Cash and Cash Equivalents [Abstract] Amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract] Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Due between one to three years Debt Securities, Available For Sale Securities, Maturity, Allocated And Single Maturity Date, After One Through Four Years, Amortized Cost Available For Sale Securities, Debt Maturities After One Through Four Years, Amortized Cost Total Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Estimated fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Due between one to three years Debt Securities, Available For Sale Securities, Maturity, Allocated And Single Maturity Date, After One Through Four Years, Fair Value Available For Sale Securities, Debt Maturities After One Through Four Years, Fair Value Total Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Fair Value Disclosures [Abstract] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Money market funds Money Market Funds [Member] Commercial paper Commercial Paper [Member] Cash equivalents Cash Equivalents [Member] U.S. Treasury securities US Treasury Securities [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Corporate notes and obligations Corporate Debt Securities [Member] Certificates of deposit Certificates of Deposit [Member] U.S. agency obligations US Government Corporations and Agencies Securities [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Total cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Total short-term investments Debt Securities, Available-for-sale Total cash equivalents and short-term investments Cash Equivalents, And Short-term Investments Cash Equivalents, and Short-term Investments Organization, Consolidation and Presentation of Financial Statements [Abstract] Conversion of Stock [Table] Conversion of Stock [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Two-Tier RSUs Two-Tier Restricted Stock Units (RSUs) [Member] Two-Tier Restricted Stock Units (RSUs) [Member] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Private Placement Private Placement [Member] Underwriters Over-allotment Option Over-Allotment Option [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Convertible preferred stock, $0.00001 par value; no shares authorized, issued and outstanding as of December 31, 2018; 151.2 shares authorized, 147.6 shares issued and outstanding with liquidation preference of $624.7 as of December 31, 2017 Convertible Preferred Stock [Member] Class B common stock Common Class B [Member] Class A common stock Common Class A [Member] Stock Conversion Description [Axis] Stock Conversion Description [Axis] Conversion of Stock, Name [Domain] Conversion of Stock, Name [Domain] Conversion of Convertible Preferred Stock to Class B Common Stock Conversion Of Convertible Preferred Stock To Class B Common Stock [Member] Conversion Of Convertible Preferred Stock To Class B Common Stock [Member] Conversion of Convertible Preferred Stock to Class A Common Stock Conversion Of Convertible Preferred Stock To Class A Common Stock [Member] Conversion Of Convertible Preferred Stock To Class A Common Stock [Member] Conversion of Class B Common Stock to Class A Common Stock Conversion Of Class B Common Stock To Class A Common Stock [Member] Conversion Of Class B Common Stock To Class A Common Stock [Member] Conversion of Stock [Line Items] Conversion of Stock [Line Items] Reverse stock split ratio Stockholders' Equity Note, Stock Split, Conversion Ratio Stock issued in IPO (in shares) Stock Issued During Period, Shares, New Issues Share price of stock issued in IPO (in dollars per share) Shares Issued, Price Per Share Proceeds from initial public offering and private placement Proceeds from Issuance Initial Public Offering Offering costs Payments of Stock Issuance Costs Shares converted in conversion (in shares) Conversion of Stock, Shares Converted Sale of stock (in shares) Sale of Stock, Number of Shares Issued in Transaction Share price of stock sold in shares (in dollars per share) Sale of Stock, Price Per Share Proceeds received in sale of stock Sale of Stock, Consideration Received on Transaction Recognized cumulative unrecognized stock-based compensation Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost Remaining unamortized stock-based compensation Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Unamortized stock-based compensation, requisite service period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Shares released (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Accelerated Vesting, Number Employer related payroll expense Labor and Related Expense Shares issued in conversion (in shares) Conversion of Stock, Shares Issued Payables and Accruals [Abstract] Schedule Of Accrued And Other Current Liabilities Schedule Of Accrued Liabilities And Other Current Liabilities [Table Text Block] Schedule Of Accrued Liabilities And Other Current Liabilities Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Fair value Debt Securities, Available-for-sale, Unrealized Loss Position [Abstract] Less than 12 months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 12 months or greater Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Total Debt Securities, Available-for-sale, Unrealized Loss Position Unrealized losses Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] Less than 12 months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 12 months or greater Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 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] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Convertible preferred stock Restricted stock units Restricted Stock Units (RSUs) [Member] Options to purchase shares of common stock Employee Stock Option [Member] Co-Founder Grants Co-Founder Grants [Member] Co-Founder Grants [Member] Shares subject to repurchase from early-exercised options and unvested restricted stock Shares Subject To Repurchase [Member] Shares Subject To Repurchase [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Restricted Stock Restricted Stock [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Shares granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Capitalized Contract Cost [Table] Capitalized Contract Cost [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Prepaid Expenses and Other Current Assets Prepaid Expenses and Other Current Assets [Member] Other Assets Other Noncurrent Assets [Member] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Domain] Capitalized Contract Cost [Domain] Deferred Commissions Deferred Commissions [Member] Deferred Commissions [Member] Capitalized Contract Cost [Line Items] Capitalized Contract Cost [Line Items] Additional contract costs deferred Capitalized Contract Costs, Additions Capitalized Contract Costs, Additions Deferred contract costs Capitalized Contract Cost, Net Deferred contract costs, amortization period Capitalized Contract Cost, Amortization Period Amortization of deferred commissions Amortization of Deferred Sales Commissions Impairment loss related to deferred costs Capitalized Contract Cost, Impairment Loss Stockholders' Equity Note [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class C common stock Common Class C [Member] Class of Stock [Line Items] Class of Stock [Line Items] Votes per share Common Stock, Votes Per Share Common Stock, Votes Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Schedule of Fair Value Assets Measured On Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Accrued and Other Current Liabilities Accrued Liabilities And Other Liabilities, Current [Text Block] Accrued Liabilities And Other Liabilities, Current Description of the Business and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Debt Disclosure [Abstract] Revolving Credit Facility Debt Disclosure [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Restricted Stock Units (RSUs) Employee Stock Option 2016 Plan Modification 2016 Plan Modification [Member] 2016 Plan Modification [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Plan modification, stock-based compensation Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost Stock options exchanged (in shares) Share-based Compensation Arrangement By Share-based Payment Award, Plan Modification, Exchanged Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Exchanged RSUs received on exchange (in shares) Share-based Compensation Arrangement By Share-based Payment Award, Plan Modification, Units Issued Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Units Issued Allocated share-based compensation expense Allocated Share-based Compensation Expense Plan modification, remaining unamortized expense Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Unamortized Compensation Cost Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Unamortized Compensation Cost Class A Class B Net loss Net Income (Loss) Attributable to Parent Weighted-average number of common shares outstanding used in computing basic and diluted net loss per common share (in shares) Weighted Average Number of Shares Outstanding, Basic and Diluted Net loss per common share, basic and diluted (in dollars per share) Earnings Per Share, Basic and Diluted Basis of presentation Basis of Accounting, Policy [Policy Text Block] Consolidation Consolidation, Policy [Policy Text Block] Use of estimates Use of Estimates, Policy [Policy Text Block] Financial information about segments and geographic areas Segment Reporting, Policy [Policy Text Block] Foreign currency transactions Foreign Currency Transactions and Translations Policy [Policy Text Block] Revenue recognition, Cost of revenue and Deferred commissions, net Revenue from Contract with Customer [Policy Text Block] Stock-based compensation Compensation Related Costs, Policy [Policy Text Block] Advertising and promotional expense Advertising Costs, Policy [Policy Text Block] Cash and cash equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Short-term investments Marketable Securities, Policy [Policy Text Block] Trade and other receivables, net/Non-trade receivables Receivables, Policy [Policy Text Block] Trade and other receivables, net Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Concentrations of credit risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Property and equipment, net Property, Plant and Equipment, Policy [Policy Text Block] Lease obligations Lessee, Leases [Policy Text Block] Internal use software Internal Use Software, Policy [Policy Text Block] Business combinations Business Combinations Policy [Policy Text Block] Long-lived assets, including goodwill and other acquired intangible assets, net Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Deferred offering costs Deferred Charges, Policy [Policy Text Block] Income taxes Income Tax, Policy [Policy Text Block] Fair value measurement Fair Value Measurement, Policy [Policy Text Block] Recently issued accounting pronouncements not yet adopted and Recently adopted accounting pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill impairment Goodwill, Impairment Loss Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, beginning of period Goodwill Effect of foreign currency translation Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, end of period Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] HelloSign Inc. HelloSign Inc. [Member] HelloSign Inc. [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Consideration transferred Business Combination, Consideration Transferred Consideration transferred, subject to on-going employee service Business Combination, Contingent Consideration, Liability Employee service period Business Combination, Required Service Period Business Combination, Required Service Period Schedule of Cash and Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Cash Cash [Member] Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Debt Securities, Available-for-sale, Current Cash in transit for credit and debit card transactions Credit and Debit Card Receivables, at Carrying Value Number of investments in unrealized loss positions Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions Other-than-temporary impairment loss Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale Investment income Investment Income, Net Series A Convertible Preferred Stock Series A Convertible Preferred Stock [Member] Series A Convertible Preferred Stock [Member] Series A-1 Convertible Preferred Stock Series A-1 Convertible Preferred Stock [Member] Series A-1 Convertible Preferred Stock Series B Convertible Preferred Stock Series B Convertible Preferred Stock [Member] Series B Convertible Preferred Stock [Member] Series C Convertible Preferred Stock Series C Convertible Preferred Stock [Member] Series C Convertible Preferred Stock [Member] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Preferred stock, per share price at issuance (in dollars per share) Aggregate liquidation preference Preferred Stock, Liquidation Preference, Value Preferred stock, dividend per share amount (in dollars per share) Preferred Stock, Dividend Rate, Per-Dollar-Amount Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States UNITED STATES International Non-US [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Property and equipment, net Property, Plant and Equipment, Net Revenue Revenue from Contract with Customer, Excluding Assessed Tax Schedule of Convertible Preferred Stock Schedule of Stock by Class [Table Text Block] Schedule of Stock Option and Restricted Stock Activity Share-based Compensation, Activity [Table Text Block] Schedule of Pre-Tax Intrinsic Value Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Income Tax Disclosure [Abstract] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance of gross unrecognized tax benefits at the beginning of the fiscal year Unrecognized Tax Benefits Gross increases related to prior period tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Gross increases related to current period tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Balance of gross unrecognized tax benefits at the end of the fiscal year Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Domestic Domestic Tax Authority [Member] State State and Local Jurisdiction [Member] Foreign Foreign Tax Authority [Member] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Research Tax Credit Carryforward Research Tax Credit Carryforward [Member] State Enterprise Tax Credit Carryforward State Enterprise Tax Credit Carryforward [Member] State Enterprise Tax Credit Carryforward [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Federal income tax rates Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Operating loss carryforwards Operating Loss Carryforwards Operating loss carryforwards, expiring in future Operating Loss Carryforwards, Subject To Expiration Operating Loss Carryforwards, Subject To Expiration Operating loss carryforwards, carryforward indefinitely Operating Loss Carryforwards, Not Subject To Expiration Operating Loss Carryforwards, Not Subject To Expiration Tax credit carryforward, amount Tax Credit Carryforward, Amount Tax credit carryforward, valuation allowance Tax Credit Carryforward, Valuation Allowance Operating loss carryforwards, acquired Operating Loss Carryforwards, Acquired Operating Loss Carryforwards, Acquired Unrecognized tax benefits Unrecognized tax benefits that would impact effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized tax benefits that would impact effective tax rate, adjustment to deferred tax assets and valuation allowance Unrecognized Tax Benefits That Would Impact Effective Tax Rate, Adjustment To Deferred Tax Assets And Valuation Allowance Unrecognized Tax Benefits That Would Impact Effective Tax Rate, Adjustment To Deferred Tax Assets And Valuation Allowance Penalties and interest accrued Income Tax Examination, Penalties and Interest Accrued Penalties and interest expense Income Tax Examination, Penalties and Interest Expense Undistributed earnings of foreign subsidiaries Undistributed Earnings of Foreign Subsidiaries Estimated reduction in deferred tax assets due to remeasurement Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Estimated tax benefit from repealed corporate AMT Tax Cuts And Jobs Act Of 2017, Alternative Minimum Tax, Income Tax Benefit Tax Cuts And Jobs Act Of 2017, Alternative Minimum Tax, Income Tax Benefit Estimated transition tax inclusion Tax Cuts And Jobs Act Of 2017, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense Tax Cuts And Jobs Act Of 2017, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable Fair Value Measurements Fair Value Disclosures [Text Block] Capitalized internal use software costs Capitalized Computer Software, Net Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Preferred stock Preferred Stock [Member] Class A and Class B common stock Common Stock [Member] Additional paid-in capital Additional Paid-in Capital [Member] Accumulated deficit Retained Earnings [Member] Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Shares outstanding, beginning of the period (in shares) Shares, Outstanding Shareholders equity, beginning balance Stockholders' Equity Attributable to Parent Vesting of early exercised stock options Stock Issued During Period, Value, Vesting Of Early Exercised Stock Options Stock Issued During Period, Value, Vesting Of Early Exercised Stock Options Issuance of common stock, options and awards related to acquisitions (in shares) Stock Issued During Period, Shares, Acquisitions Issuance of common stock, options and awards related to acquisitions Stock Issued During Period, Value, Acquisitions Cumulative-effect adjustment from adoption of ASU 2016-09 Cumulative Effect of New Accounting Principle in Period of Adoption Release of restricted stock units (in shares) Shares Released During Period, Shares Shares Released During Period, Shares Shares repurchased for tax withholdings on release of restricted stock (in shares) Shares Paid for Tax Withholding for Share Based Compensation Shares repurchased for tax withholdings on release of restricted stock Adjustments Related to Tax Withholding for Share-based Compensation Donation of common stock to charitable foundation (in shares) Stock Issued During Period, Shares, Charitable Foundation Donation Stock Issued During Period, Shares, Charitable Foundation Donation Donation of common stock to charitable foundation Stock Issued During Period, Value, Charitable Foundation Donation Stock Issued During Period, Value, Charitable Foundation Donation Conversion of preferred stock to common stock in connection with initial public offering (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Conversion of preferred stock to common stock in connection with initial public offering Stock Issued During Period, Value, Conversion of Convertible Securities Issuance of common stock in connection with initial public offering and private placement, net of underwriters' discounts and commissions and issuance costs (in shares) Issuance of common stock in connection with initial public offering and private placement, net of underwriters' discounts and commissions and issuance costs Stock Issued During Period, Value, New Issues Exercise of stock options and awards (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of stock options and awards Stock Issued During Period, Value, Stock Options Exercised Repurchase of unvested common stock (related to early exercised stock options) (in shares) Stock Repurchased During Period, Shares Repurchase of unvested common stock (related to early exercised stock options) Stock Repurchased During Period, Value Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Shareholders equity, ending balance Shares outstanding, end of the period (in shares) Lessor, Lease, Description [Table] Lessor, Lease, Description [Table] Accrued and other current liabilities Accrued And Other Current Liabilities [Member] Accrued And Other Current Liabilities [Member] Deferred rent, non-current Deferred Rent, Non-Current [Member] Deferred Rent, Non-Current [Member] Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] Lease incentive obligation Lease Incentive, Payable Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Chief Executive Officer Chief Executive Officer [Member] Director Director [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Tranche One Share-based Compensation Award, Tranche One [Member] One-Tier RSU One-Tier Restricted Stock Units (RSUs) [Member] One-Tier Restricted Stock Units (RSUs) [Member] Number of award types Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Award Types Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Award Types Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Number of tranches Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Tranches Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Tranches Shares 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 Award requisite period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Other Noncurrent Liabilities Other Noncurrent Liabilities [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Building Building [Member] Infrastructure Assets Held under Capital Leases Assets Held under Capital Leases [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Gross building asset, derecognized Property, Plant And Equipment, Gross Amount Derecognized Property, Plant and Equipment, Gross Amount Derecognized Accumulated depreciation, derecognized Accumulated Depreciation, Depletion And Amortization, Property, Plant, And Equipment, Derecognized Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Derecognized Imputed financing lease obligation Imputed Financing Lease Obligation, De-recognized Imputed Financing Lease Obligation, De-recognized Property and equipment, gross Property, Plant and Equipment, Gross Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Depreciation Depreciation Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Potentially Dilutive Securities Excluded from Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Deferred tax assets: Components of Deferred Tax Assets [Abstract] Net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Research credit carryforwards Deferred Tax Assets, Tax Credit Carryforwards, Research Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Accruals and reserves Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals Fixed assets and intangible assets Deferred Tax Assets, Fixed And Intangible Assets Deferred Tax Assets, Fixed And Intangible Assets Other Deferred Tax Assets, Other Gross deferred tax assets Deferred Tax Assets, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets, net of valuation allowance Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Components of Deferred Tax Liabilities [Abstract] Fixed assets and intangible assets Deferred Tax Liabilities, Fixed And Intangible Assets Deferred Tax Liabilities, Fixed And Intangible Assets Other Deferred Tax Liabilities, Other Total deferred tax liability Deferred Tax Liabilities, Gross Net deferred tax assets Deferred Tax Assets, Net Schedule of Goodwill Schedule of Goodwill [Table Text Block] Property and Equipment, Net Property, Plant and Equipment Disclosure [Text Block] Tax benefit at federal statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Foreign rate differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount Research and other credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount Permanent differences Effective Income Tax Rate Reconciliation, Permanent Differences, Amount Effective Income Tax Rate Reconciliation, Permanent Differences, Amount Tax Cuts and Jobs Act impact Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Change in valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Stock-based compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Other nondeductible items Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount Provision for income taxes Income Tax Expense (Benefit) Commitments and Contingencies Disclosure [Abstract] Capital lease commitments Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract] 2019 Capital Leases, Future Minimum Payments Due, Next Twelve Months 2020 Capital Leases, Future Minimum Payments Due in Two Years 2021 Capital Leases, Future Minimum Payments Due in Three Years 2022 Capital Leases, Future Minimum Payments Due in Four Years 2023 Capital Leases, Future Minimum Payments Due in Five Years Thereafter Capital Leases, Future Minimum Payments Due Thereafter Future minimum payments Capital Leases, Future Minimum Payments Due Less interest and taxes Capital Leases, Future Minimum Payments, Interest Included in Payments Less current portion of the present value of minimum lease payments Capital Lease Obligations, Current Capital lease obligations, net of current portion Capital Lease Obligations, Noncurrent Operating lease commitments Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 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 Future minimum payments Operating Leases, Future Minimum Payments Due Other commitments Other Commitment, Fiscal Year Maturity [Abstract] 2019 Other Commitment, Due in Next Twelve Months 2020 Other Commitment, Due in Second Year 2021 Other Commitment, Due in Third Year 2022 Other Commitment, Due in Fourth Year 2023 Other Commitment, Due in Fifth Year Thereafter Other Commitment, Due after Fifth Year Future minimum payments Other Commitment Rent payments from sub-tenants Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals Non-income taxes payable Accrual for Taxes Other than Income Taxes, Current Accrued legal and other external fees Accrued Professional Fees, Current Deferred rent Accrued Rent, Current Financing obligations, current Financing Obligations, Current Financing Obligations, Current Income taxes payable Accrued Income Taxes, Current Other accrued and current liabilities Other Accrued Liabilities And Other Liabilities, Current Other Accrued Liabilities and Other Liabilities, Current Total accrued and other current liabilities Accrued Liabilities and Other Liabilities, Current Accrued Liabilities and Other Liabilities, Current Goodwill Goodwill Disclosure [Text Block] Schedule of Cash, Cash Equivalents and Short-Term Investments Cash, Cash Equivalents and Investments [Table Text Block] Contractual Maturities of Short Term Investments Investments Classified by Contractual Maturity Date [Table Text Block] Short-Term Investments In Unrealized Loss Positions Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block] Number of shares available for issuance under the Plans Share-based Compensation Arrangement By Share-based Payment Award, Shares Available For Issuance [Roll Forward] Share-based Compensation Arrangement By Share-based Payment Award, Shares Available For Issuance [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Reserved for issuance under the 2018 Plan (in shares) Common Stock, Capital Shares Reserved for Future Issuance Additional shares authorized (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Options and RSUs canceled (in shares) Share-based Compensation Arrangement By Share-based Payment Award, Shares Canceled Share-based Compensation Arrangement By Share-based Payment Award, Shares Canceled Shares repurchased for tax withholdings on release of restricted stock (unaudited) (in shares) Restricted stock granted (in shares) Share-Based Compensation Arrangement By Share-based Payment Award, Decrease In Number of Shares Authorized From Stock Granted Share-Based Compensation Arrangement By Share-based Payment Award, Decrease In Number of Shares Authorized From Stock Granted Ending balance (in shares) Options Outstanding, Number of shares outstanding under the Plans Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Options exercised (in shares) Ending balance (in shares) Vested during period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares Unvested at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares Options Outstanding, Weighted- average exercise price per share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options canceled (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Options exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Ending balance (in dollars per share) Vested during period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value Unvested at end of period (in dollars per shares) Share-based Compensation Arrangement by Share-based Payment Award, Option, Nonvested, Weighted Average Exercise Price Options Outstanding, Weighted- average remaining contractual term (In years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Weighted-average contractual term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Restricted Stock Outstanding, Number of Plan shares outstanding Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number RSUs canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Restricted stock granted (in