Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Accumulated Deficit Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance (in shares) Common Stock, Shares, Outstanding Beginning Balance Stockholders' Equity Attributable to Parent Exercise of common stock options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of common stock options Stock Issued During Period, Value, Stock Options Exercised Restricted stock awards, net (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted stock awards, net Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Issuance of common stock related to RSU vesting (in shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Issuance of common stock related to RSU vesting Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Shares withheld related to net share settlement (in shares) Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Shares withheld related to net share settlement Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Issuance of common stock related to employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Issuance of common stock related to employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Other comprehensive income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Net loss Net Income (Loss) Attributable to Parent Ending Balance (in shares) Ending Balance Accounting Policies [Abstract] Basis of Presentation and Summary of Significant Accounting Policies Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Adoption of ASC 842 and Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Remaining 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 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 Earnings Per Share [Abstract] Basic and Diluted EPS: Earnings Per Share, Basic [Abstract] Net loss Weighted-average common shares outstanding Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted-average unvested restricted stock (in shares) Weighted Average Number of Shares, Restricted Stock Weighted-average common shares outstanding used to compute net loss per share Weighted Average Number Of Shares Outstanding Used To Compute Earnings Per Share, Basic and Diluted Weighted Average Number Of Shares Outstanding Used To Compute Earnings Per Share, Basic and Diluted Basic and diluted net loss per share (usd per share) Earnings Per Share, Basic and Diluted Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Covenant Terms [Axis] Debt Covenant Terms [Axis] Debt Covenant Terms [Axis] Debt Covenant Terms [Domain] Debt Covenant Terms [Domain] [Domain] for Debt Covenant Terms [Axis] Covenant Term, Scenario One Covenant Term, Scenario One [Member] Covenant Term, Scenario One [Member] Covenant Term, Scenario Two Covenant Term, Scenario Two [Member] Covenant Term, Scenario Two [Member] Debt Instrument Covenant Compliance Streamline Period [Axis] Debt Instrument Covenant Compliance Streamline Period [Axis] Debt Instrument Covenant Compliance Streamline Period [Axis] Debt Instrument Covenant Compliance Streamline Period [Domain] Debt Instrument Covenant Compliance Streamline Period [Domain] Debt Instrument Covenant Compliance Streamline Period [Domain] Streamline Period Applies Streamline Period Applies [Member] Streamline Period Applies [Member] Streamline Period Does Not Apply Streamline Period Does Not Apply [Member] Streamline Period Does Not Apply [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Debt Instrument Covenant Compliance Period [Axis] Debt Instrument Covenant Compliance Period [Axis] Debt Instrument Covenant Compliance Period [Axis] Debt Instrument Covenant Compliance Period [Domain] Debt Instrument Covenant Compliance Period [Domain] [Domain] for Debt Instrument Covenant Compliance Period [Axis] Covenant Compliance Period One Debt Instrument Covenant Compliance Period One [Member] Debt Instrument Covenant Compliance Period One [Member] Covenant Compliance Period Two Covenant Compliance Period Two [Member] Covenant Compliance Period Two [Member] Covenant Compliance Period Three Covenant Compliance Period Three [Member] Covenant Compliance Period Three [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Loan Agreement Loan Agreement [Member] Loan Agreement [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Prime Rate Prime Rate [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Capitalized debt issuance costs Debt Issuance Costs, Net Unused capacity fee, percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Variable interest rate Debt Instrument, Basis Spread on Variable Rate Adjusted Quick Ratio, in streamline period Debt Instrument Adjusted Quick Ratio Requirement In Streamline Period Debt Instrument Adjusted Quick Ratio Requirement In Streamline Period Adjusted Quick Ratio Debt Instrument Adjusted Quick Ratio1 Debt Instrument Adjusted Quick Ratio1 Adjusted EBITDA maximum Debt Instrument Covenant Compliance Adjusted Earnings Before Interest Taxes Depreciation And Amortization Maximum Debt Instrument Covenant Compliance Adjusted Earnings Before Interest Taxes Depreciation And Amortization Maximum Adjusted EBITDA minimum Debt Instrument, Covenant Compliance, Adjusted Earnings Before Interest Taxes Depreciation And Amortization Minimum Debt Instrument, Covenant Compliance, Adjusted Earnings Before Interest Taxes Depreciation And Amortization Minimum Adjusted EBITDA threshold Debt Instrument Covenant Compliance Adjusted EBITDA Variance From Projections Debt Instrument Covenant Compliance Adjusted EBITDA Variance From Projections Share-based Payment Arrangement [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Stock Option Share-based Payment Arrangement, Option [Member] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Expected term Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Revenue from Contract with Customer [Abstract] Payment terms Revenue, Payment Terms Revenue, Payment Terms Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2014 Employee Stock Purchase Plan 2014 Employee Stock Purchase Plan [Member] 2014 Employee Stock Purchase Plan [Member] Employee Stock Employee Stock [Member] Maximum employee subscription rate Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate Purchase price of common stock, percent Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent Number of shares reserved Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Annual % increase Evergreen Annual % Increase Evergreen Annual % Increase Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Domain] Contract with Customer, Sales Channel [Domain] Desktop Desktop [Member] Desktop [Member] Mobile Mobile [Member] Mobile [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenues Revenues Concentration risk, percentage Concentration Risk, Percentage Debt Debt Disclosure [Text Block] Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain on investments Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Other comprehensive loss Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Balance Sheet Related Disclosures [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Available-for-sale—short-term Short-term Investments [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] U.S. Treasury, government and agency debt securities 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 Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Fair Value Debt Securities, Available-for-sale Restricted Stock Awards Restricted Stock [Member] Number of Shares Rollforward Share-based Compensation Arrangement by Share-based Payment Award, 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 Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Ending balance (in shares) Weighted-Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value1 [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value1 [Roll Forward] 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 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 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 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 Ending balance (in dollars per share) Statement of Financial Position [Abstract] Preferred stock, par value (usd per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value (usd 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 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 revenue Cost of Sales [Member] Sales and marketing Selling and Marketing Expense [Member] Technology and development Research and Development Expense [Member] General and administrative General and Administrative Expense [Member] Restructuring and other exit costs Restructuring Charges [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Stock-based compensation expense Share-based Payment Arrangement, Expense Leases [Abstract] Remaining 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 (undiscounted) Lessee, Operating Lease, Liability, Payments, Due Less: imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Lease liabilities—total (discounted) Operating Lease, Liability New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2016-02 Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Lease liability Right-of-use lease asset Operating Lease, Right-of-Use Asset Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Restructuring and Related Activities [Abstract] Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Accrued restructuring and other exit costs, beginning balance Restructuring Reserve Restructuring and other exit costs Restructuring Charges Cash paid for restructuring and other exit costs Payments for Restructuring Non-cash stock-based compensation for restructuring and other exit costs Restructuring Reserve, Settled without Cash Restructuring and other exit costs Accrued restructuring and other exit costs, ending balance Organization and Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Schedule of Lease Liability Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Cash equivalents Money Market Funds [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Recurring Fair Value, Recurring [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] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Amortization expense of intangible assets Amortization of Intangible Assets Provision (benefit) for income taxes Income Tax Expense (Benefit) Schedule of Finite-Lived Intangible Assets 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] Intrinsic values of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Unrecognized employee stock-based compensation Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Unrecognized employee stock-based compensation, period for recognition Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Weighted average grant date fair value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Fair value of options vested in period Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Other Balance Sheet Amounts Supplemental Balance Sheet Disclosures [Text Block] Cover page. Title of 12(b) Security Title of 12(b) Security Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Entity File Number Entity File Number Document Period End Date Document Period End Date 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 Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Current Reporting Status Entity Current Reporting Status Entity Shell Company Entity Shell Company Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two 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 Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Interactive Data Current Entity Interactive Data Current Entity Ex Transition Period Entity Ex Transition Period Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Weighted-Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Fair Value, Assets Measured on Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Revenues Revenue from Contract with Customer [Text Block] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States UNITED STATES International Other International [Member] Other International [Member] Revenue Accounts payable—seller Accounts Payable, Seller, Current Description of balance sheet netting of assets and liabilities per ASC 210-20. Accounts payable—trade Accounts Payable, Trade, Current Accrued employee-related payables Employee-related Liabilities, Current Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities, Current 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] Non-compete agreements Noncompete Agreements [Member] Trademarks Trademarks [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Amortizable intangible assets, gross Finite-Lived Intangible Assets, Gross Total accumulated amortization—intangible assets Finite-Lived Intangible Assets, Accumulated Amortization Restructuring and Other Exit Costs Restructuring and Related Activities Disclosure [Text Block] Schedule of Share-based Compensation, Stock Options, Activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Nonvested Restricted Stock Shares Activity Nonvested Restricted Stock Shares Activity [Table Text Block] Schedule of Nonvested Restricted Stock Units Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs for all Plans Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Stock-Based Compensation Share-based Payment Arrangement [Text Block] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Lease terms Lessee, Operating Lease, Term of Contract Weighted average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Weighted average discount rate, percent Operating Lease, Weighted Average Discount Rate, Percent Lease expense Operating Lease, Expense Short-term lease expense Short-term Lease, Cost Rental expense under ASC 840 Operating Leases, Rent Expense, Net Sublease income under ASC 842 Sublease Income Sublease income, under ASC 840 Operating Leases, Income Statement, Sublease Revenue Lease not yet commenced, expected lease liability Lessee, Operating Lease, Lease Not yet Commenced, Expected Lease Liabilities Lessee, Operating Lease, Lease Not yet Commenced, Expected Lease Liabilities Schedule of Restructuring and Other Exit Costs Restructuring and Related Costs [Table Text Block] Unvested restricted stock awards Fair value of restricted stock vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Unrecognized employee stock-based compensation Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Intangible Assets Intangible Assets Disclosure [Text Block] Shares Under Option 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 Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Gross Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Gross Expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Ending balance (in shares) Exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted- Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Beginning balance (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Exercised (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Expired (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Forfeited (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Weighted Average Grant Date Fair Value Ending balance (usd per share) Exercisable (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted- Average Contractual Life Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value [Abstract] Outstanding, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Exercisable, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value RSAs and RSUs Restricted Stock Units And Restricted Stock Awards [Member] Restricted Stock Units And Restricted Stock Awards [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Vesting after one year of service Share-based Payment Arrangement, Tranche One [Member] Two Year RSUs Two Year RSUs [Member] Two Year RSUs [Member] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Award vesting rights, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Number of shares available for grant Statement of Cash Flows [Abstract] OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock-based compensation Share-based Payment Arrangement, Noncash Expense Loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Provision for doubtful accounts Accounts Receivable, Credit Loss Expense (Reversal) Accretion of available-for-sale securities Accretion Of Available-For-Sale Securities Accretion Of Available-For-Sale Securities Non-cash lease expense Non-Cash Lease Expense Non-Cash Lease Expense Unrealized foreign currency (gains) losses, net Foreign Currency Transaction Gain (Loss), Unrealized Deferred income taxes Deferred Income Taxes and Tax Credits Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Capitalized internal use software development costs Payments to Develop Software Investments in available-for-sale securities Payments to Acquire Available-for-sale Securities Maturities of available-for-sale securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Sales