Stem (STEM) 10-Q 2 Nov 23 2023 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2023	Oct. 25, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity Registrant Name	STEM, INC.
Entity Incorporation, State or Country Code	DE
Entity File Number	001-39455
Entity Tax Identification Number	85-1972187
Entity Address, Address Line One	100 California St., 14th Fl.
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94111
Country Region	1
City Area Code	877
Local Phone Number	374-7836
Title of 12(b) Security	Common Stock, par value $0.0001
Trading Symbol	STEM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		155,895,641
Entity Central Index Key	0001758766
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 97,064	$ 87,903
Short-term investments	28,301	162,074
Accounts receivable, net of allowances of $5,328 and $3,879 as of September 30, 2023 and December 31, 2022, respectively	288,674	223,219
Inventory, net	65,656	8,374
Deferred costs with suppliers	20,298	43,159
Other current assets (includes $53 and $74 due from related parties as of September 30, 2023 and December 31, 2022, respectively)	10,520	8,026
Total current assets	510,513	532,755
Energy storage systems, net	80,709	90,757
Contract origination costs, net	11,930	11,697
Goodwill	547,164	546,649
Intangible assets, net	158,321	162,265
Operating lease right-of-use assets	13,023	12,431
Other noncurrent assets	77,132	65,339
Total assets	1,398,792	1,421,893
Current liabilities:
Accounts payable	85,444	83,831
Accrued liabilities	60,615	85,258
Accrued payroll	10,439	12,466
Financing obligation, current portion	17,381	15,720
Deferred revenue, current portion	82,676	64,311
Other current liabilities (includes $40 and $687 due to related parties as of September 30, 2023 and December 31, 2022, respectively)	12,689	5,412
Total current liabilities	269,244	266,998
Deferred revenue, noncurrent	83,028	73,763
Asset retirement obligation	4,085	4,262
Notes payable, noncurrent	0	1,603
Convertible notes, noncurrent	523,068	447,909
Financing obligation, noncurrent	54,314	63,867
Lease liabilities, noncurrent	11,145	10,962
Other liabilities	565	362
Total liabilities	945,449	869,726
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value; 1,000,000 shares authorized as of September 30, 2023 and December 31, 2022; zero shares issued and outstanding as of September 30, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value; 500,000,000 shares authorized as of September 30, 2023 and December 31, 2022; 155,883,088 and 154,540,197 issued and outstanding as of September 30, 2023 and December 31, 2022, respectively	16	15
Additional paid-in capital	1,187,628	1,185,364
Accumulated other comprehensive income (loss)	23	(1,672)
Accumulated deficit	(734,809)	(632,081)
Total Stem’s stockholders’ equity	452,858	551,626
Non-controlling interests	485	541
Total stockholders’ equity	453,343	552,167
Total liabilities and stockholders’ equity	$ 1,398,792	$ 1,421,893

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accounts receivable, allowances	$ 5,328	$ 3,879
Other current assets	10,520	8,026
Other current liabilities	$ 12,689	$ 5,412
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	155,883,088	154,540,197
Common stock, shares outstanding (in shares)	155,883,088	154,540,197
Related Party
Other current assets	$ 53	$ 74
Other current liabilities	$ 40	$ 687

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue
Revenue	$ 133,740	$ 99,501	$ 294,091	$ 207,536
Cost of Revenue
Cost of Revenue	154,031	90,374	301,517	186,977
Gross (loss) profit	(20,291)	9,127	(7,426)	20,559
Operating expenses:
Sales and marketing	11,605	13,187	37,691	35,284
Research and development	14,420	10,526	42,020	28,432
General and administrative	21,955	18,013	58,656	54,218
Total operating expenses	47,980	41,726	138,367	117,934
Loss from operations	(68,271)	(32,599)	(145,793)	(97,375)
Other (expense) income, net:
Interest expense, net	(4,405)	(2,520)	(10,085)	(8,429)
Gain on extinguishment of debt, net	0	0	59,121	0
Change in fair value of derivative liability	(5,155)	0	(7,731)	0
Other income, net	713	863	2,114	1,822
Total other (expense) income, net	(8,847)	(1,657)	43,419	(6,607)
Loss before benefit from (provision for) income taxes	(77,118)	(34,256)	(102,374)	(103,982)
Benefit from (provision for) income taxes	46	(19)	(354)	15,201
Net loss	(77,072)	(34,275)	(102,728)	(88,781)
Net income attributed to non-controlling interests	0	4	0	0
Net loss attributable to Stem	$ (77,072)	$ (34,279)	$ (102,728)	$ (88,781)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.49)	$ (0.22)	$ (0.66)	$ (0.58)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.49)	$ (0.22)	$ (0.66)	$ (0.58)
Weighted-average shares used in computing net loss per share to common stockholders, basic (in shares)	155,829,348	154,392,573	155,474,725	153,043,010
Weighted-average shares used in computing net loss per share to common stockholders, diluted (in shares)	155,829,348	154,392,573	155,474,725	153,043,010
Services and other revenue
Revenue
Revenue	$ 16,597	$ 13,692	$ 47,630	$ 36,178
Cost of Revenue
Cost of Revenue	13,684	11,445	36,944	30,219
Hardware revenue
Revenue
Revenue	117,143	85,809	246,461	171,358
Cost of Revenue
Cost of Revenue	$ 140,347	$ 78,929	$ 264,573	$ 156,758

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (77,072)	$ (34,275)	$ (102,728)	$ (88,781)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities	60	(845)	1,650	(1,855)
Foreign currency translation adjustment	51	(141)	45	(287)
Total other comprehensive loss	(76,961)	(35,261)	(101,033)	(90,923)
Less: Comprehensive income attributable to non-controlling interests	0	4	0	0
Total comprehensive loss attributable to Stem	$ (76,961)	$ (35,265)	$ (101,033)	$ (90,923)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Non-controlling Interests
Beginning balance (in shares) at Dec. 31, 2021			144,671,624
Beginning balance at Dec. 31, 2021	$ 667,827		$ 14	$ 1,176,845		$ 20	$ (509,052)		$ 0
Beginning balance (Accounting Standards Update 2020-06) at Dec. 31, 2021		$ (129,381)			$ (130,979)			$ 1,598
Beginning balance (Accounting Standards Update 2016-13) at Dec. 31, 2021		(573)						(573)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued upon business combination (in shares)			8,621,006
Common stock issued upon business combination	108,883		$ 1	108,882
Stock option exercises, net of statutory tax withholdings (in shares)			425,167
Stock option exercises, net of statutory tax withholdings	(426)			(426)
Stock-based compensation	6,787			6,787
Unrealized gain (loss) on available-for-sale securities	(611)					(611)
Foreign currency translation adjustment	(28)					(28)
Contributions from non-controlling interests	141								141
Net loss	(22,483)						(22,483)
Ending balance (in shares) at Mar. 31, 2022			153,717,797
Ending balance at Mar. 31, 2022	630,136		$ 15	1,161,109		(619)	(530,510)		141
Beginning balance (in shares) at Dec. 31, 2021			144,671,624
Beginning balance at Dec. 31, 2021	667,827		$ 14	1,176,845		20	(509,052)		0
Beginning balance (Accounting Standards Update 2020-06) at Dec. 31, 2021		(129,381)			$ (130,979)			1,598
Beginning balance (Accounting Standards Update 2016-13) at Dec. 31, 2021		$ (573)						$ (573)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on available-for-sale securities	(1,855)
Foreign currency translation adjustment	(287)
Net loss	(88,781)
Ending balance (in shares) at Sep. 30, 2022			154,487,778
Ending balance at Sep. 30, 2022	577,225		$ 15	1,175,733		(2,122)	(596,808)		407
Beginning balance (in shares) at Mar. 31, 2022			153,717,797
Beginning balance at Mar. 31, 2022	630,136		$ 15	1,161,109		(619)	(530,510)		141
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, net of statutory tax withholdings (in shares)			355,712
Stock option exercises, net of statutory tax withholdings	(1,415)			(1,415)
Issuance of common stock upon release of restricted stock units (in shares)			131,665
Shares issued for exercise of warrants (in shares)			21,101
Shares issued for exercise of warrants	150			150
Stock-based compensation	7,021			7,021
Unrealized gain (loss) on available-for-sale securities	(399)					(399)
Foreign currency translation adjustment	(118)					(118)
Contributions from non-controlling interests	75								75
Net loss	(32,023)						(32,019)		(4)
Ending balance (in shares) at Jun. 30, 2022			154,226,275
Ending balance at Jun. 30, 2022	603,427		$ 15	1,166,865		(1,136)	(562,529)		212
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, net of statutory tax withholdings (in shares)			201,496
Stock option exercises, net of statutory tax withholdings	584			584
Issuance of common stock upon release of restricted stock units (in shares)			60,007
Stock-based compensation	8,284			8,284
Unrealized gain (loss) on available-for-sale securities	(845)					(845)
Foreign currency translation adjustment	(141)					(141)
Contributions from non-controlling interests	191								191
Net loss	(34,275)						(34,279)		4
Ending balance (in shares) at Sep. 30, 2022			154,487,778
Ending balance at Sep. 30, 2022	577,225		$ 15	1,175,733		(2,122)	(596,808)		407
Beginning balance (in shares) at Dec. 31, 2022			154,540,197
Beginning balance at Dec. 31, 2022	552,167		$ 15	1,185,364		(1,672)	(632,081)		541
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, net of statutory tax withholdings (in shares)			65,045
Stock option exercises, net of statutory tax withholdings	149			149
Issuance of common stock upon release of restricted stock units (in shares)			903,061
Issuance of common stock upon release of restricted stock units	1		$ 1
Stock-based compensation	8,108			8,108
Unrealized gain (loss) on available-for-sale securities	1,543					1,543
Foreign currency translation adjustment	127					127
Redemption of non-controlling interests, net	(72)								(72)
Net loss	(44,778)						(44,778)
Ending balance (in shares) at Mar. 31, 2023			155,508,303
Ending balance at Mar. 31, 2023	517,245		$ 16	1,193,621		(2)	(676,859)		469
Beginning balance (in shares) at Dec. 31, 2022			154,540,197
Beginning balance at Dec. 31, 2022	$ 552,167		$ 15	1,185,364		(1,672)	(632,081)		541
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, net of statutory tax withholdings (in shares)	116,717
Unrealized gain (loss) on available-for-sale securities	$ 1,650
Foreign currency translation adjustment	45
Net loss	(102,728)
Ending balance (in shares) at Sep. 30, 2023			155,883,088
Ending balance at Sep. 30, 2023	453,343		$ 16	1,187,628		23	(734,809)		485
Beginning balance (in shares) at Mar. 31, 2023			155,508,303
Beginning balance at Mar. 31, 2023	517,245		$ 16	1,193,621		(2)	(676,859)		469
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, net of statutory tax withholdings (in shares)			39,528
Stock option exercises, net of statutory tax withholdings	80			80
Issuance of common stock upon release of restricted stock units (in shares)			248,580
Stock-based compensation	10,817			10,817
Purchase of capped call options	(27,840)			(27,840)
Unrealized gain (loss) on available-for-sale securities	47					47
Foreign currency translation adjustment	(133)					(133)
Contributions from non-controlling interests	6								6
Net loss	19,122						19,122
Ending balance (in shares) at Jun. 30, 2023			155,796,411
Ending balance at Jun. 30, 2023	519,344		$ 16	1,176,678		(88)	(657,737)		475
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, net of statutory tax withholdings (in shares)			12,144
Stock option exercises, net of statutory tax withholdings	28			28
Issuance of common stock upon release of restricted stock units (in shares)			74,533
Stock-based compensation	10,922			10,922
Unrealized gain (loss) on available-for-sale securities	60					60
Foreign currency translation adjustment	51					51
Contributions from non-controlling interests	10								10
Net loss	(77,072)						(77,072)		0
Ending balance (in shares) at Sep. 30, 2023			155,883,088
Ending balance at Sep. 30, 2023	$ 453,343		$ 16	$ 1,187,628		$ 23	$ (734,809)		$ 485

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
OPERATING ACTIVITIES
Net loss	$ (102,728)	$ (88,781)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	33,593	32,060
Non-cash interest expense, including interest expenses associated with debt issuance costs	1,969	1,479
Stock-based compensation	28,320	20,410
Change in fair value of derivative liability	7,731	0
Non-cash lease expense	2,162	1,722
Accretion of asset retirement obligations	178	183
Impairment loss of energy storage systems	2,347	1,293
Impairment loss of project assets	158	0
Net (accretion of discount) amortization of premium on investments	(1,672)	301
Income tax benefit from release of valuation allowance	(335)	(15,100)
Provision for accounts receivable allowance	1,754	1,874
Net loss on investments	1,561	0
Gain on sale of project assets	0	(592)
Gain on extinguishment of debt, net	(59,121)	0
Other	(831)	(39)
Changes in operating assets and liabilities:
Accounts receivable	(67,029)	(75,390)
Inventory	(57,282)	(2,237)
Deferred costs with suppliers	30,579	(47,836)
Other assets	(17,947)	(25,242)
Contract origination costs, net	(4,184)	(4,842)
Project assets	(2,827)	0
Accounts payable	1,771	63,207
Accrued expenses and other liabilities	(28,910)	38,329
Deferred revenue	27,630	31,620
Lease liabilities	(2,135)	(1,053)
Net cash used in operating activities	(205,248)	(68,634)
INVESTING ACTIVITIES
Acquisitions, net of cash acquired	(1,847)	(533,009)
Purchase of available-for-sale investments	(58,034)	(181,541)
Proceeds from maturities of available-for-sale investments	119,650	148,064
Proceeds from sales of available-for-sale investments	73,917	10,930
Purchase of energy storage systems	(2,912)	(469)
Capital expenditures on internally-developed software	(10,123)	(12,652)
Net proceeds from sale of project assets	0	1,251
Capital expenditures on project assets	0	(3,009)
Purchase of property and equipment	(395)	(1,490)
Net cash provided by (used in) investing activities	120,256	(571,925)
FINANCING ACTIVITIES
Proceeds from exercise of stock options and warrants	257	1,194
Payments for taxes related to net share settlement of stock options	0	(2,302)
Proceeds from financing obligations	0	1,519
Repayment of financing obligations	(7,766)	(7,637)
Proceeds from issuance of convertible notes, net of issuance costs of $7,601 and $0 for the nine months ended September 30, 2023 and 2022, respectively	232,399	0
Repayment of convertible notes	(99,754)	0
Purchase of capped call options	(27,840)	0
(Redemption of) investment from non-controlling interests, net	(56)	407
Repayment of notes payable	(2,101)	0
Net cash provided by (used in) financing activities	95,139	(6,819)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	114	(304)
Net increase (decrease) in cash, cash equivalents and restricted cash	10,261	(647,682)
Cash, cash equivalents and restricted cash, beginning of year	87,903	747,780
Cash, cash equivalents and restricted cash, end of period	98,164	100,098
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	4,070	4,910
NON-CASH INVESTING AND FINANCING ACTIVITIES
Change in asset retirement costs and asset retirement obligation	354	56
Purchases of energy storage systems in accounts payable	78	0
Right-of-use asset obtained in exchange for lease liability	2,782	0
Stock-based compensation capitalized to internal-use software	3,033	1,680
RECONCILIATION OF CASH, CASH EQUIVALENTS, AND RESTRICTED CASH WITHIN THE CONDENSED CONSOLIDATED BALANCE SHEETS TO THE AMOUNTS SHOWN IN THE STATEMENTS OF CASH FLOWS ABOVE:
Cash and cash equivalents	97,064	100,098
Restricted cash included in other noncurrent assets	1,100	0
Total cash, cash equivalents, and restricted cash	$ 98,164	$ 100,098

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Convertible Notes
Payment of debt issuance costs	$ 7,601	$ 0

BUSINESS

BUSINESS	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BUSINESS	BUSINESS Description of the Business Stem, Inc., together with its consolidated subsidiaries (“Stem,” the “Company,” “we,” “us,” or “our”), is a global leader in artificial intelligence (“AI”) -driven clean energy solutions and services. The Company maintains one of the world’s largest digitally connected, intelligent renewable energy networks, providing customers (i) with an energy storage system, sourced from leading, global battery original equipment manufacturers (“OEMs”), that the Company delivers through its partners, including developers, distributors and engineering, procurement and construction (“EPC”) firms, (ii) edge hardware to aid in the collection of site data and the real-time operation and control of the site plus other optional equipment, (iii) ongoing software platform and professional services to operate standalone energy storage, integrated solar plus storage systems, and solar asset performance monitoring and control through its Athena ® clean energy optimization platform (“Athena”), and (iv) solar asset performance monitoring and control, through Athena’s PowerTrack application. In addition, in all the markets where the Company helps manage its customers’ clean energy assets, the Company has agreements to use the Athena platform to participate in such markets and to share the revenue from such market participation. The Company delivers its battery hardware and software-enabled services to its customers through its Athena platform. The Company’s hardware and recurring software-enabled services mitigate customer energy costs through services such as time-of-use and demand charge management optimization and by aggregating the dispatch of energy through a network of virtual power plants. The resulting network created by the Company’s growing customer base increases grid resilience and reliability through the real-time processing of market-based demand signals, energy prices and other factors in connection with the deployment of renewable energy resources to such customers. Additionally, the Company’s clean energy solutions support renewable energy generation by alleviating grid intermittency issues, thereby reducing customer dependence on traditional, fossil fuel resources. The Company’s Athena PowerTrack application provides a vertically integrated solution that incorporates on-site power monitoring equipment that aggregates and communicates data to enable remote control of solar generation assets. PowerTrack provides direct access to individual site performance to measure and benchmark expected energy production, maximizing asset value for our customers. From time to time, the Company, through an indirect wholly-owned development subsidiary (“DevCo”) will enter into strategic joint ventures (each a “DevCo JV”) with qualified third parties for the development of select renewable energy projects (“DevCo Projects”). In this structure, DevCo forms a new DevCo JV entity as the majority owner, with the developer as the minority owner. The purpose of the DevCo JV is to develop and sell DevCo Projects and secure Company hardware and software services for those projects. In DevCo Projects, the Company makes development capital contributions to fund project development, and recovers those capital contributions plus a fee when the developer takes ownership of the project. Given long times to secure hardware, the Company will in some cases elect to make cash advances to hardware suppliers to accelerate project construction timelines given long lead times to secure hardware. This business model is intended to allow the Company to advance development capital to key partners in strategic markets and secure hardware upfront, in order to generate higher-margin software and services and other revenue via exclusive long-term services contracts under the DevCo Projects. On February 1, 2022, the Company acquired all of the issued and outstanding capital stock of Also Energy Holdings, Inc. (“AlsoEnergy”), which has been consolidated since the date of acquisition. Through AlsoEnergy, the Company provides end-to-end turnkey solutions that monitor and manage renewable energy systems through its PowerTrack software. PowerTrack includes data acquisitions and monitoring, performance modeling, agency reporting, internal reports, work order tickets, and supervisory control and data acquisition (“SCADA”) controls. AlsoEnergy has deployed systems at various international locations, but its largest concentration of customers is in the United States, Germany and Canada. See Note 6 — Business Combinations . The Company operated as Rollins Road Acquisition Company (f/k/a Stem, Inc.) (“Legacy Stem”) prior to the Merger with Star Peak Transition Corp. (“STPK”), an entity that was then listed on the New York Stock Exchange under the trade symbol “STPK,” and STPK Merger Sub Corp., a Delaware corporation and wholly - owned subsidiary of STPK (“Merger Sub”), providing for, among other things, and subject to the conditions therein, the combination of the Company and STPK pursuant to the merger of Merger Sub with and into the Company, with the Company continuing as the surviving entity (the “Merger”). Stem, Inc. was incorporated on March 16, 2009 in the State of Delaware and is headquartered in San Francisco, California. Liquidity As of September 30, 2023, the Company had cash and cash equivalents of $97.1 million, short-term investments of $28.3 million, an accumulated deficit of $734.8 million and net working capital of $241.3 million. During the nine months ended September 30, 2023, the Company incurred a net loss of $102.7 million and had negative cash flows from operating activities of $205.2 million. Further, the Company received net proceeds of $232.4 million from the issuance of the Company’s 4.25% Green Convertible Senior Notes due 2030 (the “2030 Convertible Notes”) (as described in Note 10 — Convertible Notes ) of which $99.8 million was paid to reduce the principal balance by $163.0 million of the Company’s 0.5% Green Convertible Senior Notes due 2028 (the “2028 Convertible Notes”). The Company believes that its cash position is sufficient to meet capital and liquidity requirements for at least the next 12 months after the date that the financial statements are available to be issued. The Company’s business prospects are subject to risks, expenses, and uncertainties frequently encountered by companies in the early stages of commercial operations. The attainment of profitable operations is dependent upon future events, including securing new customers and maintaining current ones, securing and maintaining adequate supplier relationships, building the Company’s customer base, successfully executing its business and marketing strategy, obtaining adequate financing to complete the Company’s development activities, and hiring and retaining appropriate personnel. Failure to generate sufficient revenues, achieve planned gross margins and operating profitability, control operating costs, or secure additional funding may require the Company to modify, delay or abandon some of its planned future expansion or development, to seek additional equity or debt financing, or to otherwise enact operating cost reductions available to management, which could have a material adverse effect on the Company’s business, operating results and financial condition. Supply Chain Constraints and Risk The Company has in the past faced shortages and shipping delays affecting the supply of inverters, enclosures, battery modules and associated component parts for inverters and battery energy storage systems available for purchase. These shortages and delays were due in part to the evolving macroeconomic, geopolitical and business environment, including the effects of global inflationary pressures and interest rates, general economic slowdown or a recession, changes in monetary policy, instability in financial institutions, the prospect of a shutdown of the U.S. federal government, potential import tariffs, geopolitical pressures, including the Russia-Ukraine armed conflict, rising tensions between China and the United States and unknown effects of current and future trade regulations. The Company cannot predict the full effects the macroeconomic, geopolitical and business environment will continue to have on our business, cash flows, liquidity, financial condition and results of operations. In addition, the COVID-19 pandemic caused, and any new outbreaks or resurgence of COVID-19 and its variants, or outbreaks of other infectious diseases, could again cause, a significant reduction in global economic activity, significantly weakening demand for our products and services.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X, assuming the Company will continue as a going concern. Accordingly, the condensed consolidated balance sheet at December 31, 2022 has been derived from the audited financial statements at that date, but certain notes or other information that are normally required by GAAP have been omitted if they substantially duplicate the disclosures contained in the Company’s annual audited consolidated financial statements. In the opinion of Stem management, all normal and recurring adjustments considered necessary for a fair statement of the results for the interim period presented have been included in the accompanying unaudited condensed consolidated financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2022. Operating results for the three and nine months ended September 30, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023 or for any other future interim period or year. Principles of Consolidation The unaudited condensed consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, and consolidated variable interest entities (“VIEs”). The Company presents non-controlling interests within the equity section of its condensed consolidated balance sheets, and the amount of consolidated net loss that is attributable to Stem and the non-controlling interest in its condensed consolidated statements of operations. All intercompany balances and transactions have been eliminated in consolidation. Variable Interest Entities The Company forms special purpose entities (“SPEs”), some of which are VIEs, with its investors in the ordinary course of business to facilitate the funding and monetization of its energy storage systems. A legal entity is considered a VIE if it has either a total equity investment that is insufficient to finance its operations without additional subordinated financial support or whose equity holders lack the characteristics of a controlling financial interest. The Company’s variable interests arise from contractual, ownership, or other monetary interests in the entity. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity; however, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. The Company consolidates a VIE if it is deemed to be the primary beneficiary. The Company determines it is the primary beneficiary if it has the power to direct the activities that most significantly impact the VIEs’ economic performance and has the obligation to absorb losses or has the right to receive benefits of the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether it is the primary beneficiary. Beginning in January 2022, the Company formed DevCo JVs with the purpose of originating potential battery storage facility projects in specific locations and conducting early-stage planning and development activities. The Company determined that the DevCo JVs are VIEs, as they lack sufficient equity to finance their activities without additional financial support. The Company determined that it has both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance, and (2) the obligation to absorb losses or receive benefits from the VIE that could potentially be significant. Accordingly, the Company has determined that it is the primary beneficiary of the DevCo JVs, and as a result, the DevCo JVs’ operating results, assets and liabilities are consolidated by the Company, with third party minority owners’ share presented as noncontrolling interest. The Company applied the hypothetical liquidation at book value method in allocating recorded net income (loss) to each owner based on the change in the reporting period, of the amount of net assets of the entity to which each owner would be entitled to under the governing contracts in a liquidation scenario. The following table summarizes the carrying values of the assets and liabilities of the DevCo JVs that are consolidated by the Company as of September 30, 2023 and December 31, 2022 (in thousands): September 30, 2023 December 31, 2022 Assets Cash and cash equivalents $ 2,482 $ 6,686 Other current assets 5 38 Other noncurrent assets 5,877 3,208 Total assets 8,364 9,932 Liabilities Accounts payable 826 356 Other current liabilities 137 97 Total liabilities $ 963 $ 453 For the nine months ended September 30, 2023 and 2022, the Company contributed approximately $0.1 million and $6.6 million in capital investments for hardware purchases, respectively. The net income from the DevCo JVs was $1.2 million and $1.4 million during the three and nine months ended September 30, 2023, respectively, and immaterial during the three and nine months ended September 30, 2022. Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions believed to be reasonable. Actual results could differ from those estimates and such differences could be material to the financial position and results of operations. Significant estimates and assumptions reflected in these unaudited condensed consolidated financial statements include, but are not limited to, depreciable life of energy storage systems; estimates of transaction price with variable consideration; the amortization of acquired intangibles; the amortization of financing obligations; deferred commissions and contract fulfillment costs; the valuation of energy storage systems, internally developed software, and asset retirement obligations; and the fair value of equity instruments, equity-based instruments, derivative liability, accruals related to sales tax liabilities and net assets acquired in a business combination. Segment Information Operating segments are defined as components of an entity for which discrete financial information is available that is regularly reviewed by the Chief Operating Decision Maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s Chief Executive Officer is the CODM. The CODM reviews financial information presented on a consolidated basis for purposes of making operating decisions, allocating resources, and evaluating financial performance. As such, management has determined that the Company operates as one operating segment that is focused exclusively on innovative technology services that transform the way energy is distributed and consumed. The operations acquired as part of the acquisition of AlsoEnergy have been included in the Company’s operating segment. Net assets outside of the U.S. were less than 10% of total net assets as of September 30, 2023 and December 31, 2022. Concentration of Credit Risk and Other Uncertainties Financial instruments that potentially subject the Company to concentration of credit risk consist of cash and cash equivalents and accounts receivable. The Company’s cash balances are primarily invested in money market funds or on deposit at high credit quality financial institutions in the U.S. The Company’s cash and cash equivalents are held at financial institutions where account balances may at times exceed federally insured limits. Management believes the Company is not exposed to significant credit risk due to the financial strength of the depository institution in which the cash is held. The Company has no financial instruments with off-balance sheet risk of loss. At times, the Company may be subject to a concentration of credit risk in relation to certain customers due to the purchase of large energy storage systems made by such customers. The Company routinely assesses the creditworthiness of its customers. The Company has not experienced material losses related to receivables from individual customers, or groups of customers during the nine months ended September 30, 2023 and 2022 . The Company does not require collateral. Due to these factors, no additional credit risk beyond amounts provided for credit losses is believed by management to be probable in the Company ’s accounts receivable. Significant Customers A significant customer represents 10% or more of the Company’s total revenue or accounts receivable, net balance at each reporting date. For each significant customer, revenue as a percentage of total revenue and accounts receivable as a percentage of total accounts receivable are as follows: Accounts Receivable Revenue Revenue September 30, December 31, Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 2023 2022 Customers: Customer A 54 % 54 % * 58 % 18 % 52 % Customer B 10 % 16 % * * * * Customer C 14 % 11 % * * * * Customer D * * * 12 % * * Customer E * * 89 % * 41 % * *Total less than 10% for the period. There are inherent risks whenever a large percentage of total revenue is concentrated in a limited number of customers. Should a significant customer terminate or fail to renew its contracts with us, in whole or in part, for any reason, or experience significant financial or operating difficulties, it could have a material adverse effect on our financial condition and results of operations. In general, a customer that makes up a significant portion of revenues in one period, may not make up a significant portion in subsequent periods. Fair Value of Financial Instruments Assets and liabilities recorded at fair value in the unaudited condensed consolidated financial statements are categorized based upon the level of judgment associated with the inputs used to measure their fair value. The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from independent sources) and to minimize the use of unobservable inputs (internal assumptions about how market participants would price assets and liabilities). Hierarchical levels which are directly related to the amount of subjectivity associated with the inputs to the valuation of these assets or liabilities are as follows: Level 1 — Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access as of the measurement date. Level 2 — Inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. Level 3 — Unobservable inputs for the asset or liability only used when there is little, if any, market activity for the asset or liability at the measurement date. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to their fair value measurement. The Company’s assessment of the significance of a specific input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. Financial assets and liabilities held by the Company measured at fair value on a recurring basis as of September 30, 2023 and December 31, 2022 include cash and cash equivalents, short-term investments, derivative liability, and convertible notes.

REVENUE

REVENUE	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE Disaggregation of Revenue The following table provides information on the disaggregation of revenue as recorded in the condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Hardware revenue $ 117,143 $ 85,809 $ 246,461 $ 171,358 Services and other revenue 16,597 13,692 47,630 36,178 Total revenue $ 133,740 $ 99,501 $ 294,091 $ 207,536 The following table summarizes reportable revenue by geographic regions determined based on the location of the customers (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 United States $ 129,800 $ 97,815 $ 280,010 $ 201,475 Rest of the world 3,940 1,686 14,081 6,061 Total revenue $ 133,740 $ 99,501 $ 294,091 $ 207,536 Remaining Performance Obligations Remaining performance obligations represent contracted revenue that has not been recognized, which include contract liabilities (deferred revenue) and amounts that will be billed and recognized as revenue in future periods. As of September 30, 2023 and September 30, 2022, the Company had $545.3 million and $365.8 million of remaining performance obligations, respectively, and the approximate percentages expected to be recognized as revenue in the future are as follows (in thousands, except percentages): September 30, 2023 Total Remaining Percent Expected to be Recognized as Revenue Less Than Two to Greater Than Services and other revenue $ 331,520 14 % 48 % 38 % Hardware revenue 213,813 100 % — % — % Total revenue $ 545,333 September 30, 2022 Total Remaining Percent Expected to be Recognized as Revenue Less Than Two to Greater Than Services and other revenue $ 264,195 17 % 51 % 32 % Hardware revenue 101,603 98 % 2 % — % Total revenue $ 365,798 Contract Balances Deferred revenue primarily includes cash received in advance of revenue recognition related to energy optimization services and incentives. The following table presents the changes in the deferred revenue balance during the nine months ended September 30, 2023 and September 30, 2022 (in thousands): Nine Months Ended September 30, 2023 2022 Beginning balance $ 138,074 $ 37,443 Deferred revenue acquired upon business combination — 49,626 Upfront payments received from customers 217,360 113,101 Upfront or annual incentive payments received 2,805 4,592 Revenue recognized related to amounts that were included in beginning balance of deferred revenue (26,538) (16,122) Revenue recognized related to amounts that were included in acquired balance of deferred revenue — (3,338) Revenue recognized related to deferred revenue generated during the period (165,997) (66,612) Ending balance $ 165,704 $ 118,690 Parent Company Guarantees In certain customer contracts, the Company previously agreed to provide a guarantee that the value of purchased hardware will not decline for a certain period of time. Under this guarantee, if these customers were unable to install or designate the hardware to a specified project within such period of time, the Company would be required to assist the customer in re-marketing the hardware for resale by the customer. The guarantee provided that, in such cases, if the customer resold the hardware for less than the amount initially sold to the customer, the Company would be required to compensate the customer for any shortfall in fair value for the hardware from the initial contract price. The Company accounts for such contractual terms and guarantees as variable consideration at each measurement date. The Company updates its estimate of variable consideration, including changes in estimates related to such guarantees, each quarter for facts or circumstances that have changed from the time of the initial estimate. As a result, the Company recorded a revenue reduction during the third quarter of fiscal year 2023 of $32.7 million in hardware revenue relating to hardware deliveries prior to third quarter 2023. During the

SHORT-TERM INVESTMENTS

SHORT-TERM INVESTMENTS	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
SHORT-TERM INVESTMENTS	SHORT-TERM INVESTMENTS The following tables summarize the estimated fair value of the Company’s short-term investments and the gross unrealized holding gains and losses as of September 30, 2023 and December 31, 2022 (in thousands): As of September 30, 2023 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Corporate debt securities $ 5,052 $ — $ (10) $ 5,042 U.S. government bonds 9,985 — (12) 9,973 Certificate of deposits 3,000 — — 3,000 Treasury bills 6,793 — — 6,793 Agency bonds 3,503 — (10) 3,493 Total short-term investments $ 28,333 $ — $ (32) $ 28,301 As of December 31, 2022 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Corporate debt securities $ 17,056 $ — $ (164) $ 16,892 Commercial paper 18,922 — — 18,922 U.S. government bonds 106,774 — (1,515) 105,259 Certificate of deposits 9,986 — — 9,986 Treasury bills 9,518 3 (5) 9,516 Agency bonds 1,500 — (1) 1,499 Total short-term investments $ 163,756 $ 3 $ (1,685) $ 162,074 The following table presents the contractual maturities of the Company’s short-term investments as of September 30, 2023 (in thousands): As of September 30, 2023 Amortized cost Estimated Fair Value Due within one year $ 28,333 $ 28,301 Total $ 28,333 $ 28,301

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTSFair value accounting is applied for all financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. At September 30, 2023 and December 31, 2022, the carrying amount of accounts receivable, other current assets, accounts payable, and accrued and other current liabilities approximated their estimated fair value due to their relatively short maturities. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table provides the financial instruments measured at fair value (in thousands): September 30, 2023 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market fund $ 30,293 $ — $ — $ 30,293 Commercial paper — — — — Debt securities: Corporate debt securities — 5,042 — 5,042 U.S. government bonds — 9,973 — 9,973 Certificate of deposits — 3,000 — 3,000 Treasury bills — 6,793 — 6,793 Agency bonds — 3,493 — 3,493 Total financial assets $ 30,293 $ 28,301 $ — $ 58,594 Liabilities: Derivative liability $ — $ — $ 7,731 $ 7,731 December 31, 2022 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market fund $ 10,618 $ — $ — $ 10,618 Commercial paper — 2,988 — 2,988 Debt securities: Corporate debt securities — 16,892 — 16,892 Commercial paper — 18,922 — 18,922 U.S. government bonds — 105,259 — 105,259 Certificate of deposits — 9,986 — 9,986 Treasury bills — 9,516 — 9,516 Other — 1,499 — 1,499 Total financial assets $ 10,618 $ 165,062 $ — $ 175,680 The Company’s money market funds are classified as Level 1 because they are valued using quoted market prices. The Company’s short-term investments consist of available-for-sale securities and are classified as Level 2 because their value is based on valuations using significant inputs derived from or corroborated by observable market data. The Company’s other current liabilities includes a derivative liability that is attributable to a derivative feature within a revenue contract, whereby final settlement is indexed to the price per ton of lithium carbonate. The balance will be valued using a third party forecast for lithium carbonate. As the derivative instrument is not traded on an exchange they are classified within Level 3 of the fair value hierarchy. The convertible notes are recorded at face value less unamortized debt issuance costs (see Note 10 — Convertible Notes for additional details) on the condensed consolidated balance sheets as of September 30, 2023. As of September 30, 2023 and December 31, 2022, the estimated fair value of the 2028 Convertible Notes was $177.9 million and $293.1 million, respectively, based on Level 2 quoted bid prices of the convertible notes in an over-the-counter market on the last trading date of the reporting period. As of September 30, 2023, the estimated fair value of the 2030 Convertible Notes was $192.1 million, based on Level 2 quoted bid prices of the convertible notes in an over-the-counter market on the last trading date of the reporting period.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	9 Months Ended
	Sep. 30, 2023
Business Combination and Asset Acquisition [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS AlsoEnergy Acquisition On February 1, 2022, Stem, Inc. acquired 100% of the outstanding shares of AlsoEnergy. AlsoEnergy provides end-to-end turnkey solutions that monitor and manage renewable energy systems. The total consideration to acquire AlsoEnergy was $652.0 million, comprised of $543.1 million in cash, net of a working capital adjustment for an escrow recovery, and $108.9 million in the form of 8,621,006 shares of the Company’s common stock. The Company incurred $6.1 million of transaction costs related to the acquisition of AlsoEnergy, which were recorded in general and administrative expense in the nine months ended September 30, 2022. Unaudited Pro Forma Financial Information The following unaudited pro forma financial information summarizes the combined results of operations for the Company and AlsoEnergy, as if the acquisition had occurred on January 1, 2022. The pro forma financial information is as follows (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Total revenue $ 133,740 $ 99,501 $ 294,091 $ 211,372 Net loss $ (77,072) $ (34,275) $ (102,728) $ (96,686) The pro forma financial information for the periods presented above has been calculated after adjusting the results of AlsoEnergy to reflect the business combination accounting effects resulting from this acquisition, including the elimination of transaction costs incurred by the Company, amortization expense from acquired intangible assets, and settlement of stock option awards. The historical consolidated financial statements have been adjusted in the pro forma combined financial statements to give effect to pro forma events that are directly attributable to the business combination. The pro forma financial information is for informational purposes only, and is not indicative of either future results of operations, or results that may have been achieved had the acquisition been consummated as of the beginning of 2022.

GOODWILL AND INTANGIBLE ASSETS,

GOODWILL AND INTANGIBLE ASSETS, NET	9 Months Ended
	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS, NET	GOODWILL AND INTANGIBLE ASSETS, NET Goodwill Goodwill consists of the following (in thousands): September 30, December 31, 2023 2022 Goodwill $ 547,158 $ 547,556 Recovery of escrow from AlsoEnergy acquisition — (915) Effect of foreign currency translation 6 8 Total goodwill $ 547,164 $ 546,649 Intangible Assets, Net Intangible assets, net, consists of the following (in thousands): September 30, December 31, 2023 2022 Developed technology $ 32,000 $ 30,600 Trade name 11,300 11,300 Customer relationships 106,800 106,800 Backlog 3,900 3,900 Internally developed software 62,628 49,472 Intangible assets 216,628 202,072 Less: Accumulated amortization (58,309) (39,809) Add: Currency translation adjustment 2 2 Total intangible assets, net $ 158,321 $ 162,265 Amortization expense for intangible assets was $5.2 million and $6.5 million for the three months ended September 30, 2023 and 2022, respectively, and $18.5 million and $16.9 million for the nine months ended September 30, 2023 and 2022, respectively .

ENERGY STORAGE SYSTEMS, NET

ENERGY STORAGE SYSTEMS, NET	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
ENERGY STORAGE SYSTEMS, NET	ENERGY STORAGE SYSTEMS, NET Energy Storage Systems, Net Energy storage systems, net, consists of the following (in thousands): September 30, December 31, 2023 2022 Energy storage systems placed into service $ 141,759 $ 143,154 Less: accumulated depreciation (65,606) (58,782) Energy storage systems not yet placed into service 4,556 6,385 Total energy storage systems, net $ 80,709 $ 90,757 Depreciation expense for energy storage systems was approximately $3.6 million and $3.8 million for the three months ended September 30, 2023 and 2022, respectively, and approximately $10.8 million and $11.2 million for the nine months ended September 30, 2023 and 2022, respectively. Depreciation expense is recognized in cost of services and other revenue. Impairment expense for energy storage systems was approximately $0.3 million and $0.4 million for the three months ended September 30, 2023 and 2022, respectively, and approximately $2.3 million and $1.3 million for the nine months ended September 30, 2023 and 2022, respectively. Impairment expense is recognized in cost of services and other revenue.

NOTES PAYABLE

NOTES PAYABLE	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
NOTES PAYABLE	NOTES PAYABLE 2021 Credit Agreement In January 2021, a wholly-owned Canadian subsidiary of the Company entered into a credit agreement to provide a total of $2.7 million towards the financing of certain energy storage systems. The credit agreement was structured on a non-recourse basis and the systems were operated by the Company. The credit agreement had a stated interest of 5.45% and a maturity date of June 2031. The Company received an advance under the credit agreement of $1.8 million in January 2021. The repayment of advances received under the credit agreement was determined by the lender based on the proceeds generated by the Company through the operation of the underlying energy storage systems. On April 6, 2023, the Company repaid the remaining outstanding balance under the 2021 Credit Agreement with a portion of the net proceeds from the issuance of the 2030 Convertible Notes (as described in Note 10 — Convertible Notes 2028 Convertible Notes and 2028 Capped Call Options 2028 Convertible Notes On November 22, 2021, the Company issued $460.0 million aggregate principal amount of its 2028 Convertible Notes in a private placement offering to qualified institutional buyers (the “2021 Initial Purchasers”) pursuant to Rule 144A under the Securities Act of 1933, as amended. The 2028 Convertible Notes are senior, unsecured obligations of the Company and bear interest at a rate of 0.5% per year, payable in cash semi-annually in arrears in June and December of each year, beginning in June 2022. The notes will mature on December 1, 2028, unless earlier repurchased, redeemed or converted in accordance with their terms prior to such date. Upon conversion, the Company may choose to pay or deliver, as the case may be, cash, shares of common stock or a combination of cash and shares of common stock. The Notes are redeemable for cash at the Company’s option at any time given certain conditions (as discussed below), at an initial conversion rate of 34.1965 shares of common stock per $1,000 principal amount of 2028 Convertible Notes, which is equivalent to an initial conversion price of approximately $29.24 (the “2028 Conversion Price”) per share of the Company’s common stock. The conversion rate is subject to customary adjustments for certain events as described in the Indenture. The Company may redeem for cash all or any portion of the 2028 Convertible Notes, at the Company’s option, on or after December 5, 2025 if the last reported sale price of the Company’s common stock has been at least 130% of the 2028 Conversion Price then in effect for at least 20 trading days at a redemption price equal to 100% of the principal amount of the 2028 Convertible Notes to be redeemed, plus accrued and unpaid interest. The Company’s net proceeds from this offering were approximately $445.7 million , after deducting the 2021 Initial Purchasers’ discounts and debt issuance costs. To minimize potential dilution to the Company’s common stockholders upon conversion of the 2028 Convertible Notes, the Company entered into separate capped call transactions (the “2028 Capped Calls”) as described below. In connection with the issuance of the 2030 Convertible Notes during the second quarter of 2023, t he Company used approximately $99.8 million of the net proceeds to purchase and surrender for cancellation approximately $163.0 million aggregate principal amount of the Company’s 2028 Convertible Notes, which resulted in a $59.4 million gain on debt extinguishment. See 2030 Convertible Notes below for further details of the 2030 Convertible Notes . Upon adoption of ASU 2020-06, the Company allocated all of the debt discount to long-term debt. The debt discount is amortized to interest expense using the effective interest method, computed to be 0.9%, over the life of the 2028 Convertible Notes or approximately its seven-year term. The outstanding 2028 Convertible Notes balances as of September 30, 2023 and December 31, 2022 are summarized in the following table (in thousands): September 30, 2023 December 31, 2022 Long Term Debt Outstanding principal $ 297,024 $ 460,000 Unamortized initial purchaser’s debt discount and debt issuance cost (6,825) (12,091) Net carrying amount $ 290,199 $ 447,909 The following table presents total interest expense recognized related to the 2028 Convertible Notes during the three and nine months ended September 30, 2023 and 2022 (in thousands) : Three Months Ended Nine Months Ended 2023 2022 2023 2022 Cash interest expense Contractual interest expense $ 371 $ 575 $ 1,322 $ 1,725 Non-cash interest expense Amortization of debt discount and debt issuance cost 323 497 1,163 1,488 Total interest expense $ 694 $ 1,072 $ 2,485 $ 3,213 2028 Capped Call Options On November 17, 2021, in connection with the pricing of the 2028 Convertible Notes, and on November 19, 2021, in connection with the exercise in full by the 2021 Initial Purchasers of their option to purchase additional Notes, the Company entered into the 2028 Capped Calls with certain counterparties. The Company used $66.7 million of the net proceeds to pay the cost of the 2028 Capped Calls. The 2028 Capped Calls have an initial strike price of $29.2428 per share, which corresponds to the initial conversion price of the 2028 Convertible Notes and is subject to anti-dilution adjustments. The 2028 Capped Calls have a cap price of $49.6575 per share, subject to certain adjustments. The 2028 Capped Calls are considered separate transactions entered into by and between the Company and the 2028 Capped Calls counterparties, and are not part of the terms of the 2028 Convertible Notes. The Company recorded a reduction to additional paid-in capital of $66.7 million during the year ended December 31, 2021 related to the premium payments for the 2028 Capped Calls. These instruments meet the conditions outlined in FASB ASU 2022-01 Topic 815, Derivatives and Hedging (“ASC 815”) to be classified in stockholders’ equity and are not subsequently remeasured as long as the conditions for equity classification continue to be met. 2030 Convertible Notes and 2030 Capped Call Options 2030 Convertible Notes On April 3, 2023, the Company issued $240.0 million aggregate principal amount of its 2030 Convertible Notes in a private placement offering to qualified institutional buyers (the “2023 Initial Purchasers”) pursuant to Rule 144A under the Securities Act of 1933, as amended. The 2030 Convertible Notes are senior, unsecured obligations of the Company and bear interest at a rate of 4.25% per year, payable in cash semi-annually in arrears in April and October of each year, beginning on October 1, 2023. The notes will mature on April 1, 2030, unless earlier repurchased, redeemed or converted in accordance with their terms prior to such date. Upon conversion, the Company may choose to pay or deliver cash, shares of common stock or a combination of cash and shares of common stock. The Notes are redeemable for cash at the Company’s option at any time given certain conditions (as discussed below), at an initial conversion rate of 140.3066 shares of common stock per $1,000 principal amount of the 2030 Convertible Notes, which is equivalent to an initial conversion price of approximately $7.1272 (the “2030 Conversion Price”) per share of the Company’s common stock. The conversion rate is subject to customary adjustments for certain events as described in the related Indenture. The 2030 Convertible Notes will be redeemable, in whole or in part, at the Company’s option, on or after April 5, 2027 if the last reported sale price of the Company’s common stock has been at least 130% of the 2030 Conversion Price then in effect for at least 20 trading days at a redemption price equal to 100% of the principal amount of the 2030 Convertible Notes to be redeemed, plus accrued and unpaid interest. The Company’s net proceeds from this offering were approximately $232.4 million, net of $7.6 million in debt issuance costs primarily consisting of underwriters, advisory, legal, and accounting fees. The Company used approximately $99.8 million of the net proceeds to purchase and surrender for cancellation approximately $163.0 million aggregate principal amount of the Company’s 2028 Convertible Notes. See 2028 Convertible Notes above for further details on the impacts of the debt extinguishment. The outstanding 2030 Convertible Notes balances as of September 30, 2023 are summarized in the following table (in thousands): September 30, 2023 Long Term Debt Outstanding principal $ 240,000 Unamortized initial purchaser’s debt discount and debt issuance cost (7,131) Net carrying amount $ 232,869 The debt discount and debt issuance costs are amortized to interest expense using the effective interest method, computed to be 4.70%, over the life of the 2030 Convertible Notes or its approximately seven-year term. The following table presents total interest expense recognized related to the 2030 Convertible Notes during the three months ended September 30, 2023 (in thousands) : Three Months Ended Nine Months Ended Cash interest expense Contractual interest expense $ 2,550 $ 5,043 Non-cash interest expense Amortization of debt discount and debt issuance cost 239 470 Total interest expense $ 2,789 $ 5,513 2030 Capped Call Options On March 29, 2023 and March 31, 2023, in connection with the pricing of the 2030 Convertible Notes, and on April 3, 2023, in connection with the exercise in full by the 2023 Initial Purchasers of their option to purchase additional Notes, the Company entered into Capped Calls (the “2030 Capped Calls”) with certain counterparties. The Company used $27.8 million of the net proceeds from the 2030 Convertible Notes to pay the cost of the 2030 Capped Calls. The 2030 Capped Calls have an initial strike price of $7.1272 per share, which corresponds to the initial conversion price of the 2030 Convertible Notes and is subject to anti-dilution adjustments. The 2030 Capped Calls have a cap price of $11.1800 per share, subject to certain adjustments. The 2030 Capped Calls are considered separate transactions entered into by and between the Company and the 2030 Capped Calls counterparties, and are not part of the terms of the 2030 Convertible Notes. The Company recorded a reduction to additional paid-in capital of $27.8 million during the second quarter of 2023 related to the premium payments for the 2030 Capped Calls. These instruments meet the conditions outlined in ASC 815 to be classified in stockholders’ equity and are not subsequently remeasured as long as the conditions for equity classification continue to be met.

