Marin Software (MRIN) 10-K 23 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Mar. 13, 2020	Jun. 30, 2019
Cover [Abstract]
Entity Registrant Name	MARIN SOFTWARE INC
Entity Central Index Key	0001389002
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Document Annual Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		6,830,000
Entity Public Float			$ 15.3
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity File Number	001-35838
Entity Tax Identification Number	20-4647180
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	123 Mission Street
Entity Address, Address Line Two	27th Floor
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94105
City Area Code	415
Local Phone Number	399-2580
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	MRIN
Security Exchange Name	NASDAQ

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 11,134	$ 10,210
Restricted cash	971	1,293
Accounts receivable, net	8,939	12,906
Prepaid expenses and other current assets	3,522	4,642
Total current assets	24,566	29,051
Property and equipment, net	8,524	11,815
Right-of-use assets, operating leases	7,705	0
Goodwill	0	1,943
Intangible assets, net	95	1,938
Other non-current assets	1,403	2,045
Total assets	42,293	46,792
Current liabilities:
Accounts payable	1,679	2,699
Accrued expenses and other current liabilities	9,010	10,632
Operating lease liabilities	3,786	0
Total current liabilities	14,475	13,331
Operating lease liabilities, non-current	5,181	0
Other long-term liabilities	1,577	4,090
Total liabilities	21,233	17,421
Commitments and contingencies (Note 17)
Stockholders' equity:
Convertible preferred stock, $0.001 par value - 10,000 shares authorized, no shares issued and outstanding at December 31, 2019 and 2018, respectively
Common stock, $0.001 par value - 142,857 shares authorized, 6,810 and 5,938 shares issued and outstanding at December 31, 2019 and 2018, respectively	7	6
Additional paid-in capital	299,263	295,116
Accumulated deficit	(277,112)	(264,713)
Accumulated other comprehensive loss	(1,098)	(1,038)
Total stockholders' equity	21,060	29,371
Total liabilities and stockholders' equity	$ 42,293	$ 46,792

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares shares in Thousands	Dec. 31, 2019	Dec. 31, 2018
Stockholders' equity:
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, authorized (in shares)	10,000	10,000
Convertible preferred stock, issued (in shares)	0	0
Convertible preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	142,857	142,857
Common stock, issued (in shares)	6,810	5,938
Common stock, outstanding (in shares)	6,810	5,938

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenues, net	$ 49,036	$ 58,631
Cost of revenues	22,843	27,154
Gross profit	26,193	31,477
Operating expenses:
Sales and marketing	15,836	23,425
Research and development	17,845	22,450
General and administrative	10,446	13,113
Impairment of goodwill	1,910	14,740
Total operating expenses	46,037	73,728
Loss from operations	(19,844)	(42,251)
Gain on divestiture (Note 7)	5,064	0
Other income, net	2,252	1,593
Loss before (benefit from) provision for income taxes	(12,528)	(40,658)
(Benefit from) provision for income taxes	(120)	586
Net loss	(12,408)	(41,244)
Foreign currency translation adjustments	(60)	(356)
Comprehensive loss	$ (12,468)	$ (41,600)
Net loss per share available to common stockholders, basic and diluted	$ (1.95)	$ (7.13)
Weighted-average shares used to compute net loss per share available to common stockholders, basic and diluted	6,373	5,783
Stock-based compensation expense	$ 2,664	$ 3,971
Amortization of intangible assets	1,814	2,537
Cost of Revenues [Member]
Operating expenses:
Stock-based compensation expense	533	739
Amortization of intangible assets	875	938
Restructuring related expenses	96	176
Sales and Marketing [Member]
Operating expenses:
Stock-based compensation expense	681	957
Amortization of intangible assets	64	658
Restructuring related expenses	401	827
Research and Development [Member]
Operating expenses:
Stock-based compensation expense	1,025	1,398
Amortization of intangible assets	875	938
Restructuring related expenses	0	115
General and Administrative [Member]
Operating expenses:
Stock-based compensation expense	425	877
Amortization of intangible assets	0	3
Restructuring related expenses	$ 0	$ 158

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balances at beginning of period at Dec. 31, 2017	$ 62,783	$ 6	$ 291,163	$ (227,704)	$ (682)
Balances at beginning of period (in shares) at Dec. 31, 2017		5,729
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact of adoption of ASC 606 | ASC 606 [Member]	4,235	$ 0	0	4,235	0
Issuance of common stock from vesting of restricted stock units	0	$ 0	0	0	0
Issuance of common stock from vesting of restricted stock units (in shares)		123
Tax withholding related to vesting of restricted stock units	(327)	$ 0	(327)	0	0
Issuance of common stock under employee stock purchase plan	305	$ 0	305	0	0
Issuance of common stock under employee stock purchase plan (in shares)		86
Stock-based compensation expense	3,971	$ 0	3,971	0	0
Net loss	(41,244)	0	0	(41,244)	0
Foreign currency translation adjustments and other, net	(352)	0	4	0	(356)
Balances at end of period at Dec. 31, 2018	29,371	$ 6	295,116	(264,713)	(1,038)
Balances at end of period (in shares) at Dec. 31, 2018		5,938
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through at-the-market offering, net of offering costs	$ 1,643	$ 1	1,642	0	0
Issuance of common stock through at-the-market offering, net of offering costs (in shares)	658	658
Issuance of common stock from vesting of restricted stock units	$ 0	$ 0	0	0	0
Issuance of common stock from vesting of restricted stock units (in shares)		139
Tax withholding related to vesting of restricted stock units	(301)	$ 0	(301)	0	0
Issuance of common stock under employee stock purchase plan	142	$ 0	142	0	0
Issuance of common stock under employee stock purchase plan (in shares)		75
Stock-based compensation expense	2,664	$ 0	2,664	0	0
Net loss	(12,408)	0	0	(12,408)	0
Foreign currency translation adjustments and other, net	(51)	0	0	9	(60)
Balances at end of period at Dec. 31, 2019	$ 21,060	$ 7	$ 299,263	$ (277,112)	$ (1,098)
Balances at end of period (in shares) at Dec. 31, 2019		6,810

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Statement Of Stockholders Equity [Abstract]
Offering costs	$ 210

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net loss	$ (12,408)	$ (41,244)
Adjustments to reconcile net loss to net cash used in operating activities
Impairment of goodwill	1,910	14,740
Depreciation	1,934	2,658
Amortization of internally developed software	3,904	3,774
Amortization of intangible assets	1,814	2,537
Amortization of deferred costs to obtain and fulfill contracts	1,534	2,045
Gain on divestiture of Perfect Audience	(5,064)	0
Loss (gain) on disposals of property and equipment and right-of-use assets	26	(1)
Unrealized foreign currency gains	(56)	(118)
Stock-based compensation related to equity awards	2,664	3,971
Provision for bad debts	(249)	48
Net change in operating leases	(511)	0
Deferred income tax benefits	(301)	(398)
Changes in operating assets and liabilities
Accounts receivable	4,170	(668)
Prepaid expenses and other assets	220	(609)
Accounts payable	(687)	(97)
Accrued expenses and other liabilities	(136)	382
Net cash used in operating activities	(1,236)	(12,980)
Investing activities:
Purchases of property and equipment	(604)	(586)
Net proceeds from divestiture of Perfect Audience	4,267	0
Proceeds from disposal of property and equipment	0	8
Capitalization of internally developed software	(2,056)	(2,129)
Net cash provided by (used in) investing activities	1,607	(2,707)
Financing activities:
Proceeds from issuance of common shares through at-the-market offering, net of offering costs of $210	1,643	0
Payment of principal on finance lease liabilities	(1,186)	(1,304)
Employee taxes paid for withheld shares upon equity award settlement	(314)	(265)
Proceeds from employee stock purchase plan, net	117	282
Net cash provided by (used in) financing activities	260	(1,287)
Effect of foreign exchange rate changes on cash and cash equivalents and restricted cash	(29)	(360)
Net increase (decrease) in cash and cash equivalents and restricted cash	602	(17,334)
Cash and cash equivalents and restricted cash:
Beginning of year	11,503	28,837
End of year	12,105	11,503
Supplemental disclosures of other cash flow information:
Cash paid for interest	72	153
Cash paid for income taxes	589	730
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from finance leases	72	0
Operating cash flows from operating leases	8,453	0
Financing cash flows from finance leases	1,186	0
Right-of-use assets obtained in exchange for lease liabilities:
Finance lease liabilities	0	0
Operating lease liabilities	1,656	0
Supplemental disclosures of non-cash investing and financing activities:
Issuance of common stock under employee stock purchase plan	142	305
Purchases of property and equipment recorded in accounts payable and accrued expenses	$ 0	$ 10

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Financing activities:
Offering costs	$ 210

Background

Background	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Background	1. Background Marin Software Incorporated (the “Company”) was incorporated in Delaware in March 2006. The Company provides enterprise marketing software for advertisers and agencies to integrate, align and amplify their digital advertising spend across the web and mobile devices. Offered as a unified software-as-a-service (“SaaS”) advertising management solution for search, social and eCommerce advertising, the Company’s platform helps digital marketers convert precise audiences, improve financial performance and make better decisions. The Company’s corporate headquarters are located in San Francisco, California, and the Company has additional offices in the following locations References to “2019” and “2018” shall mean the years ended December 31, 2019 and 2018, respectively. All amounts presented in these notes to the consolidated financial statements are in thousands, except where noted.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Liquidity Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated upon consolidation. Accounting Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“GAAP”) requires management to make certain estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company is subject to uncertainties such as the impact of future events, economic and political factors and changes in the Company’s business environment; therefore, actual results could differ from these estimates. Accordingly, the accounting estimates used in the preparation of the Company’s financial statements will change as new events occur, as more experience is acquired, as additional information is obtained and as the Company’s operating environment changes. Changes in estimates are made when circumstances warrant. Such changes in estimates and refinements in estimation methodologies are reflected in reported results of operations and if material, the effects of changes in estimates are disclosed in the notes to the consolidated financial statements. Significant estimates and assumptions by management affect the allowances for doubtful accounts and customer revenue credits, the carrying value of long-lived assets (including goodwill and intangible assets), the useful lives of long-lived assets, the accounting for income taxes and stock-based compensation. Certain Significant Risks and Uncertainties The Company operates in a rapidly changing environment that involves a number of risks, some of which are beyond the Company’s control that could have a material adverse effect on the Company’s business, operating results and financial condition. These risks include, among others, the Company’s history of losses and negative cash flows; the highly competitive environment in which the Company operates; the ability to maintain and increase usage rates of the Company’s platform and the ability for the Company to increase demand for its solutions. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash, cash equivalents and accounts receivable. The Company’s cash and cash equivalents are placed with high-credit-quality financial institutions and issuers, and at times exceed federally insured limits. The Company has not experienced any loss relating to cash and cash equivalents in these accounts. The Company performs periodic credit evaluations of its customers and generally does not require collateral. As of December 31, 2019 and 2018, accounts receivable from one long-term strategic agreement with Google (see Note 3) accounted for 35% and 30%, respectively, of the Company's total accounts receivable, net. Revenues, net from the same long-term strategic agreement accounted for 25% of total revenues, net for the year ended December 31, 2019. No single customer accounted for 10% or more of total revenues, net for the year ended December 31, 2018. Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with an original or remaining maturity from the Company’s date of purchase of 90 days or less to be cash equivalents. Deposits held with financial institutions are likely to exceed the amount of insurance on these deposits. Cash equivalents consist of money market funds which are readily convertible into cash and have original maturity dates of less than three months from the date of their respective purchases. Cash equivalents were $8,723 and $2,806 as of December 31, 2019 and 2018, respectively. Restricted cash consists of deposits held with a financial institution to secure the Company’s non-cancelable leases for its corporate headquarters in San Francisco and its office in Paris (see Note 13). Fair Value of Financial Instruments The Company’s financial instruments, including accounts receivable, accounts payable and accrued expenses are carried at cost, which approximates fair value because of the short-term nature of those instruments. The Company measures and reports certain financial assets at fair value on a recurring basis, including its investments in money market funds. The fair value hierarchy prioritizes the inputs into three broad levels: Level 1 Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 Inputs are unobservable inputs based on the Company’s assumptions. A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Allowances for Doubtful Accounts and Revenue Credits The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the Company’s receivables portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available evidence. The Company performs a regular review of its customers’ payment histories and associated credit risks and it does not require collateral from its customers. When collection of an outstanding balance is no longer probably, the Company will either partially or fully write-off the balance against the allowance for doubtful accounts. Certain contracts with advertising agencies contain sequential liability provisions, whereby the agency does not have an obligation to pay the Company until payment is received from the agency’s customers. In these circumstances, the Company evaluates the credit worthiness of the agency’s customers, in addition to the agency itself. The following are changes in the allowance for doubtful accounts for the periods presented. Years Ended December 31, 2019 2018 Balances at beginning of year $ 2,651 $ 4,028 (Reductions) additions to expense (249 ) 48 Write-offs and other deductions (843 ) (1,425 ) Balances at end of year $ 1,559 $ 2,651 From time to time, the Company provides revenue credits to customers. These typically relate to customer disputes and billing adjustments and are recorded as a reduction of revenues, net. Reserves for these revenues credits are accounted for as variable consideration under authoritative revenue recognition guidance (see Note 3) and are estimated based on historical credit activity. As of December 31, 2019 and 2018, the Company recorded an allowance for potential customer revenue credits in the amount of $319 and $353, respectively. Property and Equipment Property and equipment are stated at historical cost less accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the related assets. Upon retirement or sale, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is reflected in operations. Major additions and improvements are capitalized while repairs and maintenance that do not extend the life of the asset are charged to operations as incurred. Depreciation and amortization expense is allocated to both cost of revenues and operating expenses. Internally Developed Software Costs incurred in the development phase are capitalized and amortized over the product’s estimated useful life, which is three years. The Company expenses all costs incurred that relate to planning and post implementation phases of development. Development phase costs generally include salaries and personnel costs and third-party contractor expenses associated with software development, configuration and coding. Capitalized costs related to internally developed software under development are treated as construction in progress until the program, feature or functionality is ready for its intended use, at which time amortization commences. For 2019 and 2018, the Company capitalized $2,056 and $2,129 of costs related to internally developed software, respectively. Amortization of capitalized costs related to internally developed software was $3,904 and $3,774 for 2019 and 2018, respectively. As of December 31, 2019 and 2018, unamortized internally developed software costs, including construction in progress, totaled $5,124 and $6,972, respectively. Amortization of internally developed software is reflected in cost of revenues. Costs associated with minor enhancements and maintenance are expensed as incurred. Goodwill, Intangible Assets and Impairment Assessments Goodwill represents the excess of the purchase price in a business combination over the fair value of net tangible and intangible assets acquired. Intangible assets that are not considered to have an indefinite useful life are amortized over their useful lives, which range from two to six years. Estimated remaining useful lives of purchased intangible assets are evaluated to assess whether events or changes in circumstances warrant a revision to the remaining periods of amortization. The Company evaluates goodwill for impairment in the fourth quarter of its fiscal year annually, or more frequently if events or changes in circumstances indicate that goodwill may be impaired. For the purposes of impairment testing, the Company has determined that it has one reporting unit. The Company performs its goodwill impairment test using the simplified method, whereby the fair value of this reporting unit is compared to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that reporting unit, goodwill is not considered impaired. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then goodwill is considered impaired by an amount equal to that difference. In November 2019, the Company performed an impairment assessment of goodwill in conjunction with the divestiture of its Perfect Audience business to SharpSpring, Inc., an unrelated third party. The assessment was performed utilizing the simplified method, and resulted in an impairment of goodwill of $1,910 at that time, reducing the goodwill balance to zero. Similarly, the Company performed an interim goodwill impairment test in the third quarter of 2018 due to a decline in the market capitalization of the Company’s common stock, which resulted in a charge for the impairment of $14,740 for the year ended December 31, 2018. Refer to Note 6 for further details on the Company’s goodwill impairment tests. Impairment of Long-Lived Assets The Company evaluates long-lived assets, excluding goodwill, for potential impairment whenever adverse events or changes in circumstances or business climate indicate that expected undiscounted future cash flows related to such long-lived assets may not be sufficient to support the net book value of such assets. An impairment loss is recognized only if the carrying value of a long-lived asset or asset group is not recoverable and exceeds its fair value. The carrying value of a long-lived asset or asset group is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. There were no such impairment losses in 2019 and 2018. Leases The Company has operating leases for corporate offices worldwide and for space at a data center. Additionally, the Company leases computer equipment through various finance leases. New contractual arrangements are evaluated at inception to determine if the contract is or contains a lease. For any contracts that are or contain a lease, the Company determines the appropriate classification of each identified lease as operating or finance. For all identified leases, the Company records the related lease liabilities and right-of-use (“ROU”) assets based on the future minimum lease payments over the lease term, which only includes options to renew the lease if it is reasonably certain that the Company will exercise that option. For leases with original terms of 12 months or less, the Company recognizes the lease expense as incurred and does not recognize lease liabilities and ROU assets. Lease liabilities are measured based on the future minimum lease payments discounted over the lease term. The Company uses the discount rate implicit in the lease whenever that rate is readily determinable. For leases where no such rate is determinable, the Company uses its incremental borrowing rate, or the rate of interest that Company would have to pay to borrow an amount equal to the lease payments, on a collateralized basis over a similar term and in a similar economic environment. Current and non-current operating lease liabilities are presented on the consolidated balance sheet beginning January 1, 2019, while current finance lease liabilities are included in accrued expenses and other current liabilities, and non-current finance lease liabilities are included in other long-term liabilities on the consolidated balance sheets. Balances classified as capital lease obligations under previous lease guidance are presented for all periods prior to 2019 to conform to the presentation of finance lease liabilities. ROU assets are measured based on the associated lease liabilities, adjusted for any lease incentives such as tenant improvement allowances. ROU assets for operating leases are presented as non-current assets on the condensed consolidated balance sheet beginning January 1, 2019, while ROU assets for finance leases are included within property and equipment, net. For operating leases, the Company recognizes the expense for lease payments on straight-line basis over the lease term. See Note 13 for further discussion on the Company’s leases. Revenue Recognition The Company generates revenues principally from subscriptions either directly with advertisers or with advertising agencies to its platform for the management of search, social and eCommerce advertising. The Company also generates revenues from strategic agreements with certain leading publishers. Under these strategic agreements, the Company receives consideration based on a percentage of the search advertising spend that customers manage on its platform. Revenues are recognized when control of these services is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those services. See Note 3 for further discussion on the Company's revenues. Cost of Revenues Cost of revenues primarily consists of costs related to hosting the Company’s cloud-based platform, providing implementation and ongoing customer support, data communications expenses, salaries and benefits of operations and support personnel, software license fees, costs associated with website development activities, indirect overhead, amortization expense associated with capitalized internally developed software and intangible assets and property and equipment depreciation. Stock-Based Compensation Expense Stock-based compensation expense is measured at grant date based on the fair value of the award and is expensed on a straight-line basis over the requisite service period. Restricted stock units (“RSUs”) are measured based on the fair market values of the underlying common stock on the dates of grant. Shares of common stock are issued on the vesting dates. Fair values of stock option awards are determined on the date of grant using the Black-Scholes option-pricing model. In applying this option-pricing model, the Company’s determination of the fair value of the stock option award on the date of grant is affected by the Company’s fair value of its common stock, as well as assumptions regarding a number of subjective variables. These variables include, but are not limited to, the Company’s expected stock price volatility, actual and projected stock option exercise behaviors and risk-free interest rate. For stock option and RSU awards with time-based vesting, the Company recognizes stock-based compensation expense over the requisite service period using the straight-line method, based on awards ultimately expected to vest. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. See Note 11 and Note 12 for further information. Research and Development Research and development costs are expensed as incurred, except for certain internal software development costs, which may be capitalized as noted above. Research and development costs consist of personnel costs, including salaries, stock-based compensation expense, benefits and bonuses, as well as non-personnel costs such as professional fees payable to third-party development resources, amortization of intangible assets and allocated overhead costs. Advertising and Promotion Advertising and promotional costs are expensed as incurred and included in sales and marketing expense in the accompanying consolidated statements of comprehensive loss. Advertising and promotion expense totaled $463 and $494 for 2019 and 2018, respectively. Sales Taxes Sales and other taxes collected from customers and remitted to governmental authorities are presented on a net basis and thus excluded from revenues. Foreign Currency For international subsidiaries whose functional currency is not the U.S. Dollar, we re-measure the monetary assets and liabilities of these subsidiaries to U.S. Dollars using rates of exchange in effect at the balance sheet date. Nonmonetary assets and liabilities are re-measured to U.S. Dollars using historical exchange rates, and other accounts are re-measured using average exchange rates in effect during each period presented. The effects of foreign currency translation adjustments are included in stockholders’ equity as a component of accumulated other comprehensive loss on the accompanying consolidated balance sheets, and related periodic movements are summarized as a line item in the consolidated statements of comprehensive loss. The Company records net gains and losses resulting from foreign exchange transactions as a component of other income, net. Aggregate foreign currency (losses) gains included in determining net loss were $(31) and $205 for 2019 and 2018, respectively. Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement and tax basis of assets and liabilities and net operating loss and credit carryforwards using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company accounts for uncertain tax positions using a more-likely-than-not threshold for financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. The Company establishes a liability for tax-related uncertainties based on estimates of whether, and the extent to which, additional taxes will be due. The Company records an income tax liability, if any, for the difference between the benefit recognized and measured and the tax position taken or expected to be taken on the Company’s tax returns. To the extent that the assessment of such tax positions changes, the change in estimate is recorded in the period in which the determination is made. The liability is adjusted in light of changing facts and circumstances, such as the outcome of a tax audit. The provision for income taxes includes changes to the liabilities that are considered appropriate. The Company would recognize interest and penalties related to uncertain tax positions as income tax expense, though such amounts were not material in 2019 or 2018. The Company does not expect that changes in the liability for uncertain tax positions for the next twelve months will have a material impact on the Company’s consolidated financial position or results of operations. Recently Accounting Pronouncements Adopted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases As a result of the adoption, the Company recorded ROU assets of $14,589 and lease liabilities of $16,425 related to operating leases on January 1, 2019. ASC 842 did not have a material impact on the Company’s consolidated statement of comprehensive loss for the year ended December 31, 2019. Refer to Note 13 for further information on leases. In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income – Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Recent Accounting Pronouncements Not Yet Effective In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses – Measurement of Credit Losses on Financial Instruments In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software In December 2019, the FASB issues ASU 2019-12, Income Taxes – Simplifying the Accounting for Income Taxes simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step up in the tax basis of goodwill, and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications

Revenues

Revenues	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Revenues	3. Revenues Adoption of ASC 606 On January 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers Revenue Recognition The Company generates its revenues principally from subscriptions either directly with advertisers or with advertising agencies to its platform for the management of search, social and eCommerce advertising. It also generates a portion of its revenues from long-term strategic agreements with certain leading publishers. Revenues are recognized when control of these services is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those services. The Company determines revenue recognition through the following steps: • Identification of the contract, or contracts, with a customer; • Identification of the performance obligations in the contract; • Determination of the transaction price; • Allocation of the transaction price to the performance obligations in the contract; and • Recognition of revenue when, or as, the Company satisfies a performance obligation. Subscriptions The Company's subscription contracts provide advertisers with access to the Company's advertising management platform. Advertisers do not have the right to take possession of the software supporting the services at any time. These contracts are generally one year or less in length, though certain contracts extend up to two years. The subscription fee under most contracts consists of the greater of a minimum monthly platform fee or variable consideration based on the volume of advertising spend managed through the Company’s platform at the contractual percentage of spend. The variable portion generally includes tiered pricing, whereby the percentage of spend charged decreases as the value of advertising spend increases. The tiered pricing resets monthly and is consistent throughout the contract term. The Company has concluded that this volume-based pricing approach does not constitute a future material right as the pricing tiers are consistent throughout the term of the contract and similar pricing is typically offered to similar classes of customers within the same geographical areas and markets. Certain subscription contracts consist of only a flat monthly platform fee. Subscription fees are generally invoiced on a monthly basis in arrears based on the actual amount of advertising spend managed on the platform. In certain limited circumstances, the Company will invoice an advertiser in advance for the contractual minimum monthly platform fee for a defined future period, which is typically three to 12 months. The Company’s subscription services comprise a single stand-ready performance obligation satisfied over time as the advertiser simultaneously receives and consumes the benefit from the Company’s performance. This performance obligation constitutes a series of services that are substantially the same in nature and are provided over time using the same measure of progress. Revenues derived from these arrangements are recognized over time using an output method based upon the passage of time as this provides a faithful depiction of the pattern of transfer of control. Fixed minimum monthly platform fees are recognized ratably over the contract term as the single performance obligation is satisfied. Variable fees are allocated to the distinct month of the series in which they are earned because the terms of the variable payments relate specifically to the outcome from transferring the distinct time increment (month) of service and because such amounts reflect the fees to which the Company expects to be entitled for providing access to the advertising management platform for that period, consistent with the allocation objective of authoritative revenue guidance under ASC 606. Expected future revenues for subscription services related to performance obligations that are unsatisfied (or partially unsatisfied) as of December 31, 2019 were as follows: Subscription Services Revenues 2020 $ 2,905 2021 777 2022 39 Total $ 3,721 The Company applies the optional exemption under ASC 606 and does not disclose the value of unsatisfied performance obligations on subscription contracts with an original term of one year or less. The amounts disclosed above as remaining performance obligations consist primarily of fixed or monthly minimum fees under contracts with an original expected duration of greater than one year. The amounts exclude estimates of variable consideration such as volume-based contracts, as well as anticipated renewals of contracts. Strategic Agreements The Company has entered into long-term strategic agreements with certain leading search publishers. Under these strategic agreements, the Company receives consideration based on a percentage of the search advertising spend that its customers manage on its platform. These strategic agreements are generally billed on a quarterly basis. The majority of the Company's strategic agreement revenue is concentrated to one revenue share agreement, executed with Google in December 2018, with an effective date of October 1, 2018 (the “Google Revenue Share Agreement”). Under the Google Revenue Share Agreement, which constitutes a single performance obligation, the Company receives both fixed and variable revenue share payments based on a percentage of the search advertising spend that is managed through the Company's platform. The Google Revenue Share Agreement requires the Company to reinvest a specified percentage of these revenue share payments in its search technology platform to drive innovation. The performance obligation is expected to be satisfied ratably over the two-year contractual term using the output method based upon the passage of time, as Google simultaneously receives and consumes the benefit from the Company’s performance, which provides a faithful depiction of the pattern of transfer of control. The Google Revenue Share Agreement has a three-year term; however, until March 2020, when the Company and Google executed the first amendment to the original agreement (the “First Amendment”), Google could terminate the Google Revenue Share Agreement after two years with no penalty if the Company did not meet certain financial metrics. Accordingly, the Company accounts for the Google Revenue Share Agreement as a two-year agreement with one optional renewal year as of December 31, 2019. The revenue impact of the third year will be accounted for prospectively as of the execution of the First Amendment in March 2020. The Company evaluates the total amount of variable revenue share payments expected to be earned from the Google Revenue Share Agreement by using the expected value method, as it believes this method represents the most appropriate estimate for this consideration, based on historical service trends, the individual contract considerations and the Company's best judgment. The Company includes estimates of variable consideration in revenues only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. For the years ended December 31, 2019 and 2018, the Company recognized $12,203 and $2,933, respectively, as revenues from the Google Revenue Share Agreement. Revenues for the year ended December 31, 2019 from the Google Revenue Share Agreement included $94 related to performance obligations satisfied in a previous period. As of December 31, 2019, the Company expects to recognize revenues totaling approximately $9,082 and for the year ending December 31, 2020, related to remaining performance obligations under the agreement. Disaggregation of Revenues, net Revenues, net by geographic area, based on the billing location of the customer, were as follows for the periods presented: Years Ended December 31, 2019 2018 United States of America $ 36,718 $ 40,907 United Kingdom 5,489 7,664 Other (1) 6,829 10,060 Total revenues, net $ 49,036 $ 58,631 (1) No individual country within the “Other” category accounted for 10% or more of revenues, net for any period presented. Revenues, net by nature of services performed were as follows for the periods presented: Years Ended December 31, 2019 2018 Subscriptions $ 36,702 $ 54,532 Strategic agreements 12,334 4,099 Total revenues, net $ 49,036 $ 58,631 Contract Balances Accounts receivable, net The timing of revenue recognition may differ from the timing of invoicing to customers. Accounts receivable are recorded at the invoice amount, net of any allowances for doubtful accounts and revenue credits. A receivable is recognized in the period the Company provides the underlying services or when the right to consideration is unconditional. The balances of accounts receivable, net of the allowances for doubtful accounts and revenue credits, as of December 31, 2019 and 2018 are presented in the accompanying consolidated balance sheets. Included in the balance of accounts receivable, net as of December 31, 2019 and 2018 was $3,101 and $3,867, respectively, related to the Google Revenue Share Agreement executed in December 2018. Customer advances In certain situations, the Company receives cash payments from customers in advance of its performance of the underlying services. These services are contracted on a weekly basis and cash payments are generally received on a weekly basis at amounts that are at the discretion of the customers, based on established advertising budgets. The unused portion of these advances from customers is included within accrued expenses and other current liabilities on the accompanying consolidated balance sheets. Under the Company's terms of service, individual customer advances that are not used by the customer for a period of 180 days become the property of the Company. The Company recognizes advances from customers that have remained outstanding for this period of time as breakage revenues at the time the Company has received full consideration and has no remaining obligations to the customer. The Company recorded historical breakage revenues up to January 1, 2018 of $1,445 as an adjustment to opening accumulated deficit, resulting in a customer advances balance of $558 on that date. For the years ended December 31, 2019 and 2018, the Company recognized $203 and $213, respectively, in breakage revenues. As a result of the Company’s divestiture of the assets and liabilities of its Perfect Audience business in November 2019 (see Note 7), the outstanding liability for customer advances was transferred to the acquirer, SharpSpring, Inc. There was no remaining balance as of December 31, 2019. Deferred Strategic Agreement Revenues Due to the timing of revenue recognition under the Google Revenue Share Agreement, the contractual billings exceed revenue recognized to date, resulting in a contract liability. As of December 31, 2019 and 2018, the Company recorded deferred strategic agreement revenues of $2,182 and $934, respectively, within accrued expenses and other current liabilities on the accompanying consolidated balance sheets. Costs to Obtain and Fulfill Contracts The Company capitalizes certain contract acquisition costs, consisting primarily of commissions and related payroll taxes, when customer contracts are signed. The Company also capitalizes certain contract fulfillment costs, consisting primarily of the portion of the payroll and fringe benefits of the Company’s professional services team that relates directly to performing on-boarding and integration services for new and existing customers (collectively, “deferred costs to obtain and fulfill contracts”). The deferred costs to obtain and fulfill contracts are amortized over the expected period of benefit, which the Company has determined to be approximately 30 months. This expected period of benefit takes into consideration the duration of the Company’s customer contracts, historical contract renewal rates, the underlying technology and other factors. Amortization expense for deferred costs to obtain and fulfill contracts is included in sales and marketing expense and cost of sales, respectively, on the accompanying consolidated statements of comprehensive loss. There were no impairment losses related to costs capitalized in 2019 and 2018. The Company classifies deferred costs to obtain and fulfill contracts as current or non-current based on the timing of when the related amortization expense is expected to be recognized. The current portion of these deferred costs is included in prepaid expenses and other current assets, while the non-current portion is included in other non-current assets on the accompanying consolidated balance sheets. Changes in the balances of deferred costs to obtain and fulfill contracts during the year ended December 31, 2019 were as follows: Deferred Costs to Obtain Contracts Deferred Costs to Fulfill Contracts Balances at December 31, 2018 $ 1,413 $ 606 Costs deferred 393 182 Amortization (1,027 ) (507 ) Balances at December 31, 2019 $ 779 $ 281

Restructuring Activities

Restructuring Activities	12 Months Ended
	Dec. 31, 2019
Restructuring And Related Activities [Abstract]
Restructuring Activities	4. Restructuring Activities 2019 Restructuring Plan In the fourth quarter 2019, the Company initiated an organizational restructuring plan (the “2019 Restructuring Plan”) designed to reduce operating expenses in response to declines in revenues. The 2019 Restructuring Plan included a headcount reduction of approximately 6% of the Company’s workforce and the closure of certain leased facilities. Actions pursuant to the 2019 Restructuring Plan were substantially complete as of December 31, 2019, and further costs associated with this plan are not expected to be material in future periods. For the year ended December 31, 2019, the Company recorded $268 of restructuring-related expenses in connection with the 2019 Restructuring Plan in the consolidated statements of comprehensive loss. As of December 31, 2019, approximately $208 in restructuring-related expenses associated with the 2019 Restructuring Plan remained unpaid and included primarily in accrued expenses and other current liabilities on the Company’s consolidated balance sheets. 2018 Restructuring Plan In January 2018, the Company initiated an organizational restructuring plan (the “2018 Restructuring Plan”) designed to reduce operating expenses in response to declines in revenues. The 2018 Restructuring Plan included a headcount reduction of approximately 13% of the Company’s workforce, the closure of certain leased facilities and the consolidation of space in the Company’s San Francisco headquarters. Actions pursuant to the 2018 Restructuring Plan are substantially complete, and further costs associated with this plan are not expected to be material in future periods. The Company initiated certain other organizational restructuring plans during 2018 that also aimed to reduce operating expenses and primarily consisted of further headcount reductions. For the years ended December 31, 2019 and 2018, the Company recorded $229 and $1,276, respectively, of restructuring-related expenses in connection with the 2018 Restructuring Plan, as well as other organizational restructuring plans, in the accompanying consolidated statements of comprehensive loss. No associated costs remained unpaid as of December 31, 2019.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2019
Balance Sheet Components [Abstract]
Balance Sheet Components	5. Balance Sheet Components The following table shows the components of property and equipment as of the dates presented: December 31, Estimated Useful Life 2019 2018 Software, including internally developed software 3 years $ 27,974 $ 25,518 Computer equipment 3 to 4 years 22,424 22,714 Finance lease ROU assets 4 years 5,067 5,067 Leasehold improvements Shorter of useful life or lease term 4,631 4,778 Office equipment, furniture and fixtures 3 to 5 years 1,986 2,140 Total property and equipment 62,082 60,217 Less: Accumulated depreciation and amortization (53,558 ) (48,402 ) Property and equipment, net $ 8,524 $ 11,815 Finance lease ROU assets consist of computer equipment held under leases, and were previously included in the “Computer equipment” line in filings for periods prior to 2019. Depreciation and amortization of internally developed software for 2019 and 2018 was $5,838 and $6,432, respectively. The following table shows the components of accrued expenses and other current liabilities as of the dates presented: December 31, 2019 2018 Accrued salary and payroll-related expenses $ 3,204 $ 3,695 Deferred strategic agreement revenues 2,182 934 Accrued liabilities 1,165 866 Finance lease liabilities 601 1,249 Income taxes payable 480 883 Advanced billings 376 859 Sales and use tax payable 9 244 Deferred rent — 538 Customer advances — 432 Other 993 932 Total accrued expenses and other current liabilities $ 9,010 $ 10,632

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6. Goodwill and Intangible Assets The Company previously maintained a goodwill balance as a result of prior business acquisitions. The Company tested goodwill for impairment on November 21, 2019 in conjunction with the divestiture of the assets and liabilities of the Company’s Perfect Audience business to SharpSpring, Inc. (see Note 7). The Company measures goodwill impairment as the amount by which the carrying amount of a reporting unit exceeds its fair value. For the purposes of the goodwill impairment test performed on November 21, 2019, the Company estimated the fair value of its sole reporting unit using the market approach. Under the market approach, the Company utilized an average market capitalization of its fully diluted common stock during the month prior to and subsequent to November 21, 2019, and applied an estimated control premium based on an analysis of control premiums paid in recent acquisitions of companies in the same or similar industries as the Company. Because the significant inputs used in this analysis are readily available from public markets or can be derived from observable market transactions, they have been classified as level 2 within the fair value hierarchy (see Note 8). Based on this analysis, the Company determined that the carrying value of its sole reporting unit exceeded its fair value by an amount in excess of $1,910, which was the carrying value of goodwill on November 21, 2019. As a result, the entire balance of goodwill was impaired to zero in the consolidated financial statements for the year ended December 31, 2019, in the fourth quarter. Additionally, there was a sustained decline in the Company's stock price in the nine months ended September 30, 2018, triggering the Company to perform an interim goodwill impairment test at that time. Using the market approach, the Company utilized the average market capitalization of its fully diluted common stock during the month prior to and subsequent to September 30, 2018, and applied an estimated control premium based on an analysis of control premiums paid in recent acquisitions of companies in the same or similar industries as the Company. The inputs used in this analysis have also been classified as level 2 within the fair value hierarchy. Based on this analysis, the Company determined that the carrying value of its sole reporting unit exceeded its fair value by $14,740, which was recorded as an impairment of goodwill in the consolidated financial statements for the year ended December 31, 2018, in the third quarter. The goodwill activity for the year ended December 31, 2019 consisted of the following: Balance at December 31, 2018 $ 1,943 Impairment (1,910 ) Foreign currency translation adjustments (33 ) Balance at December 31, 2019 $ — Intangible assets consisted of the following as of the dates presented: Estimated December 31, Useful Life 2019 2018 Developed technology 5 to 6 years $ 3,800 $ 9,910 Customer relationships 4 years — 2,080 Total intangible assets 3,800 11,990 Less: accumulated amortization (3,705 ) (10,052 ) Intangible assets, net $ 95 $ 1,938 As a result of the divestiture of Perfect Audience on November 21, 2019 (see Note 7), the Company disposed of the developed technology intangible asset associated with the Perfect Audience acquisition from June 2014. Customer relationships were fully amortized as of December 31, 2019. Amortization of intangible assets for 2019 and 2018 was $1,814 and $2,537, respectively. The remaining balance of intangible assets, net, will be fully amortized by the end of the first quarter 2020.

Divestiture of Perfect Audience

Divestiture of Perfect Audience	12 Months Ended
	Dec. 31, 2019
Discontinued Operations And Disposal Groups [Abstract]
Divestiture of Perfect Audience	7. Divestiture of Perfect Audience On November 21, 2019, the Company divested the assets and liabilities related to its Perfect Audience business to unrelated third party SharpSpring, Inc. The Company received net consideration of $4,267, which consisted of $4,566 in cash proceeds, offset by $299 in transaction costs. Net liabilities transferred to SharpSpring, Inc. totaled $797, resulting in a gain on divestiture of $5,064. The transaction did not meet the criteria for discontinued operations, as it did not represent a strategic shift that had, or will have, a major effect on the Company’s operations and financial results. Perfect Audience assets and liabilities on completion of this divestiture were as follows: Accounts receivable $ 55 Prepaid expenses and other current assets 22 Intangible assets, net 28 Accounts payable (321 ) Accrued expenses and other current liabilities (307 ) Customer advances (274 ) Net liabilities transferred $ (797 )

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	8. Fair Value Measurements Account balances measured at fair value on a recurring basis include the following as of the dates presented: December 31, 2019 2018 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash equivalents Money market funds $ 8,723 $ — $ — $ 2,806 $ — $ — The Company’s cash equivalents as of December 31, 2019 and 2018 consisted of money market funds that are classified as level 1. The fair value of the Company’s money market funds approximated amortized cost and, as such, there were no unrealized gains or losses on money market funds as of December 31, 2019 and 2018.

Common and Preferred Stock

Common and Preferred Stock	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Common and Preferred Stock	9. Common and Preferred Stock As of December 31, 2019 and 2018, the Company’s amended certificate of incorporation authorizes the issuance of 142,857 shares of $0.001 par value common stock, and 10,000 shares of $0.001 par value convertible preferred stock.

Shelf Registration and At-the-M

Shelf Registration and At-the-Market Offering	12 Months Ended
	Dec. 31, 2019
Shelf Registration And At The Market Offering [Abstract]
Shelf Registration and At-the-Market Offering	10. Shelf Registration and At-the-Market Offering On March 14, 2019, the Company filed a shelf registration statement on Form S-3 with the SEC, which was declared effective by the SEC on May 10, 2019 and enables the Company to offer its common stock, preferred stock, debt securities, warrants, subscription rights and units having an aggregate offering price of up to $50,000. As part of this shelf registration, the Company entered into an equity distribution agreement with JMP Securities, pursuant to which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $13,000 through an at-the-market offering program administered by JMP Securities. The Company is not required to sell any securities under this offering program. JMP Securities is entitled to compensation of up to 5.0% of the gross proceeds from sales of the Company’s common stock pursuant to the equity distribution agreement. For the year ended December 31, 2019, the Company sold 658 shares of its common stock under this equity distribution agreement and received proceeds of $1,643, net of offering costs of $210, at a weighted average sales price of $2.82 per share. The amount of any future proceeds that may be realized from this equity distribution agreement depends on a variety of factors, including market conditions and the price of the Company’s common stock. As of December 31, 2019, the Company had common stock with an aggregate offering price of up to $11,147 available for issuance under the equity distribution agreement .

