0001213900-21-061190 | 10-Q | XBRL Viewer | B Riley Principal 150 Merger Corp

Summary of Significant Accounting Policies (Details) - Schedule of reconciliation of the numerator and denominator used to compute basic and diluted net loss per share - shares	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2021
Redeemable common stock
Basic and diluted weighted average shares of redeemable common stock	17,250,000	13,837,912

Recurring Fair Value Measurements (Details) - Schedule of fair value, assets and liabilities measured on recurring basis	Sep. 30, 2021 USD ($)
Recurring Fair Value Measurements (Details) - Schedule of fair value, assets and liabilities measured on recurring basis [Line Items]
Public Warrants
Private Placement Warrants

Restatement of Previously Issued Financial Statements (Details) - Schedule of statement of changes in stockholders’ equity - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021
Restatement of Previously Issued Financial Statements (Details) - Schedule of statement of changes in stockholders’ equity [Line Items]
Sale of 17,250,000 Units on February 23, 2021 through IPO
Offering costs charged to stockholders' equity
Reclassification of offering costs related to warrants
Initial value of Class A common stock subject to redemption
Change in Class A common stock subject to redemption
Subsequent measurement of Class A Common Stock Subject to Redemption under ASC 480-10-S99 against additional paid-in capital
Subsequent measurement of Class A Common Stock Subject to Redemption under ASC 480-10-S99 against accumulated deficit

Label	Element	Value
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	$ 163,556,590
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	8,943,410
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	172,500,000
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	163,088,200
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	9,411,800
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	172,500,000
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	161,216,660
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	11,283,340
ClassACommonStockSubjectToPossibleRedemption	brpm_ClassACommonStockSubjectToPossibleRedemption	172,500,000
NetTangibleAssets	brpm_NetTangibleAssets	5,000,001
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	172,500,000
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	(468,390)
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	468,390
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	(2,339,930)
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	2,339,930
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption
ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_ChangeInValueOfClassAOrdinarySharesSubjectToPossibleRedemption
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	4,896,972
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	(376,472)
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	4,520,500
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	5,960,834
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	(1,128,334)
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	4,832,500
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	5,431,842
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	(754,479)
BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	brpm_BasicAndDilutedWeightedAverageSharesOutstandingNonredeemableCommonStock	4,677,363
InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	$ 163,556,590
InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	8,943,410
InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	172,500,000
InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	163,556,590
InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	8,943,410
InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	brpm_InitialValueOfClassAOrdinarySharesSubjectToPossibleRedemption	172,500,000
CashAndCashEquivalentAtCarryingValue	brpm_CashAndCashEquivalentAtCarryingValue	172,512,555
InterestEarnedOnInvestmentsHeldInTrustAccounts	brpm_InterestEarnedOnInvestmentsHeldInTrustAccounts	(12,555)
InterestEarnedOnInvestmentsHeldInTrustAccounts	brpm_InterestEarnedOnInvestmentsHeldInTrustAccounts
AccruedForInterestAndPenaltiesDescription	brpm_AccruedForInterestAndPenaltiesDescription	No amounts were accrued for interest expense and penalties related to income tax matters as of September 30, 2021.
CommonStockValueOne	brpm_CommonStockValueOne	$ 431
CommonStockValueOne	brpm_CommonStockValueOne	431
WorkingCapital	brpm_WorkingCapital	261,164
PaymentOfUnderwritingDiscounts	brpm_PaymentOfUnderwritingDiscounts	3,450,000
PaymentOfUnderwritingDiscounts	brpm_PaymentOfUnderwritingDiscounts
WarrantIssueCosts	brpm_WarrantIssueCosts	(115,404)
WarrantIssueCosts	brpm_WarrantIssueCosts
WarrantIssueCosts	brpm_WarrantIssueCosts
WarrantIssueCosts	brpm_WarrantIssueCosts
ShareOutstanding	brpm_ShareOutstanding	4,312,500
ShareOutstanding	brpm_ShareOutstanding
IncreaseDecreaseOfWarrantIssueCosts	brpm_IncreaseDecreaseOfWarrantIssueCosts	$ 115,404
IncreaseDecreaseOfWarrantIssueCosts	brpm_IncreaseDecreaseOfWarrantIssueCosts
CommonStockSubjectToPossibleRedemptionsShares	brpm_CommonStockSubjectToPossibleRedemptionsShares	17,250,000
InitialClassificationOfWarrantLiability	brpm_InitialClassificationOfWarrantLiability	$ 5,276,966
InitialClassificationOfWarrantLiability	brpm_InitialClassificationOfWarrantLiability
StockholdersEquities	brpm_StockholdersEquities	431
StockholdersEquities	brpm_StockholdersEquities	24,569
StockholdersEquities	brpm_StockholdersEquities	(472)
StockholdersEquities	brpm_StockholdersEquities	25,000
StockholdersEquities	brpm_StockholdersEquities
PayFranchiseAndIncomeTaxes	brpm_PayFranchiseAndIncomeTaxes	100,000
UnderwritersAmount	brpm_UnderwritersAmount	$ 6,037,500
UnrecognizedTaxBenefitsDescription	brpm_UnrecognizedTaxBenefitsDescription	As of September 30, 2021, there were no unrecognized tax benefits and no amounts accrued for interest and penalties.
OtherOfferingCosts	brpm_OtherOfferingCosts	$ 485,257
OperatingBankAccount	brpm_OperatingBankAccount	$ 132,824
PurchaseOfShares	brpm_PurchaseOfShares	2,200,000
PublicOfferingCost	brpm_PublicOfferingCost	$ 172,500,000
SaleOfUnit	brpm_SaleOfUnit	520,000,000
PIPEInvestmentMember
AggregatePurchasePrice	brpm_AggregatePurchasePrice	$ 22,000,000
MergerAgreementMember
SharesIssuedToStockholders	brpm_SharesIssuedToStockholders	67,023,763