v2.4.1.9
Document and Entity Information
3 Months Ended
Mar. 31, 2015
Apr. 24, 2015
Document Information [Line Items]    
Entity Registrant Name FORTINET INC  
Entity Central Index Key 0001262039  
Document Type 10-Q  
Document Period End Date Mar. 31, 2015  
Amendment Flag false  
Document Fiscal Year Focus 2015  
Document Fiscal Period Focus Q1  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   169,563,012dei_EntityCommonStockSharesOutstanding