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Business Segment and Geographic Information - Additional Information (Detail) (USD $)	12 Months Ended
	Mar. 31, 2015 Segment	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Number of reportable business segments	2us-gaap_NumberOfReportableSegments
Stock-based compensation expense	$ 5,936,000us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	$ 10,696,000us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	$ 8,138,000us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
Restructuring and impairment charges	5,400,000us-gaap_RestructuringCostsAndAssetImpairmentCharges	3,000,000us-gaap_RestructuringCostsAndAssetImpairmentCharges	7,900,000us-gaap_RestructuringCostsAndAssetImpairmentCharges
Loss contingency accrual			$ 1,800,000us-gaap_LossContingencyAccrualAtCarryingValue
Geographic Concentration Risk | Sales Revenue, Net | Outside The United States
Segment Reporting Information [Line Items]
Risk percentage	86.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_GeographicConcentrationRiskMember / us-gaap_StatementGeographicalAxis = amsc_OutsideUnitedStatesMember	87.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_GeographicConcentrationRiskMember / us-gaap_StatementGeographicalAxis = amsc_OutsideUnitedStatesMember	85.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_GeographicConcentrationRiskMember / us-gaap_StatementGeographicalAxis = amsc_OutsideUnitedStatesMember
Customer Concentration Risk | Sales Revenue, Net | Inox Wind Limited
Segment Reporting Information [Line Items]
Risk percentage	56.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember / us-gaap_MajorCustomersAxis = amsc_InoxWindLimitedMember	31.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember / us-gaap_MajorCustomersAxis = amsc_InoxWindLimitedMember	19.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember / us-gaap_MajorCustomersAxis = amsc_InoxWindLimitedMember
Customer Concentration Risk | Sales Revenue, Net | JCNE
Segment Reporting Information [Line Items]
Risk percentage		18.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember / us-gaap_MajorCustomersAxis = amsc_BeijingJingchengNewEnergyCompanyLimitedMember	13.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember / us-gaap_MajorCustomersAxis = amsc_BeijingJingchengNewEnergyCompanyLimitedMember
Minimum
Segment Reporting Information [Line Items]
Megawatts of drive trains and power ratings	2amsc_BusinessSegmentsPowerOfWindTurbines / us-gaap_RangeAxis = us-gaap_MinimumMember

X

- Definition

Business segments power of wind turbines.

+ References

No definition available.

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- Definition

This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation".

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

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- Definition

Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses resulting from the write-down of assets. Excludes expenses related to a business combination, a discontinued operation or an asset retirement obligation.

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