Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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(22))
-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 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ 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 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ 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 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=be_LetterofCreditdueDecember2021NonRecourseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=be_SeniorSecuredNotesDueMarch2027RecourseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=be_TermLoanDueSeptember2028NonRecourseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=be_TermLoanDueDecember2021NonRecourseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableOtherPayablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=be_GreenConvertibleSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=be_SeniorSecuredNotesDueMarch2030NonRecourseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=be_RecourseDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=be_NonRecourseDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Outstanding Loans and Security Agreements - Schedule of Debt (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Aug. 31, 2020	May 01, 2020
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 522,191	$ 527,054
Non-recourse debt	118,468	120,846
Long-term portion of debt	390,031	270,053
Long-term Debt, Total	508,499	390,899
Unused borrowing capacity	759	968
Letter of Credit due December 2021, Non-Recourse
Debt Instrument [Line Items]
Long-term Debt, Gross		0
Non-recourse debt		0
Long-term portion of debt		0
Long-term Debt, Total		0
10.25% Senior Secured Notes due March 2027
Debt Instrument [Line Items]
Interest rate percentage				10.25%
Letters of Credit \| Letter of Credit due December 2021, Non-Recourse
Debt Instrument [Line Items]
Unused borrowing capacity	$ 759	$ 968
Interest rate percentage	2.25%	2.25%
Term loan \| Term Loan due September 2028, Non-Recourse
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 33,393	$ 34,456
Non-recourse debt	2,985	2,826
Long-term portion of debt	27,884	28,920
Long-term Debt, Total	$ 30,869	$ 31,746
Interest rate percentage	7.50%	7.50%
Term loan \| Term Loan due December 2021, Non-Recourse
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 111,873	$ 114,761
Non-recourse debt	111,410	114,138
Long-term portion of debt	0	0
Long-term Debt, Total	$ 111,410	$ 114,138
Interest rate percentage	2.50%	2.50%
LIBOR margin (as a percentage)	2.50%
Notes \| 10.25% Senior Secured Notes due March 2027
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 70,000	$ 70,000
Non-recourse debt	0	0
Long-term portion of debt	68,703	68,614
Long-term Debt, Total	$ 68,703	$ 68,614
Interest rate percentage	10.25%	10.25%
Senior secured notes \| 2.5% Green Convertible Senior Notes due August 2025
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 230,000	$ 230,000	$ 230,000
Non-recourse debt	0	0
Long-term portion of debt	221,387	99,394
Long-term Debt, Total	221,387	$ 99,394
Interest rate percentage		2.50%	2.50%
Senior secured notes \| Senior Secured Notes due March 2030, Non-Recourse
Debt Instrument [Line Items]
Long-term Debt, Gross	76,925	$ 77,837
Non-recourse debt	4,073	3,882
Long-term portion of debt	72,057	73,125
Long-term Debt, Total	$ 76,130	$ 77,007
Interest rate percentage	6.07%	6.07%
Recourse debt
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 300,000	$ 300,000
Non-recourse debt	0	0
Long-term portion of debt	290,090	168,008
Long-term Debt, Total	290,090	168,008
Letters of Credit \| Letter of Credit due December 2021, Non-Recourse
Debt Instrument [Line Items]
Long-term Debt, Gross	0
Non-recourse debt	0
Long-term portion of debt	0
Long-term Debt, Total	0
Non-recourse debt
Debt Instrument [Line Items]
Long-term Debt, Gross	222,191	227,054
Non-recourse debt	118,468	120,846
Long-term portion of debt	99,941	102,045
Long-term Debt, Total	218,409	222,891
Unused borrowing capacity	$ 759	$ 968