Represents the number of additional shares to be issued.

No definition available.

Name:	amsc_AdditionalSharesToBeIssued
Namespace Prefix:	amsc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid in shares.

+ References

No definition available.

+ Details

Name:	amsc_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHighNumberOfShares
Namespace Prefix:	amsc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
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+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
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+ Details

Name:	us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
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+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=amsc_PublicOfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=amsc_NortheastPowerSystemsIncNepsiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 17 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended	6 Months Ended
	Oct. 26, 2020	Oct. 01, 2020	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Proceeds from Sale and Maturity of Marketable Securities, Total				$ 25,006
Certificates of Deposit [Member]
Proceeds from Sale and Maturity of Marketable Securities, Total			$ 25,000
Subsequent Event [Member] \| Public Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)	3,670,000
Shares Issued, Price Per Share (in dollars per share)	$ 15
Proceeds from Issuance of Common Stock	$ 51,400
Additional Shares to be Issued (in shares)	550,500
Northeast Power Systems, Inc (NEPSI) [Member] \| Subsequent Event [Member]
Payments to Acquire Businesses, Gross		$ 26,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)		873,657
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High, Number of Shares (in shares)		1,000,000