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Debt - Additional Information (Detail) (USD $) | 12 Months Ended | 0 Months Ended | 3 Months Ended | 0 Months Ended | 9 Months Ended | 12 Months Ended | 0 Months Ended | 3 Months Ended |  |  |  |  |
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Mar. 31, 2015 | Mar. 31, 2014 | Mar. 31, 2013 | Mar. 02, 2014 | Mar. 31, 2014 | Oct. 09, 2013 | Apr. 04, 2012 | Dec. 31, 2014 | Dec. 31, 2014 | Nov. 13, 2014 | Nov. 15, 2013 | Jun. 05, 2012 | Dec. 19, 2014 | Dec. 31, 2014 | Sep. 30, 2013 | Jun. 30, 2013 | Dec. 31, 2012 | Sep. 30, 2012 | Jun. 30, 2012
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative Liability |  |  | $ 500,000 us-gaap_DerivativeLiabilities |  |  |  | $ 3,800,000 us-gaap_DerivativeLiabilities |  |  |  |  |  |  |  | $ 200,000 us-gaap_DerivativeLiabilities | $ 500,000 us-gaap_DerivativeLiabilities | $ 1,000,000 us-gaap_DerivativeLiabilities | $ 2,800,000 us-gaap_DerivativeLiabilities | $ 4,500,000 us-gaap_DerivativeLiabilities
Warrants | 2,999,000 us-gaap_DerivativeLiabilitiesCurrent | 2,601,000 us-gaap_DerivativeLiabilitiesCurrent |  |  | 2,601,000 us-gaap_DerivativeLiabilitiesCurrent |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total debt discount being amortized into interest expense | 1,700,000 us-gaap_InterestExpense | 9,700,000 us-gaap_InterestExpense | 14,900,000 us-gaap_InterestExpense |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense amortization of debt discount | 500,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount | 7,700,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount | 12,400,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of stock discount | 85.00%amsc_PercentageOfStockDiscount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of trading days for valuation of shares | 10 days |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense issuing stock at discount |  | 2,900,000 amsc_NonCashInterestExpenseIssuingStockAtDiscount | 3,600,000 amsc_NonCashInterestExpenseIssuingStockAtDiscount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on extinguishment of debt |  | (5,197,000)us-gaap_GainsLossesOnExtinguishmentOfDebt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest expense | 1,700,000 us-gaap_InterestExpense | 9,700,000 us-gaap_InterestExpense | 14,900,000 us-gaap_InterestExpense |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense | 566,000 us-gaap_AmortizationOfFinancingCostsAndDiscounts | 7,713,000 us-gaap_AmortizationOfFinancingCostsAndDiscounts | 12,426,000 us-gaap_AmortizationOfFinancingCostsAndDiscounts |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Maturity Date, Description | As part of the Hercules Second Amendment, this Minimum Threshold was amended to be the lower of $5.0 million or the aggregate outstanding principal balance of the Term Loans. As of March 31, 2015, the Minimum Threshold was $5.0 million. As a result of the Company’s equity offering on April 29, 2015, the Minimum Threshold will be reduced to the lesser of $2.0 million or the aggregate outstanding principal balance of the Term Loans (See Note 19, “Subsequent Events”). |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Ventures International |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt conversion, shares issued |  |  |  | 663,000 us-gaap_DebtConversionConvertedInstrumentSharesIssued1 / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on extinguishment of debt |  |  |  |  | (5,200,000)us-gaap_GainsLossesOnExtinguishmentOfDebt / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Convertible Debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense amortization of debt discount |  | 4,100,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember | 8,200,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Convertible Debt | Capital Ventures International |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds after fees and expenses of purchase agreement |  |  |  |  |  |  | 23,200,000 us-gaap_ProceedsFromConvertibleDebt / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Conversion price |  |  |  |  |  |  | $ 48.50 us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Premium over closing price, percentage |  |  |  |  |  |  | 20.00%amsc_PurchaseCommitmentPremiumOfClosingPricePercent / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Period before first installment payment |  |  |  |  |  |  | 4 months |  |  |  |  |  |  |  |  |  |  |  |
Shares registered for resale |  |  |  |  |  |  | 1,026,231 amsc_CommonStockResaleShares / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Derivative Liability |  |  |  |  |  |  | 3,800,000 us-gaap_DerivativeLiabilities / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Number of shares received from warrants received to purchase common stock |  |  |  |  |  |  | 309,406 amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Strike price per share |  |  |  |  |  | $ 26.10 invest_InvestmentWarrantsExercisePrice / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember | $ 54.50 invest_InvestmentWarrantsExercisePrice / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
Fair value of warrants at issuance |  |  |  |  |  |  | 7,000,000 amsc_PurchaseCommitmentIssuanceOfWarrantsFairValueOfSharesOfCommonStock / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember |  |  |  |  |  |  |  |  |  |  |  |
New Unsecured Senior Convertible Note |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Conversion price |  |  |  |  |  |  | $ 48.50 us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  |  |  |  |  |  | $ 31.90 us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |
Debt conversion, shares issued |  |  |  | 663,000 us-gaap_DebtConversionConvertedInstrumentSharesIssued1 / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New Unsecured Senior Convertible Note | Capital Ventures International |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Warrants |  |  |  |  |  |  |  | 500,000 us-gaap_DerivativeLiabilitiesCurrent / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember | 500,000 us-gaap_DerivativeLiabilitiesCurrent / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  | 500,000 us-gaap_DerivativeLiabilitiesCurrent / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  |
Increase in derivative liability |  |  |  |  |  |  |  | 1,500,000 us-gaap_DerivativeLossOnDerivative / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  |  |  |  |  |  |  |
Total debt discount being amortized into interest expense |  |  |  |  |  |  |  |  | 13,100,000 us-gaap_InterestExpense / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  |  | 13,100,000 us-gaap_InterestExpense / us-gaap_LineOfCreditFacilityAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember |  |  |  |  |  |  |  |  |  |
Senior Secured Loan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares received from warrants received to purchase common stock |  |  |  |  |  |  |  |  |  |  | 25,641 amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |
Strike price per share |  |  |  |  |  |  |  |  |  | $ 17.00 invest_InvestmentWarrantsExercisePrice / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | $ 19.50 invest_InvestmentWarrantsExercisePrice / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |
Senior Secured Loan | Hercules Technology Growth Capital |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares received from warrants received to purchase common stock |  |  |  |  |  |  |  |  |  |  | 25,641 amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 13,927 amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |
Strike price per share |  |  |  |  |  |  |  |  |  |  | $ 19.50 invest_InvestmentWarrantsExercisePrice / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | $ 35.90 invest_InvestmentWarrantsExercisePrice / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |
Fair value of warrants at issuance |  |  |  |  |  |  |  |  |  |  |  | 400,000 amsc_PurchaseCommitmentIssuanceOfWarrantsFairValueOfSharesOfCommonStock / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |
Total debt discount being amortized into interest expense |  |  | 1,200,000 us-gaap_InterestExpense / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  | 1,000,000 us-gaap_InterestExpense / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense amortization of debt discount |  | 500,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Legal and origination costs |  | 200,000 us-gaap_LegalFees / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 300,000 us-gaap_LegalFees / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt, face amount |  |  |  |  |  |  |  |  |  |  | 10,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 10,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |
Net proceeds from debt |  |  |  |  |  |  |  |  |  |  | 9,800,000 us-gaap_ProceedsFromIssuanceOfDebt / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 9,700,000 us-gaap_ProceedsFromIssuanceOfDebt / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |
Interest rate on loan |  |  |  |  |  |  |  |  |  |  |  | 11.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |
End of term fee |  |  | 500,000 amsc_DebtInstrumentEndOfTermFee / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  | 500,000 amsc_DebtInstrumentEndOfTermFee / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  | 1,200,000 us-gaap_InterestExpense / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  | 1,000,000 us-gaap_InterestExpense / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |
Total debt discount being amortized into interest expense | 400,000 us-gaap_AmortizationOfDebtDiscountPremium / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 200,000 us-gaap_AmortizationOfDebtDiscountPremium / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum amount of proceeds from specified asset dispositions for mandatory prepayment feature |  |  |  |  |  |  |  | 1,000,000 amsc_MinimumAmountOfProceedsFromSpecifiedAssetDispositionsForMandatoryPrepaymentFeature / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 1,000,000 amsc_MinimumAmountOfProceedsFromSpecifiedAssetDispositionsForMandatoryPrepaymentFeature / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  | 1,000,000 amsc_MinimumAmountOfProceedsFromSpecifiedAssetDispositionsForMandatoryPrepaymentFeature / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |
Outstanding principal balance | 6,700,000 us-gaap_LongTermDebt / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Covenant, unrestricted cash balance requirement |  |  |  |  |  |  |  | 5,000,000 amsc_DebtInstrumentCovenantUnrestrictedCashBalanceRequirement / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember | 5,000,000 amsc_DebtInstrumentCovenantUnrestrictedCashBalanceRequirement / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  | 5,000,000 amsc_DebtInstrumentCovenantUnrestrictedCashBalanceRequirement / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  | 5,000,000 amsc_DebtInstrumentCovenantUnrestrictedCashBalanceRequirement / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |
Repayments of term loan | 2,000,000 us-gaap_RepaymentsOfDebt / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Secured Loan | Hercules Technology Growth Capital | Second Amendment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares received from warrants received to purchase common stock |  |  |  |  |  |  |  |  |  |  |  |  | 58,823 amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |
Strike price per share |  |  |  |  |  |  |  |  |  |  |  |  | $ 11.10 invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |
Total debt discount being amortized into interest expense |  |  |  |  |  |  |  | 300,000 us-gaap_InterestExpense / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |
Legal and origination costs |  |  |  |  |  |  |  |  |  |  |  |  |  | 100,000 us-gaap_LegalFees / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |
Debt, face amount |  |  |  |  |  |  |  |  |  |  |  |  | 1,500,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |
Net proceeds from debt |  |  |  |  |  |  |  |  |  |  |  |  | 1,400,000 us-gaap_ProceedsFromIssuanceOfDebt / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |
End of term fee |  |  |  |  |  |  |  | 100,000 amsc_DebtInstrumentEndOfTermFee / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |
Interest expense |  |  |  |  |  |  |  | 300,000 us-gaap_InterestExpense / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Maturity Date |  |  |  |  |  |  |  | Jun. 01, 2017 |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense | 100,000 us-gaap_AmortizationOfFinancingCostsAndDiscounts / us-gaap_DebtInstrumentAxis = amsc_SecondAmendmentMember / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Secured Loan | Hercules Technology Growth Capital | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Prime rate |  |  |  |  |  |  |  |  |  |  |  | 3.75%amsc_PrimeRate / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember / us-gaap_RangeAxis = us-gaap_MinimumMember |  |  |  |  |  |  |
Senior Secured Loan | Hercules Technology Growth Capital | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-cash interest expense amortization of debt discount | $ 100,000 amsc_NonCashInterestExpenseAmortizationOfDebtDiscount / us-gaap_LineOfCreditFacilityAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember / us-gaap_RangeAxis = us-gaap_MaximumMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

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