v2.4.0.6
Document And Entity Information (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Mar. 31, 2012
May 29, 2012
Sep. 30, 2011
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Mar. 31, 2012    
Document Fiscal Year Focus 2012    
Document Fiscal Period Focus FY    
Entity Registrant Name AMERICAN SUPERCONDUCTOR CORP /DE/    
Entity Central Index Key 0000880807    
Current Fiscal Year End Date --03-31    
Entity Filer Category Accelerated Filer    
Entity Common Stock, Shares Outstanding   51,994,311  
Entity Well-known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Public Float     $ 149.2