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Business Segments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 9 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2014 Segment | Dec. 31, 2013
Segment Reporting Information [Line Items] |  |  |  |
Number of reportable business segments |  |  | 2 us-gaap_NumberOfReportableSegments |
Stock-based compensation expense | $ 1,521 us-gaap_AllocatedShareBasedCompensationExpense | $ 3,040 us-gaap_AllocatedShareBasedCompensationExpense | $ 4,620 us-gaap_AllocatedShareBasedCompensationExpense | $ 7,328 us-gaap_AllocatedShareBasedCompensationExpense
Restructuring and impairments | $ 507 us-gaap_RestructuringSettlementAndImpairmentProvisions | $ 108 us-gaap_RestructuringSettlementAndImpairmentProvisions | $ 5,416 us-gaap_RestructuringSettlementAndImpairmentProvisions | $ 872 us-gaap_RestructuringSettlementAndImpairmentProvisions
Minimum |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Megawatts of drive trains and power ratings |  |  | 2 amsc_BusinessSegmentsPowerOfWindTurbines / us-gaap_RangeAxis = us-gaap_MinimumMember |

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- Definition Business segments power of wind turbines. + References No definition available. + Details
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Namespace Prefix: | amsc_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition 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. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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- Definition The aggregate amount provided for estimated restructuring charges, remediation costs, and asset impairment loss during an accounting period. Generally, these items are either unusual or infrequent, but not both (in which case they would be extraordinary items). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.3) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | debit
Period Type: | duration

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

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |