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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 - Share-based Compensation - Stock Option Activity (Details) Note 9 - Share-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_LesseeOperatingLeaseRenewalTerm Lessee, Operating Lease, Renewal Term Long-term marketable securities Depreciation and amortization expense Corporate Debt Securities [Member] Share-based Payment Arrangement, Cost by Plan [Table Text Block] Long-term inventories, net Total long-term inventory us-gaap_AssetsCurrent Total current assets Options exercisable at end of June 30, 2019 (in dollars per share) Stockholders' Equity Note Disclosure [Text Block] Options exercisable at end of June 30, 2019 (in shares) Common stock, par value $0.001, 50,000,000 shares authorized, 16,646,323 and 16,630,597 shares issued and outstanding us-gaap_PaymentsToAcquireMarketableSecurities Purchases of marketable securities Financial Instruments [Domain] Adjustments to reconcile net loss to net cash used in operating activities: us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice Options outstanding at beginning of year (in dollars per share) Options outstanding at June 30, 2019 (in dollars per share) Common stock, shares authorized (in shares) Americas [Member] Weighted average exercise price, forfeited prior to vesting (in dollars per share) Common stock, shares issued (in shares) Deferred product revenue us-gaap_ContractWithCustomerLiabilityCurrent Weighted average exercise price, canceled or expired (in dollars per share) Financial Instrument [Axis] Common stock, par value (in dollars per share) Weighted average exercise price, granted (in dollars per share) Weighted average exercise price, exercised (in dollars per share) Accrued liabilities Statistical Measurement [Domain] Operating cash flows from operating leases Maximum [Member] Lessee, Operating Leases [Text Block] Minimum [Member] Accounts payable us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance Options outstanding at beginning of year (in shares) Options outstanding at June 30, 2019 (in shares) Product and Service [Axis] Product and Service [Domain] Statistical Measurement [Axis] us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod Number of shares, canceled or expired (in shares) us-gaap_PolicyTextBlockAbstract Accounting Policies Geographical [Axis] Geographical [Domain] Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Trade Names [Member] Inventories, net Total current inventory Other Intangible Assets [Member] Revenue Revenue Dilutive common stock equivalents using treasury stock method (in shares) Fair Value, Inputs, Level 3 [Member] us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Purchase of property and equipment Weighted average options outstanding (in shares) Fair Value Hierarchy and NAV [Domain] us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Cash paid for income taxes Fair Value Hierarchy and NAV [Axis] Current liabilities: us-gaap_Assets Total assets Plan Name [Axis] us-gaap_IncreaseDecreaseInDeferredRevenue Deferred product revenue Shareholders' Equity and Share-based Payments [Text Block] Plan Name [Domain] us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Cash flows from operating activities: Rent expense us-gaap_OperatingLeaseExpense us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1 Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Statement [Line Items] Allowance for doubtful accounts Receivables, net of allowance for doubtful accounts of $671 and $631, respectively Patents and Technological Know-how [Member] Represents information pertaining to Patents and Technological Know-how. Finite-Lived Intangible Assets by Major Class [Axis] Proprietary Software [Member] Represents information pertaining to Proprietary Software. Finite-Lived Intangible Assets, Major Class Name [Domain] Marketable securities Additional paid-in capital AOCI Attributable to Parent [Member] 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. Schedule of Inventory Current and Noncurrent [Table Text Block] Tabular disclosure of inventories. Other income, net Shareholders' equity: Amortization of right-of-use assets The amount of amortization of right-of-use assets. 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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. 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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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