Investments, All Other Investments [Abstract] Investments in equity securities of privately-held companies Equity Securities without Readily Determinable Fair Value, Amount Leases [Abstract] LEASES Lessee, Operating Leases [Text Block] Revenue from Contract with Customer [Abstract] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] 2019 (the remainder of 2019) Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2020 Lessee, Operating Lease, Liability, Payments, Due Year Two 2021 Lessee, Operating Lease, Liability, Payments, Due Year Three 2022 Lessee, Operating Lease, Liability, Payments, Due Year Four 2023 Lessee, Operating Lease, Liability, Payments, Due Year Five Thereafter Lessee, Operating Lease, Liability, Payments, Due after Year Five Total lease payments Lessee, Operating Lease, Liability, Payments, Due Less imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Total Operating Lease, Liability Revenue Recognition Revenue from Contract with Customer [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill Goodwill Goodwill impairment Goodwill, Impairment Loss Amortization expense Amortization of Intangible Assets Income Tax Disclosure [Abstract] Effective tax rate (percent) Effective Income Tax Rate Reconciliation, Percent U.S. federal and state taxes, withholding taxes and foreign taxes Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, State and Local Income Taxes, and Foreign Income Tax Rate Differential, , Amount Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, State and Local Income Taxes, and Foreign Income Tax Rate Differential, , Amount Excess tax benefits on stock compensation Effective Income Tax Reconciliation, Excess Tax Benefit on Stock-based Compensation Effective Income Tax Reconciliation, Excess Tax Benefit on Stock-based Compensation Increase in unrecognized tax benefits related to Ninth Circuit Altera decision Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Unrecognized tax benefits and related interest release Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized tax benefits Unrecognized Tax Benefits Unrecognized tax benefits that would favorably affect effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Accrued interest and penalties related to uncertain tax benefits Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Possible decrease in unrecognized tax benefits (up to) Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit Financial Instruments and Fair Value [Abstract] Financial Instruments and Fair Value [Abstract] FINANCIAL INSTRUMENTS AND FAIR VALUE Financial Instruments Disclosure [Text Block] Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Stock Options [Member] Share-based Payment Arrangement, Option [Member] ESPP [Member] Employee Stock [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Share-based Payment Arrangement [Member] Share-based Payment Arrangement [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Anti-dilutive securities (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Cover page. Document Type Document Type Document Quarterly Report Document Quarterly Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] ZoneFox Holdings Limited [Member] ZoneFox Holdings Limited [Member] ZoneFox Holdings Limited [Member] Bradford [Member] Bradford Networks, Inc. [Member] Bradford Networks, Inc. [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Preliminary purchase price Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Goodwill not deductible for tax purposes Identifiable intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Cash consideration that may be paid as an earn-out subject to satisfaction of certain performance conditions Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High Fair value assigned to contingent consideration Business Combination, Contingent Consideration, Liability Statement of Comprehensive Income [Abstract] Statement [Table] Statement [Table] Statement, Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Statement [Line Items] Statement [Line Items] Net income Net Income (Loss) Attributable to Parent Other comprehensive income (loss): Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Change in unrealized gains (losses) on investments Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax Tax provision related to change in unrealized gains (losses) on investments Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Operating lease ROU assets - non-current Operating Lease, Right-of-Use Asset Operating lease liabilities - current Operating Lease, Liability, Current Operating lease liabilities - non-current Operating Lease, Liability, Noncurrent Total operating lease liabilities Weighted average remaining lease term in years - operating leases Operating Lease, Weighted Average Remaining Lease Term Weighted average discount rate - operating leases Operating Lease, Weighted Average Discount Rate, Percent Remaining performance obligation Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Performance obligation expected recognition period for three-fourths of remaining obligation Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Statement of Stockholders' Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income (Loss) [Member] AOCI Attributable to Parent [Member] Accumulated Deficit [Member] Retained Earnings [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance, shares Shares, Issued Balance Stockholders' Equity Attributable to Parent Issuance of common stock in connection with equity incentive plans - net of tax withholding (in shares) Stock Issued During Period, Shares, Equity Incentive Plans Stock Issued During Period, Shares, Equity Incentive Plans Issuance of common stock in connection with equity incentive plans - net of tax withholding Stock Issued During Period, Value, Equity Incentive Plans, Net of Taxes Withheld Stock Issued During Period, Value, Equity Incentive Plans, Net of Taxes Withheld Repurchase and retirement of common stock (in shares) Stock Repurchased and Retired During Period, Shares Repurchase and retirement of common stock Stock Repurchased and Retired During Period, Value Stock-based compensation expense APIC, Share-based Payment Arrangement, Increase for Cost Recognition Cumulative-effect adjustment from adoption of ASU 2018-02/ASC 606 Cumulative Effect of New Accounting Principle in Period of Adoption Net unrealized gain on investments - net of tax Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Balance, shares Balance Share-based Payment Arrangement [Abstract] Schedule of Share-based Compensation, Restricted Stock Units Award Activity Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Schedule of Share-based Compensation, Shares Withheld for Taxes Schedule of Share-based Compensation, Shares Withheld for Taxes [Table Text Block] Schedule of Share-based Compensation, Shares Withheld for Taxes [Table Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions And Allocation of Recognized Period Costs [Table Text Block] Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed. Schedule of Share-based Compensation, Stock Options, Activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Schedule of Share-based Compensation, Stock Options, Activity, Additional Information Schedule of Share-based Compensation, Stock Options, Activity, Additional Information [Table Text Block] Schedule of Share-based Compensation, Stock Options, Activity, Additional Information Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Schedule of Employee Service Share based Compensation Allocation of Recognized Period Costs by Award Type Schedule of Employee Service Share based Compensation Allocation of Recognized Period Costs by Award Type [Table Text Block] Schedule of Employee Service Share based Compensation Allocation of Recognized Period Costs by Award Type [Table Text Block] Income Tax Benefit from Stock Option Plans Income Tax Benefit from Stock Option Plans [Table Text Block] Income Tax Benefit from Stock Option Plans [Table Text Block] Accumulated Other Comprehensive (Loss) Income [Table] Accumulated Other Comprehensive Income (Loss) [Table] Unrealized Gains and Losses on Investments [Member] AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Accumulated Other Comprehensive (Loss) Income [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive (Loss) Income [Roll Forward] Accumulated Other Comprehensive Income [Roll Forward] Accumulated Other Comprehensive Income [Roll Forward] Beginning balance AOCI Including Portion Attributable to Noncontrolling Interest, before Tax Other comprehensive income before reclassifications Other Comprehensive Income (Loss), before Reclassifications, before Tax Amounts reclassified from accumulated other comprehensive loss Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Net current-period other comprehensive income Other Comprehensive Income (Loss), before Tax Ending balance Tax provision (benefit) related to unrealized gains or losses on investments Accumulated Other Comprehensive Income, Tax [Roll Forward] Accumulated Other Comprehensive Income, Tax [Roll Forward] Beginning balance, tax Accumulated Other Comprehensive Income Loss Tax Accumulated Other Comprehensive Income Loss Tax Other comprehensive income before reclassifications, tax Other Comprehensive Income (Loss) before Reclassifications, Tax Amounts reclassified from accumulated other comprehensive income, tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Tax Net current-period other comprehensive income, tax Other Comprehensive Income (Loss), Tax Ending balance, tax Statement of Financial Position [Abstract] Common Stock, par value (dollars per share) Common Stock, Par or Stated Value Per Share Common Stock, shares authorized Common Stock, Shares Authorized Common Stock, shares issued Common Stock, Shares, Issued Common Stock, shares outstanding Common Stock, Shares, Outstanding Cash paid for amounts included in the measurement of lease liabilities Cash Flow, Lessee [Abstract] Cash Flow, Lessee [Abstract] Operating cash flows used for operating leases Operating Lease, Payments Lease liabilities arising from obtaining right-of-use assets Lease Liabilities Arising from Obtaining Right-of-Use Assets [Abstract] Lease Liabilities Arising from Obtaining Right-of-Use Assets [Abstract] Operating leases Lease Liability Arising from Obtaining Right-of-Use Asset Lease Liability Arising from Obtaining Right-of-Use Asset ASSETS Assets [Abstract] CURRENT ASSETS: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Accounts receivable—net Accounts Receivable, after Allowance for Credit Loss, Current Inventory Inventory, Net Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current LONG-TERM INVESTMENTS Long-term Investments PROPERTY AND EQUIPMENT—NET Property, Plant and Equipment, Net DEFERRED CONTRACT COSTS Capitalized Contract Cost, Net DEFERRED TAX ASSETS Deferred Income Tax Assets, Net GOODWILL OTHER INTANGIBLE ASSETS—NET Intangible Assets, Net (Excluding Goodwill) OTHER ASSETS Other Assets, Noncurrent TOTAL ASSETS Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] CURRENT LIABILITIES: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Accrued payroll and compensation Employee-related Liabilities, Current Income taxes payable Accrued Income Taxes, Current Deferred revenue Contract with Customer, Liability, Current Total current liabilities Liabilities, Current DEFERRED REVENUE Contract with Customer, Liability, Noncurrent INCOME TAX LIABILITIES Accrued Income Taxes, Noncurrent OTHER LIABILITIES Other Liabilities, Noncurrent Total liabilities Liabilities COMMITMENTS AND CONTINGENCIES (Note 11) Commitments and Contingencies STOCKHOLDERS’ EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $0.001 par value—300 shares authorized; 171.0 and 169.8 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated deficit Retained Earnings (Accumulated Deficit) Total stockholders’ equity TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Inventory Disclosure [Abstract] Inventory Schedule of Inventory, Current [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] INVESTMENTS IN PRIVATELY-HELD COMPANIES Investment [Text Block] Retirement Benefits [Abstract] DEFINED CONTRIBUTION PLANS Compensation and Employee Benefit Plans [Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities, Major Types of Debt and Equity Securities [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Corporate debt securities [Member] Corporate Debt Securities [Member] Commercial paper [Member] Commercial Paper, Not Included with Cash and Cash Equivalents [Member] Certificates of deposit and term deposits [Member] Certificates of Deposit and Term Deposits [Member] Certificates of Deposit and Term Deposits [Member] U.S. government and agency securities [Member] US Treasury and Government [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Fair Value Debt Securities, Available-for-sale Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] Debt Securities, Available-for-sale, Continuous Unrealized Loss Position [Abstract] Debt Securities, Available-for-sale, Continuous Unrealized Loss Position [Abstract] Less Than 12 Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Less Than 12 Months, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 12 Months or Greater, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value 12 Months or Greater, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Total, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Due within one to three years Available-for-sale Securities, Debt Maturities, after One Year, Fair Value This item represents the fair value of debt securities which are expected to mature after one year from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Fair Value Inventory, Net [Abstract] Raw materials Inventory, Raw Materials, Net of Reserves Finished goods Inventory, Finished Goods, Net of Reserves Inventory Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2016 Share Repurchase Program [Member] Share Repurchase Program [Member] Share Repurchase Program [Member] Share Repurchase Program [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Stock repurchase program, authorized amount Stock Repurchase Program, Authorized Amount Stock repurchased in the period, shares Stock repurchased, average price (in dollars per share) Treasury Stock Acquired, Average Cost Per Share Stock repurchased in the period, value Stock repurchase program, unused balance Stock Repurchase Program, Remaining Authorized Repurchase Amount Accounting Policies [Abstract] Basis of Presentation and Preparation Presentation and Preparation of Consolidated Financial Statements [Policy Text Block] Presentation and Preparation of Consolidated Financial Statements [Policy Text Block] Recently Adopted Accounting Standards and Recent Accounting Standards Not Yet Effective New Accounting Pronouncements, Policy [Policy Text Block] Fiscal Years: Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2019 (the remainder of 2019) Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four Total Finite-Lived Intangible Assets, Net Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Balance, beginning (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Balance, ending (shares) Weighted-Average Grant Date Fair Value per Share Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Balance, beginning (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Balance, ending (in dollars per share) Compensation cost not yet recognized Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Compensation cost not yet recognized period of recognition Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Shares withheld for taxes Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Amount withheld for taxes Payment, Tax Withholding, Share-based Payment Arrangement Schedule of Finite-Lived Intangible Assets by Major Class [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Developed Technologies [Member] Developed Technology Rights [Member] Customer Relationships [Member] Customer Relationships [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Weighted average useful life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Finite-Lived Intangible Assets, Net [Abstract] Finite-Lived Intangible Assets, Net [Abstract] Gross Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Operating lease expense Operating Lease, Cost Variable lease expense Variable Lease, Cost Short-term lease expense Short-term Lease, Cost Total lease expense Lease, Cost Schedule of Finite-Lived and Indefinite-Lived Intangible Assets by Major Class Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Product [Member] Product [Member] Service [Member] Service [Member] Security Subscription [Member] Security Subscription [Member] Security Subscription [Member] Technical Support and Other [Member] Technical Support and Other [Member] Technical Support and Other [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total revenue Revenue from Contract with Customer, Excluding Assessed Tax New Accounting Pronouncement, Early Adoption [Table] New Accounting Pronouncement, Early Adoption [Table] Retained Earnings [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 Accounting Standards Update 2016-02 [Member] Accounting Standards Update 2018-02 Accounting Standards Update 2018-02 [Member] New Accounting Pronouncement, Early Adoption [Line Items] New Accounting Pronouncement, Early Adoption [Line Items] ROU assets for operating leases Lease liabilities for operating leases Cumulative-effect adjustment from adoption of accounting principle INVENTORY Inventory Disclosure [Text Block] GOODWILL AND OTHER INTANGIBLE ASSETS - Net Goodwill and Intangible Assets Disclosure [Text Block] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Remaining terms (less than for minimum) Operating Lease, Remaining Lease Term Operating Lease, Remaining Lease Term Renewal terms (up to) Lessee, Operating Lease, Renewal Term Rent expense Operating Leases, Rent Expense, Net Additional minimum lease payments relating to operating office space lease signed but not yet commenced Operating Lease, Lease Not yet Commenced, Expense Operating Lease, Lease Not yet Commenced, Expense Lease not yet commenced, approximate term Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract Property, Plant and Equipment [Abstract] PROPERTY AND EQUIPMENT—Net Property, Plant and Equipment Disclosure [Text Block] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Land [Member] Land [Member] Building and building improvements [Member] Building and Building Improvements [Member] Computer equipment and software [Member] Computer Equipment [Member] Leasehold improvements [Member] Leaseholds and Leasehold Improvements [Member] Evaluation units [Member] Evaluation Units [Member] Evaluation units [Member] Furniture and fixtures [Member] Furniture and Fixtures [Member] Construction-in-progress [Member] Construction in Progress [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, Plant and Equipment, Net, by Type [Abstract] Property, Plant and Equipment, Net, by Type [Abstract] Total property and equipment Property, Plant and Equipment, Gross Less: accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment - net Depreciation expense Depreciation Stock-based Compensation Plan [Member] Number of shares of common stock deregistered (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Deregistered Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Deregistered Remaining shares available for grant under the plans Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Expected term in years Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Dividend rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Balance - Beginning (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Balance - Ending (in shares) Weighted- Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Balance - Beginning (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Balance - Ending (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Options vested and expected to vest, Outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Options vested and expected to vest, Weighted average exercise price (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Options vested and expected to vest, Weighted average remaining contractual life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Options vested and expected to vest, Aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Options exercisable, Outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options exercisable, Weighted average exercise price (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Options exercisable, Weighted average remaining contractual life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Options exercisable, Aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Weighted-average fair value per share granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Total fair value of awards vested Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Cost of product revenue [Member] Cost of Goods Sold [Member] Cost of Goods Sold [Member] Cost of service revenue [Member] Cost of Services [Member] Cost of Services [Member] Research and development [Member] Research and Development Expense [Member] Sales and marketing [Member] Selling