Document And Entity Information
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles
Intangible assets
Foreign exchange forward contracts
Note To Financial Statement Details Textual
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost, Total
Significant Accounting Policies
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost
Due in one year or less, amortized cost
Note 1 - Summary of Significant Accounting Policies
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets
Current assets, including cash received
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value, Total
Hedging Relationship [Domain]
Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue
Due in one year or less, fair value
Note 3 - Borrowings and Credit Agreements
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
Due after one year through five years, fair value
Note 4 - Restructuring Charges
Net Investment Hedging [Member]
Note 5 - Financial Instruments Measured at Fair Value
Not Designated as Hedging Instrument [Member]
Note 7 - Derivative Financial Instruments
Note 10 - Segment and Geographic Information
Note 11 - Leases
Income Tax Disclosure [Text Block]
Hedging Relationship [Axis]
Note 13 - Guarantees
Change in unrealized gain/loss on investments
Changes in unrealized gains and losses on investments, net of tax
Note 1 - Summary of Significant Accounting Policies - Inventories (Details)
Hedging Designation [Axis]
Note 1 - Summary of Significant Accounting Policies - Property, Plant and Equipment (Details)
Hedging Designation [Domain]
Note 1 - Summary of Significant Accounting Policies - Reported Share-based Compensation in Consolidated Financial Statements (Details)
us-gaap_LiabilitiesCurrent
Total current liabilities
Designated as Hedging Instrument [Member]
Note 1 - Summary of Significant Accounting Policies - Computation of Basic and Diluted Income (Loss) Per Share (Details)
Note 1 - Summary of Significant Accounting Policies - Disaggregation of Revenue (Details)
Other comprehensive income (loss), net of tax:
Schedule of Debt [Table Text Block]
Note 1 - Summary of Significant Accounting Policies - Significant Customer Concentration Information (Details)
Asset-Backed Securities [Member]
Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Contingent Consideration (Details)
Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Purchase Price Allocation (Details)
us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
Adjustments related to postretirement benefits
ecd_TrdArrExpirationDate
Trading Arrangement Expiration Date
Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Preliminary Allocation of Intangible Assets (Details)
us-gaap_BusinessCombinationConsiderationTransferred1
Business Combination, Consideration Transferred
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms (Year)
Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Summary of Borrowings (Details)
Inventory capitalized as property, plant and equipment
Represents information about inventory capitalized as property, plant and equipment.
Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Purchased Intangible Assets (Details)
us-gaap_FinitelivedIntangibleAssetsAcquired1
Finite-lived intangible assets, estimated fair value
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Borrowings and Credit Agreements - Summary of Borrowings (Details)
us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Finite-lived intangible assets, average useful life (Year)
Note 4 - Restructuring Charges - Charges (Details)
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding
cohu_StockRepurchaseProgramAdditionalAuthorizedAmount
Stock Repurchase Program, Additional Authorized Amount
Amount of additional stock repurchase plan authorized.
Note 5 - Financial Instruments Measured at Fair Value - Short-term Investments by Security Type (Details)
Debt Security, Government, Non-US [Member]
Note 5 - Financial Instruments Measured at Fair Value - Effective Maturities of Short-term Investments (Details)
Note 5 - Financial Instruments Measured at Fair Value - Assets Measured at Fair Value on Recurring Basis (Details)
cohu_DebtSecuritiesAvailableforsaleUnrealizedLossPositionAmortizedCost
Debt Securities, Available-for-Sale, Unrealized Loss Position, Amortized Cost
Amount of investment in debt security measured at amortized cost, in unrealized loss position.
Note 7 - Derivative Financial Instruments - Locations and Amounts of Gains (Loss) (Details)
Note 7 - Derivative Financial Instruments - Foreign Currency Forward Contracts Outstanding (Details)
US Treasury Securities [Member]
Note 10 - Segment and Geographic Information - Summary of Current Segments (Details)
Sales and maturities of short-term investments
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)
Note 11 - Leases - Balance Sheet Information (Details)
Note 11 - Leases - Lease Expense (Details)
Foreign currency translation adjustments
us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax
Changes in cumulative translation adjustment
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number (in shares)
Note 11 - Leases - Future Minimum Lease Payments (Details)
Note 11 - Leases - Cash Flow Information (Details)
us-gaap_GoodwillAndIntangibleAssetImpairment
Goodwill and Intangible Asset Impairment
Schedule of Derivative Instruments [Table Text Block]
Note 13 - Guarantees - Changes in Accrued Warranty (Details)
Notes To Financial Statements
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)
Notes To Financial Statements [Abstract]
Corporate Debt Securities [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)
us-gaap_LongTermDebtCurrent
Less: current portion
Long-Term Debt, Current Maturities
Current installments of long-term debt
Guarantees [Text Block]
us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Debt Securities, Available-for-Sale, Unrealized Loss Position
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number (in shares)
cohu_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour
Thereafter, operating lease
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).
Third Facility [Member]
Represents third facility.
Revolving Credit Facility
us-gaap_LinesOfCreditCurrent
Line of Credit, Current
cohu_LesseeLeaseLiabilityPaymentsDueAfterYearFour
Thereafter, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due after fourth fiscal year following latest fiscal year.
cohu_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfSharesAvailableForIssue
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Shares Available for Issue
Represents share based compensation arrangement by share based payment award percentage of shares available for issue.
cohu_FinanceLeaseLiabilityToBePaidAfterYearFour
Thereafter, finance lease
Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid 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).
us-gaap_PaymentsToAcquireShortTermInvestments
Purchases of short-term investments
2026, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in next fiscal year following latest fiscal year.
Employee Stock Purchase Plan [Member]
Employee stock purchase plan.
Financial Instruments [Domain]
Customer advances
Financial Instrument [Axis]
cohu_PercentageOfFairValueToDeterminePriceOfCommonStock
Percentage of Fair Value to Determine Price of Common Stock
Percentage of the Fair Value to Determine the price of common stock.
Schedule of Goodwill [Table Text Block]
Accrued compensation and benefits
Income taxes payable
Accounts payable
Revolving Credit Facility [Member]
Property, plant and equipment purchases included in accounts payable
Cash received from sale of property, plant and equipment
Credit Facility [Axis]
Credit Facility [Domain]
Other accrued liabilities
Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block]
us-gaap_PolicyTextBlockAbstract
Accounting Policies
Trademarks and Trade Names [Member]
Accrued warranty
Trade Names [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchases of property, plant and equipment
cohu_StandardProductWarrantyTerm
Standard Product Warranty Term (Month)
Describes the term of the product warranty.
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)
Weighted average shares used in computing loss per share:
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)
Cash paid for income taxes
Noncompete Agreements [Member]
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage
Swiss Franc Foreign Exchange Forward [Member]
Foreign exchange forward traded on an exchange for options or future contracts to buy or sell Swiss Francs, at a specified date, at a fixed exercise exchange rate.
Euro Foreign Exchange Forward [Member]
Foreign exchange forward traded on an exchange (examples include but are not limited to the International Securities Exchange, Philadelphia Stock Exchange, or the Chicago Mercantile Exchange) for options or future contracts to buy or sell Euros, at a specified date, at a fixed exercise exchange rate.
Current liabilities:
Developed Technology Rights [Member]
Vesting [Axis]
Current and long-term operating lease liabilities
Vesting [Domain]
us-gaap_Assets
Assets
Supplemental disclosure of cash flow information:
cohu_DebtInstrumentAmortizationPercentageOfPrincipalAmount
Debt Instrument, Amortization, Percentage of Principal Amount
Percentage of quarterly installments of the original principal, with balance payable at maturity.
Secured Term Loan Facility [Member]
Represents the information pertaining to the secured term loan facility.
Plan Name [Axis]
Plan Name [Domain]
us-gaap_SubleaseIncome
Sublease income
Customer Relationships [Member]
us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
Income tax effect
us-gaap_DebtInstrumentVariableInterestRateTypeExtensibleEnumeration
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets by Major Class [Axis]
Share-Based Payment Arrangement [Text Block]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
us-gaap_ContractWithCustomerAssetNet
Contract with Customer, Asset, after Allowance for Credit Loss
Business Combination, Intangible Asset, Acquired, Finite-Lived [Table Text Block]
Business Combination, Contingent Consideration [Table Text Block]
Award Type [Domain]
Net loss
Net loss
Net loss
Award Type [Axis]
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Accumulated Amortization
Intangible assets, net
Restricted Stock Units (RSUs) [Member]
us-gaap_FiniteLivedIntangibleAssetsGross
Gross Carrying Amount, finite-lived intangible assets
Performance Shares [Member]
Share-Based Payment Arrangement, Option [Member]
Impact of currency exchange
us-gaap_GoodwillForeignCurrencyTranslationGainLoss
us-gaap_CapitalizedComputerSoftwareGross
Capitalized Computer Software, Gross
Additions
Commitments and Contingencies Disclosure [Text Block]
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Less accumulated depreciation and amortization
Property, plant and equipment, net
us-gaap_PropertyPlantAndEquipmentNet
Property, plant and equipment, net
Goodwill
Goodwill
Balance
Balance
Property, plant and equipment
Long-Term Debt, Type [Axis]
Long-Term Debt, Type [Domain]
Rest of the World [Member]
The rest of the world.
Changes in accrued retiree medical benefits
Contract amount
us-gaap_DerivativeAssets
Derivative Instrument [Axis]
Derivative Contract [Domain]
Cash flows from investing activities, excluding effects from acquisitions:
Short term investment
us-gaap_AvailableForSaleSecuritiesDebtSecurities
Short-term investments
Loss per share:
us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable
Income taxes payable
Changes in other accrued liabilities
Income tax provision (benefit)
Line of Credit [Member]
CHINA
us-gaap_IncreaseDecreaseInAccountsPayable
Accounts payable
us-gaap_DebtInstrumentTerm
Debt Instrument, Term
General & administrative
us-gaap_GeneralAndAdministrativeExpense
Cash and cash equivalents
Business Combination, Goodwill, and Intangible Assets Disclosure [Text Block]
The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities and the entire disclosure for the aggregate amount of goodwill and a description of intangible assets.
us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax
Total share-based compensation, net
Stock-based compensation
Share Based Compensation Expense
cohu_DeferredProfitLongterm
Deferred Profit Long-term
The carrying value of deferred revenue, net of expenses, as of the balance sheet date that is expected to be recognized as such after one year.
Long-term lease liabilities
Present value of lessee's discounted obligation for lease payments from operating and finance leases, classified as noncurrent.
Mark-to-mark adjustment charged to SG&A
Amendment Flag
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive loss
dei_CityAreaCode
City Area Code
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Gain from sale of property, plant and equipment
us-gaap_IncreaseDecreaseInContractWithCustomerLiability
Customer advances
Common Stock, Shares, Outstanding (in shares)
Current Fiscal Year End Date
us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Debt Instrument, Basis Spread on Variable Rate
us-gaap_DebtInstrumentInterestRateStatedPercentage
Debt Instrument, Interest Rate, Stated Percentage
Variable lease expense
us-gaap_LeaseCost
Net lease cost
us-gaap_DebtInstrumentInterestRateEffectivePercentage
Debt Instrument, Interest Rate, Effective Percentage
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating leases
Document Fiscal Period Focus
Operating leases
Document Fiscal Year Focus
Short-term operating leases
Lease, Cost [Table Text Block]
Leased assets obtained in exchange for new finance lease liabilities
dei_DocumentPeriodEndDate
Document Period End Date
Leased assets obtained in exchange for new operating lease liabilities
us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Operating leases (Year)
dei_EntityFileNumber
Entity File Number
dei_EntityEmergingGrowthCompany
Entity Emerging Growth Company
us-gaap_DebtInstrumentFaceAmount
Debt Instrument, Face Amount
us-gaap_WriteOffOfDeferredDebtIssuanceCost
Deferred Debt Issuance Cost, Writeoff
dei_DocumentType
Document Type
Loss on extinguishment of debt
us-gaap_GainsLossesOnExtinguishmentOfDebt
Loss on extinguishment of debt
dei_EntitySmallBusiness
Entity Small Business
dei_EntityShellCompany
Entity Shell Company
Document Information [Line Items]
Document Information [Table]
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Fair value of consideration
Fair value of consideration
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements
Settlements
dei_EntityFilerCategory
Entity Filer Category
Debt Instrument [Axis]
dei_EntityCurrentReportingStatus
Entity Current Reporting Status
Restructuring charges
Restructuring Charges
Debt Instrument, Name [Domain]
us-gaap_BusinessCombinationAcquisitionRelatedCosts
Business Combination, Acquisition-Related Cost, Expense
Variable Rate [Domain]
Amortization of cloud-based software implementation costs
Capitalized Computer Software, Amortization
Hedged derivative gain (loss)
Customers individually representing more than 10% of net sales
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.
Share-based compensation expense
us-gaap_IncreaseDecreaseInAccountsReceivable
Accounts receivable
Percentage of net sales
Statement of Comprehensive Income [Abstract]
Entity Tax Identification Number
Entity Central Index Key
dei_EntityRegistrantName
Entity Registrant Name
Liability Class [Axis]
Fair Value by Liability Class [Domain]
Entity [Domain]
Treasury Stock, Retired, Cost Method, Amount
Customer Concentration Risk [Member]
Legal Entity [Axis]
Entity Address, Address Line One
us-gaap_TreasuryStockValueAcquiredParValueMethod
Common stock repurchases
Amortization of purchased intangible assets
Amortization of purchased intangible assets
Amortization of Intangible Assets
us-gaap_TreasuryStockValueAcquiredCostMethod
Common stock repurchases
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Entity Address, City or Town
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Entity Address, Postal Zip Code
us-gaap_TreasuryStockCommonValue
Treasury stock, at cost; 3,050 shares in 2025 and 2,891 shares in 2024
Entity Address, State or Province
Concentration Risk Type [Axis]
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
us-gaap_AllowanceForDoubtfulAccountsReceivable
Accounts Receivable, Allowance for Credit Loss
Concentration Risk Type [Domain]
Material Terms of Trading Arrangement [Text Block]
us-gaap_StockRepurchasedDuringPeriodShares
Stock Repurchased During Period, Shares
ecd_TrdArrIndTitle
Trading Arrangement, Individual Title
ecd_TrdArrIndName
Trading Arrangement, Individual Name
ecd_TrdArrSecuritiesAggAvailAmt
Trading Arrangement, Securities Aggregate Available Amount
dei_EntityCommonStockSharesOutstanding
Entity Common Stock, Shares Outstanding (in shares)
Trading Arrangements, by Individual [Table]
us-gaap_StockRepurchasedAndRetiredDuringPeriodValue
Repurchase and retirement of stock
PHILIPPINES
us-gaap_StockRepurchasedDuringPeriodValue
Stock Repurchased During Period, Value
ecd_TrdArrAdoptionDate
Trading Arrangement Adoption Date
Revenue Benchmark [Member]
us-gaap_IncreaseDecreaseInOtherCurrentAssets
Other current assets
us-gaap_IncreaseDecreaseInOtherNoncurrentAssets
Changes in other assets
us-gaap_IncreaseDecreaseInInventories
Inventories
Trading Symbol
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
SINGAPORE
dei_LocalPhoneNumber
Local Phone Number
us-gaap_TableTextBlock
Notes Tables
us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan
Stock Issued During Period, Shares, Employee Stock Ownership Plan (in shares)
Shares issued under ESPP
Pension curtailment gain
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
Shares issued for restricted stock units vested
Selling, general and administrative
us-gaap_ProvisionForDoubtfulAccounts
Accounts Receivable, Credit Loss Expense (Reversal)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)
TAIWAN
Raw materials and purchased parts
Selling
us-gaap_SellingExpense
Other segment items (1)
us-gaap_SegmentReportingOtherItemAmount
us-gaap_LiabilitiesAndStockholdersEquity
Liabilities and Equity
Finished goods
Work in process
UNITED STATES
Retained earnings
Research and development
Research and development
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss), Net of Tax
cohu_IncreaseDecreaseInAccruedCompensationWarrantyAndOtherLiabilities
Accrued compensation, warranty and other liabilities
The increase (decrease) during the period in accrued salaries, warranty, and other liabilities.
Money Market Funds [Member]
Japanese Yen Foreign Exchange Forward [Member]
Related to Japanese Yen foreign exchange forward.
Debt Disclosure [Text Block]
Cash and Cash Equivalents [Axis]
us-gaap_InterestExpense
Interest expense
Cash and Cash Equivalents [Domain]
Derivative Instruments, Gain (Loss) [Table Text Block]
Cash [Member]
Changes in assets and liabilities, excluding effects from acquisitions:
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Derivative Instruments and Hedging Activities Disclosure [Text Block]
us-gaap_ForeignCurrencyTransactionGainLossRealized
Realized Gain (Loss), Foreign Currency Transaction, before Tax
us-gaap_OperatingLeaseLiabilityNoncurrent
Operating
Schedule of Inventory, Current [Table Text Block]
Repurchases of common stock, net
The amount of issuance (repurchase) of common stock, net of issuance (repurchase) costs.
us-gaap_OperatingLeaseLiability
Present value of lease liabilities, operating lease
Operating
us-gaap_FinanceLeaseLiabilityCurrent
Finance
us-gaap_FinanceLeaseLiabilityNoncurrent
Finance
Subsequent Events [Text Block]
Operating lease right of use assets
Operating lease assets
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total lease payments, operating lease
Lessee, Operating Lease, Liability, to be Paid
Financing cash flows from finance leases
Payments on current and long-term finance lease liabilities
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less: Interest, operating lease
us-gaap_FinanceLeaseLiability
Present value of lease liabilities, finance lease
us-gaap_DeferredIncomeTaxExpenseBenefit
Deferred income taxes
2028, operating lease
Lessee, Operating Lease, Liability, to be Paid, Year Three
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
2029, operating lease
us-gaap_FinanceLeaseRightOfUseAsset
Finance lease assets
2026, operating lease
Lessee, Operating Lease, Liability, to be Paid, Year One
2027, operating lease
Lessee, Operating Lease, Liability, to be Paid, Year Two
Segment Reporting, Policy [Policy Text Block]
us-gaap_PaymentsForRestructuring
Amounts paid or charged
South Korean Won Forward Exchange Forward [Member]
Foreign exchange forward traded on an exchange for options or future contracts to buy or sell a South Korean Won, at a specified date, at a fixed exercise exchange rate.
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Other assets
us-gaap_ShareBasedCompensation
Share-based compensation expense
Lessee, Leases [Policy Text Block]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
2025, operating lease
Pension curtailment gain
us-gaap_PensionExpenseReversalOfExpenseNoncash
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Finite-Lived Intangible Asset, Useful Life (Year)
Amortization of debt discounts and issuance costs
Earnings Per Share, Policy [Policy Text Block]
cohu_FiniteAndIndefinitelivedIntangibleAssetsAcquired
Finite-lived intangible assets, estimated fair value
Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with a finite or indefinite life, from an acquisition.
Comprehensive Income, Policy [Policy Text Block]
us-gaap_AssetsFairValueDisclosure
Assets, Fair Value Disclosure
us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments
Net accretion on investments
Internal Use Software, Policy [Policy Text Block]
us-gaap_LesseeOperatingLeaseRenewalTerm
Lessee, Operating Lease, Renewal Term
us-gaap_DepreciationDepletionAndAmortization
Depreciation and amortization
Costs Associated with Exit or Disposal Activity or Restructuring [Policy Text Block]
us-gaap_AssetsCurrent
Total current assets
us-gaap_CashAndCashEquivalentsFairValueDisclosure
Cash and cash equivalents
Share-Based Payment Arrangement [Policy Text Block]
Equity [Text Block]
Kita Term Loans [Member]
Represents information pertaining to term loans related to the Kita acquisition.
Pension and Other Postretirement Plans, Policy [Policy Text Block]
Treasury Stock, Common, Shares (in shares)
us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1
Mark to market adjustment to contingent consideration
Common stock, $1 par value; 90,000 shares authorized, 49,745 shares issued and outstanding in 2025 and 49,601 shares in 2024
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Measurement Frequency [Axis]
Measurement Frequency [Domain]
Fair Value, Recurring [Member]
Common Stock, Shares Authorized (in shares)
Ismeca [Member]
Represents information pertaining to Ismeca, a wholly-owned subsidiary of Cohu.
Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]
Common Stock, Shares, Issued (in shares)
Certificates of Deposit [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)
Facilities in San Diego, California [Member]
Represents facilities in San Diego, California.
Poway Volume Manufacturing Transition [Member]
Represents Poway Volume Manufacturing Transition.
cohu_NumberOfAvailableLinesOfCredit
Number of Available Lines of Credit
Represents the number of available lines of credit as of the balance sheet date.
Tignis, Inc [Member]
Represents Tignis, Inc.
Standard Product Warranty, Policy [Policy Text Block]
Statistical Measurement [Domain]
Operating cash flows from operating leases
Maximum [Member]
Minimum [Member]
Effective Cost of Funds (“ECOF”) [Member]
Represents Effective Cost of Funds (“ECOF”).
Other current assets
Product and Service [Axis]
2025 Strategic Restructuring [Member]
Represents 2025 Strategic Restructuring.
Product and Service [Domain]
Statistical Measurement [Axis]
Wholly Owned Subsidiary in Malaysia [Member]
Represents the wholly owned subsidiary in Malaysia.
Operating cash flows from finance leases
Total debt
Represents the aggregate of total long-term debt, including current maturities and short-term debt, before financing fees and discount.
Preferred stock, $1 par value; 1,000 shares authorized, none issued
Preferred Stock, Shares Issued (in shares)
Cash paid for interest
Prepaid expenses
Geographical [Axis]
Geographical [Domain]
Goodwill and Intangible Assets, Policy [Policy Text Block]
Property, Plant and Equipment [Table Text Block]
Preferred Stock, Shares Authorized (in shares)
Inventories
Total inventories
Preferred Stock, Par or Stated Value Per Share (in dollars per share)
Net sales
Net sales
Fair Value, Inputs, Level 3 [Member]
Foreign transaction loss
Fair Value Hierarchy and NAV [Domain]
Customer [Axis]
Customer [Domain]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value Hierarchy and NAV [Axis]
us-gaap_ProductWarrantyAccrualPayments
Warranty payments
Warranty expense accruals
us-gaap_PropertyPlantAndEquipmentUsefulLife
Property, Plant and Equipment, Useful Life
Cash flows from operating activities:
Accounts receivable, net
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Revenue [Policy Text Block]
Statement [Line Items]
us-gaap_NumberOfOperatingSegments
Number of Operating Segments
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
Semiconductor Test and Inspection [Member]
Relating to the segment, Semiconductor Test & Inspection.
Building and Building Improvements [Member]
Building [Member]
Building Improvements [Member]
Short-term investments
Paid-in capital
AOCI Attributable to Parent [Member]
Land and Land Improvements [Member]
Stockholders’ equity
Schedule of Product Warranty Liability [Table Text Block]
Property, Plant and Equipment, Policy [Policy Text Block]
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table Text Block]
Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite or indefinite life, by either major class or business segment.
Long-Lived Tangible Asset [Axis]
Long-Lived Tangible Asset [Domain]
Segment Reporting Disclosure [Text Block]
Current assets:
Semiconductor Test & Inspection Segment [Member]
The Semiconductor Test & Inspection segment.
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
Cash and cash equivalents at beginning of period
Cash and cash equivalents at end of period
Inventory, Policy [Policy Text Block]
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net decrease in cash and cash equivalents
Interest income
MALAYSIA
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash used in financing activities
Effect of exchange rate changes on cash and cash equivalents
us-gaap_OperatingIncomeLoss
Loss from operations
Other (expense) income:
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by (used in) operating activities
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash provided by (used in) investing activities
Deferred income taxes
Derivatives, Policy [Policy Text Block]
us-gaap_ContractWithCustomerLiability
Contract with Customer, Liability
us-gaap_DerivativeLiabilities
Contract amount
Impairment charge related to equity investment
Consolidated Entities [Axis]
Consolidated Entities [Domain]
Concentration Risk, Credit Risk, Policy [Policy Text Block]
us-gaap_ProductWarrantyAccrual
Balance at beginning of period
Balance at end of period
us-gaap_GainLossFromComponentsExcludedFromAssessmentOfFairValueHedgeEffectivenessNet
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net
Cost, Depreciation, Amortization and Depletion
us-gaap_CostsAndExpenses
Costs and Expenses
Cost and expenses:
us-gaap_PaymentsForRepurchaseOfCommonStock
Acquisition of treasury stock
Retained Earnings [Member]
Treasury Stock, Common [Member]
us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Share Repurchase Program, Remaining Authorized, Amount
Additional Paid-in Capital [Member]
Common Stock [Member]
Non-current Other Accrued Liabilities [Member]
Represents non-current other accrued liabilities.
Equity Components [Axis]
Equity Component [Domain]
cohu_LesseeLeaseRemainingTermOfContract
Lessee, Lease, Remaining Term of Contract
Remaining term of lessee's operating and finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.
us-gaap_LongTermDebt
Long-Term Debt
Lessee, Leases [Text Block]
The entire disclosure for operating and finance leases of lessee.
Construction Loans [Member]
us-gaap_RevenueRemainingPerformanceObligation
Revenue, Remaining Performance Obligation, Amount
cohu_LeaseRightofuseAsset
Total lease assets
Amount of lessee's right to use underlying asset under finance and operating lease.
Leases, Balance Sheet Information [Table Text Block]
Tabular disclosure of balance sheet information for leases.
2027, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in second fiscal year following latest fiscal year.
Loss before taxes
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Loss before taxes
cohu_LesseeLeaseLiabilityPaymentsRemainderOfFiscalYear
2025, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease having an initial or remaining lease term in excess of one year due in remainder of fiscal year following latest fiscal year.
Lessee, Lease, Liability, Maturity [Table Text Block]
Tabular disclosure of undiscounted cash flows of lessee's operating and finance lease liability.
cohu_LeaseLiability
Total lease liabilities
Present value of lessee's discounted obligation for lease payments from finance and operating lease.
cohu_LesseeLeaseLiabilityPaymentsDueYearFour
2029, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in fourth fiscal year following latest fiscal year.
2028, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in third fiscal year following latest fiscal year.
Lease, Cash Flow Information [Table Text Block]
Tabular disclosure of the cash flow information for leases.
cohu_LesseeLeaseLiabilityUndiscountedExcessAmount
Less: Interest, total
Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating and finance lease.
cohu_LesseeLeaseLiabilityPaymentsDue
Total lease payments, total
Amount of lessee's undiscounted obligation for lease payments for operating and finance lease.
Lines of Credit
Long-Term Line of Credit
Disaggregation of Revenue [Table Text Block]
us-gaap_RepaymentsOfLongTermDebt
Repayments of long-term debt
Repayments of Long-Term Debt
Machinery and Equipment [Member]
Statement of Financial Position Location, Balance [Axis]
Statement of Financial Position Location, Balance [Domain]
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member]
Represents a business acquired by the reporting entity.
Document Quarterly Report
Entity Incorporation, State or Country Code
Long term Debt
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]
Document Transition Report
Basis of Accounting, Policy [Policy Text Block]
Selling, General and Administrative Expenses [Member]
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]
dei_EntityInteractiveDataCurrent
Entity Interactive Data Current
Short-term borrowings
Security Exchange Name
Title of 12(b) Security
Vesting Over One Year Period [Member]
Represent a year vesting period.
Cost of Sales [Member]
Vesting Over Four Year Period [Member]
Represent four year vesting period.
Research and Development Expense [Member]
Vest on the Third Anniversary of Awards Grant [Member]
Represent awards that are versing on the third anniversary of grant.
Statement of Income Location, Balance [Axis]
Statement of Income Location, Balance [Domain]
cohu_IncreaseDecreaseInOperatingLeaseRightOfUseAssets
Operating lease right-of-use assets
Amount of increase (decrease) in operating lease right-of-use assetS.
Equity Incentive Plan 2005 [Member]
Information pertaining to the 2005 Equity Incentive Plan.
Segments [Axis]
One Customer [Member]
Information pertaining to one customer.
Segments [Domain]
Effect of dilutive securities (in shares)
us-gaap_ProductWarrantyAccrualNoncurrent
Product Warranty Accrual, Noncurrent
Other accrued liabilities
us-gaap_OtherAccruedLiabilitiesNoncurrent
us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization
Finance Lease, Right-of-Use Asset, Accumulated Amortization
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Diluted (in shares)
Weighted Average Number of Shares Outstanding, Diluted
Proceeds from revolving line of credit and revolving credit facility
Proceeds from Lines of Credit
Statement [Table]
Statement of Financial Position [Abstract]
us-gaap_EarningsPerShareDiluted
Diluted (in dollars per share)
Weighted average common shares (in shares)
Basic (in shares)
Cost of sales
Cost of sales (1)
us-gaap_EarningsPerShareBasic
Basic (in dollars per share)
Business Combination [Axis]
Business Combination [Domain]
Statement of Cash Flows [Abstract]
Construction Loan [Member]
A borrowing arrangement which provides the entity constructing a facility (such as a building and a landfill) with funds to effect construction, generally on a draw down, or as needed, basis.
Statement of Stockholders' Equity [Abstract]
us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Business Combination, Contingent Consideration, Range of Outcomes, Maximum, Amount
Lease Contractual Term [Domain]
Lease Contractual Term [Axis]
Income Statement [Abstract]
us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Other comprehensive income (loss), net of tax
First Facility [Member]
Represents the first facility.
us-gaap_RestructuringReserve
Accrued restructuring, balance
Accrued restructuring, balance
Second Facility [Member]
Represents the second facility.
Loan Facilities [Member]
Represents the loan facilities.
us-gaap_RestructuringReserveTranslationAdjustment
Impact of currency exchange
cohu_IncreaseDecreaseInDeferredProfit
Deferred profit
The amount of increase (decrease) in deferred profit during the period.
Interest on lease liabilities
Non-systems [Member]
The amount of revenue derived from all other sources that are not systems.
Systems [Member]
The amount of revenue derived from systems.
us-gaap_FinanceLeaseLiabilityPaymentsDue
Total lease payments, finance lease
Amortization of leased assets
Non-cash inventory related charges
The adjustment related to the amortization of inventory step-up and inventory related charges.
Investments Classified by Contractual Maturity Date [Table Text Block]
us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount
Less: Interest, finance lease
Machinery, Equipment and Software [Member]
Tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment and collection of computer programs and related data that provide instructions to a computer.
2026, finance lease
2027, finance lease
2028, finance lease
Unrealized Gain (Loss) on Investments [Table Text Block]
Employee Severance and Other Exit Costs [Member]
Represents employee severance and other exit costs.
us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour
2029, finance lease
Restructuring Plan [Axis]
Restructuring Plan [Domain]
Other Restructuring [Member]
srt_StockRepurchaseProgramAuthorizedAmount1
Share Repurchase Program, Authorized, Amount
Type of Restructuring [Domain]
us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent
Finance leases
Employee Severance [Member]
us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear
2025, finance lease
Restructuring and Related Activities Disclosure [Text Block]
Restructuring and Related Costs [Table Text Block]
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
Restructuring Type [Axis]
us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1
Finance leases (Year)
Cash flows from financing activities:
us-gaap_PaymentsForProceedsFromHedgeInvestingActivities
Settlement of net investment hedge
Accrued retirement benefits
Contingent Consideration [Member]
Represents contingent consideration.
Deferred profit
Deferred Profit
The carrying value of deferred revenue, net of expenses, as of the balance sheet date that is expected to be recognized as such within one year or the normal operating cycle, if longer.
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet
Net assets acquired
us-gaap_StockholdersEquity
Total stockholders’ equity
Balance
Balance
Foreign Exchange Forward [Member]
Noncurrent income tax liabilities
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
Liabilities assumed
us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Payment for purchase of Tignis, net of cash received
Payments to Acquire Businesses, Net of Cash Acquired
Position [Domain]
Long [Member]
Class of Stock [Axis]
Short [Member]
us-gaap_LongTermDebtNoncurrent
Total long-term debt
Long-term debt
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Position [Axis]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Total assets acquired
Gross unrealized losses
Gross unrealized gains
Amortized cost
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost
Due after one year through five years, amortized cost
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
Property, plant and equipment
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets
Other assets