Document And Entity Information Statistical Measurement [Axis] Note To Financial Statement Details Textual Significant Accounting Policies Note 1 - Nature of Operations and Summary of Significant Accounting Policies Income tax benefit ecd_NonRule10b51ArrTrmntdFlag Non-Rule 10b5-1 Arrangement Terminated [Flag] Note 2 - Revenue ecd_NonRule10b51ArrAdoptedFlag Non-Rule 10b5-1 Arrangement Adopted [Flag] Note 3 - Balance Sheet Components nhtc_ShareRepurchaseProgramPercentOfStockOutstanding Share Repurchase Program, Percent of Stock Outstanding The percent of outstanding stock that is repurchased. Trading Arrangements, by Individual [Table] Note 4 - Fair Value Measurements Material Terms of Trading Arrangement [Text Block] Note 5 - Leases Note 9 - Stockholders' Equity Note 11 - Segment Information Financial Instrument [Axis] Note 1 - Nature of Operations and Summary of Significant Accounting Policies - Earnings Per Share (Details) Note 2 - Revenue - Net Sales by Product and Service (Details) Minimum [Member] Note 3 - Balance Sheet Components - Summary of Balance Sheet Amounts (Details) Note 4 - Fair Value Measurements - Investments (Details) Statistical Measurement [Domain] Dividends Payable [Table] Note 5 - Leases - Lease Cost (Details) Maximum [Member] Note 5 - Leases - Maturity of Lease Liabilities (Details) Note 9 - Stockholders' Equity - Changes in Accumulated Other Comprehensive Loss (Details) Note 11 - Segment Information - Operating Information by Geographic Area (Details) Note 11 - Segment Information - Total Assets by Geographic Region (Details) Note 11 - Segment Information - Net Sales by Geographic Area (Details) Notes To Financial Statements Notes To Financial Statements [Abstract] Business Description and Basis of Presentation [Text Block] us-gaap_Dividends Dividends declared, $0.10/share Employee-related costs Income Tax Jurisdiction [Domain] Financial Instruments [Domain] Dividends declared, per share (in dollars per share) Common Stock, Dividends, Per Share, Declared (in dollars per share) us-gaap_IncreaseDecreaseInInventories Inventories us-gaap_SharesOutstanding BALANCE (in shares) BALANCE (in shares) Segment Reporting [Text Block] Award Type [Axis] Adjustments to reconcile net income (loss) to net cash used in operating activities: Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding Plan Name [Axis] Segment Reporting, Reconciliation of Profit (Loss) by Segment to Consolidated [Table Text Block] us-gaap_Liabilities Total liabilities Plan Name [Domain] Segment Reporting, Reconciliation of Revenue by Segment to Consolidated [Table Text Block] Segment Reporting, Reconciliation of Asset by Segment to Consolidated [Table Text Block] us-gaap_AllocatedShareBasedCompensationExpense Share-Based Payment Arrangement, Expense us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and stockholders’ equity Consolidation Items [Axis] Title and Position [Axis] Segment Reporting [Table] Right-of-use assets obtained in exchange for operating lease liabilities Amount of increase (decrease) in right-of-use asset obtained in exchange for operating lease liability. Commissions expense Share-based compensation us-gaap_ShareBasedCompensation Selling, general and administrative expenses Consolidation Items [Domain] Lessee, Lease, Description [Table] Share-Based Payment Arrangement [Text Block] Changes in assets and liabilities: us-gaap_IncreaseDecreaseInAccountsPayable Accounts payable Preferred stock, issued (in shares) Europe [Member] Preferred stock, outstanding (in shares) Preferred stock, authorized (in shares) us-gaap_RestrictedCash Restricted Cash Software, In-Development [Member] The Phantom Plan [Member] Information pertaining to the phantom plan. Restricted cash included in other long-term assets Phantom Shares [Member] Information pertaining to phantom shares. Fair Value, by Balance Sheet Grouping [Table] Preferred stock, par value (in dollars per share) us-gaap_IncreaseDecreaseInAccruedLiabilities Other accrued expenses us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect Net increase (decrease) in cash, cash equivalents and restricted cash Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Table Text Block] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents Cash restricted cash and cash equivalents Effect of exchange rates on cash, cash equivalents and restricted cash Employees and Non-Employee Directors [Member] Information pertaining to employees and non-employee directors. New Accounting Pronouncements, Policy [Policy Text Block] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of period CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of period Other comprehensive income (loss), net of tax: Statement [Table] Reclassification, Comparability Adjustment [Policy Text Block] us-gaap_OperatingLeasePayments Operating Lease, Payments Other accrued expenses: nhtc_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsMaximumPaymentPerShare Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Payment Per Share (in dollars per share) Represents the maximum payment value per share of equity instruments other than options under share based compensation arrangement. us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number (in shares) nhtc_PolicyTable us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) srt_StockRepurchaseProgramAuthorizedAmount1 Stock Repurchase Program, Authorized Amount us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares) Product and Service [Domain] Product and Service [Axis] us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Total lease payments Weighted-average discount rate 2027 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) Remainder of 2026 Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability, Noncurrent 2029 Commitments and Contingencies Disclosure [Text Block] 2028 Statement [Line Items] 2030 Fair Value Hierarchy and NAV [Axis] Common stock, issued (in shares) Award Type [Domain] Common stock, authorized (in shares) us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1 Share Repurchase Program, Remaining Authorized, Amount Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Common stock, $0.001 par value; 50,000,000 shares authorized; 12,979,414 shares issued at June 30, 2026 and December 31, 2025 Accounts payable us-gaap_PolicyTextBlockAbstract Accounting Policies us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements us-gaap_TableTextBlock Notes Tables Employee-related expense us-gaap_ComprehensiveIncomeNetOfTax Comprehensive income (loss) Proceeds from maturities of marketable securities Concentration Risk Type [Axis] us-gaap_AccruedLiabilitiesCurrent Accrued Liabilities, Current Accrued commissions us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount Less: imputed interest us-gaap_OperatingLeaseLiabilityNoncurrent Operating lease liabilities Present value of lease liabilities Other accrued expenses Operating lease liabilities Concentration Risk Type [Domain] Malaysia and Singapore [Member] Represents information about Malaysia and Singapore CANADA Adjusted cost Income Tax Jurisdiction, Domestic Federal [Member] CHINA Net accretion of marketable securities Represents the amount of cash outflow from the net accretion of securities. Income Tax Jurisdiction, Domestic State and Local [Member] Equity Incentive Plan 2026 [Member] The Equity Incentive Plan 2026. Statement of Stockholders' Equity [Abstract] Intangible Asset, Finite-Lived, Class [Axis] Statement of Comprehensive Income [Abstract] Intangible Asset, Finite-Lived, Class [Domain] Statement of Cash Flows [Abstract] Other comprehensive income (loss) Equity Components [Axis] Equity Component [Domain] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Fair Value, Inputs, Level 2 [Member] AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Equity [Text Block] AOCI Attributable to Parent [Member] Fair Value, Inputs, Level 1 [Member] Additional Paid-in Capital [Member] Corporate Debt Securities [Member] Retained Earnings [Member] Income Tax Jurisdiction, Foreign [Member] Cost of sales HONG KONG Property and equipment, net JAPAN Peru and Colombia [Member] Represents Peru and Colombia. Deferred tax asset Other segment items2 Represents other segment expenses, including but not limited to credit card fees, marketing-related costs, professional fees and other business expenses. Facility costs Represents all costs included under facility costs. Administrative Fees, Freight and Other [Member] Information related to administrative fees, freight and other. Share-based compensation Other inventories and inventory-related deposits1 Represents inventories classified as other and inventory-related deposits. China Segment [Member] Represents the China segment. Russia and Kazakhstan Segment [Member] Represents the Russia and Kazakhstan segment Deferred tax liability Fair Value Disclosures [Text Block] Current liabilities: us-gaap_LiabilitiesCurrent Total current liabilities Marketable securities Lease, Cost [Table Text Block] Revenue Benchmark [Member] Other Commitments [Table] Accumulated other comprehensive loss Income (loss) before income taxes Income (loss) before income taxes us-gaap_PaymentsToAcquireMarketableSecurities Purchases of marketable securities us-gaap_CashUninsuredAmount Cash, Uninsured Amount Additional paid-in capital TAIWAN us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1 Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Purchases of property and equipment Lessee, Operating Leases [Text Block] UNITED STATES Current assets: Money Market Funds [Member] Geographic Concentration Risk [Member] us-gaap_AssetsCurrent Total current assets Gross profit Gross profit Raw materials Vesting Per Quarter [Member] Relating to vesting per quarter. Related and Nonrelated Parties [Axis] Financial Results Based Award Vesting [Member] Relating to vesting based on the financial results-based award. us-gaap_TreasuryStockSharesAcquired Treasury Stock, Shares, Acquired (in shares) Repurchase of common stock (in shares) Stock Appreciation Based Award Vesting [Member] Relating to vesting based on stock appreciation based award. nhtc_SharebasedCompensationArrangementBySharebasedPaymentAwardAdditionalFinancialPerformanceConditionNeededForVestingAward Share-Based Compensation Arrangement by Share-Based Payment Award, Additional Financial Performance Condition Needed for Vesting Award Represents the amount of additional financial performance condition needed to vest share based payment award. nhtc_SharebasedCompensationArrangementBySharebasedPaymentAwardMinimumAmountOfOperatingProfitNeededToMeetServiceCondition Share-Based Compensation Arrangement by Share-Based Payment Award, Minimum Amount of Operating Profit Needed to Meet Service Condition Represents the minimum amount of operating profit needed to meet the service condition in relation to a share-based payment award. CASH FLOWS FROM OPERATING ACTIVITIES: CASH FLOWS FROM INVESTING ACTIVITIES: us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash used in operating activities CASH FLOWS FROM FINANCING ACTIVITIES: us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash provided by investing activities us-gaap_TreasuryStockAcquiredAverageCostPerShare Shares Acquired, Average Cost Per Share (in dollars per share) us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash used in financing activities Operating Segments [Member] Accounting Policies [Abstract] Segments [Domain] Segments [Axis] Other assets: Income Statement [Abstract] Non-vested restricted stock Net income (loss) available to common stockholders plus assumed dilution nhtc_OperatingLeasesMonthlyPaymentYearsOneThorughThree Operating Leases, Monthly Payment, Years One Through Three Amount of monthly rental payment under operating lease, years one through Three. us-gaap_NumberOfOperatingSegments Number of Operating Segments us-gaap_NumberOfReportableSegments Number of Reportable Segments nhtc_OperatingLeasesMonthlyManagementFee Operating Leases, Monthly Management Fee Amount of monthly management fee. nhtc_OperatingLeasesMonthlyPaymentYearsFourAndFive Operating Leases, Monthly Payment, Years Four and Five Amount of monthly rental payment under operating lease, years four and five. us-gaap_TreasuryStockCommonValue Treasury stock, at cost; 4,401,566 and 1,466,339 shares at June 30, 2026 and December 31, 2025, respectively Treasury stock, shares (in shares) BALANCE (in shares) BALANCE (in shares) Treasury Stock, Common [Member] Common Stock Outstanding [Member] Represents Common Stock Outstanding. Net income (loss) Net income (loss) Net income (loss) Net income (loss) available to common stockholders us-gaap_AmortizationOfIntangibleAssets Intangible Asset, Finite-Lived, Amortization Expense us-gaap_AreaOfRealEstateProperty Area of Real Estate Property (Square Foot) Accumulated Other Comprehensive Income (Loss) [Table] Income Tax Disclosure [Text Block] Restricted Stock [Member] Related and Nonrelated Parties [Domain] us-gaap_TreasuryStockValueAcquiredCostMethod Treasury Stock, Value, Acquired, Cost Method Repurchase of common stock Related Party Transaction [Table] Related Party Transactions Disclosure [Text Block] Supplemental Balance Sheet Disclosures [Text Block] Fair Value Hierarchy and NAV [Domain] Amounts held in eWallets Amount liability recognized from cost incurred to obtain or fulfill contract with customer; classified as current. Vesting [Axis] Statement of Financial Position [Abstract] us-gaap_DeferredTaxAssetsValuationAllowance Deferred Tax Assets, Valuation Allowance, Total Vesting [Domain] us-gaap_DividendsCommonStock Dividends, Common Stock Noncash lease expense Represents the amount of lessee's noncash lease expense during the period. Deferred income taxes Represents the amount of deferred income tax expense (benefit), excluding effects of foreign exchange. Other assets2 nhtc_RevenueFromContractWithCustomersHistoricalSalesReturnsPercent Revenue from Contract with Customers, Historical Sales Returns, Percent Represents the percentage of historical sales returns. nhtc_RevenueFromContractWithCustomersSalesReturnsPercent Revenue from Contract with Customers, Sales Returns, Percent Represents the percentage of sales returns. nhtc_IncreaseDecreaseInAccruedSalesCommissions Accrued commissions Amount of increase (decrease) in accrued sales commissions. nhtc_IncreaseDecreaseInOperatingLeaseLiabilities Operating lease liabilities Amount of increase (decrease) in operating lease liabilities. nhtc_IncreaseDecreaseInCapitalizedContractCostLiability Amounts held in eWallets Amount of increase (decrease) in capitalized contract cost liability. nhtc_RevenueFromContractWithCustomerSalesReturnsPolicyTerm Revenue from Contract with Customer, Sales Returns Policy Term (Day) Represents the sales returns policy term. nhtc_NumberOfMajorCustomers Number of Major Customers 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. Other assets Other Assets, Noncurrent nhtc_NumberOfMajorMarkets Number of Major Markets 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. Deferred revenue us-gaap_IncreaseDecreaseInDeferredRevenue us-gaap_PaymentsForRepurchaseOfCommonStock Repurchase of common stock Document Type Operating expenses: Document Information [Line Items] Document Quarterly Report us-gaap_IncreaseDecreaseInOtherNoncurrentAssets Other assets us-gaap_IncreaseDecreaseInOtherCurrentLiabilities Other current liabilities Weighted-average remaining lease term (in years) (Year) Document Information [Table] us-gaap_IncreaseDecreaseInOtherCurrentAssets Other current assets Entity Interactive Data Current us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year) Document Transition Report Weighted average common shares outstanding: Diluted (in shares) us-gaap_OperatingExpenses Total operating expenses Net income (loss) per common share: nhtc_RevenueFromContractWithCustomerSalesReturns Less: sales returns Represents the amount of sales returns during the period. Non-vested restricted stock (in shares) Basic (in shares) Basic (in dollars per share) Unshipped Product [Member] Information pertaining to unshipped product. Auto ship advances [Member] Information pertaining to auto ship advances. us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Sales returns Carrying value as of the balance sheet date of obligations incurred through that date and payable for sales returns. Earnings Per Share, Diluted, by Common Class, Including Two-Class Method [Table] Effective Income Tax Rate Reconciliation [Table] Schedule of Additional Balance Sheet Components [Table Text Block] Tabular disclosure of additional balance sheet components. Title and Position [Domain] Debt Securities, Available-for-Sale [Table Text Block] Earnings Per Share, Policy [Policy Text Block] Warehousing, inventory-related and other Carrying value as of the balance sheet date of obligations incurred through that date and payable for warehousing and inventory related expense. Income Tax Jurisdiction [Axis] Capitalized software implementation costs Intangible Asset, Finite-Lived, after Accumulated Amortization Document Fiscal Period Focus Document Fiscal Year Focus Amendment Flag us-gaap_SubleaseIncome Sublease income Document Period End Date nhtc_LesseeNumberOfBranches Lessee, Number of Branches Represents the lessees' number of branches. Legal Entity [Axis] Rolling Hills Estates [Member] Information pertaining to Rolling Hills Estates. Operating leases Short-term leases Richmond, British Columbia [Member] Information pertaining to Richmond, British Columbia. Metuchen, New Jersey [Member] Information pertaining to Metuchen, New Jersey. us-gaap_LeaseCost Total lease cost Entity File Number Entity Tax Identification Number SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES: Disaggregation of Revenue [Table] Entity [Domain] Entity Central Index Key Entity Registrant Name Entity Current Reporting Status Entity Incorporation, State or Country Code Current Fiscal Year End Date nhtc_CommonStockPercentageOfBeneficialStockOutstanding Common Stock, Percentage of Beneficial Stock Outstanding Represents the percentage of beneficial stock outstanding. BHS [Member] Information pertaining to BHS. Entity Filer Category Entity Shell Company Entity Emerging Growth Company Entity Small Business Segment income (loss) from operations Loss from operations Gross unrealized gain losses us-gaap_OperatingLossCarryforwards Operating Loss Carryforwards Royalty Agreement and License [Member] Information pertaining to the Royalty Agreement and License. Cash nhtc_RelatedPartyTransactionAutomaticRenewalPeriodOfAgreement Related Party Transaction, Automatic Renewal Period of Agreement (Year) Represents the automatic renewal period of the agreement in related party transaction. Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Primary Reporting Segment [Member] Information pertaining to the primary reporting segment. Russia and Kazakhstan [Member] Information pertaining to Russia and Kazakhstan. us-gaap_ContractWithCustomerLiabilityRevenueRecognized Contract with Customer, Liability, Revenue Recognized Entity Address, State or Province Entity Address, City or Town Other Foreign Countries [Member] Information pertaining to other foreign countries. Accumulated deficit Entity Address, Address Line One City Area Code Local Phone Number Entity Address, Postal Zip Code Revenue from Contract with Customer [Text Block] Preferred Stock [Member] Title of 12(b) Security Security Exchange Name Trading Symbol Class of Stock [Axis] Fair value Related Party Transaction [Domain] Entity Common Stock, Shares Outstanding Related Party Transaction [Axis] Other current assets Director [Member] Unrealized gains (losses) on available-for-sale securities us-gaap_RoyaltyExpense Royalty Expense Common stock, par value (in dollars per share) Basis of Accounting, Policy [Policy Text Block] Other income, net Foreign currency translation adjustment Foreign currency translation adjustments Total assets Total assets Cash and Cash Equivalents, Policy [Policy Text Block] Cash and cash equivalents Cash and cash equivalents Geographical [Domain] Cash equivalents Geographical [Axis] Net income (loss) available to common stockholders plus assumed dilution (in dollars per share) Diluted (in dollars per share) us-gaap_ContractWithCustomerLiability Contract with Customer, Liability Deferred revenue: Deferred revenue Depreciation and amortization Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Consolidation, Policy [Policy Text Block] Software, Internal-Use [Policy Text Block] Thereafter Amount of lessee's undiscounted obligation for lease payment for operating lease due after fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Finished goods Product [Member] Inventories: us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number (in shares) Inventories, net Inventory net us-gaap_IncreaseDecreaseInContractWithCustomerLiability Increase (Decrease) in Contract with Customer, Liability us-gaap_StockholdersEquity Total stockholders’ equity Balance Balance Inventories Municipal Bonds [Member] Direct costs incurred to repurchase common stock The amount of direct costs incurred from the repurchase of common stock. us-gaap_PaymentsOfDividends Dividends paid Concentration Risk Benchmark [Axis] Nature of Operation, Product Information, Concentration of Risk [Table] Concentration Risk Benchmark [Domain] Operating lease right-of-use assets Other current liabilities Refundable deposits and other Amount of refundable deposits and other. ecd_Rule10b51ArrTrmntdFlag Rule 10b5-1 Arrangement Terminated [Flag] Net sales ecd_Rule10b51ArrAdoptedFlag Rule 10b5-1 Arrangement Adopted [Flag] nhtc_StockRepurchasesDuringPeriodFeesAndExciseTax Stock Repurchases During Period, Fees and Excise Tax The amount for fees and excise tax for the stock repurchased during the period. Commitments and contingencies (Note 7)