Litigation Settlement, Number Of Installments

No definition available.

Name:	amsc_LitigationSettlementNumberOfInstallments
Namespace Prefix:	amsc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Notes Receivable, Stated Interest Rate

+ References

No definition available.

+ Details

Name:	amsc_NotesReceivableStatedInterestRate
Namespace Prefix:	amsc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Purchase and Sale Agreement, Proceeds From Sale of Property, Plant and Equipment

+ References

No definition available.

+ Details

Name:	amsc_PurchaseAndSaleAgreementProceedsFromSaleOfPropertyPlantAndEquipment
Namespace Prefix:	amsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Purchase and Sale Agreement Proceeds From Sale of Property Plant And Equipment, Net

+ References

No definition available.

+ Details

Name:	amsc_PurchaseAndSaleAgreementProceedsFromSaleOfPropertyPlantAndEquipmentNet
Namespace Prefix:	amsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Purchase And Sale Agreement, Total Consideration

+ References

No definition available.

+ Details

Name:	amsc_PurchaseAndSaleAgreementTotalConsideration
Namespace Prefix:	amsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Supply Agreement, Aggregate Value

+ References

No definition available.

+ Details

Name:	amsc_SupplyAgreementAggregateValue
Namespace Prefix:	amsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Supply Commitment, Extension Period

+ References

No definition available.

+ Details

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

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3044-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6676-107765

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

+ Details

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

- Definition

Amount awarded from other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

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

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

- Definition

Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3536-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3521-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

+ Details

Name:	us-gaap_NetCashProvidedByUsedInOperatingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date more than one year from the balance sheet date, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

+ References

+ Details

Name:	us-gaap_NotesAndLoansReceivableNetNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash received for the settlement of litigation during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3536-108585

+ Details

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

- Definition

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30)(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(a)(4))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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

Name:	us-gaap_RetainedEarningsAccumulatedDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_CounterpartyNameAxis=amsc_SinovelWindGroupCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=amsc_SixtyFourJacksonLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=amsc_InoxWindLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Nature of the Business and Operations and Liquidity - Additional Information (Detail) $ in Thousands						1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 27, 2018 USD ($)	Jul. 04, 2018 USD ($)	Jul. 03, 2018 USD ($) installment	Mar. 28, 2018 USD ($)	Feb. 01, 2018 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)
Loss Contingencies [Line Items]
Retained earnings (accumulated deficit)							$ (953,187)		$ (953,187)		$ (988,333)
Cash and cash equivalents							80,042		80,042		34,084
Net cash used in operating activities									47,786	$ (20,234)
Net Sinovel settlement							24,978	$ 0	53,698	$ 0
Notes receivable, long term portion							$ 2,832		2,832		$ 2,559
Sinovel Wind Group Co Ltd
Loss Contingencies [Line Items]
Net Sinovel settlement									$ (53,700)
Sinovel settlement			$ 57,500
Number of installments \| installment			2
Proceeds from settlement	$ 25,000	$ 32,500
64 Jackson LLC
Loss Contingencies [Line Items]
Purchase and sale agreement, total consideration				$ 23,000	$ 23,000
Purchase and sale agreement, sale of property				17,000
Notes receivable, long term portion				6,000	$ 6,000
Purchase and sale agreement, proceeds from sale of property, plant and equipment, net				$ 16,900
Interest rate				1.96%			1.96%		1.96%
Inox Wind Limited
Loss Contingencies [Line Items]
Strategic agreements value						$ 210,000
Manufacturing agreement period, additional period required						3 years