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Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2011
Approximate savings resulted from reduction of positions	$ 30.0
Headcount reduction due to 2011 Plan, positions	150
Headcount reduction due to 2011 Plan, percentage of workforce	30.00%
Minimum [Member]
Restructuring charges	3.0
Maximum [Member]
Restructuring charges	$ 4.0

X

- Definition

Approximate savings resulted from reduction of positions.

+ Details

Name:	amsc_ApproximateSavingsResultedFromReductionOfPositions
Namespace Prefix:	amsc
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The number of positions eliminated during the period as a result of restructuring activities.

+ Details

Name:	amsc_RestructuringAndRelatedCostNumberOfPositionsEliminated
Namespace Prefix:	amsc
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of positions eliminated during the period as a percentage of total positions eliminated during the period in connection with the restructuring plan(s).

+ Details

Name:	amsc_RestructuringAndRelatedCostNumberOfPositionsEliminatedPeriodPercent
Namespace Prefix:	amsc
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount charged against earnings in the period for incurred and estimated costs, excluding asset retirement obligations, associated with exit from or disposal of business activities or restructurings pursuant to a program that is planned and controlled by management, and materially changes either the scope of a business undertaken by an entity, or the manner in which that business is conducted.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 5
-Section P
-Subsection 3, 4

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration