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Income Taxes (Narrative) (Details) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Schedule of Income Taxes [Line Items]      
Deferred Tax Assets, Valuation Allowance $ 3,020,000us-gaap_DeferredTaxAssetsValuationAllowance [1] $ 0us-gaap_DeferredTaxAssetsValuationAllowance  
Tax impact from exercises and cancellations of stock options (481,000)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation 429,000us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation 1,121,000us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss) 5,000us-gaap_AvailableForSaleSecuritiesIncomeTaxExpenseOnChangeInUnrealizedHoldingGainOrLoss 16,000us-gaap_AvailableForSaleSecuritiesIncomeTaxExpenseOnChangeInUnrealizedHoldingGainOrLoss (5,000)us-gaap_AvailableForSaleSecuritiesIncomeTaxExpenseOnChangeInUnrealizedHoldingGainOrLoss
Possible reduction in liabilities for uncertain tax positions 1,100,000us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit    
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 12,300,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate    
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense 1,100,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense 446,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense 74,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued 3,000,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued 2,100,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued  
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount 78,300,000us-gaap_IncomeTaxReconciliationTaxCreditsForeign 60,500,000us-gaap_IncomeTaxReconciliationTaxCreditsForeign  
Credit Subject To Annual Usage Limitations [Member]      
Schedule of Income Taxes [Line Items]      
Tax Credit Carryforward, Amount 100,000us-gaap_TaxCreditCarryforwardAmount
/ us-gaap_TaxCreditCarryforwardAxis
= ntgr_CreditSubjectToAnnualUsageLimitationsMember		    
US Federal [Member]      
Schedule of Income Taxes [Line Items]      
Operating Loss Carryforwards 17,700,000us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember		    
Operating Loss Expiration Date, Range Start 2021    
State [Member]      
Schedule of Income Taxes [Line Items]      
Deferred Tax Assets, Valuation Allowance 3,000,000us-gaap_DeferredTaxAssetsValuationAllowance
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember		    
Operating Loss Carryforwards 100,000us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember		    
Tax Credit Carryforward, Amount $ 1,400,000us-gaap_TaxCreditCarryforwardAmount
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember		    
Operating Loss Expiration Date, Range Start 2015    
Year One [Member]      
Schedule of Income Taxes [Line Items]      
Income Tax Examination, Year under Examination 2008    
Year Two [Member]      
Schedule of Income Taxes [Line Items]      
Income Tax Examination, Year under Examination 2009    
[1] Valuation allowance is presented gross. The valuation allowance net of the federal tax effect is ($1,963).