of available-for-sale securities Proceeds from Sale of Available-for-sale Securities Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Proceeds from exercise of stock options Proceeds from Stock Options Exercised Proceeds from issuance of common stock under employee stock purchase plan Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Taxes paid related to net share settlement Payment, Tax Withholding, Share-based Payment Arrangement Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities EFFECT OF EXCHANGE RATE CHANGES ON CASH, CASH EQUIVALENTS AND RESTRICTED CASH Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Cash paid for income taxes Income Taxes Paid, Net Cash paid for interest Interest Paid, Including Capitalized Interest, Operating and Investing Activities Capitalized assets financed by accounts payable and accrued expenses Capital Expenditures Incurred but Not yet Paid Capitalized stock-based compensation Share-based Payment Arrangement, Amount Capitalized Operating lease right-of-use assets obtained in exchange for new operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability U.S. Treasury, government and agency debt securities Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Available-for-sale Securities Available-for-sale Securities ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Marketable Securities Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current TOTAL CURRENT ASSETS Assets, Current Property and equipment, net Property, Plant and Equipment, Net Internal use software development costs, net Internal Use Software Development Costs, Net The carrying amount of internal use software development costs net of accumulated amortization as of the balance sheet date. Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Other assets, non-current Other Assets, Noncurrent TOTAL ASSETS Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable and accrued expenses Lease liabilities, current Operating Lease, Liability, Current Other current liabilities Other Liabilities, Current TOTAL CURRENT LIABILITIES Liabilities, Current Lease liabilities, non-current Operating Lease, Liability, Noncurrent Other liabilities, non-current 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, 10,000 shares authorized at June 30, 2019 and December 31, 2018; 0 shares issued and outstanding at June 30, 2019 and December 31, 2018 Preferred Stock, Value, Issued Common stock, $0.00001 par value; 500,000 shares authorized at June 30, 2019 and December 31, 2018; 52,984 and 51,159 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 Accumulated other comprehensive 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 Income Statement [Abstract] Expenses: Costs and Expenses [Abstract] Cost of revenue Cost of Revenue Sales and marketing Selling and Marketing Expense Technology and development Research and Development Expense General and administrative General and Administrative Expense Total expenses Costs and Expenses Loss from operations Operating Income (Loss) Other (income) expense: Nonoperating Income (Expense) [Abstract] Interest income, net Interest Income (Expense), Net Other income Other Operating Income Foreign exchange (gain) loss, net Foreign Currency Transaction Gain (Loss), before Tax Total other income, net Nonoperating Income (Expense) Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Net loss Net loss per share: Basic and Diluted (usd per share) Weighted average shares used to compute net loss per share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic and Diluted (in shares) Net Income (Loss) Per Share Earnings Per Share [Text Block] Investments in Marketable Securities Marketable Securities [Table Text Block] Schedule of Accounts Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [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] Other Commitments [Table] Other Commitments [Table] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] Lease Arrangement, Type [Domain] Office Lease Office Lease [Member] Office Lease [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Financial Standby Letter of Credit Financial Standby Letter of Credit [Member] Other Commitments [Line Items] Other Commitments [Line Items] Letters of credit outstanding, amount Letters of Credit Outstanding, Amount 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] Options to purchase common stock Equity Option [Member] Unvested restricted stock units ESPP Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Total shares excluded from net loss per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Available-for-sale securities Realized gain (loss) Available-for-sale Securities, Gross Realized Gain (Loss) Unrealized holding gain (losses) reclassified Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Sale of available-for-sale securities Restricted cash Restricted Cash Lease Obligations Lessee, Operating Leases [Text Block] Restricted Stock units included units granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested, Included In Restricted Stock Units Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested, Included In Restricted Stock Units Granted Intrinsic value of nonvested unit Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Unrecognized employee stock-based compensation, weighted average period Employee Service Share-Based Compensation, Non-Vested Restricted Stock Units, Compensation Cost Not Yet Recognized, Period for Recognition Employee Service Share-Based Compensation, Non-Vested Restricted Stock Units, Compensation Cost Not Yet Recognized, Period for Recognition