and Marketing Expense [Member] General and administrative [Member] General and Administrative Expense [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Total stock-based compensation expense Share-based Payment Arrangement, Expense Income tax benefit from employee stock option plans Share-based Payment Arrangement, Exercise of Option, Tax Benefit Schedule of Earnings Per Share [Table] Schedule of Earnings Per Share [Table] Earnings Per Share [Line Items] Earnings Per Share [Line Items] Earnings Per Share [Line Items] Basic shares: Weighted Average Number of Shares Outstanding, Basic [Abstract] Weighted-average common shares outstanding-basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted shares: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Effect of potentially dilutive securities: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Employee stock options and purchase rights (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted-average shares used to compute diluted net income per share (in shares) Weighted Average Number of Shares Outstanding, Diluted Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted INCOME TAXES Income Tax Disclosure [Text Block] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Matching contribution on employee contributions, Percent Defined Contribution Plan, Employer Matching Contribution, Percent of Match Maximum contribution percentage of each employee's eligible earnings, Percent Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Matching contributions to the RRSP and 401(k) Plans Defined Contribution Plan, Employer Matching Contribution, Amount Defined Contribution Plan, Employer Matching Contribution, Amount Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Statement, Geographical [Axis] Geographical [Axis] Segment, Geographical [Domain] Geographical [Domain] Americas [Member] Americas [Member] U.S. UNITED STATES Canada CANADA Latin America Latin America [Member] Other Americas Other Americas [Member] Other Americas [Member] EMEA Europe, Middle East and Africa [Member] Europe, Middle East and Africa [Member] APAC Asia Pacific and Japan [Member] Asia Pacific and Japan [Member] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Exclusive Networks Group [Member] Exclusive Networks Group [Member] Exclusive Networks Group [Member] Ingram Micro [Member] Ingram Micro [Member] Ingram Micro [Member] Concentration Risk by Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk [Member] Customer Concentration Risk [Member] Concentration Risk by Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Benchmark [Member] Revenue Benchmark [Member] Accounts Receivable [Member] Accounts Receivable [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Business activity (in business activities) Number of Business Activities Number of business activities Segment managers responsible for operations (in segment managers) Number of Segment Managers Responsible for Operations Number of Segment Managers Responsible for Operations Number of operating segments (in operating segments) Number of Operating Segments Number of reportable segments (in reportable segments) Number of Reportable Segments Property and equipment - net Concentration (percent) Concentration Risk, Percentage Commitments and Contingencies Disclosure [Abstract] Inventory purchase commitments: Purchase Obligation, Fiscal Year Maturity [Abstract] Inventory purchase commitments, 2019 Purchase Obligation, Future Minimum Payments, Remainder of Fiscal Year Inventory purchase commitments, 2020 Purchase Obligation, Due in Second Year Inventory purchase commitments, 2021 Purchase Obligation, Due in Third Year Inventory purchase commitments, 2022 Purchase Obligation, Due in Fourth Year Inventory purchase commitments, 2023 Purchase Obligation, Due in Fifth Year Inventory purchase commitments, Thereafter Purchase Obligation, Due after Fifth Year Inventory purchase commitments Purchase Obligation BUSINESS COMBINATIONS Business Combination Disclosure [Text Block] Inventory purchase commitments Other contractual commitments and open purchase orders Other Commitment Revenue from external customers by geographic region Revenue from External Customers by Geographic Areas [Table Text Block] Property and equipment by geographic region Long-lived Assets by Geographic Areas [Table Text Block] Schedule of customer concentration Schedules of Concentration of Risk, by Risk Factor [Table Text Block] Summary of Investments Schedule of Amortized Costs, Unrealized Gains and Losses, and Fair Value of Available For Sale Securities [Table Text Block] Schedule of Amortized Costs, Unrealized Gains and Losses, and Fair Value of Available For Sale Securities [Table Text Block] Schedule of Unrealized Loss on Investments Schedule of Unrealized Loss on Investments [Table Text Block] Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] NET INCOME PER SHARE Earnings Per Share [Text Block] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Property, Plant and Equipment - Net Property, Plant and Equipment [Table Text Block] STOCKHOLDERS' EQUITY Share-based Payment Arrangement [Text Block] Components of Lease Expense and Supplemental Cash Flow Information Lease, Cost [Table Text Block] Supplemental Balance Sheet Information Assets And Liabilities, Lessee [Table Text Block] Assets And Liabilities, Lessee [Table Text Block] Maturities of Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Schedule of Future Principal Contractual Obligations for Operating Lease Commitments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Recurring Basis [Member] Fair Value, Recurring [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Fair Value [Member] Estimate of Fair Value Measurement [Member] Reported as [Member] Reported Value Measurement [Member] Money market funds [Member] Money Market Funds, Excluding Commercial Paper [Member] Money Market Funds, Excluding Commercial Paper [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Cash equivalents [Member] Cash Equivalents, Line Item [Member] Cash Equivalents, Line Item [Member] Short-term investments [Member] Short Term Investments, Line Item [Member] Short Term Investments, Line Item [Member] Long-term investments [Member] Long Term Investments, Line Item [Member] Long Term Investments, Line Item [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total Assets, Fair Value Disclosure Assets, Fair Value Disclosure Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Stock-based compensation Share-based Payment Arrangement, Noncash Expense Amortization of deferred contract costs Capitalized Contract Cost, Amortization Depreciation and amortization Depreciation, Depletion and Amortization Amortization of investment premiums, net of accretion of purchase discounts Accretion (Amortization) of Discounts and Premiums, Investments Other Other Noncash Income (Expense) Changes in operating assets and liabilities: Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract] Accounts receivable—net Increase (Decrease) in Accounts Receivable Inventory Increase (Decrease) in Inventories Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Deferred contract costs Increase (Decrease) in Deferred Charges Deferred tax assets Increase (Decrease) in Deferred Income Taxes Other assets Increase (Decrease) in Other Operating Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Accrued payroll and compensation Increase (Decrease) in Employee Related Liabilities Other liabilities Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Deferred revenue Increase (Decrease) in Contract with Customer, Liability Income taxes payable Increase (Decrease) in Income Taxes Payable Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of investments Payments to Acquire Investments Sales of investments Proceeds from Sale of Debt Securities, Available-for-sale Maturities of investments Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Payments made in connection with business combination, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Repurchase and retirement of common stock Payments for Repurchase of Common Stock Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Taxes paid related to net share settlement of equity awards Payments of debt assumed in connection with business combination Repayments of Assumed Debt Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Cash and Cash Equivalents, Period Increase (Decrease) CASH AND CASH EQUIVALENTS—Beginning of period CASH AND CASH EQUIVALENTS—End of period SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Operating lease liabilities arising from obtaining right-of-use assets Cash paid to settle liability incurred for repurchase of common stock Repurchase of Common Stock, Settlement of Liabilities Incurred Repurchase of Common Stock, Settlement of Liabilities Incurred NON-CASH INVESTING AND FINANCING ACTIVITIES: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Transfers of evaluation units from inventory to property and equipment Transfers of Evaluation Units from Inventory to Property and Equipment Transfers of Evaluation Units from Inventory to Property and Equipment Liability for purchase of property and equipment and asset retirement obligations Capital Expenditures Incurred but Not yet Paid Liability incurred for repurchase of common stock Repurchase of Common Stock, Liabilities Incurred Repurchase of Common Stock, Liabilities Incurred Contractual Obligation, Fiscal Year Maturity Schedule Contractual Obligation, Fiscal Year Maturity [Table Text Block] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Deferred revenue recognized in period Contract with Customer, Liability, Revenue Recognized Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss Income Statement [Abstract] REVENUE: COST OF REVENUE: Cost of Goods and Services Sold [Abstract] Total cost of revenue Cost of Goods and Services Sold GROSS PROFIT: Gross Profit [Abstract] Total gross profit Gross Profit OPERATING EXPENSES: Operating Expenses [Abstract] Research and development Research and Development Expense Sales and marketing Selling and Marketing Expense General and administrative General and Administrative Expense Total operating expenses Operating Expenses OPERATING INCOME Operating Income (Loss) INTEREST INCOME Investment Income, Net OTHER EXPENSE—NET Other Nonoperating Income (Expense) INCOME BEFORE INCOME TAXES Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest PROVISION FOR (BENEFIT FROM) INCOME TAXES Income Tax Expense (Benefit) NET INCOME Net income per share (Note 9): Diluted (in dollars per share) Weighted-average shares outstanding: Basic (in shares) Diluted (in shares)