Document and Entity Information
9 Months Ended
Dec. 31, 2012
Feb. 01, 2013
Document and Entity Information [Abstract]    
Entity Registrant Name ORION ENERGY SYSTEMS, INC.  
Entity Central Index Key 0001409375  
Document Type 10-Q  
Document Period End Date Dec. 31, 2012  
Amendment Flag false  
Document Fiscal Year Focus 2013  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --03-31  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   20,150,642