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Nature of the Business and Operations and Liquidity - Additional Information (Detail)
Share data in Millions, except Per Share data, unless otherwise specified
 0 Months Ended 3 Months Ended 9 Months Ended 0 Months Ended 0 Months Ended 3 Months Ended
Nov. 13, 2014
USD ($)
Dec. 31, 2014
USD ($)
Employee
Dec. 31, 2014
USD ($)
Employee
Dec. 31, 2013
USD ($)
Sep. 30, 2014
USD ($)
Mar. 31, 2014
USD ($)
Sep. 30, 2013
USD ($)
Mar. 31, 2013
USD ($)
Nov. 13, 2014
Senior Secured Loan
Dec. 19, 2014
New Term Loan
USD ($)
Nov. 15, 2013
New Term Loan
USD ($)
Dec. 31, 2014
Term Loan
USD ($)
Aug. 29, 2014
Ghodawat Energy Pvt Ltd
USD ($)
Aug. 29, 2014
Ghodawat Energy Pvt Ltd
EUR (€)
Feb. 04, 2015
Ghodawat Energy Pvt Ltd
Subsequent Event
USD ($)
Feb. 04, 2015
Ghodawat Energy Pvt Ltd
Subsequent Event
EUR (€)
Jun. 05, 2012
Hercules Technology Growth Capital
Senior Secured Loan
USD ($)
Dec. 31, 2014
MLV & Co. LLC
Atm Arrangement
USD ($)
Nov. 15, 2013
MLV & Co. LLC
Atm Arrangement
Maximum
USD ($)
Description Of Business [Line Items]                                      
Accumulated deficit   $ (901,681,000)us-gaap_RetainedEarningsAccumulatedDeficit $ (901,681,000)us-gaap_RetainedEarningsAccumulatedDeficit     $ (856,389,000)us-gaap_RetainedEarningsAccumulatedDeficit                          
Cash and cash equivalents   35,983,000us-gaap_CashAndCashEquivalentsAtCarryingValue 35,983,000us-gaap_CashAndCashEquivalentsAtCarryingValue   35,983,000us-gaap_CashAndCashEquivalentsAtCarryingValue 43,114,000us-gaap_CashAndCashEquivalentsAtCarryingValue 35,394,000us-gaap_CashAndCashEquivalentsAtCarryingValue 39,243,000us-gaap_CashAndCashEquivalentsAtCarryingValue                      
Net cash used in operating activities     20,934,000us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations 18,366,000us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations                              
Liability for damages                         10,100,000us-gaap_LossContingencyDamagesAwardedValue
/ dei_LegalEntityAxis
= amsc_GhodawatEnergyPvtLtdMember		 8,300,000us-gaap_LossContingencyDamagesAwardedValue
/ dei_LegalEntityAxis
= amsc_GhodawatEnergyPvtLtdMember		          
Interest rate accrued on liability for damage                         5.33%amsc_LossContingencyInterestRate
/ dei_LegalEntityAxis
= amsc_GhodawatEnergyPvtLtdMember		 5.33%amsc_LossContingencyInterestRate
/ dei_LegalEntityAxis
= amsc_GhodawatEnergyPvtLtdMember		          
Settlement amount                             8,500,000us-gaap_LitigationSettlementAmount
/ dei_LegalEntityAxis
= amsc_GhodawatEnergyPvtLtdMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		 7,450,000us-gaap_LitigationSettlementAmount
/ dei_LegalEntityAxis
= amsc_GhodawatEnergyPvtLtdMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		      
Number of workforce persons   303dei_EntityNumberOfEmployees 303dei_EntityNumberOfEmployees                                
Debt, face amount                   1,500,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= amsc_NewTermLoanMember		 10,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= amsc_NewTermLoanMember		           10,000,000us-gaap_DebtInstrumentFaceAmount
/ dei_LegalEntityAxis
= amsc_HerculesTechnologyGrowthCapitalMember
/ us-gaap_LongtermDebtTypeAxis
= amsc_SeniorSecuredLoanMember		    
Outstanding principal balance                       9,200,000us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= amsc_TermLoanMember		              
Common stock   961,000us-gaap_CommonStockValue 961,000us-gaap_CommonStockValue     789,000us-gaap_CommonStockValue                         30,000,000us-gaap_CommonStockValue
/ us-gaap_ClassOfWarrantOrRightAxis
= amsc_AtmArrangementMember
/ dei_LegalEntityAxis
= amsc_MLVAndCoMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Net proceeds from sale of common stock $ 9,100,000us-gaap_ProceedsFromIssuanceOfCommonStock $ 9,100,000us-gaap_ProceedsFromIssuanceOfCommonStock $ 9,114,000us-gaap_ProceedsFromIssuanceOfCommonStock                             $ 1,000,000us-gaap_ProceedsFromIssuanceOfCommonStock
/ us-gaap_ClassOfWarrantOrRightAxis
= amsc_AtmArrangementMember
/ dei_LegalEntityAxis
= amsc_MLVAndCoMember		  
Sale of common stock                                   0.8amsc_SaleOfCommonStock
/ us-gaap_ClassOfWarrantOrRightAxis
= amsc_AtmArrangementMember
/ dei_LegalEntityAxis
= amsc_MLVAndCoMember		  
Average sale price of share                                   $ 1.22amsc_AverageSalePriceOfShare
/ us-gaap_ClassOfWarrantOrRightAxis
= amsc_AtmArrangementMember
/ dei_LegalEntityAxis
= amsc_MLVAndCoMember		  
Common stock, shares issued 9.1us-gaap_StockIssuedDuringPeriodSharesNewIssues               9.1us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_LongtermDebtTypeAxis
= amsc_SeniorSecuredLoanMember		                    
Shares issued, price per share $ 1.10us-gaap_SaleOfStockPricePerShare $ 1.10us-gaap_SaleOfStockPricePerShare $ 1.10us-gaap_SaleOfStockPricePerShare                             $ 1.22us-gaap_SaleOfStockPricePerShare
/ us-gaap_ClassOfWarrantOrRightAxis
= amsc_AtmArrangementMember
/ dei_LegalEntityAxis
= amsc_MLVAndCoMember		  
Warrant to purchase one share of common stock 90.00%amsc_WarrantsToPurchaseOneShareOfCommonStock                                    
Number of warrants issued to purchase common stock 8.2amsc_NumberOfWarrantsIssuedToPurchaseCommonStock