0001213900-21-053915 | S-4/A | XBRL Viewer | Growth Capital Acquisition Corp

PUBLIC OFFERING (Details) - shares	3 Months Ended	12 Months Ended
Jun. 30, 2021	Mar. 31, 2021
PUBLIC OFFERING (Details) [Line Items]
Number of units issued (in Shares)	2,250,000	2,250,000
Warrants exercisable period condition one	30 days	30 days
Warrant exercise period condition two	12 months	12 months
Warrants expiry term	5 years	5 years

Label	Element	Value
Automobiles	gcac_Automobiles	$ 50,000
Automobiles	gcac_Automobiles	50,000
Automobiles	gcac_Automobiles	50,000
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	9,000
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	9,000
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	4,086
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	4,086
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition
AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition	gcac_AdjustmentsToAdditionalPaidInCapitalContributionFromStockholderIncreaseForCostRecognition
StockOverAServicePeriod	gcac_StockOverAServicePeriod	4 years
StockOverAServicePeriod	gcac_StockOverAServicePeriod	4 years
MoneyMarketFundGrossUnrealizedGain	gcac_MoneyMarketFundGrossUnrealizedGain	$ 1,898
MoneyMarketFundGrossUnrealizedGain	gcac_MoneyMarketFundGrossUnrealizedGain	1,898
MoneyMarketFundGrossUnrealizedGain	gcac_MoneyMarketFundGrossUnrealizedGain
MoneyMarketFundAmortizationOfBondDiscount	gcac_MoneyMarketFundAmortizationOfBondDiscount	4,167
MoneyMarketFundAmortizationOfBondDiscount	gcac_MoneyMarketFundAmortizationOfBondDiscount	4,167
MoneyMarketFundAmortizationOfBondDiscount	gcac_MoneyMarketFundAmortizationOfBondDiscount
FairValueOfUnrealizedGainsAndLosses	gcac_FairValueOfUnrealizedGainsAndLosses	86,251,323
FairValueOfUnrealizedGainsAndLosses	gcac_FairValueOfUnrealizedGainsAndLosses	86,255,170
FairValueOfUnrealizedGainsAndLosses	gcac_FairValueOfUnrealizedGainsAndLosses	172,506,493
MoneyMarketFundAtCarryingValue	gcac_MoneyMarketFundAtCarryingValue	86,251,323
MoneyMarketFundAtCarryingValue	gcac_MoneyMarketFundAtCarryingValue	86,253,272
MoneyMarketFundAtCarryingValue	gcac_MoneyMarketFundAtCarryingValue	$ 172,504,595
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	8,000,000
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	4,069,600
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	3,272,475
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	6,329,416
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	21,671,491
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	8,000,000
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	4,069,600
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	3,272,475
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	6,329,416
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	21,671,491
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	8,000,000
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	4,069,600
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	3,272,475
SharesIssuedAndOutstanding	gcac_SharesIssuedAndOutstanding	15,342,075
UnitsIssuedDuringPeriodNetOfFairValueSharesNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueSharesNewIssues	17,250,000
UnitsIssuedDuringPeriodNetOfFairValueSharesNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueSharesNewIssues	17,250,000
UnitsIssuedDuringPeriodNetOfFairValueSharesNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueSharesNewIssues
SharesReservedForIssuance	gcac_SharesReservedForIssuance	4,800,000
SharesReservedForIssuance	gcac_SharesReservedForIssuance	9,187,533
SharesReservedForIssuance	gcac_SharesReservedForIssuance	9,187,533
SharesReservedForIssuance	gcac_SharesReservedForIssuance	4,800,000
SharesReservedForIssuance	gcac_SharesReservedForIssuance	6,300,000
UnitsIssuedDuringPeriodNetOfFairValueNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueNewIssues	$ 1,725
UnitsIssuedDuringPeriodNetOfFairValueNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueNewIssues	161,889,525
UnitsIssuedDuringPeriodNetOfFairValueNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueNewIssues	161,891,250
UnitsIssuedDuringPeriodNetOfFairValueNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueNewIssues
UnitsIssuedDuringPeriodNetOfFairValueNewIssues	gcac_UnitsIssuedDuringPeriodNetOfFairValueNewIssues
CommonStockValue1	gcac_CommonStockValue1	431
CommonStockValue1	gcac_CommonStockValue1	431
CommonStockValue1	gcac_CommonStockValue1	$ 431
SharesAvailableForIssuance	gcac_SharesAvailableForIssuance	1,361,781
SharesAvailableForIssuance	gcac_SharesAvailableForIssuance	3,406,368
RetainedEarnings	gcac_RetainedEarnings	$ 3,473,997
RetainedEarnings	gcac_RetainedEarnings	4,999,458
RetainedEarnings	gcac_RetainedEarnings	(146,657)
RetainedEarnings	gcac_RetainedEarnings	(76,758,000)
RetainedEarnings	gcac_RetainedEarnings	(58,197,000)
RetainedEarnings	gcac_RetainedEarnings	(38,563,000)
InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption	gcac_InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption	(1,525,460)
InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption	gcac_InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption	9,978,570
InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption	gcac_InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption
InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption	gcac_InitialValueOfClassOrdinarySharesSubjectToPossibleRedemption
AwardsGrantedOutstandingPeriod	gcac_AwardsGrantedOutstandingPeriod	10 years
AwardsGrantedOutstandingPeriod	gcac_AwardsGrantedOutstandingPeriod	10 years
TotalShareholdersEquity	gcac_TotalShareholdersEquity	$ 5,000,001
TotalShareholdersEquity	gcac_TotalShareholdersEquity	5,000,002
TotalShareholdersEquity	gcac_TotalShareholdersEquity	5,000,002
TotalShareholdersEquity	gcac_TotalShareholdersEquity	5,000,002
TotalShareholdersEquity	gcac_TotalShareholdersEquity	(3,115,509)
TotalShareholdersEquity	gcac_TotalShareholdersEquity	3,115,509
TotalShareholdersEquity	gcac_TotalShareholdersEquity	8,114,967
TotalShareholdersEquity	gcac_TotalShareholdersEquity	(3,115,509)
TotalShareholdersEquity	gcac_TotalShareholdersEquity	4,999,458
TotalShareholdersEquity	gcac_TotalShareholdersEquity	5,000,002
TotalShareholdersEquity	gcac_TotalShareholdersEquity	5,000,002
TotalShareholdersEquity	gcac_TotalShareholdersEquity	2,043
TotalShareholdersEquity	gcac_TotalShareholdersEquity	(72,095,000)
TotalShareholdersEquity	gcac_TotalShareholdersEquity	(55,929,000)
TotalShareholdersEquity	gcac_TotalShareholdersEquity	(37,237,000)
TotalShareholdersEquity	gcac_TotalShareholdersEquity
TotalShareholdersEquity	gcac_TotalShareholdersEquity
TotalShareholdersEquity	gcac_TotalShareholdersEquity
CommonStockSubjectToPossibleRedemptionShares	gcac_CommonStockSubjectToPossibleRedemptionShares	152,546
CommonStockSubjectToPossibleRedemptionShares	gcac_CommonStockSubjectToPossibleRedemptionShares	(16,115,493)
CommonStockSubjectToPossibleRedemptionShares	gcac_CommonStockSubjectToPossibleRedemptionShares
CommonStockSubjectToPossibleRedemptionShares	gcac_CommonStockSubjectToPossibleRedemptionShares
FairValueOfAwardsDescription	gcac_FairValueOfAwardsDescription	Awards issued under the Plan must be priced at no less than 100% of the fair value of the shares on the date of the grant provided, however, that (i) the exercise price of an ISO will not be less than 100% of the fair value of the shares on the date of grant, and (ii) the exercise price of an ISO and NSO granted or the purchase price under the stock issuance program to a 10% stockholder will not be less than 110% of the fair value of the shares on the date of grant. Fair value is determined by the Board of Directors.
FairValueOfAwardsDescription	gcac_FairValueOfAwardsDescription	Awards issued under the Plan must be priced at no less than 100% of the fair value of the shares on the date of the grant provided, however, that (i) the exercise price of an ISO will not be less than 100% of the fair value of the shares on the date of grant, and (ii) the exercise price of an ISO and NSO granted or the purchase price under the stock issuance program to a 10% stockholder will not be less than 110% of the fair value of the shares on the date of grant. Fair value is determined by the Board of Directors.
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue	$ 15
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue	1,525,445
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue	1,525,460
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue	(1,612)
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue	(161,153,318)
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue	(161,154,930)
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue
CommonStockSubjectToPossibleRedemptionValue	gcac_CommonStockSubjectToPossibleRedemptionValue
UnrealizedGainOnFairValueChangesOfWarrant	gcac_UnrealizedGainOnFairValueChangesOfWarrant	(9,936,000)
UnrealizedGainOnFairValueChangesOfWarrant	gcac_UnrealizedGainOnFairValueChangesOfWarrant
WorkingCapitalLoansRepaid	gcac_WorkingCapitalLoansRepaid	1,500,000
WorkingCapitalLoansRepaid	gcac_WorkingCapitalLoansRepaid	$ 1,500,000
WarrantsExercisable	gcac_WarrantsExercisable	13,800,000
WarrantsExercisable	gcac_WarrantsExercisable	13,800,000
AggregateLiquidationPreference	gcac_AggregateLiquidationPreference	$ 96,700
AggregateLiquidationPreference	gcac_AggregateLiquidationPreference	96,700
AggregateLiquidationPreference	gcac_AggregateLiquidationPreference	43,700
OutstandingUnvestedRestrictedStock	gcac_OutstandingUnvestedRestrictedStock	966,000
ConvertiblePreferredStock	gcac_ConvertiblePreferredStock	99,470,000
ConvertiblePreferredStock	gcac_ConvertiblePreferredStock	99,470,000
ConvertiblePreferredStock	gcac_ConvertiblePreferredStock	46,847,000
PaymentsForInvestmentOfCashInTrustAccount	gcac_PaymentsForInvestmentOfCashInTrustAccount	172,500,000
PaymentsForInvestmentOfCashInTrustAccount	gcac_PaymentsForInvestmentOfCashInTrustAccount
ProductWarrantTerm	gcac_ProductWarrantTerm	1 year
ProductWarrantTerm	gcac_ProductWarrantTerm	1 year
CostOfRevenues	gcac_CostOfRevenues	$ 770,000
CostOfRevenues	gcac_CostOfRevenues	99,000
ProceedsFromInitialPublicOfferingNetOfUnderwritingFees	gcac_ProceedsFromInitialPublicOfferingNetOfUnderwritingFees	169,050,000
ProceedsFromInitialPublicOfferingNetOfUnderwritingFees	gcac_ProceedsFromInitialPublicOfferingNetOfUnderwritingFees
CommonStockValueSubjectToPossibleRedemption	gcac_CommonStockValueSubjectToPossibleRedemption	15,962,947
CommonStockValueSubjectToPossibleRedemption	gcac_CommonStockValueSubjectToPossibleRedemption	0
CommonStockValueSubjectToPossibleRedemption	gcac_CommonStockValueSubjectToPossibleRedemption	16,115,493
CommonStockValueSubjectToPossibleRedemption	gcac_CommonStockValueSubjectToPossibleRedemption	0
AccumulatedDeficit	gcac_AccumulatedDeficit	$ (1,925,928)
AccumulatedDeficit	gcac_AccumulatedDeficit	(1,586,625)
AccumulatedDeficit	gcac_AccumulatedDeficit	(339,303)
CurrentPortionOfDebt	gcac_CurrentPortionOfDebt	1,121,000
CurrentPortionOfDebt	gcac_CurrentPortionOfDebt	695,000
CurrentPortionOfDebt	gcac_CurrentPortionOfDebt
StandardProductWarrantyAccrualConsumption	gcac_StandardProductWarrantyAccrualConsumption	(24,000)
StandardProductWarrantyAccrualConsumption	gcac_StandardProductWarrantyAccrualConsumption	(81,000)
StandardProductWarrantyAccrualConsumption	gcac_StandardProductWarrantyAccrualConsumption	(174,000)
AccruedExpensesAndOtherCurrentLiabilities	gcac_AccruedExpensesAndOtherCurrentLiabilities	2,700,000
AccruedExpensesAndOtherCurrentLiabilities	gcac_AccruedExpensesAndOtherCurrentLiabilities	1,565,000
AccruedExpensesAndOtherCurrentLiabilities	gcac_AccruedExpensesAndOtherCurrentLiabilities	1,285,000
CommonStockValue2	gcac_CommonStockValue2
CommonStockValue2	gcac_CommonStockValue2
CommonStockValue2	gcac_CommonStockValue2
CommercialPapers	gcac_CommercialPapers	5,595,000
CommercialPapers	gcac_CommercialPapers	5,595,000
CommercialPapers	gcac_CommercialPapers	14,587,000
CommercialPapers	gcac_CommercialPapers	14,587,000
CommercialPapers	gcac_CommercialPapers
CommercialPapers	gcac_CommercialPapers
CommercialPapers	gcac_CommercialPapers
CommercialPapers	gcac_CommercialPapers
ClassFStockValue3	gcac_ClassFStockValue3
ClassFStockValue3	gcac_ClassFStockValue3
ClassFStockValue3	gcac_ClassFStockValue3
OperatingLossCarryforwardsExpirationPeriod	gcac_OperatingLossCarryforwardsExpirationPeriod	expire in 2031
OperatingLossCarryforwardsExpirationPeriod	gcac_OperatingLossCarryforwardsExpirationPeriod	which will expire beginning in the year 2037.
OperatingLossCarryforwardsExpirationPeriod	gcac_OperatingLossCarryforwardsExpirationPeriod	which begins to expire in 2038
UnitsIssuedDuringPeriodSharesNewIssues	gcac_UnitsIssuedDuringPeriodSharesNewIssues	17,250,000
UnitsIssuedDuringPeriodSharesNewIssues	gcac_UnitsIssuedDuringPeriodSharesNewIssues	2,250,000
GainLossOnSaleSecurities	gcac_GainLossOnSaleSecurities	$ 4,000
GainLossOnSaleSecurities	gcac_GainLossOnSaleSecurities	(4,000)
GainLossOnSaleSecurities	gcac_GainLossOnSaleSecurities	(3,000)
GainLossOnSaleSecurities	gcac_GainLossOnSaleSecurities
CapitalizedStockBasedCompensationExpenseIntoInventory	gcac_CapitalizedStockBasedCompensationExpenseIntoInventory	20,000
CapitalizedStockBasedCompensationExpenseIntoInventory	gcac_CapitalizedStockBasedCompensationExpenseIntoInventory	19,000
CapitalizedStockBasedCompensationExpenseIntoInventory	gcac_CapitalizedStockBasedCompensationExpenseIntoInventory	42,000,000
ForeignCurrencyTranslationAdjustments	gcac_ForeignCurrencyTranslationAdjustments	(12,000)
ForeignCurrencyTranslationAdjustments	gcac_ForeignCurrencyTranslationAdjustments	(4,000)
ForeignCurrencyTranslationAdjustments	gcac_ForeignCurrencyTranslationAdjustments	(11,000)
ForeignCurrencyTranslationAdjustments	gcac_ForeignCurrencyTranslationAdjustments	(10,000)
AggregateConsiderationReceived	gcac_AggregateConsiderationReceived	$ 303,000,000
NumberOfSharesForfeited	gcac_NumberOfSharesForfeited	257,649
NumberOfSharesForfeited	gcac_NumberOfSharesForfeited	2,833,333
NumberOfSharesForfeited	gcac_NumberOfSharesForfeited	718,750
NumberOfSharesForfeited	gcac_NumberOfSharesForfeited	2,833,333
NumberOfSharesForfeited	gcac_NumberOfSharesForfeited	718,750
FullyVestedShares	gcac_FullyVestedShares	25,000
LiabilityAssociatedWithUnvestedRestrictedShares	gcac_LiabilityAssociatedWithUnvestedRestrictedShares	$ 151,500,000
LiabilityAssociatedWithUnvestedRestrictedShares	gcac_LiabilityAssociatedWithUnvestedRestrictedShares	101,000,000
SaleOfStockTransactionCost	gcac_SaleOfStockTransactionCost	4,296,946
SaleOfStockTransactionCost	gcac_SaleOfStockTransactionCost	4,296,946
SaleOfStockUnderwritingFees	gcac_SaleOfStockUnderwritingFees	3,450,000
SaleOfStockUnderwritingFees	gcac_SaleOfStockUnderwritingFees	3,450,000
SaleOfStockOtherOfferingCosts	gcac_SaleOfStockOtherOfferingCosts	824,946
SaleOfStockOtherOfferingCosts	gcac_SaleOfStockOtherOfferingCosts	$ 824,946
MaximumCommonStockSharesSubjectToForfeiture	gcac_MaximumCommonStockSharesSubjectToForfeiture	562,500
ComprehensiveLoss	gcac_ComprehensiveLoss	$ (18,577,000)
ComprehensiveLoss	gcac_ComprehensiveLoss	(8,912,000)
ComprehensiveLoss	gcac_ComprehensiveLoss	(19,642,000)
ComprehensiveLoss	gcac_ComprehensiveLoss	(16,767,000)
BusinessCombinationCashFee	gcac_BusinessCombinationCashFee	6,037,500
BusinessCombinationCashFee	gcac_BusinessCombinationCashFee	6,037,500
MaximumNetInterestToPayDissolutionExpenses	gcac_MaximumNetInterestToPayDissolutionExpenses	100,000
MaximumNetInterestToPayDissolutionExpenses	gcac_MaximumNetInterestToPayDissolutionExpenses	100,000
MaximumNetInterestToPayDissolutionExpenses	gcac_MaximumNetInterestToPayDissolutionExpenses	100,000
ProvisionForbenefitFromIncomeTaxes	gcac_ProvisionForbenefitFromIncomeTaxes	(26,000)
ProvisionForbenefitFromIncomeTaxes	gcac_ProvisionForbenefitFromIncomeTaxes	(7,000)
MinimumNetTangibleAssetsUponConsummationOfBusinessCombination	gcac_MinimumNetTangibleAssetsUponConsummationOfBusinessCombination	5,000,001
MinimumNetTangibleAssetsUponConsummationOfBusinessCombination	gcac_MinimumNetTangibleAssetsUponConsummationOfBusinessCombination	5,000,001
SoftwareGross	gcac_SoftwareGross	10,000
SoftwareGross	gcac_SoftwareGross	3,000
UnrecognizedStockBasedCompensationRelatedToUnvestedStockOptions	gcac_UnrecognizedStockBasedCompensationRelatedToUnvestedStockOptions	15,800,000
UnrecognizedStockBasedCompensationRelatedToUnvestedStockOptions	gcac_UnrecognizedStockBasedCompensationRelatedToUnvestedStockOptions	3,000,000,000
PropertyPlantAndEquipmentAmount	gcac_PropertyPlantAndEquipmentAmount	975,000
PropertyPlantAndEquipmentAmount	gcac_PropertyPlantAndEquipmentAmount	952,000
Workingcapital	gcac_Workingcapital	$ 725,482
FounderSharesOutstanding	gcac_FounderSharesOutstanding	4,312,500
FounderSharesOutstanding	gcac_FounderSharesOutstanding	3,593,750
NumberOfDirectors	gcac_NumberOfDirectors	2
BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl	16,115,493
BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl	2,404,988
BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl
BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassACommonStockSubjectToPossibl
WarrantTransactionCosts	gcac_WarrantTransactionCosts	$ 292,875
WarrantTransactionCosts	gcac_WarrantTransactionCosts
BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption	gcac_BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption	0
BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption	gcac_BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption	0
BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption	gcac_BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption
BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption	gcac_BasicAndDilutedNetLossPerShareClassACommonStockSubjectToPossibleRedemption
ExcessValueOfUnderwriterWarrants	gcac_ExcessValueOfUnderwriterWarrants	$ 1,293,750
ExcessValueOfUnderwriterWarrants	gcac_ExcessValueOfUnderwriterWarrants
ClassSharesAnAsconvertedBasis	gcac_ClassSharesAnAsconvertedBasis	8,372,143
ClassSharesAnAsconvertedBasis	gcac_ClassSharesAnAsconvertedBasis	8,372,143
ClassSharesAnAsconvertedBasis	gcac_ClassSharesAnAsconvertedBasis	8,372,143
ClassSharesAnAsconvertedBasis	gcac_ClassSharesAnAsconvertedBasis	8,402,000
SharesIssuableUponExerciseOfWarrants	gcac_SharesIssuableUponExerciseOfWarrants	60,000
SharesIssuableUponExerciseOfWarrants	gcac_SharesIssuableUponExerciseOfWarrants	60,000
SharesIssuableUponExerciseOfWarrants	gcac_SharesIssuableUponExerciseOfWarrants	60,000
SharesIssuableUponExerciseOfWarrants	gcac_SharesIssuableUponExerciseOfWarrants	60,000
AggregateWarrantsToPurchaseOfShares	gcac_AggregateWarrantsToPurchaseOfShares	60,000
AggregateWarrantsToPurchaseOfShares	gcac_AggregateWarrantsToPurchaseOfShares	60,000
BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	5,447,007
BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	3,750,000
BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	4,648,608
BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	gcac_BasicAndDilutedWeightedAverageSharesOutstandingClassBCommonStock	3,750,000
LeaseAgreementDescription	gcac_LeaseAgreementDescription	The lease is estimated to begin on June 1, 2021 and is set to expire on January 31, 2023.
LeaseTerm	gcac_LeaseTerm	$ 143,400
MoneyMarketFunds	gcac_MoneyMarketFunds	7,190,000
NetCashProvidedByUsedInOperatingActivitiesOne	gcac_NetCashProvidedByUsedInOperatingActivitiesOne	(18,000,000)
PurchasesOfPropertyAndEquipment	gcac_PurchasesOfPropertyAndEquipment	23,000
PurchasesOfPropertyAndEquipment	gcac_PurchasesOfPropertyAndEquipment	3,000
PurchasesOfPropertyAndEquipment	gcac_PurchasesOfPropertyAndEquipment	80,000
PurchasesOfPropertyAndEquipment	gcac_PurchasesOfPropertyAndEquipment	148,000
RetainedEarningAccumulatedDeficit	gcac_RetainedEarningAccumulatedDeficit	76,800,000
CashEquivalentAtCarryingValue	gcac_CashEquivalentAtCarryingValue	12,400,000
ProceedsFromLongtermSecurityDeposit	gcac_ProceedsFromLongtermSecurityDeposit	1,000
ProceedsFromLongtermSecurityDeposit	gcac_ProceedsFromLongtermSecurityDeposit
PurchasesOfShorttermInvestments	gcac_PurchasesOfShorttermInvestments	8,455,000
PurchasesOfShorttermInvestments	gcac_PurchasesOfShorttermInvestments	19,234,000
PurchasesOfShorttermInvestments	gcac_PurchasesOfShorttermInvestments	33,676,000
PurchasesOfShorttermInvestments	gcac_PurchasesOfShorttermInvestments
ProceedsFromIssuanceOfLongtermDebtAndWarrantsNet	gcac_ProceedsFromIssuanceOfLongtermDebtAndWarrantsNet	4,982,000
ProceedsFromIssuanceOfLongtermDebtAndWarrantsNet	gcac_ProceedsFromIssuanceOfLongtermDebtAndWarrantsNet
DescriptionOfBusinessPolicyPolicyTextBlock	gcac_DescriptionOfBusinessPolicyPolicyTextBlock	Description of BusinessCepton provides state-of-the-art, intelligent, lidar-based solutions for a range of markets such as automotive (ADAS/AV), smart cities, smart spaces, and smart industrial applications. Cepton’s patented MMT®-based lidar technology enables reliable, scalable, and cost-effective solutions that deliver long range, high resolution 3D perception for smart applications.Founded in April 2016 and led by industry veterans with over two decades of collective experience across a wide range of advanced lidar and imaging technologies, Cepton is focused on the mass market commercialization of high performance, high quality lidar solutions. Cepton is headquartered in San Jose, California, USA, with a presence in Germany, Canada, Japan, China and India, to serve a fast-growing global customer base.
RepaymentOfLongtermDebt	gcac_RepaymentOfLongtermDebt	$ (5,000,000)
RepaymentOfLongtermDebt	gcac_RepaymentOfLongtermDebt	(5,000,000)
RepaymentOfLongtermDebt	gcac_RepaymentOfLongtermDebt
RepaymentOfLongtermDebt	gcac_RepaymentOfLongtermDebt
ChangesInAccruedPurchasesOfPropertyAndEquipment	gcac_ChangesInAccruedPurchasesOfPropertyAndEquipment	3,000
ChangesInAccruedPurchasesOfPropertyAndEquipment	gcac_ChangesInAccruedPurchasesOfPropertyAndEquipment	(3,000)
ChangesInAccruedPurchasesOfPropertyAndEquipment	gcac_ChangesInAccruedPurchasesOfPropertyAndEquipment	3,000
ChangesInAccruedPurchasesOfPropertyAndEquipment	gcac_ChangesInAccruedPurchasesOfPropertyAndEquipment
VestingOfEarlyExercisesOfStockOptions	gcac_VestingOfEarlyExercisesOfStockOptions	76,000
VestingOfEarlyExercisesOfStockOptions	gcac_VestingOfEarlyExercisesOfStockOptions
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodStockTransfer	gcac_StockIssuedDuringPeriodStockTransfer
StockIssuedDuringPeriodSharesStockTransfer	gcac_StockIssuedDuringPeriodSharesStockTransfer	29,857
StockIssuedDuringPeriodSharesStockTransfer	gcac_StockIssuedDuringPeriodSharesStockTransfer	(29,857)
StockIssuedDuringPeriodSharesStockTransfer	gcac_StockIssuedDuringPeriodSharesStockTransfer
NumberOfIndependentDirectors	gcac_NumberOfIndependentDirectors	2
ValueOfClassCommonStockSubjectToPossibleRedemption	gcac_ValueOfClassCommonStockSubjectToPossibleRedemption	$ 151,176,360
ValueOfClassCommonStockSubjectToPossibleRedemption	gcac_ValueOfClassCommonStockSubjectToPossibleRedemption
UnvestedShares	gcac_UnvestedShares	254,794
NumberOfSharesHeldByInitialStockholders	gcac_NumberOfSharesHeldByInitialStockholders	4,312,500
InitialClassificationOfWarrantLiability	gcac_InitialClassificationOfWarrantLiability	$ 17,077,500
InitialClassificationOfWarrantLiability	gcac_InitialClassificationOfWarrantLiability
DeferredOfferingCostsIncludedInAccruedOfferingCostsIncurredDuringNonCashOrPartialNonCashTransaction	gcac_DeferredOfferingCostsIncludedInAccruedOfferingCostsIncurredDuringNonCashOrPartialNonCashTransaction	20,000
DeferredOfferingCostsIncludedInAccruedOfferingCostsIncurredDuringNonCashOrPartialNonCashTransaction	gcac_DeferredOfferingCostsIncludedInAccruedOfferingCostsIncurredDuringNonCashOrPartialNonCashTransaction
NumberOfVendors	gcac_NumberOfVendors	2
NumberOfVendors	gcac_NumberOfVendors	3
TotalAssetsMeasuredAtFairValue	gcac_TotalAssetsMeasuredAtFairValue	$ 7,192,000
TotalAssetsMeasuredAtFairValue	gcac_TotalAssetsMeasuredAtFairValue	32,058,000
TotalAssetsMeasuredAtFairValue	gcac_TotalAssetsMeasuredAtFairValue	39,250,000
TotalAssetsMeasuredAtFairValue	gcac_TotalAssetsMeasuredAtFairValue
AggregatePurchasePrice	gcac_AggregatePurchasePrice	250,011
InterestIncomeTrustAccount	gcac_InterestIncomeTrustAccount	(6,225)
InterestIncomeTrustAccount	gcac_InterestIncomeTrustAccount
NetIncomeAllocableToShareSubjectToPossibleRedemption	gcac_NetIncomeAllocableToShareSubjectToPossibleRedemption
NetIncomeAllocableToShareSubjectToPossibleRedemption	gcac_NetIncomeAllocableToShareSubjectToPossibleRedemption
PropertyPlantAndEquipmentEstimatedUsefulLive	gcac_PropertyPlantAndEquipmentEstimatedUsefulLive	3
PropertyPlantAndEquipmentEstimatedUsefulLive	gcac_PropertyPlantAndEquipmentEstimatedUsefulLive	7
SharesAvailableForFutureIssuance	gcac_SharesAvailableForFutureIssuance	3,406,368
SharesAvailableForFutureIssuance	gcac_SharesAvailableForFutureIssuance	1,020,294
PayrollTaxReceivable	gcac_PayrollTaxReceivable	$ 1,000,000
PayrollTaxReceivable	gcac_PayrollTaxReceivable	$ 700,000
TermOfDemandExercise	gcac_TermOfDemandExercise	5 years
TermOfDemandExercise	gcac_TermOfDemandExercise	5 years
TermOfPiggybackRegistrationRightsExercise	gcac_TermOfPiggybackRegistrationRightsExercise	7 years
TermOfPiggybackRegistrationRightsExercise	gcac_TermOfPiggybackRegistrationRightsExercise	7 years
RevenueFromCustomerAndInvestor	gcac_RevenueFromCustomerAndInvestor	$ 320,000
OperatingLossCarryforwardExpirationPeriod	gcac_OperatingLossCarryforwardExpirationPeriod	20 years

