: Public Warrants $ 1,337 $ 1,337 $ — $ — Private Placement Warrants 10,584 — 10,584 — Total $ 11,921 $ 1,337 $ 10,584 $ — December 31, 2020 Total (Level 1) (Level 2) (Level 3) Assets: Cash equivalents: U.S. Treasury Bills $ 16,000 $ 16,000 $ — $ — Total $ 16,000 $ 16,000 $ — $ — Financial liabilities: Public Warrants $ 71,453 $ 71,453 $ — $ — Private Placement Warrants 67,013 — 67,013 — Total $ 138,466 $ 71,453 $ 67,013 $ —
Fair Value Measurement Inputs and Valuation Techniques	The key assumptions used to determine the fair value of the Private Placement Warrants as of March 31, 2021 and December 31, 2020 using the Black-Scholes model were as follows: Fair Value Assumptions March 31, 2021 December 31, 2020 Risk-free interest rate 0.85% 0.17% Expected term (in years) 4.75 5 Expected volatility 58% 57% Dividend yield — — Fair value of common stock $8.33 $22.49

NET INCOME (LOSS) PER SHARE (Ta

NET INCOME (LOSS) PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Net Income (Loss) per Share	The calculation of basic and diluted net income (loss) per share for the three months ended March 31, 2021 and 2020 is presented below (in thousands, except share and per share data): Three Months Ended March 31, 2021 2020 Net income (loss) $ 90,012 $ (6,769) Weighted average common shares outstanding – basic 128,788,715 74,647,985 Dilutive effect of potentially issuable shares 7,023,982 — Weighted average common shares outstanding – diluted 135,812,697 74,647,985 Basic net income (loss) per share $ 0.70 $ (0.09) Diluted net income (loss) per share $ 0.66 $ (0.09)

SEGMENTS (Tables)

SEGMENTS (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Net revenues and gross profit (loss) from each of our reportable segments are as follows (in thousands): Three Months Ended March 31, 2021 2020 Net revenues: Romeo Power North America $ 612 $ 1,640 Joint Venture Support 442 882 Total net revenues $ 1,054 $ 2,522 Gross loss: Romeo Power North America $ (3,826) $ (1,242) Joint Venture Support 53 132 Total gross loss $ (3,773) $ (1,110)

DESCRIPTION OF BUSINESS AND B_2

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION - Narrative (Details)	Dec. 29, 2020$ / shares	Mar. 31, 2021$ / shares	Dec. 31, 2020$ / shares
Exchange ratio	0.121730
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
BorgWarner Romeo Power LLC
Percentage of right to receive the profit		40.00%

REVENUES - Changes in Contract

REVENUES - Changes in Contract Liabilities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Changes in contract liabilities
Beginning balance	$ 815
Revenues recognized	(926)
Increase due to billings	1,783
Ending balance	$ 1,672

REVENUES - Contract Liabilities

REVENUES - Contract Liabilities Performance Obligations (Details) $ in Millions	Mar. 31, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations, expected to be earned	$ 23.4
Unsatisfied performance obligations, expected to be earned, satisfaction period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations, expected to be earned	$ 442.4
Unsatisfied performance obligations, expected to be earned, satisfaction period	24 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations, expected to be earned	$ 89.3
Unsatisfied performance obligations, expected to be earned, satisfaction period
Unsatisfied Performance Obligations with Make-Whole Provisions
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations, expected to be earned	$ 311.9
Maximum amount receivable if customers do not follow minimum purchase commitments	292.5
Unsatisfied Performance Obligations with Customary Remedies
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations, expected to be earned	243.2
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations, expected to be earned	$ 555.1

REVENUES - Disaggregation of Re

REVENUES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Related party revenues	$ 713	$ 882
Total revenues	1,054	2,522
Point in time
Disaggregation of Revenue [Line Items]
Total revenues	612	1,640
Over time
Disaggregation of Revenue [Line Items]
Total revenues	442	882
Romeo Power North America
Disaggregation of Revenue [Line Items]
Related party revenues	271	0
Total revenues	612	1,640
Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Related party revenues	442	882
Total revenues	442	882
Product revenues
Disaggregation of Revenue [Line Items]
Revenue	341	1,588
Product revenues | Romeo Power North America
Disaggregation of Revenue [Line Items]
Revenue	341	1,588
Product revenues | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Revenue	0	0
Modules
Disaggregation of Revenue [Line Items]
Revenue	91	1,588
Modules | Romeo Power North America
Disaggregation of Revenue [Line Items]
Revenue	91	1,588
Modules | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Revenue	0	0
Packs
Disaggregation of Revenue [Line Items]
Revenue	250	0
Packs | Romeo Power North America
Disaggregation of Revenue [Line Items]
Revenue	250	0
Packs | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Revenue	0	0
Service revenues
Disaggregation of Revenue [Line Items]
Revenue	0	52
Service revenues | Romeo Power North America
Disaggregation of Revenue [Line Items]
Revenue	0	52
Service revenues | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Revenue	0	0
Non-recurring engineering and prototype
Disaggregation of Revenue [Line Items]
Revenue	0	52
Non-recurring engineering and prototype | Romeo Power North America
Disaggregation of Revenue [Line Items]
Revenue	0	52
Non-recurring engineering and prototype | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Revenue	0	0
Related party modules
Disaggregation of Revenue [Line Items]
Related party revenues	15	0
Related party modules | Romeo Power North America
Disaggregation of Revenue [Line Items]
Related party revenues	15	0
Related party modules | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Related party revenues	0	0
Related party packs
Disaggregation of Revenue [Line Items]
Related party revenues	256	0
Related party packs | Romeo Power North America
Disaggregation of Revenue [Line Items]
Related party revenues	256	0
Related party packs | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Related party revenues	0	0
Joint Venture support
Disaggregation of Revenue [Line Items]
Related party revenues	442	882
Joint Venture support | Romeo Power North America
Disaggregation of Revenue [Line Items]
Related party revenues	0	0
Joint Venture support | Joint Venture Support Segment
Disaggregation of Revenue [Line Items]
Related party revenues	$ 442	$ 882

INVENTORY - Schedule of Invento

INVENTORY - Schedule of Inventory (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 3,780,000		$ 4,064,000
Work-in-process	1,204,000		531,000
Finished goods	705,000		342,000
Total inventories	5,689,000		$ 4,937,000
Write-down in cost of sales	$ 400,000	$ 0

EQUITY METHOD INVESTMENTS - Bor

EQUITY METHOD INVESTMENTS - Borg Warner Romeo Power LLC (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2021	Feb. 28, 2019
Schedule of Equity Method Investments [Line Items]
Payments to to fund joint venture		$ 4,000	$ 0
BorgWarner Romeo Power LLC
Schedule of Equity Method Investments [Line Items]
Payments to to fund joint venture	$ 4,000
BorgWarner Romeo Power LLC | Forecast
Schedule of Equity Method Investments [Line Items]
Payments to to fund joint venture				$ 10,000
BorgWarner Romeo Power LLC | BorgWarner
Schedule of Equity Method Investments [Line Items]
Percentage of interest in the joint venture					60.00%
BorgWarner Romeo Power LLC | Legacy Romeo
Schedule of Equity Method Investments [Line Items]
Percentage of interest in the joint venture					40.00%

EQUITY METHOD INVESTMENTS - Her

EQUITY METHOD INVESTMENTS - Heritage Battery Recycling LLC (Details) - HBR $ in Millions	Dec. 29, 2020USD ($)
Schedule of Equity Method Investments [Line Items]
Amount agreed to fund a pilot	$ 10
PIPE Investors
Schedule of Equity Method Investments [Line Items]
Equity method investments	25
Legacy Romeo
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 35

