v2.4.1.9
Segment and Significant Customer Information Significant Customers (Details) (Customer Concentration Risk [Member])
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Sales Revenue [Member] | Exclusive Networks Group [Member]
   
Concentration Risk [Line Items]    
Percentage from a single customer 17.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= ftnt_SalesRevenueMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_ExclusiveNetworksGroupMember
14.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= ftnt_SalesRevenueMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_ExclusiveNetworksGroupMember
Sales Revenue [Member] | Ingram Micro [Member]
   
Concentration Risk [Line Items]    
Percentage from a single customer 0.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= ftnt_SalesRevenueMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_IngramMicroMember
10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= ftnt_SalesRevenueMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_IngramMicroMember
Accounts Receivable [Member] | Exclusive Networks Group [Member]
   
Concentration Risk [Line Items]    
Percentage from a single customer 19.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_ExclusiveNetworksGroupMember
18.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_ExclusiveNetworksGroupMember
Accounts Receivable [Member] | Fin Tec Computer [Member]
   
Concentration Risk [Line Items]    
Percentage from a single customer 12.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_FineTecComputerMember
0.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_AccountsReceivableMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= ftnt_FineTecComputerMember