Document And Entity Information
Expected dividend yield
Note To Financial Statement Details Textual
Significant Accounting Policies
Note 1 - Business Description, Basis of Presentation and Significant Accounting Policies
us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
Tax benefit (provision) at federal statutory rate
Due within one year, amortized cost
Note 2 - Marketable Securities
Risk-free interest rate, average
Note 3 - Business Combinations, Goodwill and Intangible Assets
Due within one year, estimated fair value
Note 4 - Inventories
Due after one year through five years, estimated fair value
Note 5 - Property and Equipment
Note 6 - Leases and Deferred Rent
Note 7 - Accrued Liabilities
Note 9 - Share-based Payments
us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax
Unrealized gain on available-for-sale securities, net of tax
Income Tax Disclosure [Text Block]
Note 10 - Significant Customers
Note 11 - Fair Value Measurements
Unrealized gain (loss) on available-for-sale securities, net of tax
Note 12 - Income Taxes
Note 13 - Geographic Sales Information
Expected price volatility, average
us-gaap_LiabilitiesCurrent
Total current liabilities
Note 1 - Business Description, Basis of Presentation and Significant Accounting Policies - Allowance for Doubtful Accounts Activity (Details)
Note 1 - Business Description, Basis of Presentation and Significant Accounting Policies - Deferred Revenue and Associated Costs of Goods Sold and Gross Profit (Details)
Note 1 - Business Description, Basis of Presentation and Significant Accounting Policies - Revenue by Product Group (Details)
Note 1 - Business Description, Basis of Presentation and Significant Accounting Policies - Warranty Liability (Details)
Expected option life, average (Year)
Note 1 - Business Description, Basis of Presentation and Significant Accounting Policies - Earnings Per Share (Details)
Note 2 - Marketable Securities - Available-for-sale Securities by Major Security Type (Details)
Note 2 - Marketable Securities - Maturities of Available-for-sale Securities (Details)
Note 2 - Marketable Securities - Available-for-sale Marketable Securities in Gross Unrealized Loss Position (Details)
Note 3 - Business Combinations, Goodwill and Intangible Assets - Intangible Assets (Details)
Note 3 - Business Combinations, Goodwill and Intangible Assets - Estimated Future Amortization Expense of Intangible Assets (Details)
clro_AmortizationReversalOfDeferredCharges
Amortization of deferred rent
Represents the amount of amortization (reversal) deferred charges.
US States and Political Subdivisions Debt Securities [Member]
Software and Licenses [Member]
Information related to software and licenses.
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Note 4 - Inventories - Inventories (Details)
Equipment Sales [Member]
Information related to equipment sales.
Note 5 - Property and Equipment - Property and Equipment (Details)
Note 6 - Leases and Deferred Rent - Future Minimum Lease Payments (Details)
Note 7 - Accrued Liabilities - Accrued Liabilities (Details)
Note 9 - Share-based Payments - Black-scholes Assumptions (Details)
Share-based Compensation, Stock Options, Activity [Table Text Block]
Note 9 - Share-based Payments - Stock Option Activity (Details)
Note 9 - Share-based Payments - Employee Stock Purchase Plans (Details)
Change in foreign currency translation adjustment
Foreign currency translation adjustment
Note 10 - Significant Customers - Concentration Risk by Risk Factor of Sales Revenue and Accounts Receivable (Details)
Proceeds from maturities and sales of marketable securities
Note 11 - Fair Value Measurements - Fair Value of Financial Instruments (Details)
Note 12 - Income Taxes - Consolidated Income Before Taxes (Details)
us-gaap_LitigationSettlementExpense
Litigation Settlement, Expense
Note 12 - Income Taxes - Provision for Income Taxes (Details)
Note 12 - Income Taxes - Income Tax (Provision) for Federal Statutory Corporate Income Tax Rate (Details)
Note 12 - Income Taxes - Net Deferred Tax Assets and Liabilities (Details)
Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity [Table Text Block]
Note 12 - Income Taxes - Reconciliation of Uncertain Tax Positions (Details)
Note 13 - Geographic Sales Information - Revenue by Geographic Area (Details)
Weighted average remaining contractual term, vested (Year)
Impairment of goodwill and intangible assets
Notes To Financial Statements
clro_PaymentsForRepurchaseOfStockOptions
Repurchase and cancellation of stock options
The cash outflow associated with the repurchase of stock options.
Notes To Financial Statements [Abstract]
Corporate Debt Securities [Member]
Weighted average remaining contractual term, vested and expected to vest (Year)
Aggregate intrinsic value, vested
Number of shares, vested and expected to vest (in shares)
Weighted average exercise price, vested and expected to vest (in dollars per share)
Aggregate intrinsic value, vested and expected to vest
Weighted average exercise price, vested at end of period (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value
Weighted average remaining contractual term (Year)
Aggregate intrinsic value
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value
Number of shares, vested at end of period (in shares)
us-gaap_PaymentsToAcquireMarketableSecurities
Purchase of marketable securities
Financial Instruments [Domain]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted average exercise price, beginning of period (in dollars per share)
Weighted average exercise price, end of period (in dollars per share)
Weighted average exercise price, forfeited prior to vesting (in dollars per share)
Deferred product revenue
Contract with Customer, Liability, Current
Weighted average exercise price, expired and canceled (in dollars per share)
Financial Instrument [Axis]
Weighted average exercise price, granted (in dollars per share)
Weighted average exercise price, exercised (in dollars per share)
Accrued liabilities
Total
Accounts payable
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance
Number of shares, outstanding at beginning of period (in shares)
Number of shares, outstanding at end of period (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
Number of shares, expired and canceled (in shares)
Other accrued liabilities
Accrued salaries and other compensation
us-gaap_PolicyTextBlockAbstract
Accounting Policies
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]
Trade Names [Member]
Product warranty
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant
Other Intangible Assets [Member]
Sales and marketing programs
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent
us-gaap_PaymentsToAcquireIntangibleAssets
Purchase of intangible assets
Dilutive common stock equivalents using treasury stock method (in shares)
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchase of property and equipment
Weighted average options outstanding (in shares)
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Cash paid for income taxes
Current liabilities:
us-gaap_Assets
Total assets
Supplemental disclosure of cash flow information:
Plan Name [Axis]
Shareholders' Equity and Share-based Payments [Text Block]
Plan Name [Domain]
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition
Customer Relationships [Member]
us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Net loss
Net loss
Net loss
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Accumulated amortization
us-gaap_FiniteLivedIntangibleAssetsNet
Total
Intangible assets, net
Intangible assets, gross
us-gaap_FiniteLivedIntangibleAssetsGross
Litigation for Intellectual Property Infringement [Member]
Information pertaining to the litigation for intellectual property infringement.
us-gaap_GoodwillPeriodIncreaseDecrease
Goodwill, Period Increase (Decrease), Total
Inventory [Axis]
Inventory [Domain]
clro_LitigationSettlementExpenseCapitalized
Litigation Settlement, Expense Capitalized
Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees, capitalized during the period.
Commitments and Contingencies Disclosure [Text Block]
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Accumulated Depreciation and Amortization
Property and equipment, net
Property, Plant and Equipment, Net
Property, Plant and Equipment, Gross
Leases of Lessee Disclosure [Text Block]
Cash flows from investing activities:
Income taxes payable
us-gaap_AvailableForSaleSecuritiesDebtSecurities
Total available-for-sale securities, estimated fair value
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Loss before income taxes
us-gaap_IncreaseDecreaseInAccruedLiabilities
Accrued liabilities
Provision for/(benefit from) income taxes
Tax benefit (provision)
us-gaap_IncreaseDecreaseInAccountsPayable
Accounts payable
us-gaap_OperatingExpenses
Total operating expenses
General and administrative
us-gaap_LeaseAndRentalExpense
Operating Leases, Rent Expense, Total
Cash and cash equivalents
Cash and cash equivalents at the beginning of the year
Cash and cash equivalents at the end of the year
us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities
Other long-term liabilities
us-gaap_AllocatedShareBasedCompensationExpense
Allocated Share-based Compensation Expense, Total
Amendment Flag
Comprehensive loss:
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive loss
Use of Estimates, Policy [Policy Text Block]
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_SharesOutstanding
Balance (in shares)
Balance (in shares)
Common stock, shares outstanding (in shares)
Current Fiscal Year End Date
Lease Arrangement, Type [Axis]
Lease Arrangement, Type [Domain]
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other assets
Fiscal Period, Policy [Policy Text Block]
Document Fiscal Period Focus
Document Fiscal Year Focus
Consolidation, Policy [Policy Text Block]
Document Period End Date
us-gaap_DividendsCash
Cash dividends
Entity Emerging Growth Company
Document Type
Entity Small Business
us-gaap_GainLossRelatedToLitigationSettlement
Legal settlement
Entity Shell Company
Document Information [Line Items]
Document Information [Table]
us-gaap_AreaOfRealEstateProperty
Area of Real Estate Property
Entity Public Float
Entity Filer Category
Entity Current Reporting Status
Entity Voluntary Filers
Entity Well-known Seasoned Issuer
us-gaap_ImpairmentOfIntangibleAssetsFinitelived
Impairment of Intangible Assets, Finite-lived
us-gaap_IncreaseDecreaseInReceivables
Receivables
Impairment of goodwill
Goodwill, Impairment Loss
Concentration risk, percentage
Entity Central Index Key
Entity Registrant Name
Stock-based compensation expense
Entity [Domain]
Customer Concentration Risk [Member]
Legal Entity [Axis]
us-gaap_AmortizationOfDeferredCharges
Amortization of Deferred Charges, Total
us-gaap_AmortizationOfIntangibleAssets
Amortization of Intangible Assets, Total
Concentration Risk Type [Axis]
us-gaap_AllowanceForDoubtfulAccountsReceivable
Balance at beginning of the year
Balance at end of the year
Concentration Risk Type [Domain]
us-gaap_StockRepurchasedDuringPeriodShares
Stock Repurchased During Period, Shares
Stock repurchased (in shares)
Entity Common Stock, Shares Outstanding (in shares)
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]
us-gaap_StockRepurchasedDuringPeriodValue
Stock repurchased
us-gaap_AdvertisingExpense
Advertising Expense
Sales Revenue, Net [Member]
Accounts Receivable [Member]
us-gaap_IncreaseDecreaseInInventories
Inventories
Trading Symbol
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
Shares purchased under ESPP plan (in shares)
Stock Issued During Period, Shares, Employee Stock Purchase Plans
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]
Exercise of stock options (in shares)
Number of shares, exercised (in shares)
us-gaap_TableTextBlock
Notes Tables
Proceeds from employee stock purchase plan
Stock Issued During Period, Value, Employee Stock Purchase Plan
us-gaap_GainLossOnDispositionOfAssets1
Loss on disposal of assets
Restricted stock granted (in shares)
Exercise of stock options
Restricted stock granted
Provision for doubtful accounts, net
Number of shares, granted (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Number of shares, forfeited prior to vesting (in shares)
Sales and marketing
us-gaap_StockIssuedDuringPeriodSharesNewIssues
Stock Issued During Period, Shares, New Issues
Raw materials
us-gaap_InventoryRawMaterialsNetOfReserves
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and shareholders’ equity
Finished goods
us-gaap_InventoryFinishedGoodsNetOfReserves
us-gaap_StockIssuedDuringPeriodValueNewIssues
Issuance of common stock
UNITED STATES
Retained earnings/(accumulated deficit)
Research and product development
Accumulated other comprehensive loss
Distributor channel inventories
Retail Related Inventory, Total
Changes in operating assets and liabilities:
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Inventory Disclosure [Text Block]
us-gaap_DeferredIncomeTaxesAndTaxCredits
Deferred income taxes
us-gaap_DeferredIncomeTaxExpenseBenefit
Total deferred
Thereafter
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive
2020
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
2021
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
2022
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
2023
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
2019
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Other assets
us-gaap_ShareBasedCompensation
Stock-based compensation expense
Title of Individual [Axis]
Estimated useful lives (Year)
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Finite-Lived Intangible Asset, Useful Life
Relationship to Entity [Domain]
Earnings Per Share, Policy [Policy Text Block]
Operating expenses:
Income Tax, Policy [Policy Text Block]
us-gaap_LesseeOperatingLeaseRenewalTerm
Lessee, Operating Lease, Renewal Term
Research and Development Expense, Policy [Policy Text Block]
us-gaap_Depreciation
Depreciation, Total
Long-term marketable securities
Depreciation and amortization expense
us-gaap_SharesIssuedPricePerShare
Shares Issued, Price Per Share
Long-term inventories, net
Inventory, Noncurrent, Total
Total
us-gaap_AssetsCurrent
Total current assets
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]
Impairment of an intangible asset
Advertising Cost, Policy, Expensed Advertising Cost [Policy Text Block]
Common stock, par value $0.001, 50,000,000 shares authorized, 16,630,597 and 8,319,022 shares issued and outstanding as of December 31, 2018 and 2017 respectively
Adjustments to reconcile net loss to net cash used in operating activities:
Common stock, shares authorized (in shares)
Americas [Member]
Common stock, shares issued (in shares)
Common stock, par value (in dollars per share)
Change in valuation allowance
Standard Product Warranty, Policy [Policy Text Block]
Range [Domain]
Maximum [Member]
Minimum [Member]
us-gaap_DeferredTaxAssetsValuationAllowanceNoncurrent
Less: Valuation allowance
Product and Service [Axis]
Deferred income taxes
Net deferred income tax asset (liability)
Product and Service [Domain]
Range [Axis]
Litigation Case [Axis]
Litigation Case [Domain]
us-gaap_DeferredTaxAssetsGrossNoncurrent
Deferred Tax Assets, Gross, Noncurrent
Total net deferred income tax asset
us-gaap_NumberOfReportingUnits
Number of Reporting Units
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]
Other
Property, Plant and Equipment Disclosure [Text Block]
Geographical [Axis]
Goodwill and Intangible Assets, Policy [Policy Text Block]
Property, Plant and Equipment [Table Text Block]
Geographical [Domain]
Inventories
Inventory, Net, Total
Total
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]
Revenue
Revenue
Revenue from Contract with Customer, Including Assessed Tax
Fair Value, Inputs, Level 3 [Member]
us-gaap_DeferredTaxAssetsDeferredIncome
Deferred revenue
Fair Value Hierarchy and NAV [Domain]
Inventory reserve
Customer [Axis]
Basis difference in intangible assets
Customer [Domain]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value Hierarchy and NAV [Axis]
us-gaap_ProductWarrantyAccrualPayments
Usage/claims
Accruals/additions
us-gaap_PropertyPlantAndEquipmentDisposals
Property, Plant and Equipment, Disposals
Accrued expenses
Property, Plant and Equipment, Useful Life (Year)
Property, Plant and Equipment, Useful Life
us-gaap_IncreaseDecreaseInDeferredRevenue
Deferred product revenue
Cash flows from operating activities:
Allowance for sales returns and doubtful accounts
Revenue Recognition, Policy [Policy Text Block]
Statement [Line Items]
Allowance for doubtful accounts
Receivables, net of allowance for doubtful accounts of $631 and $472, as of December 31, 2018 and 2017 respectively
Stock-based compensation
Patents and Technological Know-how [Member]
Represents information pertaining to Patents and Technological Know-how.
Proprietary Software [Member]
Represents information pertaining to Proprietary Software.
Marketable securities
Additional paid-in capital
AOCI Attributable to Parent [Member]
Schedule of Product Warranty Liability [Table Text Block]
Raw materials
clro_InventoryNoncurrentRawMaterialsNetOfReserves
Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items that are classified as noncurrent.