PUBLIC AND PRIVATE PLACEMENT _2

PUBLIC AND PRIVATE PLACEMENT WARRANTS - Narrative (Details) - $ / shares	Apr. 05, 2021	Feb. 28, 2019
Subsequent Event
Class of Warrant or Right [Line Items]
Number of warrants redeemed (in shares)	7,223,683
Cash outflow for redemption of warrants	$ 72,200
Public Warrants
Class of Warrant or Right [Line Items]
Number of warrants issued (in shares)		7,666,648
Price per share (USD per share)		$ 11.50
Public Warrants | Subsequent Event
Class of Warrant or Right [Line Items]
Price per share (USD per share)	11.50
Redemption price per public warrant (USD per share)	$ 0.01
Private Placement Warrants
Class of Warrant or Right [Line Items]
Number of warrants issued (in shares)		4,600,000
Price per share (USD per share)		$ 11.50

STOCK-BASED COMPENSATION - Time

STOCK-BASED COMPENSATION - Time-based Awards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Exercises in period (in shares)	836,749
Exercise of stock options	$ 4,681	$ 0

STOCK-BASED COMPENSATION- Assum

STOCK-BASED COMPENSATION- Assumptions Used in Estimating the Fair Value of Stock Options (Details) - Class A common stock - Stock options	3 Months Ended
	Mar. 31, 2021$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	92.00%
Expected term (in years)	6 years 6 months
Expected volatility	60.00%
Dividend yield	0.00%
Grant date fair value per share (USD per share)	$ 1.44

STOCK-BASED COMPENSATION - Perf

STOCK-BASED COMPENSATION - Performance and Market-based Award (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Aug. 31, 2020	Mar. 31, 2021
Performance and market-based award
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Grant date fair value	$ 9.6
$6.6869 - $8.9452
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower range limit (USD per share)		$ 6.6869
Exercise price range, upper range limit (USD per share)		$ 8.9452
$6.6869 - $8.9452 | Performance and market-based award
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Cumulative number of shares (in shares)		926,795
$8.9453 - $11.9272
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower range limit (USD per share)		$ 8.9453
Exercise price range, upper range limit (USD per share)		$ 11.9272
$8.9453 - $11.9272 | Performance and market-based award
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Cumulative number of shares (in shares)		1,853,591
$11.9273 - $14.9092
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower range limit (USD per share)		$ 11.9273
Exercise price range, upper range limit (USD per share)		$ 14.9092
$11.9273 - $14.9092 | Performance and market-based award
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Cumulative number of shares (in shares)		3,243,781
$14.9093
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower range limit (USD per share)		$ 14.9093
Exercise price range, upper range limit (USD per share)		$ 14.9093
$14.9093 | Performance and market-based award
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Cumulative number of shares (in shares)		4,633,978
Chairman and CEO | Performance and market-based award
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock options awarded (in shares)	4,633,978
Exercise price (USD per share)	$ 6.69
Stock options, outstanding (in shares)	4,633,978

STOCK-BASED COMPENSATION - Stoc

STOCK-BASED COMPENSATION - Stock- based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 6,553	$ 277
Cost of revenues
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	121	33
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	61	0
Selling, general, and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 6,371	$ 244

INCOME TAXES (Details)

INCOME TAXES (Details)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate, percent	0.00%	0.00%

INVESTMENTS - Schedule of Avail

INVESTMENTS - Schedule of Available-for-Sale Debt Securities Amortized Cost, Unrealized Gains (Losses) and Fair Value (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 246,519,000
Gross Unrealized Gains	58,000
Gross Unrealized and Credit Losses	(362,000)
Available-for-sale debt investments:	246,215,000	$ 0
Debt securities, available-for-sale, unsettled sales	0
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	52,018,000
Gross Unrealized Gains	4,000
Gross Unrealized and Credit Losses	(9,000)
Available-for-sale debt investments:	52,013,000
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	59,160,000
Gross Unrealized Gains	25,000
Gross Unrealized and Credit Losses	(87,000)
Available-for-sale debt investments:	59,098,000
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	69,783,000
Gross Unrealized Gains	15,000
Gross Unrealized and Credit Losses	(222,000)
Available-for-sale debt investments:	69,576,000
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,196,000
Gross Unrealized Gains	1,000
Gross Unrealized and Credit Losses	(12,000)
Available-for-sale debt investments:	18,185,000
U.S. agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,140,000
Gross Unrealized Gains	0
Gross Unrealized and Credit Losses	(31,000)
Available-for-sale debt investments:	18,109,000
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	24,222,000
Gross Unrealized Gains	13,000
Gross Unrealized and Credit Losses	0
Available-for-sale debt investments:	24,235,000
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,000,000
Gross Unrealized Gains	0
Gross Unrealized and Credit Losses	(1,000)
Available-for-sale debt investments:	$ 4,999,000

INVESTMENTS - Realized Gains (L

INVESTMENTS - Realized Gains (Losses) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 34
Gross realized losses	(72)
Gross realized loss, net	$ (38)

INVESTMENTS - Schedule of Accum

INVESTMENTS - Schedule of Accumulated Unrealized Losses (Details) $ in Thousands	Mar. 31, 2021USD ($)
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	$ 163,292
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(362)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	163,292
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(362)
U.S. government securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	20,998
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(9)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	20,998
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(9)
Municipal securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	37,691
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(87)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	37,691
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(87)
Corporate debt securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	66,561
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(222)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	66,561
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(222)
Asset-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	14,934
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(12)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	14,934
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(12)
U.S. agency mortgage-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	18,109
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(31)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	18,109
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(31)
Certificates of deposit
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months	4,999
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(1)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	0
Debt securities, available-for-sale, unrealized loss position	4,999
Debt securities, available-for-sale, unrealized loss position, accumulated loss	$ (1)

INVESTMENTS - Schedule of Ava_2

INVESTMENTS - Schedule of Available-for-sale Debt Securities Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract]
Less than 1 year	$ 94,989
1 year through 5 years	133,390
Mortgage-backed securities with no single maturity	18,140
Amortized Cost	246,519
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract]
Less than 1 year	94,998
1 year through 5 years	133,108
Mortgage-backed securities with no single maturity	18,109
Fair Value	$ 246,215	$ 0

FAIR VALUE - Narrative (Details

FAIR VALUE - Narrative (Details)	Mar. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Expected term (in years)	4 years 9 months	5 years

FAIR VALUE - Schedule of Assets

FAIR VALUE - Schedule of Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets:
Available-for-sale debt investments:	$ 246,215	$ 0
U.S. government securities
Assets:
Available-for-sale debt investments:	52,013
Municipal securities
Assets:
Available-for-sale debt investments:	59,098
Corporate debt securities
Assets:
Available-for-sale debt investments:	69,576
Asset-backed securities
Assets:
Available-for-sale debt investments:	18,185
U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	18,109
Commercial paper
Assets:
Available-for-sale debt investments:	24,235
Certificates of deposit
Assets:
Available-for-sale debt investments:	4,999
Recurring
Assets:
Total	265,215	16,000
Financial Liabilities:
Total	11,921	138,466
Recurring | U.S. government securities
Assets:
Available-for-sale debt investments:	52,013
Recurring | Municipal securities
Assets:
Available-for-sale debt investments:	59,098
Recurring | Corporate debt securities
Assets:
Available-for-sale debt investments:	69,576
Recurring | Asset-backed securities
Assets:
Available-for-sale debt investments:	18,185
Recurring | U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	18,109
Recurring | Commercial paper
Assets:
Available-for-sale debt investments:	24,235
Recurring | Certificates of deposit
Assets:
Available-for-sale debt investments:	4,999
Recurring | Public Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	1,337	71,453
Recurring | Private Placement Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	10,584	67,013
Recurring | Level 1
Assets:
Total	19,000	16,000
Financial Liabilities:
Total	1,337	71,453
Recurring | Level 1 | U.S. government securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | Municipal securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | Corporate debt securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | Asset-backed securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | Commercial paper
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | Certificates of deposit
Assets:
Available-for-sale debt investments:	0
Recurring | Level 1 | Public Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	1,337	71,453
Recurring | Level 1 | Private Placement Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	0	0
Recurring | Level 2
Assets:
Total	246,215	0
Financial Liabilities:
Total	10,584	67,013
Recurring | Level 2 | U.S. government securities
Assets:
Available-for-sale debt investments:	52,013
Recurring | Level 2 | Municipal securities
Assets:
Available-for-sale debt investments:	59,098
Recurring | Level 2 | Corporate debt securities
Assets:
Available-for-sale debt investments:	69,576
Recurring | Level 2 | Asset-backed securities
Assets:
Available-for-sale debt investments:	18,185
Recurring | Level 2 | U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	18,109
Recurring | Level 2 | Commercial paper
Assets:
Available-for-sale debt investments:	24,235
Recurring | Level 2 | Certificates of deposit
Assets:
Available-for-sale debt investments:	4,999
Recurring | Level 2 | Public Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	0	0
Recurring | Level 2 | Private Placement Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	10,584	67,013
Recurring | Level 3
Assets:
Total	0	0
Financial Liabilities:
Total	0	0
Recurring | Level 3 | U.S. government securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | Municipal securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | Corporate debt securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | Asset-backed securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | Commercial paper
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | Certificates of deposit
Assets:
Available-for-sale debt investments:	0
Recurring | Level 3 | Public Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	0	0
Recurring | Level 3 | Private Placement Warrants
Financial Liabilities:
Public Warrants and Private Placement Warrants	0	0
Money Market Funds | Recurring
Assets:
Cash equivalents:	19,000
Money Market Funds | Recurring | Level 1
Assets:
Cash equivalents:	19,000
Money Market Funds | Recurring | Level 2
Assets:
Cash equivalents:	0
Money Market Funds | Recurring | Level 3
Assets:
Cash equivalents:	$ 0
U.S. government securities | Recurring
Assets:
Cash equivalents:		16,000
U.S. government securities | Recurring | Level 1
Assets:
Cash equivalents:		16,000
U.S. government securities | Recurring | Level 2
Assets:
Cash equivalents:		0
U.S. government securities | Recurring | Level 3
Assets:
Cash equivalents:		$ 0

FAIR VALUE - Private Placement

FAIR VALUE - Private Placement Warrants Valuation Assumptions (Details)	Mar. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected term (in years)	4 years 9 months	5 years
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Private Placement Warrants, measurement input	0.0085	0.0017
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Private Placement Warrants, measurement input	0.58	0.57
Dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Private Placement Warrants, measurement input	0	0
Fair value of common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Private Placement Warrants, measurement input	8.33	22.49

NET INCOME (LOSS) PER SHARE - (

NET INCOME (LOSS) PER SHARE - (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 90,012	$ (6,769)
Weighted average common shares outstanding - basic (in shares)	128,788,715	74,647,985
Dilutive effect of potentially issuable shares (in shares)	7,023,982	0
Weighted average common shares outstanding - diluted (in shares)	135,812,697	74,647,985
Basic net income (loss) per share (USD per share)	$ 0.70	$ (0.09)
Diluted net income (loss) per share (USD per share)	$ 0.66	$ (0.09)
Antidilutive shares (in shares)	11,277,997	22,196,804

SEGMENTS - Narrative (Details)

SEGMENTS - Narrative (Details)	3 Months Ended
	Mar. 31, 2021segment
Segment Reporting [Abstract]
Number of operating segments	2

SEGMENTS - Net Revenues and Gro

SEGMENTS - Net Revenues and Gross Loss by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Total net revenues	$ 1,054	$ 2,522
Total gross loss	(3,773)	(1,110)
Romeo Power North America
Segment Reporting Information [Line Items]
Total net revenues	612	1,640
Total gross loss	(3,826)	(1,242)
Joint Venture support
Segment Reporting Information [Line Items]
Total net revenues	442	882
Total gross loss	$ 53	$ 132

TRANSACTIONS WITH RELATED PAR_2

TRANSACTIONS WITH RELATED PARTIES - Narrative (Details) $ in Thousands	Dec. 29, 2020USD ($)batteryElectricVehicle	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)	Dec. 29, 2021batteryElectricVehicle
Related Party Transaction [Line Items]
Related party revenues		$ 713	$ 882
HBR
Related Party Transaction [Line Items]
Amount agreed to fund a pilot	$ 10,000
Number Of Battery Electric Vehicles (BEV) To Purchase | batteryElectricVehicle	10
Length Of Pilot Program	1 year
HBR | Forecast
Related Party Transaction [Line Items]
Number Of Battery Electric Vehicles (BEV) To Purchase | batteryElectricVehicle				500
HBR | PIPE Investors
Related Party Transaction [Line Items]
Equity method investments	$ 25,000
HBR | Legacy Romeo
Related Party Transaction [Line Items]
Equity method investments	$ 35,000
BorgWarner Romeo Power LLC
Related Party Transaction [Line Items]
Related party revenues		$ 700	$ 900

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	1 Months Ended
	Jul. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Settlement agreement amount	$ 6,000
Legal settlement payable		$ 6,000	$ 6,000
Insurance receivable		$ 6,000	$ 6,000

CONCENTRATION OF RISK (Details)

CONCENTRATION OF RISK (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Customer Concentration Risk | Revenue from Contract with Customer Benchmark
Concentration Risk [Line Items]
Concentration risk, percentage	90.00%	97.00%
Customer Concentration Risk | Revenue from Contract with Customer Benchmark | Customer One
Concentration Risk [Line Items]
Concentration risk, percentage	26.00%	62.00%
Customer Concentration Risk | Revenue from Contract with Customer Benchmark | Customer Two
Concentration Risk [Line Items]
Concentration risk, percentage	22.00%
Customer Concentration Risk | Revenue from Contract with Customer Benchmark | Joint Venture Engineering Services
Concentration Risk [Line Items]
Concentration risk, percentage	42.00%	35.00%
Customer Concentration Risk | Accounts receivable
Concentration Risk [Line Items]
Concentration risk, percentage			70.00%
Customer Concentration Risk | Accounts receivable | Customer One
Concentration Risk [Line Items]
Concentration risk, percentage			13.00%
Customer Concentration Risk | Accounts receivable | Customer Two
Concentration Risk [Line Items]
Concentration risk, percentage			13.00%
Customer Concentration Risk | Accounts receivable | Joint Venture Engineering Services
Concentration Risk [Line Items]
Concentration risk, percentage			44.00%
Supplier Concentration Risk | Cost of Goods and Service Benchmark | Three Third-Party Suppliers
Concentration Risk [Line Items]
Concentration risk, percentage	21.00%
Supplier Concentration Risk | Cost of Goods and Service Benchmark | One Third-Party Supplier
Concentration Risk [Line Items]
Concentration risk, percentage	17.00%
Supplies Concentration Risk | Cost of Goods and Service Benchmark | Battery Cells
Concentration Risk [Line Items]
Concentration risk, percentage	26.00%
Supplies Concentration Risk | Cost of Goods and Service Benchmark | Two Battery Cell Suppliers | Battery Cells
Concentration Risk [Line Items]
Concentration risk, percentage	96.00%

SUBSEQUENT EVENTS - Narrative (

SUBSEQUENT EVENTS - Narrative (Details) - $ / shares	Apr. 06, 2021	Apr. 05, 2021	Feb. 28, 2019
Subsequent Event
Subsequent Event [Line Items]
Number of warrants redeemed (in shares)		7,223,683
Cash outflow for redemption of warrants		$ 72,200
Subsequent Event | Paccar Inc
Subsequent Event [Line Items]
Stock issued during period for services (in shares)	650,000
Public Warrants
Subsequent Event [Line Items]
Price per share (USD per share)			$ 11.50
Public Warrants | Subsequent Event
Subsequent Event [Line Items]
Price per share (USD per share)		11.50
Redemption price per public warrant (USD per share)		$ 0.01