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Details) - Schedule of accrued expenses - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Details) - Schedule of accrued expenses [Line Items]
Accrued unvested option liability	$ 152	$ 151
Warranty reserve	$ 49	$ 40	$ 31

Recurring Fair Value Measurements (Details) - Schedule of the changes in the fair value of the Level 3 assets and liabilities measured at fair value	12 Months Ended
	Mar. 31, 2021 USD ($)
Recurring Fair Value Measurements (Details) - Schedule of the changes in the fair value of the Level 3 assets and liabilities measured at fair value [Line Items]
Initial fair value of warrant liability upon issuance at IPO on February 2, 2021	$ 10,608,750
Public warrants reclassified to level 1
Change in fair value	$ (6,210,000)

STOCK-BASED COMPENSATION (Details) - Schedule of employee and nonemployee stock option activity $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
STOCK-BASED COMPENSATION (Details) - Schedule of employee and nonemployee stock option activity [Line Items]
Options Outstanding Weighted Average Remaining Contract Term (in years), Beginning Balance	7 years 7 months 6 days
Options Outstanding Weighted Average Remaining Contract Term (in years), Ending Balance	7 years 10 months 24 days
Options Outstanding Weighted Average Remaining Contract Term (in years), Exercisable	6 years 3 months 18 days
Options Outstanding Aggregate Intrinsic Value, Exercisable	$ 37,994
Options Outstanding Aggregate Intrinsic Value, Vested and expected to vest	$ 60,890

INCOME TAX (Details) - Schedule of components of income tax provision - USD ($)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
State
Current		$ 32
Change in valuation allowance	18,428	2,033
Income tax provision		$ 32

PRIVATE PLACEMENT (Details) - USD ($)		3 Months Ended
PRIVATE PLACEMENT (Details) - USD ($)	Feb. 02, 2021	Jun. 30, 2021
Private Placement [Abstract]
Gross proceeds	$ 5,175,000	$ 5,175,000

WARRANTS (Details) - USD ($)	1 Months Ended		12 Months Ended
WARRANTS (Details) - USD ($)	Dec. 31, 2019	Aug. 31, 2019	Dec. 31, 2019
WARRANTS (Details) [Line Items]
Warrant to purchase additional shares of common stock (in Shares)	30,000		30,000
Withdrawn loan amount	$ 5,000,000		$ 5,000,000
Fair values of the warrants	$ 49,000	$ 39,000	$ 49,000

Recurring Fair Value Measurements (Details) - Schedule of assets and liabilities that were measured at fair value on a recurring basis and indicates the fair value hierarchy of the valuation techniques	Mar. 31, 2021 USD ($)
Assets:
Investments held in Trust Account-Money Market Mutual Funds	$ 86,251,323
Cash and Investments held in Trust Account-Treasury Bills	$ 86,255,170

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - Schedule of basic and diluted net income per common share	3 Months Ended
	Jun. 30, 2021 USD ($) shares
Numerator: Earnings allocable to Redeemable Common Stock
Denominator: Weighted Average Redeemable Common Stock \| $
Redeemable Common Stock outstanding, Basic and Diluted (in Shares) \| shares	16,115,493

INCOME TAX (Details) - Schedule of reconciliation of the federal income tax rate to the Company’s effective tax rate	12 Months Ended
	Mar. 31, 2021
Schedule of reconciliation of the federal income tax rate to the Company’s effective tax rate [Abstract]
Change in FV of warrant liability	(21.9)
Transaction costs associated with the issuance of warrants	0.7

INCOME TAXES (Details) - Schedule of deferred income tax assets and liabilities - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforward	$ 13,945	$ 8,700

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - Schedule of basic and diluted net income per common share	12 Months Ended
	Mar. 31, 2021 USD ($) shares
Numerator: Earnings allocable to Redeemable Common Stock
Net income allocable to shares subject to possible redemption \| $
Denominator: Weighted Average Redeemable Common Stock
Redeemable Common Stock outstanding, Basic and Diluted (in Shares) \| shares	2,360,836