WARRANTS	9 Months Ended
WARRANTS	Sep. 30, 2021
Equity [Abstract]
WARRANTS	WARRANTS Legacy Stem Warrants Since inception the Company has issued warrants to purchase shares of Legacy Stem’s preferred stock in conjunction with various debt financings. See Note 5 - Fair Value Measurements, for further information regarding fair value measurements associated with the resulting warrant liabilities, which are remeasured on a recurring basis each period. 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 Class A 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. As of September 30, 2021, there were 23,634 Legacy Stem Warrants outstanding. These instruments are exercisable into the Company’s Class A common stock and are equity classified. Public Warrants and Private Placement Warrants As part of STPK’s initial public offering, under the Warrant Agreement dated as of August 20, 2020 (the “Warrant Agreement”) and, prior to the effectiveness of the Merger, STPK issued 12,786,168 warrants each of which entitled the holder to purchase one share of Class A common stock at an exercise price of $11.50 per share of common stock (the “Public Warrants”). Simultaneously with the closing of the IPO, STPK completed the private sale of 7,181,134 million warrants to STPK’s sponsor (the “Private Warrants”). Upon issuance, these warrants met the criteria for liability classification. Upon the effectiveness of the Merger, Stem assumed the outstanding Public Warrants and Private Warrants, which continued to meet the criteria for liability classification, resulting in assumed warrant liabilities of $185.9 million and $118.4 million, respectively, or a total warrant liability of $304.3 million. On June 25, 2021, the Company entered into an exchange agreement (the “Exchange Agreement”) with the holders of the 7,181,134 outstanding Private Placement Warrants, pursuant to which such holders received 4,683,349 shares of the Company’s common stock on June 30, 2021, in exchange for the cancellation of the outstanding Private Placement Warrants. The Exchange Shares were issued in reliance upon the exemption provided by Section 3(a)(9) of the Securities Act of 1933, as amended. Immediately prior to the exchange, the Private Warrants were marked to fair value, resulting in a loss of $52.0 million. As a result of the Exchange Agreement, there were no Private Warrants outstanding as of September 30, 2021. On August 20, 2021, the Company issued an irrevocable notice for redemption of all 12,786,129 of the Company’s outstanding public warrants at 5:00 p.m. Eastern time on September 20, 2021 (“Redemption Date”). Pursuant to the notice of redemption, holders exercised 12,638,723 Public Warrants for a purchase price of $11.50 per share, for proceeds to the Company of approximately $145.3 million. The Company redeemed all remaining outstanding Public Warrants that had not been exercised as of 5:00 p.m. Eastern time on the Redemption Date. As a result of the settlement of the Public Warrants, the Company recorded a gain of $134.9 million on the revaluation of the warrant liability. The Company also recorded a gain of $2.1 million on the redemption of unexercised public warrants. These gains are recorded in “change in fair value of warrants and embedded derivative” in the condensed consolidated statements of operation, in the three and nine months ended September 30, 2021. The public warrants have been delisted from the NYSE, and there are no public warrants left outstanding. Warrants Issued for Services On April 7, 2021, the Company entered into a strategic relationship with an existing shareholder not deemed to be a related party to jointly explore on a non-exclusive basis possible business opportunities to advance projects in the United States, the United Kingdom, Europe and Asia. As consideration for the strategic relationship, upon closing of the Merger, the Company issued warrants to purchase 350,000 shares of the Company’s common stock at an exercise price of $0.01 per share. These warrants were deemed to have been fully earned as of the grant date. The warrants were valued at fair market value as of the grant date totaling $9.2 million and recorded to general and administrative expense in the Company’s statement of operations. In May 2021, all of these warrants were exercised for shares of the Company’s common stock.