Beneficial Ownership, Limitation Option, Percentage

No definition available.

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Period Type:	duration

- Definition

Beneficial ownership limitation percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	amsc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Class of Warrant or Right, Number of Warrants to Purchase One Share of Stock

+ References

No definition available.

+ Details

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

- Definition

Gain (loss) in change of fair value of derivative instruments and warrants.

+ References

No definition available.

+ Details

Name:	amsc_GainLossInChangeOfFairValueOfDerivativeInstrumentsAndWarrants
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of warrants issued to purchase common stock.

+ References

No definition available.

+ Details

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

- Definition

Ownership percentage notification period requirement.

+ References

No definition available.

+ Details

Name:	amsc_OwnershipPercentageNotificationPeriodRequirement
Namespace Prefix:	amsc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase commitment issuance of warrants shares of common stock.

+ References

No definition available.

+ Details

Name:	amsc_PurchaseCommitmentIssuanceOfWarrantsSharesOfCommonStock
Namespace Prefix:	amsc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Warrant exercise period.

+ References

No definition available.

+ Details

Name:	amsc_WarrantExercisePeriod
Namespace Prefix:	amsc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Warrant exercise waiting period.

+ References

No definition available.

+ Details

Name:	amsc_WarrantExerciseWaitingPeriod
Namespace Prefix:	amsc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Expiration date of warrants held.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column A

+ Details

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Namespace Prefix:	invest_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- 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 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

Reference 2: 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

Reference 3: 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

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

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

- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=amsc_CapitalVenturesInternationalMember
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- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=amsc_ExchangedWarrantsMember
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Data Type:	na
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- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleDebtMember
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- Details

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- Details

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- Details

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- Details

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Warrants and Derivative Liabilities - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended
	Dec. 19, 2014	Apr. 04, 2012	Oct. 31, 2013	Jun. 30, 2017	Jun. 30, 2016	Nov. 13, 2014
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million Hercules warrants)				$ 925	$ (678)
Hercules Warrants
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million Hercules warrants)				100	(100)
November 2014 Warrant
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million Hercules warrants)				$ 900	(600)
Warrants expiration date				Nov. 13, 2019
Common stock units offered (in shares)						909,090
Warrants to purchase one share of common stock						0.9
Number of warrants issued to purchase common stock (in shares)						818,181
Sale of stock, price per share (in dollars per share)						$ 7.98
Capital Ventures International \| Exchanged Warrants
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million Hercules warrants)				$ 0	$ 0
Senior convertible note warrant \| Capital Ventures International \| Original Warrants
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		309,406
Senior convertible note warrant \| Capital Ventures International \| Exchanged Warrants
Derivative [Line Items]
Warrant exercise, waiting period			6 months
Warrant exercise period			5 years
Warrant exercise price (in dollars per share)			$ 12.83
Senior convertible note warrant \| Capital Ventures International \| Maximum \| Exchanged Warrants
Derivative [Line Items]
Beneficial ownership limitation percentage			4.99%
Beneficial ownership, limitation option, percentage			9.99%
Required notification period			61 days
Senior secured loan \| Hercules Technology Growth Capital \| Hercules Warrants
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)	58,823
Warrant exercise price (in dollars per share)	$ 11.00			$ 8.02
Warrants expiration date				Jun. 30, 2020