XML 61 R41.htm IDEA: XBRL DOCUMENT
v3.21.1

Fair Value Measurements - Quantitative information regarding Level 3 fair value measurements inputs as their measurement dates (Details) - Star Peak Energy Transition Corp [Member] - Level 3 | Mar. 31, 2021 USD ($) Y | Dec. 31, 2020 Y | Sep. 30, 2020 Y
--- | --- | --- | ---
Exercise price |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 11.50 | 11.50 | 11.50
Stock price |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 20.58 | 20.46 | 9.90
Expected term (in years) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 5.09 | 5.33 | 5.58
Volatility |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 15.00 | 21.00 | 21.50
Risk-free interest rate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 0.94 | 0.41 | 0.34
Probability of completing a Business Combination |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 95.00 | 85.00 | 50.00
Discount for lack of marketability |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Measurement input | 1.5 | 3.00 | 4.00

X
- Definition Value of input used to measure derivative liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_DerivativeLiabilityMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExercisePriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputSharePriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExpectedTermMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputPriceVolatilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputRiskFreeInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=stem_MeasurementInputProbabilityOfCompletingBusinessCombinationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |