Commitments and Contingencies - Life Insurance and Controll Agreements (Details) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Maximum
Commitment and contingencies
Professional outplacement services that would be received by the participants	$ 10,000
2002 Plan
Commitment and contingencies
Period of graded vesting schedule	5 years
Annual vesting by the participants (as a percent)	20.00%
Expenses incurred	$ 327,000	$ 207,000
2002 Plan \| Officer participants
Commitment and contingencies
Bonus to be paid as a percentage of the participants base annual salary	15.00%
2002 Plan \| Other participants
Commitment and contingencies
Bonus to be paid as a percentage of the participants base annual salary	10.00%
Agreement(s) \| Officer participants
Commitment and contingencies
Period of continued participation in health, disability and life insurance plans after involuntary termination	3 years
Agreement(s) \| Other participants
Commitment and contingencies
Period of continued participation in health, disability and life insurance plans after involuntary termination	2 years

Represents the annual vesting percentage of participants under the plan of the entity.

No definition available.

Name:	nsys_AnnualVestingPercentage
Namespace Prefix:	nsys_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of bonus to be paid as a percentage of the participants' base annual salary.

+ References

No definition available.

+ Details

Name:	nsys_BonusToBePaidAsPercentageOfParticipantsBaseAnnualSalary
Namespace Prefix:	nsys_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	nsys_CommitmentLineItems
Namespace Prefix:	nsys_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the period of continued participation in health, disability and life insurance plans for the participants in the event of an involuntarily termination.

+ References

No definition available.

+ Details

Name:	nsys_DisabilityAndLifeInsurancePlansPeriod
Namespace Prefix:	nsys_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the period of graded vesting schedule in which the participants vest under the plan of the entity.

+ References

No definition available.

+ Details

Name:	nsys_GradedVestingSchedulePeriod
Namespace Prefix:	nsys_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of professional outplacement services that would be received by the participants in the event of an involuntarily termination.

+ References

No definition available.

+ Details

Name:	nsys_ProfessionalOutplacementServicesWouldBeReceivedAmount
Namespace Prefix:	nsys_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of labor-related expenses classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_OtherLaborRelatedExpenses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=nsys_ExecutiveBonusLifeInsurancePlan2002Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TitleOfIndividualAxis=us-gaap_OfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TitleOfIndividualAxis=nsys_OtherParticipantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=nsys_ChangeOfControlAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: