Coupon rate on corporate bond (in percent)

No definition available.

Name:	nssi_CorporateBondCouponPercentage
Namespace Prefix:	nssi_
Data Type:	num:percentItemType
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Period Type:	duration

Corporate bond with maturity date of June 2015 , Face Value

No definition available.

Name:	nssi_CorporateBondFaceValue
Namespace Prefix:	nssi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	nssi_NatureOfBusinessAndSummaryOfSignificantAccountingPoliciesMarketableSecuritiesDetailsNarrativeAbstract
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Data Type:	xbrli:stringItemType
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Period Type:	duration