Convertible notes fair value as percentage of par value.

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- Definition

Fair value assumptions, dilution effect.

+ References

No definition available.

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- Definition

Fair value assumptions, recovery rate.

+ References

No definition available.

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- Definition

Fair value assumptions, redeemable.

+ References

No definition available.

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- Definition

Percentage volume condition met.

+ References

No definition available.

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- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Publisher FASB

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313

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- Definition

Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

+ Details

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- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

+ Details

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- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

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Warrants and Derivative Liabilities - Schedule of Fair Value Assumptions Used to Calculate Value of Convertible Note Derivative Feature (Detail) (USD $)	0 Months Ended	3 Months Ended							12 Months Ended	0 Months Ended
	Apr. 04, 2012	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2015	Dec. 20, 2012
Combined principal balances of the term loans	$ 25,000,000us-gaap_DebtInstrumentCarryingAmount	$ 10,411,000us-gaap_DebtInstrumentCarryingAmount	$ 10,411,000us-gaap_DebtInstrumentCarryingAmount	$ 14,389,000us-gaap_DebtInstrumentCarryingAmount	$ 15,380,000us-gaap_DebtInstrumentCarryingAmount	$ 20,944,000us-gaap_DebtInstrumentCarryingAmount	$ 24,074,000us-gaap_DebtInstrumentCarryingAmount	$ 25,000,000us-gaap_DebtInstrumentCarryingAmount
Stock price	$ 39.70us-gaap_SharePrice	$ 16.40us-gaap_SharePrice	$ 23.40us-gaap_SharePrice	$ 26.40us-gaap_SharePrice	$ 26.70us-gaap_SharePrice	$ 26.20us-gaap_SharePrice	$ 41.50us-gaap_SharePrice	$ 46.80us-gaap_SharePrice
Percentage volume condition met	85.90%amsc_PercentageVolumeConditionMet	87.20%amsc_PercentageVolumeConditionMet	80.20%amsc_PercentageVolumeConditionMet	87.50%amsc_PercentageVolumeConditionMet	80.50%amsc_PercentageVolumeConditionMet	94.50%amsc_PercentageVolumeConditionMet	51.00%amsc_PercentageVolumeConditionMet	75.20%amsc_PercentageVolumeConditionMet
Expected volatility	75.00%	68.63%	66.26%	65.80%	66.91%	73.50%	70.00%	71.00%
Risk-free interest rate	0.44%	0.12%	0.10%	0.21%	0.20%	0.23%	0.23%	0.33%
Expected annual dividend yield	15.00%	16.50%	15.50%	16.70%	16.50%	16.50%	15.00%	16.00%
Recovery rate	30.00%amsc_FairValueAssumptionsRecoveryRate	35.00%amsc_FairValueAssumptionsRecoveryRate	35.00%amsc_FairValueAssumptionsRecoveryRate	37.00%amsc_FairValueAssumptionsRecoveryRate	30.00%amsc_FairValueAssumptionsRecoveryRate	30.00%amsc_FairValueAssumptionsRecoveryRate	30.00%amsc_FairValueAssumptionsRecoveryRate	30.00%amsc_FairValueAssumptionsRecoveryRate
Redeemable									yes
Term (years)	2 years 6 months	9 months	1 year	1 year 3 months 4 days	1 year 6 months 4 days	1 year 9 months 4 days	2 years 4 days	2 years 3 months 11 days
Dilution effect									yes
Derivative Liability	3,800,000us-gaap_DerivativeLiabilities		200,000us-gaap_DerivativeLiabilities	500,000us-gaap_DerivativeLiabilities	500,000us-gaap_DerivativeLiabilities	1,000,000us-gaap_DerivativeLiabilities	2,800,000us-gaap_DerivativeLiabilities	4,500,000us-gaap_DerivativeLiabilities
Fair value as a percent of par	15.10%	0.02%	0.70%	3.30%	3.40%	4.90%	11.40%	17.90%
Post Modification
Combined principal balances of the term loans										20,944,000
Stock price										$ 29.50
Percentage volume condition met										94.90%
Expected volatility										72.50%
Risk-free interest rate										0.25%
Expected annual dividend yield										16.50%
Recovery rate										30.00%
Redeemable									yes
Term (years)										1 year 9 months 15 days
Dilution effect									yes
Derivative Liability										1,500,000
Fair value as a percent of par										7.10%
Pre Modification
Combined principal balances of the term loans										24,074,000
Stock price										$ 29.50
Percentage volume condition met										28.60%
Expected volatility										72.50%
Risk-free interest rate										0.25%
Expected annual dividend yield										16.50%
Recovery rate										30.00%
Redeemable									yes
Term (years)										1 year 9 months 15 days
Dilution effect									yes
Derivative Liability										$ 900,000
Fair value as a percent of par										3.90%