shares) RSUs released (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Released in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Released in Period Ending balance (in shares) Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Restricted Stock Outstanding, 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] Beginning balance (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 RSUs released (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Released in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Released in Period, Weighted Average Grant Date Fair Value RSUs canceled (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 Shares repurchased for tax withholdings on release of restricted stock (in dollars per share) Shares Paid For Tax Withholding For Share Based Compensation, Weighted Average Grant Date Fair Value Shares Paid For Tax Withholding For Share Based Compensation, Weighted Average Grant Date Fair Value Restricted stock granted (in dollars per share) Ending balance (in dollars per share) RSUs 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 Fair value of RSUs Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Statement of Cash Flows [Abstract] Cash flow from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net loss Adjustments to reconcile net loss to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Deprecation, Depletion And Amortization (Excluding Amortization Of Deferred Sales Commissions Deprecation, Depletion And Amortization (Excluding Amortization Of Deferred Sales Commissions Stock-based compensation Share-based Compensation Donation of common stock to charitable foundation Noncash Contribution Expense Other Other Noncash Income (Expense) Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Trade and other receivables, net Increase (Decrease) in Accounts and Other Receivables Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Other assets Increase (Decrease) in Other Operating Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued and other current liabilities Increase (Decrease) In Accrued Liabilities And Other Liabilities Increase (Decrease) In Accrued Liabilities and Other Liabilities Accrued compensation and benefits Increase (Decrease) in Employee Related Liabilities Deferred revenue Increase (Decrease) in Contract with Customer, Liability Non-current liabilities Increase (Decrease) in Other Noncurrent Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flow from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Capital expenditures Payments to Acquire Property, Plant, and Equipment Purchase of intangible assets Payments to Acquire Intangible Assets Purchases of short-term investments Payments to Acquire Debt Securities, Available-for-sale Proceeds from maturities of short-term investments Proceeds from Sale of Short-term Investments Proceeds from sales of short-term investments Proceeds from Maturities, Prepayments and Calls of Short-term Investments Other Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flow from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from initial public offering and private placement, net of underwriters' discounts and commissions Payments of deferred offering costs Shares repurchased for tax withholdings on release of restricted stock Payments Related to Tax Withholding for Share-based Compensation Proceeds from issuance of common stock, net of repurchases Proceeds from Issuance of Common Stock Principal payments on capital lease obligations Repayments of Long-term Capital Lease Obligations Principal payments against note payable Repayments of Notes Payable Proceeds from sale-leaseback agreement Sale Leaseback Transaction, Net Proceeds, Financing Activities Fees paid for revolving credit facility Payments of Financing Costs Other Proceeds from (Payments for) Other Financing Activities Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Change 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 cash flow data: Supplemental Cash Flow Information [Abstract] Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Income taxes Income Taxes Paid, Net Non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Property and equipment received and accrued in accounts payable and accrued liabilities Capital Expenditures Incurred but Not yet Paid Property and equipment acquired under capital leases Capital Lease Obligations Incurred Fair value of shares issued related to acquisitions of businesses and other assets Stock Issued Deferred offering costs accrued in accounts payable and accrued liabilities Deferred Offering Costs Incurred But Not Yet Paid Deferred Offering Costs Incurred But Not Yet Paid Schedule of Property and Equipment, Net Property, Plant and Equipment [Table Text Block] Geographic Areas Segment Reporting Disclosure [Text Block] Amortization expense Amortization of Intangible Assets Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] 2019 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 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 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Finite-Lived Intangible Assets, Net Income Statement [Abstract] Cost of revenue Cost of Goods and Services Sold 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 Loss from operations Operating Income (Loss) Interest income (expense), net Interest Income (Expense), Nonoperating, Net Other income, net Other Nonoperating Income (Expense) Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision for income taxes Net loss Net loss per share attributable to common stockholders, basic and diluted (in dollars per share) Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares) Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Cost of revenue Cost of Sales [Member] Research and development Research and Development Expense [Member] Sales and marketing Selling and Marketing Expense [Member] General and administrative General and Administrative Expense [Member] Cash contributions to charitable foundation Cash Contributions To Charitable Foundation Cash Contributions To Charitable Foundation Revenue, performance obligation, description of timing Revenue, Performance Obligation, Description of Timing Revenue recognized Contract with Customer, Liability, Revenue Recognized Remaining performance obligation Revenue, Remaining Performance Obligation, Amount Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Remaining performance obligation, expected timing of satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Schedule of Income before Income Tax, Domestic and Foreign Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Components of Income Tax Expense (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Unrecognized Tax Benefits Roll Forward Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Statement of Financial Position [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, liquidation preference value Non-trade receivables Nontrade Receivables, Current Tenant improvement allowance receivable related to the new corporate headquarters included in prepaid expenses and other current assets and other assets Tenant Improvement Allowance Receivable Tenant Improvement Allowance Receivable Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate, Type [Domain] Change in Accounting Estimate, Type [Domain] Change in Accounting Method Accounted for as Change in Estimate Change in Accounting Method Accounted for as Change in Estimate [Member] Infrastructure Equipment Infrastructure Equipment [Member] Infrastructure Equipment [Member] Buildings Datacenter and other computer equipment Computer Equipment [Member] Office equipment and other Office Equipment [Member] Property and equipment, useful life Property, Plant and Equipment, Useful Life Depreciation Business Combinations [Abstract] Business Combinations Business Combination Disclosure [Text Block] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Trade and other receivables, net Accounts Receivable, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Goodwill Other assets Other Assets, Noncurrent Total assets Assets Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Liabilities Liabilities [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued and other current liabilities Accrued compensation and benefits Employee-related Liabilities, Current Capital lease obligation Deferred revenue Contract with Customer, Liability, Current Total current liabilities Liabilities, Current Capital lease obligation, non-current Deferred rent, non-current Deferred Rent Credit, Noncurrent Other non-current liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 10) Commitments and Contingencies Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.00001 par value; 240.0 shares authorized and no shares issued and outstanding as of December 31, 2018; no shares authorized, issued and outstanding as of December 31, 2017 Preferred Stock, Value, Issued Common stock Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Total liabilities and stockholders’ equity Liabilities and Equity Net Loss Per Share Earnings Per Share [Text Block] Current: Current Federal, State and Local, Tax Expense (Benefit) [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Deferred: Deferred Federal, State and Local, Tax Expense (Benefit) [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Expiration period Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Percentage vested maximum Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Weighted average grant date fair value (in dollars per share) Award requisite period Stock-based compensation related to the Co-Founder Grants Schedule of Future Minimum Payments Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Net foreign currency transaction gain (loss) Foreign Currency Transaction Gain (Loss), before Tax Intangible Assets, Net Intangible Assets Disclosure [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Other Noncurrent Liabilities Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Letter of credit Financial Standby Letter of Credit [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Gross rent expense Operating Leases, Rent Expense Sublease income Sublease Income Operating leases, future minimum payments no longer obligated to pay Operating Leases, Future Minimum Payments, No Longer Obligated To Pay Operating Leases, Future Minimum Payments, No Longer Obligated To Pay Imputed financing obligation Finance Lease, Liability Operating lease, minimum obligation Operating Lease, Minimum Obligations Operating Lease, Minimum Obligations Tenant improvement reimbursements Tenant Improvements Letter of credit supporting obligations Loss Contingency, Estimate of Possible Loss 2018 Plan 2018 Plan [Member] 2018 Plan [Member] 2008 Equity Incentive Plan, 2017 Equity Incentive Plan, and 2018 Plan 2008 Equity Incentive Plan, 2017 Equity Incentive Plan, and 2018 Plan [Member] 2008 Equity Incentive Plan, 2017 Equity Incentive Plan, and 2018 Plan [Member] Options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Number of shares reserved for future issuance (in shares) Shares issued and outstanding (in shares) Shares available for grant (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Schedule of Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Deferred offering costs Deferred Offering Costs Subsequent Events Subsequent Events [Text Block] Income Taxes Income Tax Disclosure [Text Block] Cash, Cash Equivalents and Short-Term Investments Cash, Cash Equivalents, and Short-term Investments [Text Block] Advertising and promotional expense Marketing and Advertising Expense Statement of Comprehensive Income [Abstract] Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Change in foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Change in net unrealized losses on short-term investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Total other comprehensive income (loss), net of tax Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Schedule of Finite-Lived Intangible Assets [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 technology Developed Technology Rights [Member] Patents Patents [Member] Software Computer Software, Intangible Asset [Member] Assembled workforce in asset acquisitions Assembled Workforce In Asset Acquisition [Member] Assembled Workforce In Asset Acquisition [Member] Licenses Licensing Agreements [Member] Non-compete agreements, trademarks and other Noncompete Agreements, Trademarks, And Other Intangible Assets [Member] Noncompete Agreements, Trademarks, And Other Intangible Assets [Member] Weighted Average Weighted Average [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Total intangibles Intangible Assets, Gross (Excluding Goodwill) Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Intangible assets, net Weighted- average remaining useful life (In years) Finite-Lived Intangible Asset, Useful Life Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk Customer Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Trade and Other Receivables Accounts Receivable And Other Receivable [Member] Accounts Receivable And Other Receivable [Member] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Customer A Customer A [Member] Customer A [Member] Customer B Customer B [Member] Customer B [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration risk, percentage Concentration Risk, Percentage Schedule of Estimated Useful Lives of Property and Equipment Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Controlling Shareholders Majority Shareholder [Member] Affiliated Entity Affiliated Entity [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Dropbox Charitable Foundation Dropbox Charitable Foundation [Member] Dropbox Charitable Foundation [Member] Infrastructure Equipment Under Capital Leases and Commercial Products and Services Infrastructure Equipment Under Capital Leases And Commercial Products And Services [Member] Infrastructure Equipment Under Capital Leases And Commercial Products And Services [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Number of controlling shareholders in related party transaction Related Party Transaction, Number Of Controlling Shareholders Related Party Transaction, Number Of Controlling Shareholders Payments to related party Related Party Transaction, Amounts of Transaction General and administrative expense from donated shares Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Datacenter and other computer equipment Furniture and fixtures Furniture and Fixtures [Member] Leasehold improvements Leasehold Improvements [Member] Construction in process Construction in Progress [Member] Total property and equipment Accumulated depreciation and amortization Property and equipment, net Stockholders' Equity Shareholders' Equity and Share-based Payments [Text Block] Long-lived Assets by Geographic Areas Long-lived Assets by Geographic Areas [Table Text Block] Revenue by Geographic Areas Revenue from External Customers by Geographic Areas [Table Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Credit And Guarantee Agreement Credit And Guarantee Agreement [Member] Credit And Guarantee Agreement [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Line of Credit Line of Credit [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Letter of Credit Letter of Credit [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Base Rate Base Rate [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Line of credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Debt issuance fees Debt Issuance Costs, Line of Credit Arrangements, Gross Debt instrument, term Debt Instrument, Term Line of credit facility, accordion feature, increase limit Line Of Credit Facility, Accordion Feature, Increase Limit Line of Credit Facility, Accordion Feature, Increase Limit Unused capacity, commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Fronting fee Line Of Credit Facility, Fronting Fee Percentage Line Of Credit Facility, Fronting Fee Percentage Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Covenant terms, minimum liquidity balance Line Of Credit Facility, Covenant Terms, Liquidity Ratio Required, Minimum Line Of Credit Facility, Covenant Terms, Liquidity Ratio Required, Minimum Aggregate letters of credit outstanding amount Letters of Credit Outstanding, Amount Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Cash and cash equivalents Short-term investments, amortized cost Debt Securities, Available-for-sale, Amortized Cost Short-term investments, unrealized gain Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Short-term investments, unrealized loss Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Short-term investments, estimated fair value Total cash, cash equivalents, and short term investments, before unrealized gains (losses) on investments Cash, Cash Equivalents, And Short Term Investments, Amortized Cost Cash, Cash Equivalents, And Short Term Investments, Amortized Cost Total cash, cash equivalents, and short term investments Cash, Cash Equivalents, and Short-term Investments Document And Entity Information [Abstract] Document and Entity Information [Abstract] Document Information [Table] Document Information [Table] Document Information [Line Items] Document Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Shell Company Entity Shell Company Entity Public Float Entity Public Float