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Accounts Receivable - Additional Information (Detail) (Credit Concentration Risk, Accounts Receivable)
12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Inox Wind Limited
   
Accounts Notes And Loans Receivable [Line Items]    
Risk percentage 56.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= amsc_InoxWindLimitedMember
20.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= amsc_InoxWindLimitedMember
CG Power Solutions UK Ltd
   
Accounts Notes And Loans Receivable [Line Items]    
Risk percentage   14.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= amsc_CGPowerSolutionsUKLtdMember
JINGCHENG New Energy
   
Accounts Notes And Loans Receivable [Line Items]    
Risk percentage   13.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= amsc_JINGCHENGNewEnergyMember