Document And Entity Information
Dividend yield
Note To Financial Statement Details Textual
Significant Accounting Policies
Note 1 - Nature of Business and Significant Accounting Policies
us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
Tax computed at statutory rates
Note 3 - Inventories
Weighted average risk-free interest rate
Note 4 - Property and Equipment, Net
Note 5 - Patents and Trademarks, Net
Note 6 - Investments in Joint Ventures
Note 8 - Stockholders' Equity
LONG-TERM LIABILITIES:
Note 9 - Net Income (Loss) Per Common Share
Note 10 - Stock-based Compensation
Income Tax Disclosure [Text Block]
Note 11 - Segment and Geographic Information
Note 14 - Income Taxes
ntic_AllocatedShareBasedCompensationExpenseEstimateFiscalYearTwo
Allocated Share-based Compensation Expense, Estimate, Fiscal Year Two
Estimated expense to be recognized for the second fiscal year following the most recent fiscal year arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.
Note 15 - Commitments and Contingencies
Note 16 - Statements of Cash Flows
Expected volatility
Note 17 - Fair Value Measurements
us-gaap_LiabilitiesCurrent
Total current liabilities
Current liabilities
Note 1 - Nature of Business and Significant Accounting Policies - Property and Equipment, Useful Life (Details)
Note 3 - Inventories - Inventories (Details)
Note 4 - Property and Equipment, Net - Components of Property and Equipment, Net (Details)
ntic_ForeignWithholdingTax
Foreign Withholding Tax
The amount of foreign withholding tax.
Note 5 - Patents and Trademarks, Net - Patents and Trademarks, Net (Details)
Expected life of option (in years) (Year)
Note 6 - Investments in Joint Ventures - Condensed Balance Sheet of EXCOR and All Other Joint Ventures (Details)
Inside the USA to Unaffiliated Customers [Member]
Inside the USA to Unaffiliated Customers.
Note 6 - Investments in Joint Ventures - Condensed Income Statement of EXCOR and All Other Joint Ventures (Details)
Note 8 - Stockholders' Equity - Cash Dividends Declared (Details)
Joint Ventures in Which the Company is a Shareholder Directly and Indirectly Outside the USA [Member]
Joint ventures in which the company is a shareholder directly and indirectly outside the USA [member]
Note 9 - Net Income (Loss) Per Common Share - Reconciliation of the Earnings Per Share Computations (Details)
Unaffiliated Customers Outside the USA [Member]
Unaffiliated customers outside the USA [member]
Note 10 - Stock-based Compensation - Black-Scholes Option-pricing Model Assumptions (Details)
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Note 10 - Stock-based Compensation - Stock Option Activity (Details)
Note 11 - Segment and Geographic Information - Net Sales by Segment (Details)
Note 11 - Segment and Geographic Information - Cost of Goods Sold by Segment (Details)
Note 11 - Segment and Geographic Information - Net Sales by Geographic Location (Details)
Note 11 - Segment and Geographic Information - Fees for Services Provided to Joint Ventures by Geographic Location as a Percentage of Total Fees (Details)
Share-based Payment Arrangement, Option, Activity [Table Text Block]
Fees for Services Provided to Joint Ventures [Member]
Represents fees for services provided to joint ventures.
Note 11 - Segment and Geographic Information - Total Long-lived Assets by Geographic Distribution (Details)
Note 11 - Segment and Geographic Information - Total Net Sales by Geographic Distribution (Details)
Note 14 - Income Taxes - Provision for Income Taxes (Details)
us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Business Acquisition, Percentage of Voting Interests Acquired
ntic_TotalFeesForServicesProvidedToJointVenturesGeographicLocation
Fees
Total fees for services provided to joint ventures by geographic locations.
Note 14 - Income Taxes - Reconciliations of the Expected Federal Income Tax at the Statutory Rate with the Provisions for Income Taxes (Details)
Note 14 - Income Taxes - Tax Effect of the Temporary Differences and Tax Carry Forwards Comprising Net Deferred Taxes (Details)
Note 14 - Income Taxes - Reconciliation of the Total Amounts of Unrecognized Tax Benefits (Details)
Note 15 - Commitments and Contingencies - Present Value of Long-term Leases (Details)
Note 15 - Commitments and Contingencies - Future Minimum Rents Due (Details)
us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax
OTHER COMPREHENSIVE INCOME (LOSS) – FOREIGN CURRENCY TRANSLATION ADJUSTMENT
Note 16 - Statements of Cash Flows - Supplemental Disclosures of Cash Flow Information (Details)
Note 17 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value Recurring Basis (Details)
Proceeds from the sale of available for sale securities
Notes To Financial Statements
Notes To Financial Statements [Abstract]
ntic_EntityWideFeesForServicesProvidedToJointVenturesGeographicPercentage
Percentage of Total Fees
Percentage of entity wide fees for services provided to joint ventures generated from geographic location.
Other comprehensive income (loss)
Weighted average exercise price, Exercisable (in dollars per share)
Aggregate intrinsic value, Exercisable
Number of shares, Exercisable (in shares)
us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
Total equity
BALANCE
BALANCE
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)
Aggregate intrinsic value, Outstanding
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)
us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt
Purchase of available for sale securities
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted average exercise price, Outstanding (in dollars per share)
Weighted average exercise price, Outstanding (in dollars per share)
Weighted average exercise price, Options terminated (in dollars per share)
Weighted average exercise price, Options granted (in dollars per share)
Weighted average exercise price, Options exercised (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price (in dollars per share)
Payroll and related benefits
Income taxes payable
Accounts payable
Revolving Credit Facility [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Number of shares, Outstanding (in shares)
Number of shares, Outstanding (in shares)
ZERUST [Member]
Represents ZERUST.
NaturTec [Member]
Represents NaturTec segment.
Reconciliation of Cost of Goods Sold from Segments to Consolidated [Table Text Block]
Tabular disclosure of all significant reconciling items in the reconciliation of total cost of goods sold from reportable segments to the entity's consolidated revenues.
Credit Facility [Axis]
Proceeds from the sale of property and equipment
Credit Facility [Domain]
Cost of Goods Sold Type [Axis]
Cost of goods sold type [axis]
Other
Cost of Goods Sold Type [Domain]
Direct Cost of Goods Sold [Member]
Direct cost of goods sold [member]
Indirect Cost of Goods Sold [Member]
Indirect cost of goods sold [member]
us-gaap_PolicyTextBlockAbstract
Accounting Policies
ntic_PercentageOfIndividualBonusPayoutDeterminedByActualVersusTargetedEBITOIResults
Percentage of Individual Bonus Payout Determined by Actual Versus Targeted EBITOI Results
Percentage of individual's bonus payout determined based upon the Company's actual EBITOI for the fiscal year compared to pre-established target EBITOI for the fiscal year.
JOINT VENTURE OPERATIONS:
Joint venture operations
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)
ntic_PercentageOfIndividualsPayoutDeterminedUponAchievementOfCertainPreEstablishedIndividualPerformanceObjectives
Percentage of Individuals Payout Determined Upon Achievement of Certain Pre-Established Individual Performance Objectives
Percentage of individual's payout determined based upon achievement of certain pre-established individual performance objectives.
ntic_EntityWideTradeJointVentureReceivablesThreeJointVenturesPercentage
Entity Wide Trade Joint Venture Receivables, Three Joint Ventures, Percentage
Percentage of total trade joint venture receivables accounted for by three joint ventures.
Other Countries [Member]
Countries identified as "Other".
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent
us-gaap_PaymentsToAcquireIntangibleAssets
Investments in patents
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchases of property and equipment
us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements
Weighted shares assumed upon exercise of stock options (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)
Accrued liabilities:
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)
WEIGHTED AVERAGE COMMON SHARES ASSUMED OUTSTANDING:
Cash paid during the year for income tax
CURRENT LIABILITIES:
Vesting [Axis]
Vesting [Domain]
us-gaap_Assets
Total assets
Total assets
PNC Bank [Member]
Represents PNC bank.
Plan Name [Axis]
Plan Name [Domain]
us-gaap_OperatingLeaseExpense
Operating Lease, Expense
Zerust Brazil [Member]
Information about the entity of Zerust Brazil.
One Year after Date of Grant [Member]
The vesting term that options become exercisable.
ntic_NumberOfJointVentureArrangements
Number of Joint Venture Arrangements
Number of active joint venture arrangements in which the company participates, either directly or indirectly.
Receivables from Joint Ventures Policy [Policy Text Block ]
Treatment of any premiums or discounts or unearned income, the entity's income recognition policies for such receivables, including those that are impaired, past due or placed on nonaccrual status and the treatment of foreclosures or repossessions, the nature and amount of any guarantees to repurchase receivables.
Property and Equipment Useful Life [Table Text Block]
Tabular disclosure of property and equipment useful life.
Deferred income taxes
Stock option expense
Finite-Lived Intangible Assets by Major Class [Axis]
Share-based Payment Arrangement [Text Block]
Finite-Lived Intangible Assets, Major Class Name [Domain]
The 2019 Plan [member]
Information pertaining to the 2019 Plan.
us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders
Dividend received by non-controlling interest
Consulting Payment Expense [Member]
The Expenses related to consulting services.
ntic_AssetsNoncurrentOtherThanPropertyPlantAndEquipment
Total other assets
Sum of the carrying amounts as of the balance sheet date of all assets, excluding property, plant, and equipment that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer.
ntic_DefinedContributionPlanMaximumAmountOfEmployeesContributionsPercent
Defined Contribution Plan Maximum Amount of Employees Contributions Percent
Maximum percentage employer matches of the employee's percentage contribution matched.
us-gaap_NetIncomeLoss
NET INCOME (LOSS) ATTRIBUTABLE TO NTIC
Net income (loss) attributable to NTIC
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Less accumulated amortization
Bioplastic Polymers LLC [Member]
information about Bioplastic Polymers LLC.
Patents and trademarks, net
Patents and trademarkes, net
Federal and State Tax [Member]
Designated tax department of the government and state or local government entitled to levy and collect income taxes from the entity.
us-gaap_FiniteLivedIntangibleAssetsGross
Patents and trademarks
NET INCOME ATTRIBUTABLE TO NON-CONTROLLING INTERESTS
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities [Axis]
Antidilutive Securities, Name [Domain]
us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest
LESS: COMPREHENSIVE INCOME ATTRIBUTABLE TO NON-CONTROLLING INTERESTS
Commitments and Contingencies Disclosure [Text Block]
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Less accumulated depreciation
PROPERTY AND EQUIPMENT, NET
Net
us-gaap_PropertyPlantAndEquipmentGross
Gross
us-gaap_MachineryAndEquipmentGross
Machinery and equipment
us-gaap_Land
Land
us-gaap_Dividends
Dividends paid to stockholders
us-gaap_BuildingsAndImprovementsGross
Buildings and improvements
Net income (loss)
Net income (loss)
NET INCOME (LOSS)
NET INCOME (LOSS)
us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest
COMPREHENSIVE INCOME
CASH FLOWS FROM INVESTING ACTIVITIES:
Available for sale securities
us-gaap_AvailableForSaleSecuritiesDebtSecurities
JP Morgan Chase Bank [Member]
Represents information regarding the JP Morgan Chase Bank.
NET INCOME (LOSS) ATTRIBUTABLE TO NTIC PER COMMON SHARE:
Earnings Per Share [Text Block]
BRAZIL
us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable
Income tax payable
Equity in income from joint ventures
Northern Technologies International Corporation’s share of equity in income of joint ventures
Equity in income from joint ventures
Zerust Singapore Pte Ltd [Member]
Represents Zerust Singapore Pte Ltd.
us-gaap_RelatedPartyTransactionAmountsOfTransaction
Related Party Transaction, Amounts of Transaction
Zerust Vietnam Co. Ltd [Member]
Represents Zerust Vietnam Co. Ltd.
Investments in joint ventures
Related Party Transactions Disclosure [Text Block]
INCOME TAX EXPENSE
Total income tax expense
us-gaap_IncreaseDecreaseInAccruedLiabilities
Accrued liabilities
Joint Ventures in France [Member]
Represents the joint ventures in France.
Joint Ventures in Finland [Member]
Represents the joint ventures in Finland.
Joint Ventures in India [Member]
Represents the joint ventures in India.
CHINA
Joint Ventures in Thailand [Member]
Represents the joint ventures in Thailand.
us-gaap_IncreaseDecreaseInAccountsPayable
Accounts payable
ntic_DeferredTaxAssetsLeaseLiability
Lease liability
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from lease liability.
CZECHIA
GERMANY
us-gaap_OperatingExpenses
Total operating expenses
us-gaap_DefinedContributionPlanCostRecognized
Defined Contribution Plan, Cost
Stock Options Granted to Management [Member]
Represents the stock options granted to management.
Paid Out in Cash and Profit Sharing [Member]
Represents the expenses that will be paid out in cash and profit sharing.
General and administrative expenses
us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent
us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
FINLAND
FRANCE
Cash and cash equivalents
UNITED KINGDOM
Amendment Flag
us-gaap_ComprehensiveIncomeNetOfTax
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO NTIC
City Area Code
Use of Estimates, Policy [Policy Text Block]
INDONESIA
INDIA
us-gaap_SharesOutstanding
BALANCE (in shares)
BALANCE (in shares)
Common stock, shares outstanding (in shares)
Preferred stock, shares outstanding (in shares)
Current Fiscal Year End Date
us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Debt Instrument, Basis Spread on Variable Rate
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other
JAPAN
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating Lease, Weighted Average Discount Rate, Percent
Document Fiscal Period Focus
Document Fiscal Year Focus
Consolidation, Policy [Policy Text Block]
us-gaap_IncreaseDecreaseInDeferredIncomeTaxes
Deferred income taxes
Document Period End Date
Entity File Number
Fiscal 2018 Bonus Plan [Member]
Related to the fiscal 2018 bonus plan.
KOREA, REPUBLIC OF
Entity Emerging Growth Company
Document Type
Interim Period, Costs Not Allocable [Domain]
Entity Small Business
us-gaap_NumberOfCountriesInWhichEntityOperates
Number of Countries in which Entity Operates
Entity Shell Company
Document Information [Line Items]
Document Information [Table]
Nature of Expense [Axis]
Entity Public Float
Entity Filer Category
Entity Current Reporting Status
Entity Voluntary Filers
Entity Well-known Seasoned Issuer
London Interbank Offered Rate (LIBOR) [Member]
Variable Rate [Domain]
us-gaap_IncreaseDecreaseInIncomeTaxesReceivable
Income taxes
Variable Rate [Axis]
Statement of Comprehensive Income [Abstract]
Entity Tax Identification Number
Entity Central Index Key
Entity Registrant Name
Entity [Domain]
Legal Entity [Axis]
Entity Address, Address Line One
Entity Address, City or Town
Entity Address, Postal Zip Code
Entity Address, State or Province
us-gaap_AllowanceForDoubtfulAccountsReceivable
Accounts Receivable, Allowance for Credit Loss, Ending Balance
Entity Common Stock, Shares Outstanding
us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
Stock Repurchased and Retired During Period, Shares (in shares)
POLAND
us-gaap_IncreaseDecreaseInInventories
Inventories
Trading Symbol
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Stock issued for employee stock purchase plan (in shares)
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)
SWEDEN
Local Phone Number
Stock options exercised (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)
us-gaap_GainLossOnDispositionOfAssets
Loss on disposal of property and patents
us-gaap_TableTextBlock
Notes Tables
Stock issued for employee stock purchase plan
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
Stock options exercised
Related Party [Axis]
Related Party [Domain]
THAILAND
Change in allowance for doubtful accounts
Number of shares, Options granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Number of shares, Options terminated (in shares)
Line of Credit Facility, Lender [Domain]
us-gaap_InventoryRawMaterialsNetOfReserves
Production materials
Lender Name [Axis]
Selling expenses
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and equity
us-gaap_InventoryFinishedGoodsNetOfReserves
Finished goods
UNITED STATES
Research and development expenses
Retained earnings
Accumulated other comprehensive loss
Debt Disclosure [Text Block]
us-gaap_InterestExpense
INTEREST EXPENSE
ntic_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodIncludingCashlessExercises
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Including Cashless Exercises (in shares)
Number of shares, Options exercised (in shares)
Number of share options (or share units) exercised during the current period, including cashless exercises.
Changes in current assets and liabilities:
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Inventory Disclosure [Text Block]
Subsequent Event [Member]
Lease liability, less current portion
Operating lease, less current portion
Long-term operating lease obligations
Schedule of Inventory, Current [Table Text Block]
Total lease liability
us-gaap_OperatingLeaseLiability
Present value of obligations under operating leases
Subsequent Event Type [Axis]
Current portion of lease liability
Current portion of operating lease
Less current portion
Subsequent Event Type [Domain]
Retirement Benefits [Text Block]
Subsequent Events [Text Block]
Right-of-use assets, net
us-gaap_OperatingLeaseRightOfUseAsset
Operating lease right of use asset
us-gaap_EquityMethodInvestmentDividendsOrDistributions
Northern Technologies International Corporation’s dividends received from joint ventures
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total future minimum lease payments
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less amount representing interest
us-gaap_DeferredIncomeTaxExpenseBenefit
Total deferred
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
Fiscal 2024
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
Fiscal 2025
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
Finite-Lived Intangible Assets, Amortization Expense, Year Two
Fair Value of Financial Instruments, Policy [Policy Text Block]
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
Finite-Lived Intangible Assets, Amortization Expense, Year Three
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
Finite-Lived Intangible Assets, Amortization Expense, Year Four
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
Fiscal 2022
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
Fiscal 2023
Subsequent Events, Policy [Policy Text Block]
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
Finite-Lived Intangible Asset, Expected Amortization, Year One
us-gaap_StockOptionPlanExpense
Stock or Unit Option Plan Expense
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Lessee, Operating Lease, Liability, Maturity [Table Text Block]
us-gaap_ShareBasedCompensation
Stock-based compensation
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Finite-Lived Intangible Asset, Useful Life (Year)
Amortization expense
us-gaap_AdjustmentForAmortization
Amortization, Total
us-gaap_Revenues
Total net sales
Net sales by segment
Northern Technologies International Corporation’s share of joint ventures’ undistributed earnings
OPERATING EXPENSES:
Income Tax, Policy [Policy Text Block]
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis]
Research, Development, and Computer Software, Policy [Policy Text Block]
Deferred Bonus and Profit Sharing Arrangement, Individual Contract, Type of Deferred Compensation [Domain]
us-gaap_Depreciation
Depreciation expense
Intangible Assets Disclosure [Text Block]
us-gaap_AssetsCurrent
Total current assets
Current assets
Share-based Payment Arrangement [Policy Text Block]
Stockholders' Equity Note Disclosure [Text Block]
Income taxes
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
Common stock, $0.02 par value per share; authorized 15,000,000 shares as of August 31, 2021 and August 31, 2020; issued and outstanding 9,184,811 and 9,099,990, respectively
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Measurement Frequency [Axis]
Measurement Frequency [Domain]
Fair Value, Recurring [Member]
Common stock, shares authorized (in shares)
Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]
Common stock, shares issued (in shares)
Common stock, par value (in dollars per share)
Stockholders' Equity, Policy [Policy Text Block]
us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount
us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Common Stock, Capital Shares Reserved for Future Issuance (in shares)
us-gaap_DeferredTaxAssetsValuationAllowance
Valuation allowance
Statistical Measurement [Domain]
ntic_FinanceAndOperatingLeaseWeightedAverageRemainingLeaseTerm
Finance and Operating Lease, Weighted Average Remaining Lease Term (Year)
Weighted average remaining lease term for operating and finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.
Maximum [Member]
ntic_LesseeOperatingLeaseOptionToExtendTermTwo
Lessee, Operating Lease, Option to Extend Term Two (Year)
Represents option to extend term two for operating lease.
Minimum [Member]
ntic_LesseeOperatingLeaseOptionToExtendTermOne
Lessee, Operating Lease, Option to Extend Term One (Year)
Represents option to extend term one for operating lease.
Ownership [Domain]
Product and Service [Axis]
Product and Service [Domain]
us-gaap_DeferredTaxAssetsNet
Total deferred tax assets after valuation allowance
Statistical Measurement [Axis]
Schedule of Components of Operating Lease Assets and Liabilities [Table Text Block]
Tabular disclosure of components of operating lease assets and liabilities.
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]
Ownership [Axis]
Preferred stock, no par value; authorized 10,000 shares; none issued and outstanding
us-gaap_DeferredTaxAssetsLiabilitiesNet
Net deferred tax assets
Preferred stock, shares issued (in shares)
Intangible Assets, Finite-Lived, Policy [Policy Text Block]
Cash paid during the year for interest
Cash Flow, Supplemental Disclosures [Text Block]
Prepaid expenses
Preferred stock, par value (in dollars per share)
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]
us-gaap_NoncurrentAssets
Total long-lived assets
Property, Plant and Equipment Disclosure [Text Block]
Geographical [Axis]
Property, Plant and Equipment [Table Text Block]
Geographical [Domain]
us-gaap_DeferredTaxAssetsGross
Total deferred tax assets
Preferred stock, shares authorized (in shares)
us-gaap_DeferredIncomeTaxLiabilities
Total deferred tax liabilities
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]
us-gaap_InventoryNet
Total inventory
Fair Value, Inputs, Level 3 [Member]
Fair Value Hierarchy and NAV [Domain]
Inventory costs
Inventories
Goodwill and other intangible assets
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value Hierarchy and NAV [Axis]
us-gaap_ProceedsFromDividendsReceived
Dividends received from joint ventures
Other accrued expenses
Reconciliation of Revenue from Segments to Consolidated [Table Text Block]
Property and equipment (Year)
Non-controlling interests
CASH FLOWS FROM OPERATING ACTIVITIES:
Statement [Line Items]
Trade receivable excluding joint ventures, allowance for doubtful accounts
us-gaap_NumberOfOperatingSegments
Number of Operating Segments
Revenue Recognition, Deferred Revenue [Policy Text Block]
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
Stock-based compensation
Building and Building Improvements [Member]
Receivables:
Accrued compensation
NET SALES:
Additional paid-in capital
AOCI Attributable to Parent [Member]
Available for sale securities
Other credit and loss carryforwards
Property, Plant and Equipment, Policy [Policy Text Block]
Long-Lived Tangible Asset [Axis]
Segment Reporting Disclosure [Text Block]
Long-Lived Tangible Asset [Domain]
Foreign tax credit carryforward
us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal
Deferred Tax Assets, Operating Loss Carryforwards, State and Local
INTEREST INCOME
CURRENT ASSETS:
us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration
us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic
Deferred Tax Assets, Operating Loss Carryforwards, Domestic
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR
CASH AND CASH EQUIVALENTS AT END OF YEAR
Inventory, Policy [Policy Text Block]
us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign
Deferred Tax Assets, Operating Loss Carryforwards, Foreign
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
NET INCREASE IN CASH AND CASH EQUIVALENTS
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash used in financing activities
OTHER ASSETS:
COMMITMENTS AND CONTINGENCIES (Note 15)
Executive Officer [Member]
us-gaap_OperatingIncomeLoss
OPERATING INCOME
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by operating activities
us-gaap_DeferredTaxLiabilitiesOther
Other
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash used in investing activities
us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS
us-gaap_GrossProfit
Gross profit
Gross profit
Cost of goods sold
Cost of goods sold
EQUITY:
us-gaap_DeferredTaxLiabilitiesLeasingArrangements
Right-of-use asset
us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total
us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings
Unremitted foreign earnings
Marketable Securities, Policy [Policy Text Block]
Equity Method Investments [Policy Text Block]
us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Property and equipment
us-gaap_LettersOfCreditOutstandingAmount
Letters of Credit Outstanding, Amount
us-gaap_PaymentsOfDividendsMinorityInterest
Dividend received by non-controlling interest
Shipping and Handling Cost, Policy [Policy Text Block]
Condensed Balance Sheet [Table Text Block]
us-gaap_AccruedBonusesCurrentAndNoncurrent
Accrued Bonuses
Condensed Income Statement [Table Text Block]
Equity Method Investments and Joint Ventures Disclosure [Text Block]
us-gaap_PaymentsOfDividendsCommonStock
Dividends paid on NTIC common stock
Noncontrolling Interest [Member]
us-gaap_ProceedsFromStockPlans
Proceeds from employee stock purchase plan
Geographic Distribution [Axis]
Geographic Distribution [Domain]
Retained Earnings [Member]
Proceeds from exercise of stock options
Trade excluding joint ventures, less allowance for doubtful accounts of $382,000 as of August 31, 2021 and $90,000 as of August 31, 2020
Amount due from customers or clients, but not joint ventures, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.
Title of Individual [Domain]
State
Title of Individual [Axis]
Trade joint ventures
Amounts due from joint ventures, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold to joint ventures in the normal course of business.
us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit
State
us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Stock Repurchase Program, Remaining Authorized Repurchase Amount
Foreign
us-gaap_DeferredForeignIncomeTaxExpenseBenefit
Foreign
Additional Paid-in Capital [Member]
Federal
Common Stock [Member]
us-gaap_StockRepurchaseProgramAuthorizedAmount1
Stock Repurchase Program, Authorized Amount
Fees for services provided to joint ventures
Amounts due for royalties and service fees outside of the normal course of business from entities in which the reporting entity shares joint control with another party or group, due within 1 year (or 1 business cycle).
us-gaap_DeferredFederalIncomeTaxExpenseBenefit
Federal
Net sales, excluding joint ventures
Net sales either directly to end users or to distributors worldwide, but not sales to the reporting entity's joint ventures and not sales by the reporting entity's joint ventures.
Net sales, to joint ventures
Net sales by the reporting entity to the reporting entity's joint ventures, but not sales by the reporting entity either directly to end users or to distributors or sales by the reporting entity’s joint ventures.
Equity Components [Axis]
Equity Component [Domain]
ntic_FeesForServicesProvidedToJointVentures
Fees for services provided to joint ventures
Royalties and service fees from transactions directly with the reporting entity's joint ventures outside the normal course of business.
us-gaap_CurrentIncomeTaxExpenseBenefit
Total current
us-gaap_LineOfCredit
Long-term Line of Credit, Total
us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest
INCOME BEFORE INCOME TAX EXPENSE
Income Tax Authority [Axis]
Income Tax Authority [Domain]
Foreign Tax Authority [Member]
Acquisition of Remaining Ownership Interest in Harita-NTI Limited [Member]
Represents information regarding the acquisition of the remaining ownership interest in Harita-NTI Limited.
Document Annual Report
Machinery and Equipment [Member]
Cash and Cash Equivalents, Policy [Policy Text Block]
Receivable [Policy Text Block]
Entity Incorporation, State or Country Code
us-gaap_UnrecognizedTaxBenefits
Gross unrecognized tax benefits – beginning balance
Gross unrecognized tax benefits – ending balance
Accounting Policies [Abstract]
Document Transition Report
ntic_TaxCreditCarryforwardForeignExpirationsInPeriod
Tax Credit Carryforward, Foreign, Expirations in Period
Represents the amount of foreign tax credit carryforward expirations during the period.
Entity Interactive Data Current
CASH DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)
Amount (in dollars per share)
Common Stock, Dividends, Per Share, Declared (in dollars per share)
Gross increases – prior period tax positions
Security Exchange Name
us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions
Gross increases – current period tax positions
Title of 12(b) Security
Equity Method Investment, Nonconsolidated Investee [Axis]
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Equity Method Investment, Nonconsolidated Investee [Domain]
ntic_IncreaseDecreaseInTradeReceivablesExcludingJointVentures
Trade, excluding joint ventures
The net change during the reporting period in amount due within one year (or one business cycle) from customers or clients, but not joint ventures, for the credit sale of goods and services.
ntic_IncreaseDecreaseInTradeReceivablesJointVentures
Trade, joint ventures
The net change during the reporting period in amount due within one year (or one business cycle) from joint ventures for the credit sale of goods and services that have been delivered or sold to joint ventures in the normal course of business.
ntic_AccruedBonusesToBePaidAsStockOptionsPeriod
Accrued Bonuses, to Be Paid as Stock Options, Period (Year)
Represents the period of time over which accrued bonuses are expensed in the form of stock options.
Income Statement Location [Axis]
ntic_IncreaseDecreaseInFeesReceivableForServicesProvidedToJointVentures
Fees for services provided to joint ventures
The net change during the reporting period in amount due within one year (or one business cycle) from joint ventures for royalties and service fees outside of the normal course of business.
Income Statement Location [Domain]
Expired foreign tax credit
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to foreign tax credit expirations.
ntic_IncomeFromJointVentureOperations
To Total joint venture operations
Represents the amount of income from joint venture operations recognized during the period.
Summary of Income Tax Contingencies [Table Text Block]
us-gaap_TaxCreditCarryforwardValuationAllowance
Tax Credit Carryforward, Valuation Allowance
Segments [Axis]
Segments [Domain]
us-gaap_TaxCreditCarryforwardAmount
Tax Credit Carryforward, Amount
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)
Diluted (in shares)
Diluted – weighted shares outstanding (in shares)
Statement [Table]
us-gaap_MinorityInterestOwnershipPercentageByParent
Noncontrolling Interest, Ownership Percentage by Parent
Statement of Financial Position [Abstract]
Diluted (in dollars per share)
Diluted net income (loss) per share: (in dollars per share)
Basic (in shares)
Basic-weighted shares outstanding (in shares)
Patents and Trademarks [Member]
Represents patents and trademarks.
Business Acquisition [Axis]
Basic (in dollars per share)
Basic net income (loss) per share: (in dollars per share)
Business Acquisition, Acquiree [Domain]
Statement of Cash Flows [Abstract]
NTI Asean LLC [Member]
Represents the legal entity of NTI Asean LLC.
EXCOR [Member]
Represents EXCOR.
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]
Statement of Stockholders' Equity [Abstract]
Income Statement [Abstract]
All Other [Member]
Represents all other joint ventures.
Revenue from External Customers by Geographic Areas [Table Text Block]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Accounting Standards Update and Change in Accounting Principle [Text Block]
ntic_DebtInstrumentCovenantsFixedChargeCoverageRatio
Debt Instrument, Covenants, Fixed Charge Coverage Ratio
Represents the fixed charge coverage ratio for the debt instrument under the covenant terms.
us-gaap_LiabilitiesNoncurrent
Total long-term liabilities
Noncurrent liabilities
Payable date
Dividends Payable, Date to be Paid
Dividends Declared [Table Text Block]
CASH FLOWS FROM FINANCING ACTIVITIES:
us-gaap_IncomeTaxReconciliationOtherReconcilingItems
Other
us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Record date
Dividends Payable, Date of Record
us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance
Valuation allowance
Deemed repatriation
us-gaap_IncomeTaxReconciliationEquityInEarningsLossesOfUnconsolidatedSubsidiary
Tax effect on equity in income of international joint ventures
us-gaap_IncomeTaxReconciliationMinorityInterestIncomeExpense
Non-controlling interest
Natur Tec Lanka [Member]
Related to Natur Tec Lanka.
Natur-Tech India [Member]
Related to Natur-Tech India.
us-gaap_PaymentsToAcquireInterestInJointVenture
Payments to Acquire Interest in Joint Venture
Joint ventures’ equity
Stockholders’ equity
Various Joint Ventures [Member]
Related to various joint ventures.
Class of Stock [Axis]
Stock based compensation
us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
us-gaap_PaymentsToAcquireBusinessesGross
Payments to Acquire Businesses, Gross
ESPP [Member]
Represents Northern Technologies International Corporation Employee Stock Purchase Plan (the ESPP).
us-gaap_IncomeTaxReconciliationTaxCredits
Research and development credit
us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
State income tax, net of federal benefit
us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential
Tax effect of foreign operations