Finished goods
clro_InventoryNoncurrentFinishedGoodsNetOfReserves
Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are classified as noncurrent.
clro_DistributorChannelInventories
Distributor Channel Inventories
The carrying value of distributor channel inventories.
Schedule of Inventory Current and Noncurrent [Table Text Block]
Tabular disclosure of inventories.
Leasehold Improvements [Member]
Property, Plant and Equipment, Policy [Policy Text Block]
Other income, net
Property, Plant and Equipment, Type [Axis]
Segment Reporting Disclosure [Text Block]
Shareholders’ equity:
Property, Plant and Equipment, Type [Domain]
Net operating loss carryforwards
Research and development tax credits
Current assets:
Fair Value Disclosures [Text Block]
Inventory, Policy [Policy Text Block]
us-gaap_Liabilities
Total liabilities
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash used in financing activities
us-gaap_OperatingIncomeLoss
Operating loss
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash used in operating activities
Prepaid expenses and other assets
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash provided by investing activities
Effect of exchange rate changes on cash and cash equivalents
Advance Replacement Units [Member]
Represents the advance replacement units which reported at cost.
us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
Net increase (decrease) in cash and cash equivalents
us-gaap_GrossProfit
Gross profit
Cost of goods sold
Accounting Standards Update 2014-09 [Member]
Schedule of Deferred Revenue and Associated Cost of Goods Sold and Gross Profit [Table Text Block]
Tabular disclosure of deferred revenue and associated cost of goods sold and gross profit.
Write-down of inventory to net realizable value
Inventory Write-down
clro_DeferredGrossProfit
Deferred gross profit
Amount of deferred gross profit as of balance sheet date.
us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total
Deferred cost of goods sold
Amount of deferred cost of goods sold as of balance sheet date.
Marketable Securities, Policy [Policy Text Block]
Type of Adoption [Domain]
Concentration Risk, Credit Risk, Policy [Policy Text Block]
us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Difference in property and equipment basis
Adjustments for New Accounting Pronouncements [Axis]
us-gaap_PaymentsOfDividends
Dividend payments
Office Furniture and Equipment [Member]
Represents the information pertaining to office furniture and equipment.
Manufacturing and Test Equipment [Member]
Represents the information pertaining to manufacturing and test equipment.
us-gaap_ProductWarrantyAccrual
Balance at the beginning of year
Balance at end of year
us-gaap_PaymentsForRepurchaseOfCommonStock
Payments for stock repurchases
us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability
Retained Earnings [Member]
Initial Application Period Cumulative Effect Transition [Axis]
Issuance of common stock
us-gaap_ProceedsFromIssuanceOfCommonStock
Proceeds from Issuance of Common Stock
us-gaap_CurrentStateAndLocalTaxExpenseBenefit
State
Initial Application Period Cumulative Effect Transition [Domain]
us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit
State
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Net proceeds from equity-based compensation programs
us-gaap_CurrentForeignTaxExpenseBenefit
Foreign
us-gaap_DeferredForeignIncomeTaxExpenseBenefit
Foreign
Additional Paid-in Capital [Member]
Common Stock [Member]
us-gaap_CurrentFederalTaxExpenseBenefit
Federal
us-gaap_DeferredFederalIncomeTaxExpenseBenefit
Federal
Equity Components [Axis]
Equity Component [Domain]
Available-for-sale Securities, Debt Maturities [Table Text Block]
Tabular disclosure of maturities of available-for-sale securities.
us-gaap_CurrentIncomeTaxExpenseBenefit
Total current
clro_StockIssuedDuringPeriodSharesRestrictedStockAndStockOptionsForfeited
Cancellation of restricted stock and stock options (in shares)
Number of shares related to restricted stock award and stock options forfeited during the period.
Business Combinations, Goodwill and Intangibles Disclosure [Text Block]
The entire disclosure for business combinations, goodwill and intangibles.
clro_StockIssuedDuringPeriodValueRestrictedStockAndStockOptionsForfeitures
Cancellation of restricted stock and stock options
Value of stock related to restricted stock awards and stock options forfeited during the period.
Foreign
us-gaap_IncomeTaxExaminationYearUnderExamination
Income Tax Examination, Year under Examination
clro_CapitalizedPatentDefenseCosts
Capitalized patent defense costs
Represents payments for capitalized patent defense costs.
Tax Authority, Spain [Member]
Domestic
Other comprehensive income/loss:
Inland Revenue, Hong Kong [Member]
State and Local Jurisdiction [Member]
Income Tax Authority, Name [Axis]
Vehicles [Member]
Income Tax Authority, Name [Domain]
Internal Revenue Service (IRS) [Member]
Deferred revenue
Income Tax Authority [Axis]
Income Tax Authority [Domain]
Disaggregation of Revenue [Table Text Block]
Domestic Tax Authority [Member]
Foreign Tax Authority [Member]
Trade and Other Accounts Receivable, Policy [Policy Text Block]
clro_IncreaseDecreaseOfNetDeferredTaxAssets
Increase (Decrease) of Net Deferred Tax Assets
Amount of adjustment of deferred tax assets from a revaluation as a result of the Tax Cuts and Jobs Act.
Cash and Cash Equivalents, Policy [Policy Text Block]
us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits, Ending Balance
Balance - beginning of year
Uncertain tax positions, ending balance
us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Unrecognized Tax Benefits that Would Impact Effective Tax Rate
Accounting Policies [Abstract]
us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Lapse in statutes of limitations
Concentration Risk Disclosure [Text Block]
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]
us-gaap_CommonStockDividendsPerShareDeclared
Common Stock, Dividends, Per Share, Declared
Cash dividends, per share (in dollars per share)
Allowance increase (decrease)
us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities
Settlements
us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Cumulative Effect of New Accounting Principle in Period of Adoption
Impact on retained earnings for change in revenue recognition policy
Additions for tax positions of prior years
us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
Reductions for tax positions of prior years
Additions based on tax positions related to the current year
us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs
Write offs, net of recoveries
Asia Middle East and Australia [Member]
Information related to the regions of Asia, the Middle East and Australia.
Europe and Africa [Member]
Information related to the regions of Europe and Africa.
Video Products [Member]
Information related to video products.
Earliest Tax Year [Member]
Latest Tax Year [Member]
Tax Period [Domain]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Audio Conferencing [Member]
Represents information pertaining to Audio Conferencing.
Change in Accounting Policy [Policy Text Block]
Disclosure of accounting policy for change in accounting policy.
Facility in Chennai, India [Member]
Represents the leased facility in Chennai, India.
Facility in Zaragoza, Spain [Member]
Represents the leased facility in Zaragoza, Spain.
clro_CapitalizedLegalExpensesNetOfAmortizationRelatedToDefenseOfPatentsFromInfringement
Capitalized Legal Expenses, Net of Amortization, Related to Defense of Patents from Infringement
The capitalized legal expenses related to defense of patents from infringement by the competitors, net of amortization.
Tax Period [Axis]
Microphones [Member]
Represents information pertaining to Microphones.
Employee Stock Purchase Plan [Member]
Represents information relating to an Employee Stock Purchase Plan.
clro_NumberOfSharesOversubscribed
Number of Shares, Oversubscribed
The number of shares were oversubscribed.
Customer C [Member]
Represents information about Customer C.
All Other Countries [Member]
All countries outside the United States.
The 1998 Incentive Plan [Member]
Represents a share-based compensation plan approved by the company in 1998.
us-gaap_OtherAccruedLiabilitiesNoncurrent
Other Accrued Liabilities, Noncurrent
Other Employees [Member]
Represents information pertaining to employees other than directors and officers.
clro_SharebasedCompensationArrangementBySharebasedPaymentAwardNumberOfSharesAuthorizedAndUnissued
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares, Authorized and Unissued
Represents the number of shares authorized but not issued.
The 2007 Equity Incentive Plan [Member]
The equity incentive plan approved by the company in 2007.
Anti-dilutive options not included in the computation (in shares)
Directors and Officers [Member]
Represents information pertaining to directors and officers of the company.
Diluted weighted average shares outstanding (in shares)
clro_StockRepurchaseProgramAdditionalAuthorizedAmount
Stock Repurchase Program, Additional Authorized Amount
Amount of additional stock repurchase plan authorized in a renewed and extended stock repurchase program.
clro_ShareRepurchaseProgramAveragePurchasePricePerShare
Share Repurchase Program, Average Purchase Price Per Share
Total cost of shares repurchased divided by the total number of shares repurchased.
clro_ESPPParticipationCriteriaMaximumPercentageOfVotingPower
ESPP Participation Criteria, Maximum Percentage of Voting Power
The maximum percentage of the voting power of the Company, its parent or subsidiary that an employee can have to participate in the ESPP.
clro_SharebasedCompensationArrangementBySharebasedPaymentAwardDiscountOnPurchasePriceOfCommonStockPercent
Share-based Compensation Arrangement by Share-based Payment Award, Discount on Purchase Price of Common Stock, Percent
Discount on the purchase price of common stock expressed as a percentage of its fair value.
us-gaap_OperatingLossCarryforwards
Operating Loss Carryforwards, Total
Customer A [Member]
Represents a significant customer of the Company, designated as Customer A.
Statement [Table]
Customer B [Member]
Represents a significant customer of the Company, designated as Customer B.
Scenario [Axis]
Statement of Financial Position [Abstract]
Diluted loss per common share: (in dollars per share)
Diluted loss per common share (in dollars per share)
clro_DeferredIncomeTaxExpenseBenefitBeforeValuationAllowanceDeferredTaxAssetChangeInAmount
Total
Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations, before the valuation allowance adjustment.
Scenario, Unspecified [Domain]
Thereafter
us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter
Basic weighted average shares outstanding (in shares)
Accounts Payable and Accrued Liabilities Disclosure [Text Block]
us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Total minimum lease payments
2022
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears
Basic loss per common share: (in dollars per share)
Basic loss per common share (in dollars per share)
Available-for-sale securities
2023
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears
2020
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears
Statement of Cash Flows [Abstract]
2021
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears
Facility in Salt Lake City [Member]
Represents the leased facility in Salt Lake City.
Warehouse in Shenzhen, China [Member]
Represents the leased Warehouse in Shenzhen, China.
Statement of Stockholders' Equity [Abstract]
Facility in Gainesville [Member]
Represents the leased facility in Gainesville.
2019
us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent
Income Statement [Abstract]
Facility in Austin, Texas [Member[
Represents the leased facility in Austin, Texas.
Warehouse in Salt Lake City, Utah [Member]
Represented the leased warehouse in Salt Lake City, Utah.
Amortized cost
Schedule of Accrued Liabilities [Table Text Block]
Gross unrealized holding losses
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]
Gross unrealized holding losses, less than 12 months
Gross unrealized holding losses, more than 12 months
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]
Estimated fair value, less than 12 months
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block]
Estimated fair value, more than 12 months
Estimated fair value
Gross unrealized holding gains
us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross unrealized holding losses
us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Dividends Payable, Date to be Paid
us-gaap_IncomeTaxReconciliationOtherAdjustments
Other
Cash flows from financing activities:
us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Other long-term liabilities
us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate
Tax rate change
us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Dividends Payable, Date of Record
us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance
Change in valuation allowance
us-gaap_IncomeTaxReconciliationRepatriationOfForeignEarnings
Subpart F inclusion
Plan compensation expense
Deferred rent
us-gaap_StockholdersEquity
Total shareholders’ equity
Balance
Balance
Class of Stock [Axis]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Total available-for-sale securities, amortized cost
us-gaap_LongTermPurchaseCommitmentAmount
Long-term Purchase Commitment, Amount
us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
State income tax benefit (provision), net of federal benefit
Due after one year through five years, amortized cost
us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential
Foreign earnings or losses taxed at different rates
Research and development tax credits
us-gaap_IncomeTaxReconciliationTaxCreditsResearch