v3.3.1.900
Document and Entity Information - shares
9 Months Ended
Dec. 31, 2015
Feb. 05, 2016
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, 2015  
Amendment Flag false  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --03-31  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   27,754,478