Annual report pursuant to Section 13 and 15(d)

Note 3 - Commitments and Contingencies (Details Textual)

v2.4.1.9
Note 3 - Commitments and Contingencies (Details Textual)
1 Months Ended 12 Months Ended 1 Months Ended 3 Months Ended
Dec. 31, 2014
USD ($)
Apr. 21, 2013
Apr. 21, 2009
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Oct. 31, 2007
USD ($)
Oct. 19, 2007
Nov. 18, 2007
Five Year Warrants [Member]
Oct. 31, 2007
One Year Warrants [Member]
Dec. 31, 2007
Seven Year Warrants [Member]
Dec. 31, 2014
Korean Business Segment [Member]
USD ($)
Dec. 31, 2014
Korean Business Segment [Member]
KRW
Commitments and Contingencies Disclosure [Abstract]                        
Operating Leases, Rent Expense       $ 777,000us-gaap_LeaseAndRentalExpense $ 787,000us-gaap_LeaseAndRentalExpense              
Purchase Commitment, Monthly Amount, Minimum 40,000nhtc_PurchaseCommitmentMonthlyAmountMinimum     40,000nhtc_PurchaseCommitmentMonthlyAmountMinimum                
Purchase Commitment, Remaining Minimum Amount Committed 3,300,000us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted     3,300,000us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted                
Purchase Commitment, Term 3 years                      
Purchase Commitment, Renewal Term 3 years                      
Supplemental Unemployment Benefits, Severance Benefits 12,000us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits     12,000us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits                
Other Assets, Noncurrent 372,000us-gaap_OtherAssetsNoncurrent     372,000us-gaap_OtherAssetsNoncurrent 300,000us-gaap_OtherAssetsNoncurrent           180,000us-gaap_OtherAssetsNoncurrent
/ us-gaap_NetAmountAtRiskByProductAndGuaranteeGuaranteeTypeAxis
= nhtc_KoreanBusinessSegmentMember
197,000,000us-gaap_OtherAssetsNoncurrent
/ us-gaap_NetAmountAtRiskByProductAndGuaranteeGuaranteeTypeAxis
= nhtc_KoreanBusinessSegmentMember
Convertible Debt           $ 4,250,000us-gaap_ConvertibleDebt            
Term Of Warrant   5 years 1 year 7 years       7 years 1 year 7 years    
Class of Warrant or Right, Number of Securities Called by Warrants or Rights 88,097us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights     88,097us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights     3,141,499us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights 1,495,952us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_RangeAxis
= nhtc_FiveYearWarrantsMember
1,495,952us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_RangeAxis
= nhtc_OneYearWarrantsMember
1,495,952us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_RangeAxis
= nhtc_SevenYearWarrantsMember