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Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data in Millions, unless otherwise specified | 0 Months Ended | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | ---
Nov. 13, 2014 | Dec. 31, 2014 | Dec. 31, 2014 | Mar. 31, 2014 | Nov. 15, 2013
Schedule Of Capitalization Equity [Line Items] |  |  |  |  |
Common stock |  | $ 961 us-gaap_CommonStockValue | $ 961 us-gaap_CommonStockValue | $ 789 us-gaap_CommonStockValue |
Net proceeds from sale of common stock | 9,100 us-gaap_ProceedsFromIssuanceOfCommonStock | 9,100 us-gaap_ProceedsFromIssuanceOfCommonStock | 9,114 us-gaap_ProceedsFromIssuanceOfCommonStock |  |
Shares issued, price per share | $ 1.10 us-gaap_SaleOfStockPricePerShare | $ 1.10 us-gaap_SaleOfStockPricePerShare | $ 1.10 us-gaap_SaleOfStockPricePerShare |  |
Common stock units offered | 9.1 us-gaap_CommonUnitIssued |  |  |  |
Number Of Warrants Issued To Purchase Common Stock | 8.2 amsc_NumberOfWarrantsIssuedToPurchaseCommonStock |  |  |  |
Warrant to purchase one share of common stock | 90.00%amsc_WarrantsToPurchaseOneShareOfCommonStock |  |  |  |
MLV & Co. LLC | Atm Arrangement |  |  |  |  |
Schedule Of Capitalization Equity [Line Items] |  |  |  |  |
Commission on sale of common stock under the ATM |  |  |  |  | 3.00%amsc_CommissionAsPercentageOfGrossProceedsFromSaleOfCommonStock / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember
Net proceeds from sale of common stock |  | 1,000 us-gaap_ProceedsFromIssuanceOfCommonStock / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember |  |  |
Common stock, shares issued |  | 0.8 us-gaap_CommonStockSharesIssued / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember | 0.8 us-gaap_CommonStockSharesIssued / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember |  |
Shares issued, price per share |  | $ 1.22 us-gaap_SaleOfStockPricePerShare / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember | $ 1.22 us-gaap_SaleOfStockPricePerShare / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember |  |
MLV & Co. LLC | Maximum | Atm Arrangement |  |  |  |  |
Schedule Of Capitalization Equity [Line Items] |  |  |  |  |
Common stock |  |  |  |  | 30,000 us-gaap_CommonStockValue / us-gaap_ClassOfWarrantOrRightAxis = amsc_AtmArrangementMember / dei_LegalEntityAxis = amsc_MLVAndCoMember / us-gaap_RangeAxis = us-gaap_MaximumMember

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- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 + Details
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- Definition Number of common units issued of limited liability company (LLC). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 272 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 272 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055 + Details
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- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585 + Details
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