v3.10.0.1
Document and Entity Information - shares
6 Months Ended
Sep. 30, 2018
Nov. 02, 2018
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
Entity Registrant Name AMERICAN SUPERCONDUCTOR CORP /DE/  
Trading Symbol AMSC  
Entity Central Index Key 0000880807  
Current Fiscal Year End Date --03-31  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   21,364,053
Entity Emerging Growth Company false  
Entity Small Business true