Document And Entity Information
Statistical Measurement [Axis]
Note To Financial Statement Details Textual
Significant Accounting Policies
Income tax expense
Income Tax Expense (Benefit)
Income Tax Expense (Benefit)
Note 2 - Net Income (Loss) Per Share
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Note 3 - Cash and Cash Equivalents
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Note 4 - Investments
Trading Arrangements, by Individual [Table]
Note 5 - Fair Value Measurements
Material Terms of Trading Arrangement [Text Block]
Note 6 - Other Comprehensive Income (Loss)
Note 7 - Stock-based Compensation
Financial Instrument [Axis]
Note 8 - Revenue
us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation
Repurchase of shares for payment of withholding taxes for vested restricted stock grants (in shares)
Note 10 - Inventories
Note 11 - Goodwill and Intangible Assets
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Unrealized losses
Minimum [Member]
Note 13 - Assets Held for Sale and Discontinued Operations
Unrealized gains
Note 15 - Leases
us-gaap_GoodwillGross
Goodwill
Statistical Measurement [Domain]
Note 2 - Net Income (Loss) Per Share - Weighted Average Common Shares Outstanding (Details)
Maximum [Member]
Note 3 - Cash and Cash Equivalents - Schedule of Cash and Cash Equivalents (Details)
Note 4 - Investments - Available-for-sale Investments (Details)
Note 4 - Investments - Securities in a Continuous Unrealized Loss Position (Details)
us-gaap_IncreaseDecreaseInAccountsReceivable
Accounts receivable
Note 5 - Fair Value Measurements - Fair Value Measurements (Details)
Accounts payable and accrued expenses
Schedule of Investments [Table]
Certificates of Deposit [Member]
Note 6 - Other Comprehensive Income (Loss) - Changes in Other Comprehensive Income (Loss) (Details)
Note 7 - Stock-based Compensation - Option Transaction Summary (Details)
Note 7 - Stock-based Compensation - Restricted Stock Transactions (Details)
Note 7 - Stock-Based Compensation - Performance Stock Performance (Details)
Note 8 - Revenue - Disaggregation of Revenue (Details)
Note 10 - Inventories - Components of Inventory (Details)
Note 11 - Goodwill and Intangibles - Finite Lived Intangible Assets (Details)
clfd_OperatingLeasePaymentsAnnualIncreasePercentage
Operating Lease, Payments, Annual Increase, Percentage
Annual percentage increase in operating lease payments.
Note 11 - Goodwill and Intangibles - Future Estimated Amortization Expense for Intangibles (Details)
Note 13 - Assets Held for Sale and Discontinued Operations - Discontinued Operations (Details)
Note 15 - Leases - Operating Lease Expense (Details)
Note 15 - Leases - Maturities of Lease Liabilities (Details)
Notes To Financial Statements
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Effective Income Tax Rate Reconciliation, Percent, Total
Tijuana, Mexico 3 [Member]
Represents a third categorization of information related to Tijuana, Mexico.
Notes To Financial Statements [Abstract]
Lease Mandatory Contractual Term [Member]
Mandatory contractual term of lease arrangement.
us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Brooklyn Park, MN [Member]
Represents Brooklyn Park, MN.
Exercised, weighted-average exercise price (in dollars per share)
Performance Shares [Member]
Financial Instruments [Domain]
us-gaap_IncreaseDecreaseInInventories
Inventories, net
us-gaap_SharesOutstanding
Balance (in shares)
Balance (in shares)
Change in cash held for sale
clfd_CashHeldForSalePeriodIncreaseDecrease
Amount of increase (decrease) in cash held for sale.
Segment Reporting [Text Block]
Fair value unrealized loss, greater than 12 months
Fair value unrealized loss, less than 12 months
Current liabilities held for sale
Current liabilities held for sale
Award Type [Axis]
Non-current liabilities held for sale
Non-current liabilities held for sale
Preferred stock, $0.01 par value; 500,000 shares; no shares issued or outstanding
Adjustments to reconcile net income to net cash provided by operating activities:
us-gaap_Liabilities
Total liabilities
Plan Name [Axis]
Plan Name [Domain]
us-gaap_LiabilitiesAndStockholdersEquity
Total Liabilities and Shareholders’ Equity
us-gaap_AllocatedShareBasedCompensationExpense
Share-Based Payment Arrangement, Expense
Cash and Cash Equivalent [Table]
Intangible assets, net
us-gaap_DisposalGroupIncludingDiscontinuedOperationIntangibleAssetsNoncurrent
Cash and Cash Equivalents [Axis]
Title and Position [Axis]
Segment Reporting [Table]
Property, plant and equipment, net
us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent
us-gaap_SellingGeneralAndAdministrativeExpense
Selling, general and administrative
Stock-based compensation
Lessee, Lease, Description [Table]
Share-Based Payment Arrangement [Text Block]
Lease Contractual Term [Axis]
Lease Contractual Term [Domain]
Changes in operating assets and liabilities:
Preferred Stock, Shares Issued (in shares)
Useful life (Year)
Intangible Asset, Finite-Lived, Useful Life
Preferred Stock, Shares Outstanding (in shares)
Preferred Stock, Shares Authorized (in shares)
Fair Value, by Balance Sheet Grouping [Table]
Preferred Stock, Par or Stated Value Per Share (in dollars per share)
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net (decrease) increase in cash and cash equivalents
Effect of exchange rates on cash and cash equivalents
us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
clfd_OperatingLeaseMonthlyPayment
Operating Lease, Monthly Payment
Amount of monthly cash outflow for operating lease payments.
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash and cash equivalents, beginning of period
Cash and cash equivalents, end of period
Antidilutive Securities, Name [Domain]
Comprehensive income (loss):
Share-Based Payment Arrangement, Tranche One [Member]
Statement [Table]
us-gaap_OperatingLeasePayments
Operating Lease, Payments
Credit Facility [Axis]
Credit Facility [Domain]
Effect of exchange rates on cash and cash equivalents
Revolving Credit Facility [Member]
Share-Based Payment Arrangement, Tranche Two [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block]
Right of use assets obtained through lease liabilities
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability
us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Debt Instrument, Basis Spread on Variable Rate
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
clfd_NumberOfPatentsGranted
Number of Patents Granted
Represents the number of patents granted in the United States.
us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Unvested shares, number of shares (in shares)
Unvested, number of shares (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Unvested shares, weighted average grant date fair value (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Granted, weighted average grant date fair value (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Forfeited, number of shares (in shares)
Forfeited, number of shares (in shares)
Condensed Statement of Comprehensive Income [Table]
Product and Service [Domain]
Product and Service [Axis]
us-gaap_LineOfCredit
Long-Term Line of Credit
Vested, weighted average grant date fair value (in dollars per share)
Vested, weighted average grant date fair value (in dollars per share)
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period
Vested, number of shares (in shares)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total lease payments
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating Lease, Weighted Average Discount Rate, Percent
FY 2027
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
Unrealized gain (loss) on foreign currency translation
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant
us-gaap_OperatingLeaseExpense
Total lease expense
FY 2026 (remaining)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Options, outstanding (in shares)
Options, outstanding (in shares)
FY 2029
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
Nature of Expense [Axis]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted-average exercise price, outstanding (in dollars per share)
Weighted-average exercise price, outstanding (in dollars per share)
FY 2028
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
Statement [Line Items]
Fair Value Hierarchy and NAV [Axis]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value
FY 2030
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
Common Stock, Shares, Issued (in shares)
Grantee Status [Domain]
Common Stock, Shares, Outstanding (in shares)
Award Type [Domain]
Share-Based Payment Arrangement, Employee [Member]
Common Stock, Shares Authorized (in shares)
Grantee Status [Axis]
Proceeds from maturities of investments
Non-current assets held for sale
Non-current assets held for sale
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Common stock, authorized 50,000,000, $0.01 par value; 13,597,691 and 13,839,675 shares issued and outstanding as of June 30, 2026 and September 30, 2025, respectively
Share-Based Payment Arrangement, Nonemployee [Member]
FY 2028
FY 2029
FY 2027
Schedule of Inventory, Current [Table Text Block]
Schedule of Cash and Cash Equivalents [Table Text Block]
Accounts payable
Short-term Investment [Member]
Represents short-term investment.
Long-term Investment [Member]
Represents long-term investment.
us-gaap_PolicyTextBlockAbstract
Accounting Policies
FY 2026 (remaining)
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Short-term Certificates of Deposit [Member]
Represents Short-term Certificates of Deposit.
FY 2030
us-gaap_TableTextBlock
Notes Tables
Comprehensive Income (Loss) Note [Text Block]
us-gaap_ComprehensiveIncomeNetOfTax
Total comprehensive income (loss)
clfd_DebtInstrumentMinimumInterestRateRequired
Debt Instrument, Minimum Interest Rate Required
The minimum interest rate required for debt instrument.
Short-term investments
clfd_DebtInstrumentCovenantMinimumDebtServiceCoverageRatio
Debt Instrument, Covenant, Minimum Debt Service Coverage Ratio
Minimum debt service coverage ratio required under debt instrument.
clfd_CashEquivalentsFairValueDisclosure
Cash equivalents
Cash Equivalents, Fair Value Disclosure
Concentration Risk [Table]
clfd_DebtInstrumentCovenantMaximumDebtToCashFlowRatio
Debt Instrument, Covenant, Maximum Debt to Cash Flow Ratio
Maximum debt to cash flow ratio required under debt instrument.
Accrued expenses
clfd_SharebasedCompensationArrangementBySharebasedPaymentAwardMarketPricePercentageOfferingDate
Share-based Compensation Arrangement by Share-based Payment Award, Market Price Percentage, Offering Date
Percentage of market price of one share of common stock on offering date that participants pay for shares.
Concentration Risk Type [Axis]
clfd_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePrice
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price
Represents information about the purchase price of each share under the employee stock purchase plan.
Concentration Risk Disclosure [Text Block]
Loan and Security Agreement With Bremer Bank, National Association [Member]
Represents loan and security agreement with Bremer Bank, National Association.
Lessee, Operating Lease Expense [Table Text Block]
Tabular disclosure of a lessee's operating lease expense.
Accrued compensation
The 2022 Plan [Member]
represents the 2022 plan.
Significant Accounting Policies [Text Block]
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less: Interest
Long-term portion of lease liability
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)
Present value of lease liabilities
Current portion of lease liability
Inventories, net
us-gaap_DisposalGroupIncludingDiscontinuedOperationInventoryCurrent
Accounts Receivable [Member]
Concentration Risk Type [Domain]
Amortized cost
clfd_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSettledInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Settled in Period
Settled, number of shares (in shares)
The number of equity-based payment instruments, excluding stock (or unit) options, that was settled during the reporting period.
Long-term investments
Settled, weighted average grant date fair value (in dollars per share)
Settled, weighted average grant date fair value (in dollars per share)
Per share or unit weighted-average fair value of settled award under share-based payment arrangement.
Other comprehensive (loss) income, net of tax
Statement of Stockholders' Equity [Abstract]
Intangible Asset, Finite-Lived, Class [Axis]
Statement of Comprehensive Income [Abstract]
Intangible Asset, Finite-Lived, Class [Domain]
Statement of Cash Flows [Abstract]
Other comprehensive income (loss)
Total other comprehensive (loss) income
Other comprehensive income (loss)
Shareholders’ equity
Equity Components [Axis]
us-gaap_IncreaseDecreaseInOperatingLeaseLiability
Increase (Decrease) in Operating Lease Liability
Other non-current liabilities
us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities
Equity Component [Domain]
Fair Value, Inputs, Level 2 [Member]
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Fair Value, Inputs, Level 3 [Member]
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
AOCI Attributable to Parent [Member]
Fair Value, Inputs, Level 1 [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Property, plant and equipment, net
us-gaap_DiscontinuedOperationProvisionForLossGainOnDisposalBeforeIncomeTax
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax
Deferred tax asset
Comprehensive Income (Loss) [Table Text Block]
Cost of sales
Stock based compensation expense
clfd_PaymentsForDisposalOfBusiness
Cash paid on disposal of business
The cash paid on the disposal of business.
Intangible Asset and Goodwill [Text Block]
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
Fair Value Disclosures [Text Block]
Share-Based Payment Arrangement, Option [Member]
Supplemental disclosures for cash flow information
Current liabilities
us-gaap_LiabilitiesCurrent
Total current liabilities
us-gaap_DebtInstrumentVariableInterestRateTypeExtensibleEnumeration
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]
us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss
Operating loss
us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments
Amortization of premium and discount on investments, net
Accounts receivables, net
Short-term US Treasury Securities [Member]
This category includes information about debt securities issued by the United States Department of the Treasury and backed by the United States government that are classified as short-term. Such securities primarily consist of treasury bills (short-term maturities - one year or less), treasury notes (intermediate term maturities - two to ten years), and treasury bonds (long-term maturities - ten to thirty years).
Long-term US Treasury Securities [Member]
This category includes information about debt securities issued by the United States Department of the Treasury and backed by the United States government classified as longt-term. Such securities primarily consist of treasury bills (short-term maturities - one year or less), treasury notes (intermediate term maturities - two to ten years), and treasury bonds (long-term maturities - ten to thirty years).
Cash flows from investing activities (continuing)
Customer Concentration Risk [Member]
Thereafter
clfd_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour
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).
us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations
Net cash used in financing activities (continuing)
Cash flows from financing activities (continuing)
us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations
Net cash used in investing activities (continuing)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
Forfeited or expired, options (in shares)
Customer Relationships [Member]
Revenue Benchmark [Member]
Net cash (used in) provided by financing activities
Net cash provided by (used in) operating activities
Discontinued operations (in dollars per share)
us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare
Discontinued operations (in dollars per share)
Net cash used in investing activities
Accumulated other comprehensive (loss) income
Discontinued operations (in dollars per share)
us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare
Discontinued operations (in dollars per share)
us-gaap_PaymentsToAcquireInvestments
Purchases of investments
Forfeited or expired, weighted-average exercise price (in dollars per share)
Forfeited, weighted average grant date fair value (in dollars per share)
Accumulated amortization
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income from continuing operations before income taxes
Additional paid-in capital
Debt Disclosure [Text Block]
Performance Stock Units [Member]
Represents performance stock units.
Thereafter
Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized 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_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition
Issuance of common stock under employee stock purchase plan
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period
us-gaap_PaymentsToAcquireProductiveAssets
Purchases of property, plant and equipment and intangible assets
Lessee, Operating Leases [Text Block]
UNITED STATES
Non-US [Member]
us-gaap_StockRepurchasedAndRetiredDuringPeriodValue
Repurchase of common stock
Money market funds
Current assets
Money Market Funds [Member]
us-gaap_AssetsCurrent
Total current assets
Issuance of common stock under equity compensation plans, net
Issuance of common stock under employee stock purchase plan (in shares)
Stock Issued During Period, Shares, Employee Stock Purchase Plans
us-gaap_GrossProfit
Gross profit
Restricted Stock Units (RSUs) [Member]
Debt Instrument, Name [Domain]
us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Exercised, options (in shares)
Issuance of common stock under equity compensation plans, net (in shares)
us-gaap_DebtInstrumentInterestRateDuringPeriod
Debt Instrument, Interest Rate During Period
Trademarks [Member]
us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
Repurchase of common stock (in shares)
Cash flows from operating activities (continuing)
us-gaap_NetCashProvidedByUsedInDiscontinuedOperations
Net cash provided by (used in) discontinued operations
Schedule of Long-Term Debt Instruments [Table]
us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations
Net cash provided by operating activities (continuing)
Debt Instrument [Axis]
Cash flows from discontinued operations
Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block]
clfd_DebtSecuritiesAvailableForSaleOtherThanTemporaryImpairment
Debt Securities, Available for Sale, Other than Temporary Impairment
Represents other than temporary impairment of debt securities available for sale.
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
Accounting Policies [Abstract]
us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
Impairment of Intangible Assets (Excluding Goodwill), Total
us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Accounts Receivable, Allowance for Credit Loss, Current
US Treasury Securities [Member]
Continuing operations (in dollars per share)
us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare
Continuing operations (in dollars per share)
Continuing operations (in dollars per share)
us-gaap_IncomeLossFromContinuingOperationsPerBasicShare
Continuing operations (in dollars per share)
7050 Winnetka Avenue North, Brooklyn Park, Minnesota [Member]
Represents 7050 Winnetka Avenue North, Brooklyn Park, Minnesota.
Income Statement [Abstract]
us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits, Ending Balance
us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax
Loss from discontinued operations before income taxes
us-gaap_NumberOfOperatingSegments
Number of Operating Segments
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
Income Tax Contingency [Table]
Schedule of Available-for-Sale Securities Reconciliation [Table Text Block]
Net loss
Net income
Net income
Net loss
Nestor Cables [Member]
Represents information pertaining to Nestor Cables.
Certification Marks [Member]
us-gaap_AmortizationOfIntangibleAssets
Intangible Asset, Finite-Lived, Amortization Expense
us-gaap_AreaOfRealEstateProperty
Area of Real Estate Property
Income Tax Disclosure [Text Block]
Proceeds from issuance of common stock under employee stock purchase plan
Restricted Stock [Member]
Accounting Standards Update and Change in Accounting Principle [Table]
Cost of Sales 1 [Member]
Primary financial statement caption encompassing cost of sales.
Selling, general and administrative expenses
clfd_PolicyTable
Selling, General and Administrative Expenses 1 [Member]
Primary financial statement caption encompassing selling, general and administrative expense.
Newly Appointed Non-Employee Directors [Member]
Represents the newly appointed non-employee directors.
us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss
Debt Securities, Available-for-Sale, Allowance for Credit Loss
Fair Value Hierarchy and NAV [Domain]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share
Accounts payable
us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent
Vesting [Axis]
Statement of Financial Position [Abstract]
Vesting [Domain]
Current assets held for sale
Current assets held for sale
Cash (refunded) paid for income taxes, net
clfd_IssuanceOfCommonStockFundedThroughSharesSoldToCompany
Cashless exercise of stock options
The issuance of common stock funded through shares sold to the company.
Other liabilities
Other non-current assets
us-gaap_PaymentsForRepurchaseOfCommonStock
Repurchase of common stock
us-gaap_IncreaseDecreaseInOtherOperatingAssets
Other assets
dei_DocumentType
Document Type
Operating expenses
Document Information [Line Items]
Document Quarterly Report
us-gaap_ConcentrationRiskPercentage1
Concentration Risk, Percentage
us-gaap_LesseeOperatingLeaseTermOfContract
Lessee, Operating Lease, Term of Contract
us-gaap_LesseeOperatingLeaseRenewalTerm
Lessee, Operating Lease, Renewal Term
us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Operating Lease, Weighted Average Remaining Lease Term
Document Information [Table]
Legacy Customers [Member]
Information related to legacy customers.
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
us-gaap_IncrementalCommonSharesAttributableToContingentlyIssuableShares
Dilutive potential common shares (in shares)
Antidilutive Securities [Axis]
Diluted
dei_EntityInteractiveDataCurrent
Entity Interactive Data Current
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period
Document Transition Report
Diluted (in shares)
us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Weighted average dilutive common shares outstanding (in shares)
Basic
Basic (in shares)
us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Weighted average common shares (in shares)
us-gaap_EarningsPerShareBasic
Basic income per share (in dollars per share)
Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table]
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage
Title and Position [Domain]
Intangible assets, net
Employee Stock Purchase Plan [Member]
The employee stock purchase plan.
Net carrying amount
Total
Document Fiscal Period Focus
Customer [Domain]
Gross carrying amount
Document Fiscal Year Focus
Amendment Flag
Common Stock [Member]
us-gaap_DebtInstrumentCollateralAmount
Debt Instrument, Collateral Amount
dei_DocumentPeriodEndDate
Document Period End Date
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross
Legal Entity [Axis]
clfd_NumberOfMajorCustomers
Number of Major Customers
Represents the number of major customers accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc.
dei_EntityFileNumber
Entity File Number
Entity Tax Identification Number
Non-cash financing activities
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Gross unrealized loss, less than 12 months
Disaggregation of Revenue [Table Text Block]
Change in cash held for sale
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Gross unrealized loss, greater than 12 months
Disaggregation of Revenue [Table]
Entity [Domain]
Entity Central Index Key
dei_EntityRegistrantName
Entity Registrant Name
Software, Internally Developed [Member]
dei_EntityCurrentReportingStatus
Entity Current Reporting Status
Entity Incorporation, State or Country Code
Total Net Sales, percentage
Represents the percentage of revenues.
Current Fiscal Year End Date
Other comprehensive income
Other comprehensive income
Broadband Service Providers [Member]
Information pertaining to broadband service providers.
Entity Filer Category
Exercise of stock options, net of shares exchanged for payment (in shares)
Number of share options (or share units) exercised during the current period.
dei_EntityShellCompany
Entity Shell Company
Exercise of stock options, net of shares exchanged for payment
Value of stock issued as a result of withholding related to stock options exercised.
Entity Emerging Growth Company
Entity Small Business
us-gaap_OperatingIncomeLoss
Income (loss) from continuing operations
Cash and Cash Equivalents [Domain]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Other current liabilities
us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities
Other current assets
us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets
Cash and cash equivalents
us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents
Accounts receivable, net
us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet
Entity Address, State or Province
Entity Address, City or Town
Inventory, Current [Table]
Retained earnings
Entity Address, Address Line One
City Area Code
us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation
Repurchase of shares for payment of withholding taxes for vested restricted stock grants
clfd_PaymentsForProceedsFromTaxWithholdingStockOptionsExercised
Withholding related to exercise of stock options
Amount of cash outflow (inflow) to satisfy tax withholding obligation from stock options exercised.
Local Phone Number
Entity Address, Postal Zip Code
Revenue from Contract with Customer [Text Block]
Title of 12(b) Security
Cash and Cash Equivalents Disclosure [Text Block]
Security Exchange Name
Trading Symbol
Class of Stock [Axis]
Fair value
Investment securities:
Current portion of lease liability
clfd_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilityCurrent
Amount classified as lease liability attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.
Right-of-use lease assets
clfd_DisposalGroupIncludingDiscontinuedOperationRightofuseAssetsNoncurrent
Amount classified as right-of-use assets attributable to disposal group held for sale or disposed of, expected to be disposed of beyond one year or the normal operating cycle, if longer.
Entity Common Stock, Shares Outstanding (in shares)
Earnings Per Share [Text Block]
Prepaid and other current assets
clfd_DisposalGroupIncludingDiscontinuedOperationImpairmentOfLonglivedAssets
Disposal Group, Including Discontinued Operation, Impairment of Long-lived Assets
Total loss recognized during the period from the impairment of long-lived assets attributable to a disposal group.
clfd_DisposalGroupIncludingDiscontinuedOperationsGoodwillImpairment
Disposal Group, Including Discontinued Operations, Goodwill Impairment
Total loss recognized during the period from the impairment of goodwill attributable to a disposal group.
Accrued compensation
clfd_DisposalGroupIncludingDiscontinuedOperationAccruedCompensationCurrent
Amount classified as accrued compensation attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.
Current maturities of long-term debt
clfd_DisposalGroupIncludingDiscontinuedOperationLongtermDebtCurrent
Amount classified as long-term debt attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.
Long-term portion of lease liability
clfd_DisposalGroupIncludingDiscontinuedOperationLongtermDebtNoncurrent
Amount classified as long-term debt attributable to disposal group held for sale or disposed of, expected to be disposed of beyond one year or the normal operating cycle, if longer.
us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax
Unrealized (loss) gain on available-for-sale investments
Factoring liability
clfd_DisposalGroupIncludingDiscontinuedOperationFactoringLiabilityCurrent
Amount classified as factoring liability attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.
Other non-current assets
clfd_DisposalGroupIncludingDiscontinuedOperationOtherAssetsNoncurrentNet
Amount classified as other assets attributable to disposal group held for sale or disposed of, expected to be disposed of after one year or the normal operating cycle, if longer.
Deferred taxes
Weighted average shares outstanding:
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]
us-gaap_CommonStockParOrStatedValuePerShare
Common Stock, Par or Stated Value Per Share (in dollars per share)
Basis of Accounting, Policy [Policy Text Block]
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]
Cash, including money market accounts
us-gaap_Assets
Total assets
Cash and cash equivalents
Total cash and cash equivalents
Geographical [Domain]
Geographical [Axis]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]
clfd_ShareBasedCompensationArrangementByShareBasedPaymentAwardPayoutPercentage
Share-Based Compensation Arrangement by Share-Based Payment Award, Payout Percentage
The payout percentage of the share-based compensation arrangement by share-based payment award.
us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest
Income from continuing operations, net of tax
Net loss from continuing operations
us-gaap_EarningsPerShareDiluted
Diluted income per share (in dollars per share)
Investment [Text Block]
Customer [Axis]
Depreciation and amortization
us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation
Repurchase of shares for payment of withholding taxes for vested restricted stock grants
Share-Based Payment Arrangement, Performance Shares, Activity [Table Text Block]
Cost of sales
us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold
Consolidation, Policy [Policy Text Block]
clfd_AllocatedShareBasedCompensationExpenseReversalBenefit
Allocated Share-Based Compensation Expense, Reversal, Benefit
Amount of expense (benefit) of allocated share-based compensation expense.
Interest expense
us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense
Disposal Group Name [Domain]
us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss
Gross profit
Net investment income
Inventory Disclosure [Text Block]
Income tax expense (benefit)
us-gaap_DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod
Finished goods
Net sales
us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
Intangible Asset, Finite-Lived [Table Text Block]
Intangible Asset, Finite-Lived [Table]
Interim Period, Costs Not Allocable [Domain]
Disposal Groups, Including Discontinued Operations [Table]
Disposal Groups, Including Discontinued Operations [Table Text Block]
Inventories, net
Inventories, net
Loss from discontinued operations, net of tax
Loss from discontinued operations, net of tax
Loss from discontinued operations, net of tax
Disposal Group Name [Axis]
clfd_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRightsOver100PercentPercentage
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights Over 100 Percent, Percentage
Percentage of vesting of award under share-based payment arrangement that is over 100 percent.
Customer A [Member]
Disclosure for customer A.
Raw materials
us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates
Proceeds from Divestiture of Businesses and Interests in Affiliates
Customer B [Member]
Disclosure for customer B.
us-gaap_StockholdersEquity
Total shareholders’ equity
Balance
Balance
us-gaap_InventoryGross
Inventories, gross
Customer C [Member]
Disclosure for customer C.
Work-in-process
Patents [Member]
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
us-gaap_InventoryValuationReserves
Inventory reserve
Right-of-use lease assets
Net sales
Total Net Sales
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]