v2.4.0.8

Summary of Significant Accounting Policies , Inventory (Details) (USD $) | Dec. 31, 2013 | Dec. 31, 2012
--- | --- | ---
Accounting Policies [Abstract] |  |
Consignment inventory | $ 4,260,000 | $ 2,344,000
Consignment inventory, raw materials | 4,100,000 | 2,100,000
Consignment inventory, finished goods | $ 200,000 | $ 200,000

X
- Definition Consigned Inventory + References No definition available. + Details
Name: | ftnt_ConsignedInventory
Namespace Prefix: | ftnt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Consignment Inventory, Finished Goods + References No definition available. + Details
Name: | ftnt_ConsignmentInventoryFinishedGoods
Namespace Prefix: | ftnt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Consignment Inventory, Raw Materials + References No definition available. + Details
Name: | ftnt_ConsignmentInventoryRawMaterials
Namespace Prefix: | ftnt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration