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Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Mar. 31, 2015 | Mar. 31, 2014 | Mar. 31, 2013
General Discussion Of Pension And Other Postretirement Benefits [Abstract] |  |  |
Percentage of common stock matched under deferred compensation plan | 50.00%amsc_DefinedContributionPlanCompanyContributionPercentageMatchCommonStock |  |
First certain percentage of eligible contribution under deferred compensation plan | 6.00%amsc_DefinedContributionPlanPercentageOfFirstEligibleEmployeeContributionMatchedByEmployer |  |
Recorded expense under deferred compensation plan | $ 0.4 us-gaap_DefinedContributionPlanCostRecognized | $ 0.4 us-gaap_DefinedContributionPlanCostRecognized | $ 0.5 us-gaap_DefinedContributionPlanCostRecognized

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- Definition Defined Contribution Plan Company Contribution Percentage Match Common Stock. + References No definition available. + Details
Name: | amsc_DefinedContributionPlanCompanyContributionPercentageMatchCommonStock
Namespace Prefix: | amsc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Defined contribution plan percentage of first eligible employee contribution matched by employer + References No definition available. + Details
Name: | amsc_DefinedContributionPlanPercentageOfFirstEligibleEmployeeContributionMatchedByEmployer
Namespace Prefix: | amsc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
Name: | us-gaap_GeneralDiscussionOfPensionAndOtherPostretirementBenefitsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration