XML 88 R68.htm IDEA: XBRL DOCUMENT
v3.21.1

Related Party Transactions - Founder Shares (Details) - USD ($) |  |  |  |  | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 08, 2020 | Aug. 26, 2020 | Jul. 29, 2020 | Jul. 13, 2020 | Mar. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Nov. 08, 2018
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Common shares, shares outstanding (in shares) |  |  |  |  | 17,694,228 | 11,228,371 |  |
Common stock, shares issued |  |  |  |  | 17,694,228 | 11,228,371 | 9,392,682 |
Star Peak Energy Transition Corp [Member] |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Aggregate purchase price |  |  |  |  |  | $ 376,932,978 |  |
Star Peak Energy Transition Corp [Member] | Private Placement |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Aggregate purchase price |  |  |  |  | $ 1.50 | $ 1.50 |  |
Number of shares transferred (in shares) |  |  |  |  | 6,733,333 | 6,733,333 |  |
Star Peak Energy Transition Corp [Member] | Founder Shares |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Number of shares subject to forfeiture (in shares) |  | 472,874 | 1,312,500 |  |  |  |  |
Percentage of issued and outstanding shares after the Initial Public Offering collectively held by initial stockholders |  |  | 20.00% |  |  |  |  |
Star Peak Energy Transition Corp [Member] | Sponsor |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Number of shares transferred (in shares) |  |  |  | 10,062,500 |  |  |  |
Star Peak Energy Transition Corp [Member] | Sponsor | Private Placement |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Number of shares with respect to which stock dividend is effected |  | 447,801 |  |  |  |  |  |
Star Peak Energy Transition Corp [Member] | Sponsor | Founder Shares |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Aggregate purchase price |  |  |  |  | $ 25,000 | $ 25,000 |  |
Number of shares transferred (in shares) |  |  | 40,000 |  |  |  |  |
Star Peak Energy Transition Corp [Member] | Class A shares |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Common shares, shares outstanding (in shares) |  |  |  |  | 29,717,672 | 14,082,976 |  |
Percentage of issued and outstanding shares after the Initial Public Offering collectively held by initial stockholders |  |  |  |  | 20.00% | 20.00% |  |
Stock price trigger to transfer, assign or sell any shares or warrants of the company, after the completion of the initial business combination (in dollars per share) |  |  |  |  | $ 11.50 | $ 11.50 |  |
Common stock, shares issued |  |  |  |  | 29,717,672 | 14,082,976 |  |
Star Peak Energy Transition Corp [Member] | Class A shares | Founder Shares |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Stock price trigger to transfer, assign or sell any shares or warrants of the company, after the completion of the initial business combination (in dollars per share) |  |  |  |  | $ 12.00 | $ 12.00 |  |
Star Peak Energy Transition Corp [Member] | Class A shares | Sponsor | Founder Shares |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Threshold period for not to transfer, assign or sell any of their shares or warrants after the completion of the initial business combination |  |  |  |  |  | 1 year |  |
Threshold trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination |  |  |  |  |  | 20 days |  |
Threshold consecutive trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination |  |  |  |  |  | 30 days |  |
Threshold period after the business combination in which the 20 trading days within any 30 trading day period commences |  |  |  |  |  | 150 days |  |
Transfer, Assign Or Sell Any Shares Or Warrants After Completion Of Initial Business Combination, Threshold Trading Days |  |  |  |  |  | 20 days |  |
Star Peak Energy Transition Corp [Member] | Common Class B |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Common shares, shares outstanding (in shares) |  |  |  | 10,062,500 | 9,589,626 | 9,589,626 | 10,062,500 |
Percentage of issued and outstanding shares after the Initial Public Offering collectively held by initial stockholders |  |  |  | 20.00% |  |  |  |
Class B common stock forfeited (in shares) |  |  |  |  |  | 472,874 |  |
Common stock, shares issued |  |  |  |  | 9,589,626 | 9,589,626 | 10,062,500 | 2,875,000
Star Peak Energy Transition Corp [Member] | Common Class B | Over-allotment |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Class B common stock forfeited (in shares) |  | 472,874 |  |  |  |  |  |
Star Peak Energy Transition Corp [Member] | Common Class B | Sponsor | Founder Shares |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Number of shares issued | 2,875,000 |  |  |  |  |  |  |
Aggregate purchase price | $ 25,000 |  |  |  |  |  |  |
Threshold period for not to transfer, assign or sell any of their shares or warrants after the completion of the initial business combination |  |  |  |  | 1 year |  |  |
Stock price trigger to transfer, assign or sell any shares or warrants of the company, after the completion of the initial business combination (in dollars per share) | $ 0.0001 |  |  |  |  |  |  |
Threshold trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination |  |  |  |  | 20 days |  |  |
Threshold consecutive trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination |  |  |  |  | 30 days | 30 days |  |
Threshold period after the business combination in which the 20 trading days within any 30 trading day period commences |  |  |  |  | 150 days |  |  |
Transfer, Assign Or Sell Any Shares Or Warrants After Completion Of Initial Business Combination, Threshold Trading Days |  |  |  |  | 20 days |  |  |

X
- Definition Number of common stock, forfeited. + References No definition available. + Details
Name: | stem_CommonStockSharesForfeited
Namespace Prefix: | stem_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares of the company that are subject to forfeiture during the period. + References No definition available. + Details
Name: | stem_NumberOfSharesSubjectToForfeiture
Namespace Prefix: | stem_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares with respect to which stock dividend is effected. + References No definition available. + Details
Name: | stem_NumberOfSharesWithRespectToWhichStockDividendIsEffected
Namespace Prefix: | stem_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of issued and outstanding shares after the Initial Public Offering collectively held by initial stockholders. + References No definition available. + Details
Name: | stem_PercentageOfIssuedAndOutstandingSharesAfterInitialPublicOfferingCollectivelyHeldByInitialStockholders
Namespace Prefix: | stem_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares transferred to others during the period. + References No definition available. + Details
Name: | stem_StockTransferredToOthersDuringPeriodShares
Namespace Prefix: | stem_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The threshold period after the business combination in which the 20 trading days within any 30 trading day period commences for the transfer, assigning or sale of any shares of the company, after the completion of the initial business combination. + References No definition available. + Details
Name: | stem_ThresholdPeriodAfterBusinessCombinationInWhichSpecifiedTradingDaysWithinAnySpecifiedTradingDayPeriodCommences
Namespace Prefix: | stem_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The threshold period for not to transfer, assign or sell any of the shares or warrants, after the completion of the initial business combination. + References No definition available. + Details
Name: | stem_ThresholdPeriodForNotToTransferAssignOrSellAnySharesOrWarrantsAfterCompletionOfInitialBusinessCombination
Namespace Prefix: | stem_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Price of the entity's common stock which would be required to be attained to trigger the transfer, assign or sale of any shares or warrants of the company, after the completion of the initial business combination. + References No definition available. + Details
Name: | stem_TransferAssignOrSellAnySharesOrWarrantsAfterCompletionOfInitialBusinessCombinationStockPriceTrigger
Namespace Prefix: | stem_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold period of specified consecutive trading days for stock price trigger considered for the transfer, assigning or sale of any shares or warrants of the company, after the completion of the initial business combination. + References No definition available. + Details
Name: | stem_TransferAssignOrSellAnySharesOrWarrantsAfterCompletionOfInitialBusinessCombinationThresholdConsecutiveTradingDays
Namespace Prefix: | stem_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold number of specified trading days for stock price trigger considered for the transfer, assigning or sale of any shares or warrants of the company, after the completion of the initial business combination. + References No definition available. + Details
Name: | stem_TransferAssignOrSellAnySharesOrWarrantsAfterCompletionOfInitialBusinessCombinationThresholdTradingDays
Namespace Prefix: | stem_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodValueNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=stem_StarPeakEnergyTransitionCorpMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=stem_FounderSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stem_SponsorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_OverAllotmentOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |