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Warrants and Derivative Liabilities - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended				12 Months Ended			3 Months Ended	0 Months Ended			1 Months Ended	0 Months Ended	3 Months Ended
	Mar. 24, 2015	Nov. 13, 2014	Nov. 15, 2013	Jun. 05, 2012	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2014	Oct. 09, 2013	Apr. 04, 2012	Mar. 02, 2014	Dec. 31, 2012	Dec. 19, 2014	Dec. 31, 2013
Derivative [Line Items]
Warrants to purchase one share of common stock		90.00%amsc_WarrantsToPurchaseOneShareOfCommonStock
Reverse stock split	0.1us-gaap_StockholdersEquityNoteStockSplitConversionRatio1	0.1us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Gain (loss) in change of fair value of derivative instruments and warrants					$ 3,963amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants	$ 1,872amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants	$ 7,556amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants
Convertible debt instrument redemption waiting period					1 year
Convertible debt instrument contractual term					30 months
Warrants expiration date			May 15, 2019	Dec. 05, 2017
Common stock units offered		909,090us-gaap_CommonUnitIssued
Number of warrants issued to purchase common stock		818,181amsc_NumberOfWarrantsIssuedToPurchaseCommonStock
Shares issued, price per share		$ 11.00us-gaap_SaleOfStockPricePerShare
Convertible Bond
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants						500amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_ClassOfWarrantOrRightAxis = amsc_ConvertibleBondMember	3,800amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_ClassOfWarrantOrRightAxis = amsc_ConvertibleBondMember
Senior Secured Term Loan First Warrant
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants					100amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_ClassOfWarrantOrRightAxis = amsc_SeniorSecuredTermLoanFirstWarrantMember	100amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_ClassOfWarrantOrRightAxis = amsc_SeniorSecuredTermLoanFirstWarrantMember	200amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_ClassOfWarrantOrRightAxis = amsc_SeniorSecuredTermLoanFirstWarrantMember
Hudson Warrant
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants					1,800amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_ClassOfWarrantOrRightAxis = amsc_HudsonWarrantMember
Capital Ventures International
Derivative [Line Items]
Warrant exercise, waiting period					6 months
Warrant exercise period					5 years
Common stock, shares issued								909,090us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember
Required notification period					61 days
Warrants to purchase one share of common stock								90.00%amsc_WarrantsToPurchaseOneShareOfCommonStock / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember
Reverse stock split	0.1us-gaap_StockholdersEquityNoteStockSplitConversionRatio1 / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember
Gain (loss) in change of fair value of derivative instruments and warrants					1,900amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember	1,200amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember	3,600amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember
Senior Convertible Debt | Capital Ventures International
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock										309,406amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember
Exercise price								22.10invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember	$ 26.10invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember	$ 54.50invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = us-gaap_ConvertibleDebtMember
New Unsecured Senior Convertible Note
Derivative [Line Items]
Conversion price										$ 48.50us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember		31.90us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember
Debt conversion, shares issued											663,000us-gaap_DebtConversionConvertedInstrumentSharesIssued1 / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember
New Unsecured Senior Convertible Note | Capital Ventures International | Minimum
Derivative [Line Items]
Beneficial ownership limitation percentage												4.99%amsc_BeneficialOwnershipLimitationPercentage / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember / us-gaap_RangeAxis = us-gaap_MinimumMember
New Unsecured Senior Convertible Note | Capital Ventures International | Maximum
Derivative [Line Items]
Beneficial ownership limitation percentage												9.99%amsc_BeneficialOwnershipLimitationPercentage / us-gaap_DebtInstrumentAxis = amsc_CapitalVenturesInternationalMember / us-gaap_LongtermDebtTypeAxis = amsc_NewUnsecuredSeniorConvertibleNoteMember / us-gaap_RangeAxis = us-gaap_MaximumMember
Senior Secured Loan
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock			25,641amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember
Exercise price		$ 17.00invest_InvestmentWarrantsExercisePrice / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember	19.50invest_InvestmentWarrantsExercisePrice / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember
Common stock, shares issued		909,090us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember
Senior Secured Loan | Maximum
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants					$ 300amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember / us-gaap_RangeAxis = us-gaap_MaximumMember	$ 0amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember / us-gaap_RangeAxis = us-gaap_MaximumMember
Senior Secured Loan | Hercules Technology Growth Capital
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock				13,927amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember									58,823amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember
Exercise price				35.90invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember	$ 17.00invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember								$ 11.00invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember	$ 19.50invest_InvestmentWarrantsExercisePrice / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember
Common stock, shares issued		909,090us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_DebtInstrumentAxis = amsc_HerculesTechnologyGrowthCapitalMember / us-gaap_LongtermDebtTypeAxis = amsc_SeniorSecuredLoanMember

X

- Definition

Beneficial ownership limitation percentage.

+ References

No definition available.

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X

- Definition

Convertible debt instrument contractual term.

+ References

No definition available.

+ Details

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X

- Definition

Convertible debt instrument redemption waiting period.

+ References

No definition available.

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- Definition

Gain (loss) in change of fair value of derivative instruments and warrants.

+ References

No definition available.

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- Definition

Number of warrants issued to purchase common stock.

+ References

No definition available.

+ Details

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- Definition

Ownership percentage notification period requirement.

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- Definition

Purchase commitment issuance of warrants shares of common stock.

+ References

No definition available.

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X

- Definition

Warrant exercise period.

+ References

No definition available.

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X

- Definition

Warrant exercise waiting period.

+ References

No definition available.

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X

- Definition

Warrants to purchase one share of common stock.

+ References

No definition available.

+ Details

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X

- Definition

Exercise price of the warrants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

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X

- Definition

Expiration date of warrants held.

+ References

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-Name Regulation S-X (SX)

-Number 210

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X

- Definition

Number of common units issued of limited liability company (LLC).

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-Publisher FASB

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-SubTopic 10

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X

- Definition

The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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- Definition

The price per share of the conversion feature embedded in the debt instrument.

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- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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- Definition

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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- Definition

Number of new stock issued during the period.

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