CONVERTIBLE NOTES

CONVERTIBLE NOTES	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
CONVERTIBLE NOTES	NOTES PAYABLE 2021 Credit Agreement In January 2021, a wholly-owned Canadian subsidiary of the Company entered into a credit agreement to provide a total of $2.7 million towards the financing of certain energy storage systems. The credit agreement was structured on a non-recourse basis and the systems were operated by the Company. The credit agreement had a stated interest of 5.45% and a maturity date of June 2031. The Company received an advance under the credit agreement of $1.8 million in January 2021. The repayment of advances received under the credit agreement was determined by the lender based on the proceeds generated by the Company through the operation of the underlying energy storage systems. On April 6, 2023, the Company repaid the remaining outstanding balance under the 2021 Credit Agreement with a portion of the net proceeds from the issuance of the 2030 Convertible Notes (as described in Note 10 — Convertible Notes 2028 Convertible Notes and 2028 Capped Call Options 2028 Convertible Notes On November 22, 2021, the Company issued $460.0 million aggregate principal amount of its 2028 Convertible Notes in a private placement offering to qualified institutional buyers (the “2021 Initial Purchasers”) pursuant to Rule 144A under the Securities Act of 1933, as amended. The 2028 Convertible Notes are senior, unsecured obligations of the Company and bear interest at a rate of 0.5% per year, payable in cash semi-annually in arrears in June and December of each year, beginning in June 2022. The notes will mature on December 1, 2028, unless earlier repurchased, redeemed or converted in accordance with their terms prior to such date. Upon conversion, the Company may choose to pay or deliver, as the case may be, cash, shares of common stock or a combination of cash and shares of common stock. The Notes are redeemable for cash at the Company’s option at any time given certain conditions (as discussed below), at an initial conversion rate of 34.1965 shares of common stock per $1,000 principal amount of 2028 Convertible Notes, which is equivalent to an initial conversion price of approximately $29.24 (the “2028 Conversion Price”) per share of the Company’s common stock. The conversion rate is subject to customary adjustments for certain events as described in the Indenture. The Company may redeem for cash all or any portion of the 2028 Convertible Notes, at the Company’s option, on or after December 5, 2025 if the last reported sale price of the Company’s common stock has been at least 130% of the 2028 Conversion Price then in effect for at least 20 trading days at a redemption price equal to 100% of the principal amount of the 2028 Convertible Notes to be redeemed, plus accrued and unpaid interest. The Company’s net proceeds from this offering were approximately $445.7 million , after deducting the 2021 Initial Purchasers’ discounts and debt issuance costs. To minimize potential dilution to the Company’s common stockholders upon conversion of the 2028 Convertible Notes, the Company entered into separate capped call transactions (the “2028 Capped Calls”) as described below. In connection with the issuance of the 2030 Convertible Notes during the second quarter of 2023, t he Company used approximately $99.8 million of the net proceeds to purchase and surrender for cancellation approximately $163.0 million aggregate principal amount of the Company’s 2028 Convertible Notes, which resulted in a $59.4 million gain on debt extinguishment. See 2030 Convertible Notes below for further details of the 2030 Convertible Notes . Upon adoption of ASU 2020-06, the Company allocated all of the debt discount to long-term debt. The debt discount is amortized to interest expense using the effective interest method, computed to be 0.9%, over the life of the 2028 Convertible Notes or approximately its seven-year term. The outstanding 2028 Convertible Notes balances as of September 30, 2023 and December 31, 2022 are summarized in the following table (in thousands): September 30, 2023 December 31, 2022 Long Term Debt Outstanding principal $ 297,024 $ 460,000 Unamortized initial purchaser’s debt discount and debt issuance cost (6,825) (12,091) Net carrying amount $ 290,199 $ 447,909 The following table presents total interest expense recognized related to the 2028 Convertible Notes during the three and nine months ended September 30, 2023 and 2022 (in thousands) : Three Months Ended Nine Months Ended 2023 2022 2023 2022 Cash interest expense Contractual interest expense $ 371 $ 575 $ 1,322 $ 1,725 Non-cash interest expense Amortization of debt discount and debt issuance cost 323 497 1,163 1,488 Total interest expense $ 694 $ 1,072 $ 2,485 $ 3,213 2028 Capped Call Options On November 17, 2021, in connection with the pricing of the 2028 Convertible Notes, and on November 19, 2021, in connection with the exercise in full by the 2021 Initial Purchasers of their option to purchase additional Notes, the Company entered into the 2028 Capped Calls with certain counterparties. The Company used $66.7 million of the net proceeds to pay the cost of the 2028 Capped Calls. The 2028 Capped Calls have an initial strike price of $29.2428 per share, which corresponds to the initial conversion price of the 2028 Convertible Notes and is subject to anti-dilution adjustments. The 2028 Capped Calls have a cap price of $49.6575 per share, subject to certain adjustments. The 2028 Capped Calls are considered separate transactions entered into by and between the Company and the 2028 Capped Calls counterparties, and are not part of the terms of the 2028 Convertible Notes. The Company recorded a reduction to additional paid-in capital of $66.7 million during the year ended December 31, 2021 related to the premium payments for the 2028 Capped Calls. These instruments meet the conditions outlined in FASB ASU 2022-01 Topic 815, Derivatives and Hedging (“ASC 815”) to be classified in stockholders’ equity and are not subsequently remeasured as long as the conditions for equity classification continue to be met. 2030 Convertible Notes and 2030 Capped Call Options 2030 Convertible Notes On April 3, 2023, the Company issued $240.0 million aggregate principal amount of its 2030 Convertible Notes in a private placement offering to qualified institutional buyers (the “2023 Initial Purchasers”) pursuant to Rule 144A under the Securities Act of 1933, as amended. The 2030 Convertible Notes are senior, unsecured obligations of the Company and bear interest at a rate of 4.25% per year, payable in cash semi-annually in arrears in April and October of each year, beginning on October 1, 2023. The notes will mature on April 1, 2030, unless earlier repurchased, redeemed or converted in accordance with their terms prior to such date. Upon conversion, the Company may choose to pay or deliver cash, shares of common stock or a combination of cash and shares of common stock. The Notes are redeemable for cash at the Company’s option at any time given certain conditions (as discussed below), at an initial conversion rate of 140.3066 shares of common stock per $1,000 principal amount of the 2030 Convertible Notes, which is equivalent to an initial conversion price of approximately $7.1272 (the “2030 Conversion Price”) per share of the Company’s common stock. The conversion rate is subject to customary adjustments for certain events as described in the related Indenture. The 2030 Convertible Notes will be redeemable, in whole or in part, at the Company’s option, on or after April 5, 2027 if the last reported sale price of the Company’s common stock has been at least 130% of the 2030 Conversion Price then in effect for at least 20 trading days at a redemption price equal to 100% of the principal amount of the 2030 Convertible Notes to be redeemed, plus accrued and unpaid interest. The Company’s net proceeds from this offering were approximately $232.4 million, net of $7.6 million in debt issuance costs primarily consisting of underwriters, advisory, legal, and accounting fees. The Company used approximately $99.8 million of the net proceeds to purchase and surrender for cancellation approximately $163.0 million aggregate principal amount of the Company’s 2028 Convertible Notes. See 2028 Convertible Notes above for further details on the impacts of the debt extinguishment. The outstanding 2030 Convertible Notes balances as of September 30, 2023 are summarized in the following table (in thousands): September 30, 2023 Long Term Debt Outstanding principal $ 240,000 Unamortized initial purchaser’s debt discount and debt issuance cost (7,131) Net carrying amount $ 232,869 The debt discount and debt issuance costs are amortized to interest expense using the effective interest method, computed to be 4.70%, over the life of the 2030 Convertible Notes or its approximately seven-year term. The following table presents total interest expense recognized related to the 2030 Convertible Notes during the three months ended September 30, 2023 (in thousands) : Three Months Ended Nine Months Ended Cash interest expense Contractual interest expense $ 2,550 $ 5,043 Non-cash interest expense Amortization of debt discount and debt issuance cost 239 470 Total interest expense $ 2,789 $ 5,513 2030 Capped Call Options On March 29, 2023 and March 31, 2023, in connection with the pricing of the 2030 Convertible Notes, and on April 3, 2023, in connection with the exercise in full by the 2023 Initial Purchasers of their option to purchase additional Notes, the Company entered into Capped Calls (the “2030 Capped Calls”) with certain counterparties. The Company used $27.8 million of the net proceeds from the 2030 Convertible Notes to pay the cost of the 2030 Capped Calls. The 2030 Capped Calls have an initial strike price of $7.1272 per share, which corresponds to the initial conversion price of the 2030 Convertible Notes and is subject to anti-dilution adjustments. The 2030 Capped Calls have a cap price of $11.1800 per share, subject to certain adjustments. The 2030 Capped Calls are considered separate transactions entered into by and between the Company and the 2030 Capped Calls counterparties, and are not part of the terms of the 2030 Convertible Notes. The Company recorded a reduction to additional paid-in capital of $27.8 million during the second quarter of 2023 related to the premium payments for the 2030 Capped Calls. These instruments meet the conditions outlined in ASC 815 to be classified in stockholders’ equity and are not subsequently remeasured as long as the conditions for equity classification continue to be met.

WARRANTS

WARRANTS	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
WARRANTS	WARRANTSLegacy Stem WarrantsPrior to the Merger, the Company had issued warrants to purchase shares of Legacy Stem’s preferred stock in conjunction with various debt financings. The Company has also issued warrants to purchase shares of Legacy Stem’s common stock. Upon effectiveness of the Merger, the Company had 50,207,439 warrants outstanding, of which substantially all were converted into 2,759,970 shares of common stock of Stem. Upon conversion of the warrants, the existing warrant liabilities were remeasured to fair value resulting in a gain on remeasurement of $100.9 million and a total warrant liability of $60.6 million, which was then reclassified to additional paid-in-capital. At September 30, 2023, there were 2,533 Legacy Stem Warrants outstanding. These instruments are exercisable into the Company’s common stock and are equity classified.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION Equity Incentive Plans Under both the Stem, Inc. 2009 Equity Incentive Plan (the “2009 Plan”) and the Stem, Inc. 2021 Equity Incentive Plan (the “2021 Plan,” and together with the 2009 Plan, the “Plans”), the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units (“RSUs”), performance stock units (“PSUs”), and other awards that are settled in shares of the Company’s common stock. The Company does not intend to grant new awards under the 2009 Plan. All shares that remain available for future grants are under the 2021 Plan. Stock Options The following table summarizes the stock option activity for the period ended September 30, 2023: Number of Weighted- Weighted- Aggregate Balances as of December 31, 2022 8,243,637 $ 6.88 6.6 $ 35,566 Options granted 1,291,349 10.25 Options exercised (116,717) 2.20 Options forfeited and expired (356,188) 15.64 Balances as of September 30, 2023 9,062,081 $ 7.08 6.2 $ 10,278 Options vested and exercisable — September 30, 2023 6,091,126 $ 4.88 5.1 $ 10,230 As of September 30, 2023, the Company had approximately $17.3 million of remaining unrecognized stock-based compensation expense for stock options, which is expected to be recognized over a weighted average period of 1.5 years. Restricted Stock Units The following table summarizes the RSU activity for the period ended September 30, 2023: Number of RSUs Outstanding (1) Weighted-Average Balances as of December 31, 2022 6,719,490 $ 15.34 RSUs granted 7,542,131 5.62 RSUs vested (1,226,174) 10.78 RSUs forfeited (1,791,088) 8.65 Balances as of September 30, 2023 11,244,359 $ 10.56 (1) Includes certain restricted stock units with service and market-based vesting criteria. As of September 30, 2023, the Company had approximately $79.5 million of remaining unrecognized stock-based compensation expense for RSUs, which is expected to be recognized over a weighted average period of 1.9 years. Stock-Based Compensation The following table summarizes stock-based compensation expense recorded in each component of operating expenses in the Company’s condensed consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Sales and marketing $ 1,614 $ 1,172 $ 4,109 $ 3,102 Research and development 2,467 1,589 6,733 3,458 General and administrative 7,117 4,917 17,478 13,850 Total stock-based compensation expense $ 11,198 $ 7,678 $ 28,320 $ 20,410 Research and development expenses of $1.2 million and $0.6 million corresponding to internal-use software, were capitalized during the three months ended September 30, 2023 and 2022, respectively. Research and development expenses of $3.1 million and $1.7 million, corresponding to internal-use software, were capitalized during the nine months ended September 30, 2023 and 2022, respectively. Awards under our stock bonus program issued through the 2021 Plan are accounted for as liability-classified awards, because the obligations are based predominantly on fixed monetary amount determined at a future date to be settled with a variable number of shares of our common stock. We recognized stock-based compensation expense related to such bonuses in the amount of $1.5 million during the three and nine

NET LOSS PER SHARE

NET LOSS PER SHARE	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share amounts): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Numerator: Net loss per share attributable to common stockholders, basic and diluted $ (77,072) $ (34,279) $ (102,728) $ (88,781) Denominator: Weighted-average number of shares outstanding used to compute net loss per share attributable to common stockholders, basic and diluted 155,829,348 154,392,573 155,474,725 153,043,010 Net loss per share attributable to common stockholders, basic and diluted $ (0.49) $ (0.22) $ (0.66) $ (0.58) The following table shows total outstanding potentially dilutive shares excluded from the computation of diluted loss per share as their effect would have been anti-dilutive, as of September 30, 2023 and 2022: September 30, 2023 September 30, 2022 Outstanding 2028 Convertible Notes 10,157,181 15,730,390 Outstanding 2030 Convertible Notes 33,673,584 — Outstanding stock options 9,062,081 8,296,551 Outstanding warrants 2,533 2,533 Outstanding RSUs 11,244,359 6,557,284 Total 64,139,738 30,586,758

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The following table reflects the Company’s (provision for) benefit from income taxes and the effective tax rates for the periods presented below (in thousands, except effective tax rate): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Loss before benefit from (provision for) income taxes $ (77,118) $ (34,256) $ (102,374) $ (103,982) Benefit from (provision for) income taxes $ 46 $ (19) $ (354) $ 15,201 Effective tax rate 0.1 % (0.1) % (0.3) % 14.6 % For the three months ended September 30, 2023 , the Company recognized a benefit from income taxes of $46 thousand , representing an effective tax rate of 0.1%, which was lower than the statutory federal tax rate because the Company maintains a valuation allowance on its U.S. deferred tax assets. For the nine months ended September 30, 2023 , the Company recognized a provision for income taxes of $0.4 million, representing an effective tax rate of (0.3)%, which was lower than the statutory federal tax rate due to a $0.3 million tax benefit from an acquisition for a partial valuation allowance release on U.S. deferred tax assets due to the deferred tax liability established in purchase accounting on acquired intangibles during the nine months ended September 30, 2023 . For the nine months ended September 30, 2022, the Company recognized a benefit from income taxes of $15.2 million , representing an effective tax rate of 14.6%, which was lower than the statutory federal tax rate due to a $15.1 million tax benefit from the acquisition of AlsoEnergy for a partial valuation allowance release on U.S. Deferred tax assets due to the deferred tax liability established in purchase accounting on the acquired intangibles.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Contingencies The Company is party to various legal proceedings from time to time. A liability is accrued when a loss is both probable and can be reasonably estimated. Management believes that the probability of a material loss with respect to any currently pending legal proceeding is remote. However, litigation is inherently uncertain and it is not possible to predict the ultimate disposition of any of these proceedings. As of the date of this filing, the Company does not believe that there are any pending legal proceedings or other loss contingencies that will, either individually or in the aggregate, have a material adverse effect on the Company taken as a whole. Commitments On March 1, 2023, the Company recognized a $2.8 million operating lease liability and a corresponding operating lease right-of-use (“ROU”) asset, which are included in the condensed consolidated balance sheets as of September 30, 2023. The operating lease liability and operating lease ROU asset correspond to 41,811 square feet of leased office in Gurugram, India. As of the commencement date of the lease, the remaining lease term was 58 months. The lease agreement contemplates options to extend the non-cancelable lease term, which have been determined not reasonably certain to be exercised. Base rent is approximately $58,500 per month with escalating payments. Non-Income Related Taxes

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net loss attributable to Stem	$ (77,072)	$ (34,279)	$ (102,728)	$ (88,781)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X, assuming the Company will continue as a going concern. Accordingly, the condensed consolidated balance sheet at December 31, 2022 has been derived from the audited financial statements at that date, but certain notes or other information that are normally required by GAAP have been omitted if they substantially duplicate the disclosures contained in the Company’s annual audited consolidated financial statements. In the opinion of Stem management, all normal and recurring adjustments considered necessary for a fair statement of the results for the interim period presented have been included in the accompanying unaudited condensed consolidated financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2022. Operating results for the three and nine months ended September 30, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023 or for any other future interim period or year.
Principles of Consolidation	Principles of ConsolidationThe unaudited condensed consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, and consolidated variable interest entities (“VIEs”). The Company presents non-controlling interests within the equity section of its condensed consolidated balance sheets, and the amount of consolidated net loss that is attributable to Stem and the non-controlling interest in its condensed consolidated statements of operations. All intercompany balances and transactions have been eliminated in consolidation.
Variable Interest Entities	Variable Interest Entities The Company forms special purpose entities (“SPEs”), some of which are VIEs, with its investors in the ordinary course of business to facilitate the funding and monetization of its energy storage systems. A legal entity is considered a VIE if it has either a total equity investment that is insufficient to finance its operations without additional subordinated financial support or whose equity holders lack the characteristics of a controlling financial interest. The Company’s variable interests arise from contractual, ownership, or other monetary interests in the entity. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity; however, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. The Company consolidates a VIE if it is deemed to be the primary beneficiary. The Company determines it is the primary beneficiary if it has the power to direct the activities that most significantly impact the VIEs’ economic performance and has the obligation to absorb losses or has the right to receive benefits of the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether it is the primary beneficiary.
Use of Estimates	Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions believed to be reasonable. Actual results could differ from those estimates and such differences could be material to the financial position and results of operations. Significant estimates and assumptions reflected in these unaudited condensed consolidated financial statements include, but are not limited to, depreciable life of energy storage systems; estimates of transaction price with variable consideration; the amortization of acquired intangibles; the amortization of financing obligations; deferred commissions and contract fulfillment costs; the valuation of energy storage systems, internally developed software, and asset retirement obligations; and the fair
Segment Information	Segment Information Operating segments are defined as components of an entity for which discrete financial information is available that is regularly reviewed by the Chief Operating Decision Maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s Chief Executive Officer is the CODM. The CODM reviews financial information presented on a consolidated basis for purposes of making operating decisions, allocating resources, and evaluating financial performance. As such, management has determined that the Company operates as one
Concentration of Credit Risk and Other Uncertainties	Concentration of Credit Risk and Other Uncertainties Financial instruments that potentially subject the Company to concentration of credit risk consist of cash and cash equivalents and accounts receivable. The Company’s cash balances are primarily invested in money market funds or on deposit at high credit quality financial institutions in the U.S. The Company’s cash and cash equivalents are held at financial institutions where account balances may at times exceed federally insured limits. Management believes the Company is not exposed to significant credit risk due to the financial strength of the depository institution in which the cash is held. The Company has no financial instruments with off-balance sheet risk of loss. At times, the Company may be subject to a concentration of credit risk in relation to certain customers due to the purchase of large energy storage systems made by such customers. The Company routinely assesses the creditworthiness of its customers. The Company has not experienced material losses related to receivables from individual customers, or groups of customers during the nine months ended September 30, 2023 and 2022 . The Company does not require collateral. Due to these factors, no additional credit risk beyond amounts provided for credit losses is believed by management to be probable in the Company ’s accounts receivable.
Significant Customers	Significant CustomersA significant customer represents 10% or more of the Company’s total revenue or accounts receivable, net balance at each reporting date.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Assets and liabilities recorded at fair value in the unaudited condensed consolidated financial statements are categorized based upon the level of judgment associated with the inputs used to measure their fair value. The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from independent sources) and to minimize the use of unobservable inputs (internal assumptions about how market participants would price assets and liabilities). Hierarchical levels which are directly related to the amount of subjectivity associated with the inputs to the valuation of these assets or liabilities are as follows: Level 1 — Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access as of the measurement date. Level 2 — Inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. Level 3 — Unobservable inputs for the asset or liability only used when there is little, if any, market activity for the asset or liability at the measurement date. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to their fair value measurement. The Company’s assessment of the significance of a specific input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. Financial assets and liabilities held by the Company measured at fair value on a recurring basis as of September 30, 2023 and December 31, 2022 include cash and cash equivalents, short-term investments, derivative liability, and convertible notes.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Schedule of Variable Interest Entities	The following table summarizes the carrying values of the assets and liabilities of the DevCo JVs that are consolidated by the Company as of September 30, 2023 and December 31, 2022 (in thousands): September 30, 2023 December 31, 2022 Assets Cash and cash equivalents $ 2,482 $ 6,686 Other current assets 5 38 Other noncurrent assets 5,877 3,208 Total assets 8,364 9,932 Liabilities Accounts payable 826 356 Other current liabilities 137 97 Total liabilities $ 963 $ 453
Schedule of Significant Customers	For each significant customer, revenue as a percentage of total revenue and accounts receivable as a percentage of total accounts receivable are as follows: Accounts Receivable Revenue Revenue September 30, December 31, Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 2023 2022 Customers: Customer A 54 % 54 % * 58 % 18 % 52 % Customer B 10 % 16 % * * * * Customer C 14 % 11 % * * * * Customer D * * * 12 % * * Customer E * * 89 % * 41 % * *Total less than 10% for the period.

REVENUE (Tables)

REVENUE (Tables)	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table provides information on the disaggregation of revenue as recorded in the condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Hardware revenue $ 117,143 $ 85,809 $ 246,461 $ 171,358 Services and other revenue 16,597 13,692 47,630 36,178 Total revenue $ 133,740 $ 99,501 $ 294,091 $ 207,536 The following table summarizes reportable revenue by geographic regions determined based on the location of the customers (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 United States $ 129,800 $ 97,815 $ 280,010 $ 201,475 Rest of the world 3,940 1,686 14,081 6,061 Total revenue $ 133,740 $ 99,501 $ 294,091 $ 207,536
Schedule of Remaining Performance Obligations	As of September 30, 2023 and September 30, 2022, the Company had $545.3 million and $365.8 million of remaining performance obligations, respectively, and the approximate percentages expected to be recognized as revenue in the future are as follows (in thousands, except percentages): September 30, 2023 Total Remaining Percent Expected to be Recognized as Revenue Less Than Two to Greater Than Services and other revenue $ 331,520 14 % 48 % 38 % Hardware revenue 213,813 100 % — % — % Total revenue $ 545,333 September 30, 2022 Total Remaining Percent Expected to be Recognized as Revenue Less Than Two to Greater Than Services and other revenue $ 264,195 17 % 51 % 32 % Hardware revenue 101,603 98 % 2 % — % Total revenue $ 365,798
Schedule of Contract Balances	The following table presents the changes in the deferred revenue balance during the nine months ended September 30, 2023 and September 30, 2022 (in thousands): Nine Months Ended September 30, 2023 2022 Beginning balance $ 138,074 $ 37,443 Deferred revenue acquired upon business combination — 49,626 Upfront payments received from customers 217,360 113,101 Upfront or annual incentive payments received 2,805 4,592 Revenue recognized related to amounts that were included in beginning balance of deferred revenue (26,538) (16,122) Revenue recognized related to amounts that were included in acquired balance of deferred revenue — (3,338) Revenue recognized related to deferred revenue generated during the period (165,997) (66,612) Ending balance $ 165,704 $ 118,690

SHORT-TERM INVESTMENTS (Tables)

SHORT-TERM INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of Short-Term Investments	The following tables summarize the estimated fair value of the Company’s short-term investments and the gross unrealized holding gains and losses as of September 30, 2023 and December 31, 2022 (in thousands): As of September 30, 2023 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Corporate debt securities $ 5,052 $ — $ (10) $ 5,042 U.S. government bonds 9,985 — (12) 9,973 Certificate of deposits 3,000 — — 3,000 Treasury bills 6,793 — — 6,793 Agency bonds 3,503 — (10) 3,493 Total short-term investments $ 28,333 $ — $ (32) $ 28,301 As of December 31, 2022 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Corporate debt securities $ 17,056 $ — $ (164) $ 16,892 Commercial paper 18,922 — — 18,922 U.S. government bonds 106,774 — (1,515) 105,259 Certificate of deposits 9,986 — — 9,986 Treasury bills 9,518 3 (5) 9,516 Agency bonds 1,500 — (1) 1,499 Total short-term investments $ 163,756 $ 3 $ (1,685) $ 162,074
Schedule of Contractual Maturities of Short-Term Investments	The following table presents the contractual maturities of the Company’s short-term investments as of September 30, 2023 (in thousands): As of September 30, 2023 Amortized cost Estimated Fair Value Due within one year $ 28,333 $ 28,301 Total $ 28,333 $ 28,301

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Financial Instruments Measured at Fair Value	The following table provides the financial instruments measured at fair value (in thousands): September 30, 2023 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market fund $ 30,293 $ — $ — $ 30,293 Commercial paper — — — — Debt securities: Corporate debt securities — 5,042 — 5,042 U.S. government bonds — 9,973 — 9,973 Certificate of deposits — 3,000 — 3,000 Treasury bills — 6,793 — 6,793 Agency bonds — 3,493 — 3,493 Total financial assets $ 30,293 $ 28,301 $ — $ 58,594 Liabilities: Derivative liability $ — $ — $ 7,731 $ 7,731 December 31, 2022 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market fund $ 10,618 $ — $ — $ 10,618 Commercial paper — 2,988 — 2,988 Debt securities: Corporate debt securities — 16,892 — 16,892 Commercial paper — 18,922 — 18,922 U.S. government bonds — 105,259 — 105,259 Certificate of deposits — 9,986 — 9,986 Treasury bills — 9,516 — 9,516 Other — 1,499 — 1,499 Total financial assets $ 10,618 $ 165,062 $ — $ 175,680

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	9 Months Ended
	Sep. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Schedule of Unaudited Pro Forma Information	The pro forma financial information is as follows (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Total revenue $ 133,740 $ 99,501 $ 294,091 $ 211,372 Net loss $ (77,072) $ (34,275) $ (102,728) $ (96,686)

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS, NET (Tables)	9 Months Ended
	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Goodwill consists of the following (in thousands): September 30, December 31, 2023 2022 Goodwill $ 547,158 $ 547,556 Recovery of escrow from AlsoEnergy acquisition — (915) Effect of foreign currency translation 6 8 Total goodwill $ 547,164 $ 546,649
Schedule of Intangible Assets	Intangible assets, net, consists of the following (in thousands): September 30, December 31, 2023 2022 Developed technology $ 32,000 $ 30,600 Trade name 11,300 11,300 Customer relationships 106,800 106,800 Backlog 3,900 3,900 Internally developed software 62,628 49,472 Intangible assets 216,628 202,072 Less: Accumulated amortization (58,309) (39,809) Add: Currency translation adjustment 2 2 Total intangible assets, net $ 158,321 $ 162,265

ENERGY STORAGE SYSTEMS, NET (Ta

ENERGY STORAGE SYSTEMS, NET (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Schedule of Energy Storage Systems, Net	Energy storage systems, net, consists of the following (in thousands): September 30, December 31, 2023 2022 Energy storage systems placed into service $ 141,759 $ 143,154 Less: accumulated depreciation (65,606) (58,782) Energy storage systems not yet placed into service 4,556 6,385 Total energy storage systems, net $ 80,709 $ 90,757

CONVERTIBLE NOTES (Tables)

CONVERTIBLE NOTES (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule Of Convertible Debt	The outstanding 2028 Convertible Notes balances as of September 30, 2023 and December 31, 2022 are summarized in the following table (in thousands): September 30, 2023 December 31, 2022 Long Term Debt Outstanding principal $ 297,024 $ 460,000 Unamortized initial purchaser’s debt discount and debt issuance cost (6,825) (12,091) Net carrying amount $ 290,199 $ 447,909 The following table presents total interest expense recognized related to the 2028 Convertible Notes during the three and nine months ended September 30, 2023 and 2022 (in thousands) : Three Months Ended Nine Months Ended 2023 2022 2023 2022 Cash interest expense Contractual interest expense $ 371 $ 575 $ 1,322 $ 1,725 Non-cash interest expense Amortization of debt discount and debt issuance cost 323 497 1,163 1,488 Total interest expense $ 694 $ 1,072 $ 2,485 $ 3,213 The outstanding 2030 Convertible Notes balances as of September 30, 2023 are summarized in the following table (in thousands): September 30, 2023 Long Term Debt Outstanding principal $ 240,000 Unamortized initial purchaser’s debt discount and debt issuance cost (7,131) Net carrying amount $ 232,869 The following table presents total interest expense recognized related to the 2030 Convertible Notes during the three months ended September 30, 2023 (in thousands) : Three Months Ended Nine Months Ended Cash interest expense Contractual interest expense $ 2,550 $ 5,043 Non-cash interest expense Amortization of debt discount and debt issuance cost 239 470 Total interest expense $ 2,789 $ 5,513

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Activity Under the Plan	The following table summarizes the stock option activity for the period ended September 30, 2023: Number of Weighted- Weighted- Aggregate Balances as of December 31, 2022 8,243,637 $ 6.88 6.6 $ 35,566 Options granted 1,291,349 10.25 Options exercised (116,717) 2.20 Options forfeited and expired (356,188) 15.64 Balances as of September 30, 2023 9,062,081 $ 7.08 6.2 $ 10,278 Options vested and exercisable — September 30, 2023 6,091,126 $ 4.88 5.1 $ 10,230
Schedule of Restricted Stock Activity	The following table summarizes the RSU activity for the period ended September 30, 2023: Number of RSUs Outstanding (1) Weighted-Average Balances as of December 31, 2022 6,719,490 $ 15.34 RSUs granted 7,542,131 5.62 RSUs vested (1,226,174) 10.78 RSUs forfeited (1,791,088) 8.65 Balances as of September 30, 2023 11,244,359 $ 10.56 (1) Includes certain restricted stock units with service and market-based vesting criteria.
Schedule of Stock-based Compensation Expense	The following table summarizes stock-based compensation expense recorded in each component of operating expenses in the Company’s condensed consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Sales and marketing $ 1,614 $ 1,172 $ 4,109 $ 3,102 Research and development 2,467 1,589 6,733 3,458 General and administrative 7,117 4,917 17,478 13,850 Total stock-based compensation expense $ 11,198 $ 7,678 $ 28,320 $ 20,410

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share amounts): Three Months Ended Nine Months Ended 2023 2022 2023 2022 Numerator: Net loss per share attributable to common stockholders, basic and diluted $ (77,072) $ (34,279) $ (102,728) $ (88,781) Denominator: Weighted-average number of shares outstanding used to compute net loss per share attributable to common stockholders, basic and diluted 155,829,348 154,392,573 155,474,725 153,043,010 Net loss per share attributable to common stockholders, basic and diluted $ (0.49) $ (0.22) $ (0.66) $ (0.58)
Schedule of Potentially Dilutive Shares	The following table shows total outstanding potentially dilutive shares excluded from the computation of diluted loss per share as their effect would have been anti-dilutive, as of September 30, 2023 and 2022: September 30, 2023 September 30, 2022 Outstanding 2028 Convertible Notes 10,157,181 15,730,390 Outstanding 2030 Convertible Notes 33,673,584 — Outstanding stock options 9,062,081 8,296,551 Outstanding warrants 2,533 2,533 Outstanding RSUs 11,244,359 6,557,284 Total 64,139,738 30,586,758

INCOME TAXES (Tables)

INCOME TAXES (Tables)	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Schedule of (Provision for) Benefit from Income Taxes and Effective Tax Rates	The following table reflects the Company’s (provision for) benefit from income taxes and the effective tax rates for the periods presented below (in thousands, except effective tax rate): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Loss before benefit from (provision for) income taxes $ (77,118) $ (34,256) $ (102,374) $ (103,982) Benefit from (provision for) income taxes $ 46 $ (19) $ (354) $ 15,201 Effective tax rate 0.1 % (0.1) % (0.3) % 14.6 %

BUSINESS (Details)

BUSINESS (Details) - USD ($) $ in Thousands			3 Months Ended						9 Months Ended
	Apr. 03, 2023	Nov. 22, 2021	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Apr. 06, 2023	Dec. 31, 2022
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Cash and cash equivalents			$ 97,064			$ 100,098			$ 97,064	$ 100,098		$ 87,903
Short-term investments			28,300						28,300
Accumulated deficit			(734,809)						(734,809)			$ (632,081)
Working capital			241,300						241,300
Net loss			$ (77,072)	$ 19,122	$ (44,778)	$ (34,275)	$ (32,023)	$ (22,483)	(102,728)	(88,781)
Net cash used in operating activities									(205,248)	(68,634)
Proceeds from convertible notes									$ 232,399	$ 0
2030 Convertible Notes | Convertible Notes
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Proceeds from convertible notes	$ 232,400
Fixed interest rate, annual	4.25%										4.25%
2028 Convertible Notes | Convertible Notes
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Proceeds from convertible notes		$ 445,700		99,800
Fixed interest rate, annual		0.50%
Cancellation of aggregate principal				$ 163,000

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Variable Interest Entities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Assets
Cash and cash equivalents	$ 97,064	$ 87,903	$ 100,098
Other current assets	10,520	8,026
Other noncurrent assets	77,132	65,339
Total assets	1,398,792	1,421,893
Liabilities
Other current liabilities	12,689	5,412
Total liabilities	945,449	869,726
Variable Interest Entity, Primary Beneficiary
Assets
Cash and cash equivalents	2,482	6,686
Other current assets	5	38
Other noncurrent assets	5,877	3,208
Total assets	8,364	9,932
Liabilities
Accounts payable	826	356
Other current liabilities	137	97
Total liabilities	$ 963	$ 453

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)
Concentration Risk [Line Items]
Net loss attributable to Stem	$ (77,072)	$ (34,279)	$ (102,728)	$ (88,781)
Number of operating segments | segment			1
Variable Interest Entity, Primary Beneficiary
Concentration Risk [Line Items]
Contribution paid			$ 100	6,600
Net loss attributable to Stem	$ 1,200	$ 0	$ 1,400	$ 0

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Significant Customers (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Customer A | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			54%		54%
Customer A | Revenue
Concentration Risk [Line Items]
Concentration risk, percentage		58%	18%	52%
Customer B | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			10%		16%
Customer C | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			14%		11%
Customer D | Revenue
Concentration Risk [Line Items]
Concentration risk, percentage		12%
Customer E | Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	89%		41%

REVENUE - Disaggregation of Rev

REVENUE - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 133,740	$ 99,501	$ 294,091	$ 207,536
United States
Disaggregation of Revenue [Line Items]
Revenue	129,800	97,815	280,010	201,475
Rest of the world
Disaggregation of Revenue [Line Items]
Revenue	3,940	1,686	14,081	6,061
Hardware revenue
Disaggregation of Revenue [Line Items]
Revenue	117,143	85,809	246,461	171,358
Services and other revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 16,597	$ 13,692	$ 47,630	$ 36,178

REVENUE - Narrative (Details)

REVENUE - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Capitalized Contract Cost [Line Items]
Total Remaining Performance Obligations	$ 545,333	$ 365,798
Revenue reduction	(32,700)
Hardware revenue
Capitalized Contract Cost [Line Items]
Total Remaining Performance Obligations	213,813	$ 101,603
Revenue reduction	$ (4,700)

REVENUE - Remaining Performance

REVENUE - Remaining Performance Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	$ 545,333	$ 365,798
Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	331,520	264,195
Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	$ 213,813	$ 101,603
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01 | Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue		17%
Percent Expected to be Recognized as Revenue		3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01 | Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue		98%
Percent Expected to be Recognized as Revenue		3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue		51%
Percent Expected to be Recognized as Revenue		4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue		2%
Percent Expected to be Recognized as Revenue		4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01 | Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue	14%
Percent Expected to be Recognized as Revenue	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01 | Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue	100%
Percent Expected to be Recognized as Revenue	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue	48%
Percent Expected to be Recognized as Revenue	4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue	0%
Percent Expected to be Recognized as Revenue	4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 | Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue		32%
Percent Expected to be Recognized as Revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 | Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue		0%
Percent Expected to be Recognized as Revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 | Services and other revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue	38%
Percent Expected to be Recognized as Revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 | Hardware revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent Expected to be Recognized as Revenue	0%
Percent Expected to be Recognized as Revenue

REVENUE - Contract Balances (De

REVENUE - Contract Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 138,074	$ 37,443
Deferred revenue acquired upon business combination	0	49,626
Upfront payments received from customers	217,360	113,101
Upfront or annual incentive payments received	2,805	4,592
Revenue recognized related to amounts that were included in beginning balance of deferred revenue	(26,538)	(16,122)
Revenue recognized related to amounts that were included in acquired balance of deferred revenue	0	(3,338)
Revenue recognized related to deferred revenue generated during the period	(165,997)	(66,612)
Ending balance	$ 165,704	$ 118,690

SHORT-TERM INVESTMENTS - Schedu

SHORT-TERM INVESTMENTS - Schedule of Short-Term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Short-term investments:
Amortized Cost	$ 28,333	$ 163,756
Unrealized Gain	0	3
Unrealized Loss	(32)	(1,685)
Estimated Fair Value	28,301	162,074
Corporate debt securities
Short-term investments:
Amortized Cost	5,052	17,056
Unrealized Gain	0	0
Unrealized Loss	(10)	(164)
Estimated Fair Value	5,042	16,892
Commercial paper
Short-term investments:
Amortized Cost		18,922
Unrealized Gain		0
Unrealized Loss		0
Estimated Fair Value		18,922
U.S. government bonds
Short-term investments:
Amortized Cost	9,985	106,774
Unrealized Gain	0	0
Unrealized Loss	(12)	(1,515)
Estimated Fair Value	9,973	105,259
Certificate of deposits
Short-term investments:
Amortized Cost	3,000	9,986
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	3,000	9,986
Treasury bills
Short-term investments:
Amortized Cost	6,793	9,518
Unrealized Gain	0	3
Unrealized Loss	0	(5)
Estimated Fair Value	6,793	9,516
Agency bonds
Short-term investments:
Amortized Cost	3,503	1,500
Unrealized Gain	0	0
Unrealized Loss	(10)	(1)
Estimated Fair Value	$ 3,493	$ 1,499

SHORT-TERM INVESTMENTS - Sche_2

SHORT-TERM INVESTMENTS - Schedule of Contractual Maturities of Short-Term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Amortized cost
Due within one year	$ 28,333
Amortized Cost	28,333	$ 163,756
Estimated Fair Value
Due within one year	28,301
Estimated Fair Value	$ 28,301	$ 162,074

SHORT-TERM INVESTMENTS - Additi

SHORT-TERM INVESTMENTS - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Investments, Debt and Equity Securities [Abstract]
Allowance for credit losses recorded	$ 0

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt securities:
Debt securities, available-for-sale	$ 28,301	$ 162,074
Corporate debt securities
Debt securities:
Debt securities, available-for-sale	5,042	16,892
Commercial paper
Debt securities:
Debt securities, available-for-sale		18,922
U.S. government bonds
Debt securities:
Debt securities, available-for-sale	9,973	105,259
Certificate of deposits
Debt securities:
Debt securities, available-for-sale	3,000	9,986
Treasury bills
Debt securities:
Debt securities, available-for-sale	6,793	9,516
Agency bonds
Debt securities:
Debt securities, available-for-sale	3,493	1,499
Fair Value, Recurring
Debt securities:
Total financial assets	58,594	175,680
Liabilities:
Derivative liability	7,731
Fair Value, Recurring | Corporate debt securities
Debt securities:
Debt securities, available-for-sale	5,042	16,892
Fair Value, Recurring | Commercial paper
Debt securities:
Debt securities, available-for-sale		18,922
Fair Value, Recurring | U.S. government bonds
Debt securities:
Debt securities, available-for-sale	9,973	105,259
Fair Value, Recurring | Certificate of deposits
Debt securities:
Debt securities, available-for-sale	3,000	9,986
Fair Value, Recurring | Treasury bills
Debt securities:
Debt securities, available-for-sale	6,793	9,516
Fair Value, Recurring | Agency bonds
Debt securities:
Debt securities, available-for-sale	3,493
Fair Value, Recurring | Other
Debt securities:
Debt securities, available-for-sale		1,499
Fair Value, Recurring | Money market fund
Cash equivalents:
Cash equivalents	30,293	10,618
Fair Value, Recurring | Commercial paper
Cash equivalents:
Cash equivalents	0	2,988
Level 1 | Fair Value, Recurring
Debt securities:
Total financial assets	30,293	10,618
Liabilities:
Derivative liability	0
Level 1 | Fair Value, Recurring | Corporate debt securities
Debt securities:
Debt securities, available-for-sale	0	0
Level 1 | Fair Value, Recurring | Commercial paper
Debt securities:
Debt securities, available-for-sale		0
Level 1 | Fair Value, Recurring | U.S. government bonds
Debt securities:
Debt securities, available-for-sale	0	0
Level 1 | Fair Value, Recurring | Certificate of deposits
Debt securities:
Debt securities, available-for-sale	0	0
Level 1 | Fair Value, Recurring | Treasury bills
Debt securities:
Debt securities, available-for-sale	0	0
Level 1 | Fair Value, Recurring | Agency bonds
Debt securities:
Debt securities, available-for-sale	0
Level 1 | Fair Value, Recurring | Other
Debt securities:
Debt securities, available-for-sale		0
Level 1 | Fair Value, Recurring | Money market fund
Cash equivalents:
Cash equivalents	30,293	10,618
Level 1 | Fair Value, Recurring | Commercial paper
Cash equivalents:
Cash equivalents	0	0
Level 2 | Fair Value, Recurring
Debt securities:
Total financial assets	28,301	165,062
Liabilities:
Derivative liability	0
Level 2 | Fair Value, Recurring | Corporate debt securities
Debt securities:
Debt securities, available-for-sale	5,042	16,892
Level 2 | Fair Value, Recurring | Commercial paper
Debt securities:
Debt securities, available-for-sale		18,922
Level 2 | Fair Value, Recurring | U.S. government bonds
Debt securities:
Debt securities, available-for-sale	9,973	105,259
Level 2 | Fair Value, Recurring | Certificate of deposits
Debt securities:
Debt securities, available-for-sale	3,000	9,986
Level 2 | Fair Value, Recurring | Treasury bills
Debt securities:
Debt securities, available-for-sale	6,793	9,516
Level 2 | Fair Value, Recurring | Agency bonds
Debt securities:
Debt securities, available-for-sale	3,493
Level 2 | Fair Value, Recurring | Other
Debt securities:
Debt securities, available-for-sale		1,499
Level 2 | Fair Value, Recurring | Money market fund
Cash equivalents:
Cash equivalents	0	0
Level 2 | Fair Value, Recurring | Commercial paper
Cash equivalents:
Cash equivalents	0	2,988
Level 3 | Fair Value, Recurring
Debt securities:
Total financial assets	0	0
Liabilities:
Derivative liability	7,731
Level 3 | Fair Value, Recurring | Corporate debt securities
Debt securities:
Debt securities, available-for-sale	0	0
Level 3 | Fair Value, Recurring | Commercial paper
Debt securities:
Debt securities, available-for-sale		0
Level 3 | Fair Value, Recurring | U.S. government bonds
Debt securities:
Debt securities, available-for-sale	0	0
Level 3 | Fair Value, Recurring | Certificate of deposits
Debt securities:
Debt securities, available-for-sale	0	0
Level 3 | Fair Value, Recurring | Treasury bills
Debt securities:
Debt securities, available-for-sale	0	0
Level 3 | Fair Value, Recurring | Agency bonds
Debt securities:
Debt securities, available-for-sale	0
Level 3 | Fair Value, Recurring | Other
Debt securities:
Debt securities, available-for-sale		0
Level 3 | Fair Value, Recurring | Money market fund
Cash equivalents:
Cash equivalents	0	0
Level 3 | Fair Value, Recurring | Commercial paper
Cash equivalents:
Cash equivalents	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - Convertible Notes - Level 2 - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
2028 Convertible Notes
Debt Instrument [Line Items]
Convertible debt	$ 177.9	$ 293.1
2030 Convertible Notes
Debt Instrument [Line Items]
Convertible debt	$ 192.1

BUSINESS COMBINATIONS - Narrati

BUSINESS COMBINATIONS - Narrative (Details) - AlsoEnergy, Inc - USD ($) $ in Millions		9 Months Ended
	Feb. 01, 2022	Sep. 30, 2022
Business Acquisition [Line Items]
Percent of outstanding shares acquired	100%
Aggregate purchase price	$ 652
Cash paid, net of working capital adjustment	543.1
Transaction costs		$ 6.1
Common Stock
Business Acquisition [Line Items]
Business combination, consideration transferred, equity interests issued and issuable	$ 108.9
Business acquisition, equity interest Issued or issuable (in shares)	8,621,006

BUSINESS COMBINATIONS - Unaudit

BUSINESS COMBINATIONS - Unaudited Pro Forma Information (Details) - AlsoEnergy, Inc - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Business Acquisition [Line Items]
Total revenue	$ 133,740	$ 99,501	$ 294,091	$ 211,372
Net loss	$ (77,072)	$ (34,275)	$ (102,728)	$ (96,686)

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS, NET - Goodwill Consists (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 547,158	$ 547,556
Recovery of escrow from AlsoEnergy acquisition	0	(915)
Effect of foreign currency translation	6	8
Total goodwill	$ 547,164	$ 546,649

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS, NET - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 216,628		$ 216,628		$ 202,072
Less: Accumulated amortization	(58,309)		(58,309)		(39,809)
Add: Currency translation adjustment	2		2		2
Total intangible assets, net	158,321		158,321		162,265
Amortization of intangible assets	5,200	$ 6,500	18,500	$ 16,900
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	32,000		32,000		30,600
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	11,300		11,300		11,300
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	106,800		106,800		106,800
Backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	3,900		3,900		3,900
Internally developed software
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 62,628		$ 62,628		$ 49,472

ENERGY STORAGE SYSTEMS, NET - S

ENERGY STORAGE SYSTEMS, NET - Schedule of Energy Storage Systems, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	$ (65,606)	$ (58,782)
Total energy storage systems, net	80,709	90,757
Energy storage systems placed into service
Property, Plant and Equipment [Line Items]
Total energy storage systems, gross	141,759	143,154
Energy storage systems not yet placed into service
Property, Plant and Equipment [Line Items]
Total energy storage systems, gross	$ 4,556	$ 6,385

ENERGY STORAGE SYSTEMS, NET - N

ENERGY STORAGE SYSTEMS, NET - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 3,600	$ 3,800	$ 10,800	$ 11,200
Impairment loss of energy storage systems	$ 300	$ 400	$ 2,347	$ 1,293

NOTES PAYABLE - Narrative (Deta

NOTES PAYABLE - Narrative (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 06, 2023	Jan. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Apr. 03, 2023
Debt Instrument [Line Items]
Loss on extinguishment of debt			$ 0	$ 0	$ (59,121)	$ 0
Line of Credit | 2021 Credit Agreement
Debt Instrument [Line Items]
Total capacity		$ 2,700
Fixed interest rate, annual		5.45%
Proceeds from credit agreement		$ 1,800
Convertible Notes | 2030 Convertible Notes
Debt Instrument [Line Items]
Fixed interest rate, annual	4.25%						4.25%
Loss on extinguishment of debt	$ 300

CONVERTIBLE NOTES - Narrative (

CONVERTIBLE NOTES - Narrative (Details) $ / shares in Units, $ in Thousands					3 Months Ended			9 Months Ended		12 Months Ended
	Apr. 06, 2023 USD ($)	Apr. 03, 2023 USD ($) day $ / shares	Nov. 22, 2021 USD ($) day $ / shares	Nov. 19, 2021 USD ($) $ / shares	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 29, 2023 $ / shares
Debt Instrument [Line Items]
Proceeds from convertible notes								$ 232,399	$ 0
Gain on extinguishment of debt, net					$ 0		$ 0	$ 59,121	$ 0
Capped Call Options
Debt Instrument [Line Items]
Cost of capped calls				$ 66,700		$ 27,800				$ 66,700
Initial strike price (in dollars per share) | $ / shares				$ 29.2428							$ 7.1272
Cap price (in dollars per share) | $ / shares				$ 49.6575							$ 11.1800
2028 Convertible Notes | Convertible Notes
Debt Instrument [Line Items]
Face amount			$ 460,000
Fixed interest rate, annual			0.50%
Conversion ratio			0.0341965
Conversion price (in dollars per share) | $ / shares			$ 29.24
Redemption price, percentage			100%
Proceeds from convertible notes			$ 445,700			99,800
Cancellation of aggregate principal						163,000
Gain on extinguishment of debt, net						$ 59,400
Effective interest percentage			0.90%
Term			7 years
2028 Convertible Notes | Convertible Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Conversion price, percentage			130%
2028 Convertible Notes | Convertible Notes | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Threshold trading days | day			20
2030 Convertible Notes | Convertible Notes
Debt Instrument [Line Items]
Face amount		$ 240,000
Fixed interest rate, annual	4.25%	4.25%
Conversion ratio		0.1403066
Conversion price (in dollars per share) | $ / shares		$ 7.1272
Redemption price, percentage		100%
Proceeds from convertible notes		$ 232,400
Gain on extinguishment of debt, net	$ (300)
Effective interest percentage		4.70%
Term		7 years
Debt issuance costs		$ 7,600
2030 Convertible Notes | Convertible Notes | Capped Call Options
Debt Instrument [Line Items]
Proceeds from convertible notes		$ 27,800
2030 Convertible Notes | Convertible Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Conversion price, percentage		130%
2030 Convertible Notes | Convertible Notes | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Threshold trading days | day		20

CONVERTIBLE NOTES - Outstanding

CONVERTIBLE NOTES - Outstanding Convertible Notes (Details) - Convertible Notes - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
2028 Convertible Notes
Debt Instrument [Line Items]
Outstanding principal	$ 297,024	$ 460,000
Unamortized initial purchaser’s debt discount and debt issuance cost	(6,825)	(12,091)
Long-Term Debt, Total	290,199	$ 447,909
2030 Convertible Notes
Debt Instrument [Line Items]
Outstanding principal	240,000
Unamortized initial purchaser’s debt discount and debt issuance cost	(7,131)
Long-Term Debt, Total	$ 232,869

CONVERTIBLE NOTES - Interest Ex

CONVERTIBLE NOTES - Interest Expense Recognized Related to Convertible Note (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Debt Instrument [Line Items]
Amortization of debt discount and debt issuance cost			$ 1,969	$ 1,479
2028 Convertible Notes | Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense	$ 371	$ 575	1,322	1,725
Amortization of debt discount and debt issuance cost	323	497	1,163	1,488
Total interest expense	694	$ 1,072	2,485	$ 3,213
2030 Convertible Notes | Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense	2,550		5,043
Amortization of debt discount and debt issuance cost	239		470
Total interest expense	$ 2,789		$ 5,513

WARRANTS (Details)

WARRANTS (Details) - Legacy Stem Warrants - USD ($) $ in Millions	Apr. 28, 2021	Sep. 30, 2023
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	50,207,439	2,533
Conversion of securities into common stock (in shares)	2,759,970
Gain from fair value adjustment	$ 100.9
Conversion of securities into common stock	$ 60.6

STOCK-BASED COMPENSATION - Opti

STOCK-BASED COMPENSATION - Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Number of Options Outstanding
Options outstanding, beginning of period (in shares)	8,243,637
Options granted (in shares)	1,291,349
Options exercised (in shares)	(116,717)
Options forfeited (in shares)	(356,188)
Options outstanding, end of period (in shares)	9,062,081	8,243,637
Options vested and exercisable (in shares)	6,091,126
Weighted- Average Exercise Price Per Share
Options outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 7.08	$ 6.88
Options granted, weighted average exercise price (in dollars per share) | $ / shares	10.25
Options exercised, weighted average exercise price (in dollars per share) | $ / shares	2.20
Options forfeited, weighted average exercise price (in dollars per share) | $ / shares	15.64
Options vested and exercisable, weighted-average exercise price (in dollars per share) | $ / shares	$ 4.88
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life, options outstanding	6 years 2 months 12 days	6 years 7 months 6 days
Weighted average remaining contractual life, options vested and exercisable	5 years 1 month 6 days
Aggregate intrinsic value, options outstanding | $	$ 10,278	$ 35,566
Aggregate intrinsic value, options vested and exercisable | $	$ 10,230

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation expense	$ 17.3		$ 17.3
Internally developed software | Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount capitalized	1.2	$ 0.6	3.1	$ 1.7
RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation expense	$ 79.5		$ 79.5
Weighted average period for recognition of stock-based compensation expense			1 year 10 months 24 days
Outstanding stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period for recognition of stock-based compensation expense			1 year 6 months

STOCK-BASED COMPENSATION - RSU

STOCK-BASED COMPENSATION - RSU Activity (Details) - RSU	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Number of RSUs Outstanding
RSUs outstanding, beginning (in shares) | shares	6,719,490
RSUs granted (in shares) | shares	7,542,131
RSUs vested (in shares) | shares	(1,226,174)
RSUs forfeited (in shares) | shares	(1,791,088)
RSUs outstanding, ending (in shares) | shares	11,244,359
Weighted-Average Grant Date Fair Value Per Share
RSUs outstanding, weighted average grant date fair value, beginning (in dollars per share) | $ / shares	$ 15.34
RSUs granted, weighted average grant date fair value (in dollars per share) | $ / shares	5.62
RSUs vested, weighted average grant date fair value (in dollars per share) | $ / shares	10.78
RSUs forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	8.65
RSUs outstanding, weighted average grant date fair value, ending (in dollars per share) | $ / shares	$ 10.56

STOCK-BASED COMPENSATION - Stoc

STOCK-BASED COMPENSATION - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 11,198	$ 7,678	$ 28,320	$ 20,410
Liability-Classified Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,500		1,500
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,614	1,172	4,109	3,102
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,467	1,589	6,733	3,458
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 7,117	$ 4,917	$ 17,478	$ 13,850

NET LOSS PER SHARE - Basic and

NET LOSS PER SHARE - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Net loss per share attributable to common stockholders, basic	$ (77,072)	$ (34,279)	$ (102,728)	$ (88,781)
Net loss per share attributable to common stockholders, diluted	$ (77,072)	$ (34,279)	$ (102,728)	$ (88,781)
Denominator:
Weighted-average number of shares outstanding used to compute net loss per share attributable to common stockholders, basic (in shares)	155,829,348	154,392,573	155,474,725	153,043,010
Weighted-average number of shares outstanding used to compute net loss per share attributable to common stockholders, diluted (in shares)	155,829,348	154,392,573	155,474,725	153,043,010
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.49)	$ (0.22)	$ (0.66)	$ (0.58)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.49)	$ (0.22)	$ (0.66)	$ (0.58)

NET LOSS PER SHARE - Antidiluti

NET LOSS PER SHARE - Antidilutive Securities (Details) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	64,139,738	30,586,758
Outstanding 2028 Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	10,157,181	15,730,390
Outstanding 2030 Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	33,673,584	0
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	9,062,081	8,296,551
Outstanding warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	2,533	2,533
Outstanding RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	11,244,359	6,557,284

INCOME TAXES - Provision (Benef

INCOME TAXES - Provision (Benefit) for Income Taxes and the Effective Tax Rates (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Loss before benefit from (provision for) income taxes	$ (77,118)	$ (34,256)	$ (102,374)	$ (103,982)
Benefit from (provision for) income taxes	$ 46	$ (19)	$ (354)	$ 15,201
Effective tax rate	0.10%	(0.10%)	(0.30%)	14.60%

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Tax provision (benefit)	$ (46)	$ 19	$ 354	$ (15,201)
Effective tax rate	0.10%	(0.10%)	(0.30%)	14.60%
(Benefit) for income taxes, federal			$ 300	$ 15,100

COMMITMENTS AND CONTINGNECIES (

COMMITMENTS AND CONTINGNECIES (Details)	Mar. 01, 2023 USD ($) ft²	Sep. 30, 2023 USD ($)
Loss Contingencies [Line Items]
Operating lease liability	$ 2,800,000
Lease term	58 months
Base rent per month	$ 58,500
Loss contingency accrual amount		$ 5,600,000
Gurugram, India
Loss Contingencies [Line Items]
Area of lease | ft²	41,811