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Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Note 4 - Marketable Securities - Available-for-sale Marketable Securities in Gross Unrealized Loss Position (Details) Note 5 - Intangible Assets - Intangible Assets (Details) Estimated useful lives (Year) us-gaap_FiniteLivedIntangibleAssetUsefulLife Note 5 - Intangible Assets - Schedule of Amortization of Intangible Assets (Details) Note 5 - Intangible Assets - Estimated Future Amortization Expense of Intangible Assets (Details) Note 6 - Inventories - Inventories (Details) Note 6 - Inventories - Write-off (Details) Note 7 - Leases - Supplemental Cash Flow Information Related to Leases (Details) Note 7 - Leases - Maturities of Operating Lease Liabilities (Details) clro_AmortizationReversalOfDeferredCharges Amortization of deferred rent Represents the amount of amortization (reversal) deferred charges. US States and Political Subdivisions Debt Securities [Member] Note 8 - Shareholders' Equity - Shareholders' Equity (Details) Note 8 - Shareholders' Equity - Shareholders' Equity (Details) (Parentheticals) Operating expenses: Note 9 - Stock-based Compensation - Stock Option Activity (Details) Note 9 - Stock-based Compensation - Schedule of Share-based Compensation Expense (Details) Note 10 - Fair Value Measurements - Fair Value of Financial Instruments (Details) Notes To Financial Statements Share-based Payment Arrangement, Option, Activity [Table Text Block] Notes To Financial Statements [Abstract] Change in foreign currency translation adjustment Foreign currency translation adjustment Proceeds from maturities and sales of marketable securities us-gaap_LitigationSettlementExpense Litigation Settlement, Expense us-gaap_LesseeOperatingLeaseRenewalTerm Lessee, Operating Lease, Renewal Term Long-term marketable securities Depreciation and amortization expense Corporate Debt Securities 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Nonvested Award, Cost Not yet Recognized, Period for Recognition Statement [Line Items] Allowance for doubtful accounts Receivables, net of allowance for doubtful accounts of $709 and $631, respectively Patents and Technological Know-how [Member] Represents information pertaining to Patents and Technological Know-how. 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Europe and Africa [Member] Information related to the regions of Europe and Africa. Current Fiscal Year End Date Video Products [Member] Information related to video products. Cost of Sales [Member] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets Prepaid expenses and other assets Weighted average discount rate for operating leases Research and Development Expense [Member] Document Fiscal Period Focus Document Fiscal Year Focus Lease, Cost [Table Text Block] Document Period End Date Operating leases Income Statement Location [Axis] Weighted average remaining lease term for operating leases (in years) (Year) Income Statement Location [Domain] us-gaap_DividendsCash Cash dividends, $0.07 per share Entity Emerging Growth Company Document Type Audio Conferencing [Member] Represents information pertaining to Audio Conferencing. Entity Small Business Entity Shell Company Facility in Chennai, India [Member] Represents the leased facility in Chennai, India. Document Information [Line Items] Facility in Zaragoza, Spain [Member] Represents the leased facility in Zaragoza, Spain. Document Information [Table] us-gaap_AreaOfRealEstateProperty Area of Real Estate Property Microphones [Member] Represents information pertaining to Microphones. Entity Filer Category Entity Current Reporting Status us-gaap_IncreaseDecreaseInReceivables Receivables 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 computations (in shares) Diluted weighted average shares outstanding (in shares) us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue Share-based compensation expense us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear 2019 (Remainder) Entity Central Index Key Entity Registrant Name Entity [Domain] Legal Entity [Axis] Statement [Table] Statement of Financial Position [Abstract] Diluted loss per common share (in dollars per share) Diluted loss per share (in dollars per share) Basic weighted average shares outstanding (in shares) Amortization of intangible assets Basic loss per common share (in dollars per share) Basic loss per share (in dollars per share) Available-for-sale securities Statement of Cash Flows [Abstract] Entity Common Stock, Shares Outstanding (in shares) 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. Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Facility in Gainesville [Member] Represents the leased facility in Gainesville. Income Statement [Abstract] us-gaap_StockRepurchasedDuringPeriodValue Stock repurchased 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. 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