Revenue (Narrative) (Details) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($) region segment
Revenue from Contract with Customer [Abstract]
Revenue deferred due to unsatisfied performance obligations	$ 3.7
Revenue recognized for satisfaction of performance obligations over time	$ 2.0
Number of geographic regions in which the Company conducts business \| region	3
Number of operating segments \| segment	2
Number of reportable segments \| segment	2
Contract with Customer, Liability Included In Beginning Balance, Revenue Recognized	$ 1.7

Contract with Customer, Liability Included In Beginning Balance, Revenue Recognized

No definition available.

Name:	ntgr_ContractwithCustomerLiabilityIncludedInBeginningBalanceRevenueRecognized
Namespace Prefix:	ntgr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contract with Customer, Liability, Increase Due to Unsatisfied Performance Obligations

+ References

No definition available.

+ Details

Name:	ntgr_ContractwithCustomerLiabilityIncreaseDuetoUnsatisfiedPerformanceObligations
Namespace Prefix:	ntgr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of Geographic Regions

+ References

No definition available.

+ Details

Name:	ntgr_NumberofGeographicRegions
Namespace Prefix:	ntgr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

+ Details

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration