Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Fair Value Disclosures [Abstract]
Amount of additional convertible notes and warrants	$ 15.0

Derivative liability additional convertible notes and warrants.

No definition available.

Name:	amsc_DerivativeLiabilityAdditionalConvertibleNotesAndWarrants
Namespace Prefix:	amsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant