Name:	nhtc_ContractWithCustomerLiabilityIncreaseFromCashReceipts
Namespace Prefix:	nhtc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the number of major customers accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc.

No definition available.

Name:	nhtc_NumberOfMajorCustomers
Namespace Prefix:	nhtc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the number of major markets accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc.

No definition available.

Name:	nhtc_NumberOfMajorMarkets
Namespace Prefix:	nhtc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the sales returns policy term.

No definition available.

Name:	nhtc_RevenueFromContractWithCustomerSalesReturnsPolicyTerm
Namespace Prefix:	nhtc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of historical sales returns.

No definition available.

Name:	nhtc_RevenueFromContractWithCustomersHistoricalSalesReturnsPercent
Namespace Prefix:	nhtc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of sales returns.

No definition available.

Name:	nhtc_RevenueFromContractWithCustomersSalesReturnsPercent
Namespace Prefix:	nhtc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130549-203045

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

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_GeographicConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: