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Ambrell [Member] Related to the acquisition of Ambrell. Net Carrying Amount us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill Indefinite-lived, Gross Carrying Amount us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment Less: accumulated depreciation us-gaap_PropertyPlantAndEquipmentNet Property and Equipment Net property and equipment Goodwill Goodwill, Ending Balance us-gaap_PropertyPlantAndEquipmentGross Gross property and equipment Machinery and equipment Leasehold improvements Operating lease liabilities The amount of increase (decrease) in operating lease liabilities. EMS [Member] Represents the information pertaining to inTEST Electromechanical Semiconductor Products (EMS). Accrued professional fees intt_IncreaseDecreaseInAccruedProfessionalFees The amount of increase (decrease) in accrued professional fees. Employees [Member] Related to employees. CASH FLOWS FROM INVESTING ACTIVITIES Range of remaining lease terms (in years) (Year) The remaining lease term of operating leases. 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33,077 shares Entity Common Stock, Shares Outstanding (in shares) us-gaap_StockRepurchasedAndRetiredDuringPeriodValue Stock Repurchased and Retired During Period, Value Repurchase and retirement of common stock us-gaap_StockRepurchasedAndRetiredDuringPeriodShares Stock Repurchased and Retired During Period, Shares (in shares) Repurchase and retirement of common stock (in shares) Revenue Benchmark [Member] intt_BusinessCombinationContingentConsiderationArrangementsPaymentOfEarnoutForPriorYearAcquisitionOperatingActivities Payment of earnout for 2018 related to Ambrell acquisition Amount of the payment for prior year acquisition earnout payables that affects operating activities. intt_DecreaseInOperatingLeaseLiabilitiesAndRightOfUseAssetsNonCash Decrease In Operating Lease Liabilities and Right-of-Use Assets, Non-cash Represents the non-cash decrease in operating lease liabilities and right-of-use assets. us-gaap_IncreaseDecreaseInOtherNoncurrentAssets Other assets us-gaap_IncreaseDecreaseInInventories Inventories Trading Symbol Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Nature of Operations [Text Block] Exercised, number of shares (in shares) us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised us-gaap_TableTextBlock Notes Tables Issuance of unvested shares of restricted stock (in shares) us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited Forfeiture of unvested shares of restricted stock (in shares) us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity Issuance of unvested shares of restricted stock Granted, number of shares (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross Forfeited, number of shares (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod Line of Credit, Issue Date Line of Credit, Expiration Date Line of Credit Facility, Lender [Domain] Raw materials Lender Name [Axis] Selling expense us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and stockholders' equity Finished goods Work in process UNITED STATES Engineering and product development expense Retained earnings Accumulated other comprehensive earnings Debt Disclosure [Text Block] Changes in assets and liabilities: us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements Inventory Disclosure [Text Block] Subsequent Event [Member] Operating lease liabilities, net of current portion Schedule of Inventory, Current [Table Text Block] Total Subsequent Event Type [Axis] Current portion of operating lease liabilities Subsequent Event Type [Domain] Retirement Benefits [Text Block] Intangible Assets, Gross Carrying Amount Subsequent Events [Text Block] Right-of-use assets, net us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Total lease payments us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount Less imputed interest Deferred income tax benefit us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree 2022 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear 2020 (remainder) us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour 2023 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive 2024 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive Thereafter us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo 2021 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree 2022 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour 2023 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive 2024 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo 2021 Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Subsequent Events, Policy [Policy Text Block] Lessee, Operating Lease, Liability, Maturity [Table Text Block] us-gaap_ShareBasedCompensation Amortization of deferred compensation related to stock-based awards Other assets Lessee, Leases [Policy Text Block] us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear 2020 (remainder) Business Combinations Policy [Policy Text Block] Earnings Per Share, Policy [Policy Text Block] Operating expenses: Income Tax, Policy [Policy Text Block] us-gaap_LesseeOperatingLeaseTermOfContract Lessee, Operating Lease, Term of Contract (Year) us-gaap_LesseeOperatingLeaseRenewalTerm Lessee, Operating Lease, Renewal Term (Month) Depreciation and amortization us-gaap_AssetsCurrent Total current assets Share-based Payment Arrangement [Policy Text Block] Treasury stock, shares (in shares) Common stock, $0.01 par value; 20,000,000 shares authorized; 10,450,060 and 10,413,982 shares issued, respectively Adjustments to reconcile net earnings (loss) to net cash used in operating activities: Common stock, shares authorized (in shares) Common stock, shares issued (in shares) Balance (in shares) Balance (in shares) Common stock, par value (in dollars per share) Statistical Measurement [Domain] Maximum [Member] Minimum [Member] Product and Service [Axis] Product and Service [Domain] Statistical Measurement [Axis] Preferred stock, $0.01 par value; 5,000,000 shares authorized; no shares issued or outstanding Preferred stock, shares issued (in shares) Domestic and foreign income taxes Geographical [Axis] Geographical [Domain] Preferred stock, shares authorized (in shares) Inventories Total inventories Preferred stock par value (in dollars per share) Net revenues Net revenues Revenue from Contract with Customer, Including Assessed Tax us-gaap_ForeignCurrencyTransactionGainLossBeforeTax Foreign exchange loss Customer [Axis] Customer [Domain] OEM and Integrators [Member] Customers who are original equipment manufacturers and/or integrators. Inventory consigned to others End User [Member] Customers who are the end user of the company's products. Semiconductor Market [Member] The semiconductor market into which the reporting entity sells products. Service and Other Products [Member] Represents information about services and other products sold by the reporting entity. Semiconductor Production Test Products [Member] Represents information about semiconductor production test products sold by the reporting entity. Other Non-semiconductors Markets [Member] Markets other than the semiconductor market into which the reporting entity sells products. Telecommunications Market [Member] The telecommunications market into which the reporting entity sells products. Industrial Market [Member] The industrial market into which the reporting entity sells products. CASH FLOWS FROM OPERATING ACTIVITIES 401(k) Plan [Member] A 401(k) plan offered by the reporting entity to eligible employees. Schedule of Segment Reporting Information, by Segment [Table Text Block] Revenue [Policy Text Block] Statement [Line Items] Allowance for doubtful accounts us-gaap_NumberOfOperatingSegments Number of Operating Segments Trade accounts receivable, net of allowance for doubtful accounts of $210 and $211, respectively us-gaap_NumberOfReportableSegments Number of Reportable Segments Additional paid-in capital AOCI Attributable to Parent [Member] Stockholders' equity: Other income (expense) Segment Reporting Disclosure [Text Block] Proceeds from sale of demonstration equipment, net of gain Proceeds from sale of machinery and equipment net of gain. Current assets: Thermonics [Member] Represents information about Thermonics. Sigma [Member] Represents information about Sigma. Inventory, Policy [Policy Text Block] Texas Instruments Incorporated [Member] Texas instruments incorporated member. us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash used in financing activities us-gaap_Liabilities Total liabilities Commitments and Contingencies Schedule Of Outstanding Letters Of Credit [Table Text Block] Schedule of outstanding letters of credit table text block. Mt Laurel [Member] Represents information about Mt laurel. us-gaap_OperatingIncomeLoss Operating income (loss) us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash used in operating activities Mansfield [Member] Represents information about Mansfield. us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities Prepaid expenses and other current assets Effects of exchange rates on cash us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease Net cash used in all activities Cost of revenues us-gaap_GrossProfit Gross margin intt_DefinedContributionPlanEmployerMatchingContributionVestingPeriod Defined Contribution Plan Employer Matching Contribution Vesting Period (Year) Defined contribution plan employer matching contribution vesting period. Counterparty Name [Axis] Counterparty Name [Domain] Consolidation Items [Domain] Deferred tax liabilities Provision for excess and obsolete inventory Inventory Write-down Thermal Testing Products [Member] Represents information about Thermal products sold by the reporting entity. Consolidation Items [Axis] M&T [Member] Represents information about M&T. Letters of Credit Amount Outstanding intt_DebtInstrumentCovenantInterestRateInExcessOfApplicableNondefaultInterestRate Debt Instrument, Covenant, Interest Rate in Excess of Applicable Non-default Interest Rate Represents interest rate in excess of applicable non-default interest rate after expiration of contract period or if a continued event of default occurs. Lease Agreement, EMS Facility in Fremont, California [Member] Represents lease agreement, EMS facility in Fremont, California. Lease Agreement, Ambrell’s U.K [Member] Represents lease agreement, Ambrell’s U.K. us-gaap_PaymentsForRepurchaseOfCommonStock Repurchases of common stock Retained Earnings [Member] Title of Individual [Domain] Title of Individual [Axis] Treasury Stock [Member] Additional Paid-in Capital [Member] Common Stock [Member] us-gaap_StockRepurchaseProgramAuthorizedAmount1 Stock Repurchase Program, Authorized Amount intt_IncreaseDecreaseInAccruedSalesCommission Accrued sales commissions The increase (decrease) during the reporting period in accrued sales commission. intt_IncreaseInOperatingLeaseLiabilitiesAndRightofuseAssetsNonCash Increase in Operating Lease Liabilities and Right-of-Use Assets, Non-cash Represents the non-cash increase in operating lease liabilities and right-of-use assets. 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Segments [Axis] Segments [Domain] Industry Sector [Domain] Average number of potentially dilutive securities excluded from calculation (in shares) Weighted average common shares and common share equivalents outstanding - diluted (in shares) Industry Sector [Axis] Non-US [Member] us-gaap_ProceedsFromLinesOfCredit Proceeds from Lines of Credit, Total Statement [Table] Statement of Financial Position [Abstract] Net earnings (loss) per common share - diluted (in dollars per share) Weighted average common shares outstanding - basic (in shares) Weighted average common shares outstanding - basic (in shares) Business Acquisition [Axis] Net earnings (loss) per common share - basic (in dollars per share) Business Acquisition, Acquiree [Domain] Statement of Cash Flows [Abstract] Lease Contractual Term [Domain] Statement of Stockholders' Equity [Abstract] Lease Contractual Term [Axis] Income Statement [Abstract] Other comprehensive loss Revenue from External Customers by Geographic Areas [Table Text Block] Long-lived Assets by Geographic Areas [Table Text Block] Thermal Process [Member] Represents thermal process. CASH FLOWS FROM FINANCING ACTIVITIES Defense/ Aerospace [Member] Represents defense/ aerospace. Stock Repurchase Plan [Text Block] The entire disclosure for stock repurchase plan. intt_ProceedsFromPaycheckProtectionProgramUnderCaresAct Proceeds from Paycheck Protection Program Under CARES Act The cash inflow received from loan funding under the Paycheck Protection Program which was established under the Coronavirus Aid, Relief and Economic Security (CARES) Act in March 2020. Corporate, Non-Segment [Member] Independent Directors [Member] Represents the independent directors. us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense Operating Lease, Right-of-Use Asset, Amortization Expense us-gaap_StockholdersEquity Total stockholders' equity Balance Balance Schedule of Carrying Value of Finite-lived Intangible Assets [Table Text Block] Tabular disclosure of the carrying value of finite-lived intangible assets. intt_CovenantFutureAmountReceivable Covenant, Future Amount Receivable Future amount receivable if we create and maintain specified levels of employment in the specified location through various dates ending in 2023. Class of Stock [Axis] Schedule of Weighted Average Number of Shares [Table Text Block] Operating Segments [Member]