Equity Award Plans

Equity Award Plans	12 Months Ended
	Dec. 31, 2019
Equity Award Plans [Abstract]
Equity Award Plans	11. Equity Award Plans In April 2006, the Company’s Board of Directors (the “Board”) adopted and the stockholders approved the 2006 Stock Option Plan (“2006 Plan”), which provided for the grant of incentive and non-statutory stock options. In February 2013, the Board adopted and the stockholders approved the 2013 Equity Incentive Plan (“2013 Plan”), which became effective on March 21, 2013. At that time, the Company ceased to grant equity awards under the 2006 Plan. Under the 2013 Plan, 643 shares of common stock were originally reserved for issuance. Additionally, all reserved and unissued shares under the 2006 Plan are eligible for issuance under the 2013 Plan. The 2013 Plan authorizes the award of incentive and non-statutory stock options, restricted stock awards, stock appreciation rights, RSUs, performance awards and stock bonuses to the Company’s employees, directors, consultants, independent contractors and advisors. On January 1 of each calendar year through 2023, the number of shares of common stock reserved under the 2013 Plan will automatically increase by an amount equal to 5% of the total outstanding shares as of immediately preceding December 31, or such lesser number of shares as determined by the Board. Pursuant to terms of the 2013 Plan, the shares available for issuance increased by 341 shares of common stock on January 1, 2020. As of December 31, 2019, 718 shares of common stock were available for future grants under the 2013 Plan. Stock Options Under the 2006 Plan and the 2013 Plan, the term of options granted may not exceed ten years. Unless the terms of an optionee's stock option agreement provide otherwise, if an optionee's service relationship with the Company, or any of its affiliates, ceases for any reason other than disability or death, the optionee may exercise the vested portion of any options for three months after the date of such termination. If an optionee's service relationship with the Company, or any of its affiliates, ceases due to disability or death (or an optionee dies within a certain period following cessation of service), the optionee or a beneficiary may exercise any vested options for a period of 12 months. In no event, however, may an option be exercised beyond the expiration of its term. A summary of stock option activity under the 2006 Plan and the 2013 Plan is as follows: Options Outstanding Number of Shares Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value Balance at December 31, 2017 436 $ 37.60 7.04 $ 65 Options granted 122 7.06 7.93 Options forfeited and cancelled (122 ) 37.55 — Balance at December 31, 2018 436 $ 29.01 6.79 $ — Options granted 128 4.00 9.37 Options forfeited and cancelled (64 ) 23.19 — Balance at December 31, 2019 500 $ 23.38 5.77 $ — Options exercisable as of December 31, 2019 363 30.35 4.49 — Options vested as of December 31, 2019 363 30.35 4.49 — Options vested and expected to vest as of December 31, 2019 486 23.91 5.68 — The total estimated fair value of options vested during 2019 and 2018 was $410 and $778, respectively. RSUs A summary of RSU activity under the 2013 Plan is as follows: RSUs Outstanding Number of Shares Weighted Average Grant Date Fair Value Per Unit Granted and unvested at December 31, 2017 568 $ 14.22 RSUs granted 709 6.34 RSUs vested (123 ) 14.87 RSUs cancelled and withheld to cover taxes (320 ) 12.75 Granted and unvested at December 31, 2018 834 $ 7.99 RSUs granted 934 3.49 RSUs vested (139 ) 9.57 RSUs cancelled and withheld to cover taxes (525 ) 6.80 Granted and unvested at December 31, 2019 1,104 $ 4.55 Employee Stock Purchase Plan In February 2013, the Board and stockholders approved the 2013 Employee Stock Purchase Plan (“2013 ESPP”), under which 143 shares of common stock were originally reserved for issuance. The 2013 ESPP became effective on March 22, 2013. The 2013 ESPP generally provides for six-month purchase periods and the purchase price for shares of common stock purchased under the 2013 ESPP is 85% of the lesser of the fair market value of the common stock on (1) the first trading day of the applicable offering period and (2) the last trading day of each purchase period in the applicable offering period. On January 1 of each calendar year following the first offering date, the number of shares reserved under the 2013 ESPP automatically increases by an amount equal to 1% of the total outstanding shares as of the immediately preceding December 31, but not to exceed 100 shares. Pursuant to the terms of the 2013 ESPP, the shares available for issuance increased by 68 shares on January 1, 2020. As of December 31, 2019, 138 shares were reserved for issuance under the 2013 ESPP. In 2019 and 2018, 75 and 86 shares, respectively, were issued under the 2013 ESPP.

Stock-Based Compensation Expens

Stock-Based Compensation Expense	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense	12. Stock-Based Compensation Expense The Company recorded stock-based compensation expense of $2,664 and $3,971 for 2019 and 2018, respectively. Stock Options The Company uses the Black-Scholes option-pricing model to estimate the fair value of options. This model requires the input of highly subjective assumptions including the expected volatility, risk-free interest rate and the expected life of options. The Company used the following assumptions for its Black-Scholes option-pricing model for the periods presented: Years Ended December 31, 2019 2018 Dividend yield — — Expected volatility 66.4 % 55.9 % Risk-free interest rate 2.18 % 2.54 % Expected life of options (in years) 4.00 4.00 Weighted-average grant-date fair value $ 2.06 $ 3.20 Weighted-average grant-date exercise price $ 4.00 $ 7.06 The Company estimates the expected volatility of its common stock and expected life of its stock options based on its own historical experience. The expected volatility reflects the actual historical volatility of the price of the Company’s common stock since it began trading publicly in March 2013. The expected life represents the period of time that stock options are expected to be outstanding, based on historical exercise and employee departure behavior. The Company has no history or expectation of paying cash dividends on its common stock. The risk-free interest rate is based on the U.S. Treasury yield for a term consistent with the expected life of the options in effect at the time of grant. The Company recognizes stock-based compensation expense only for those shares expected to vest over the requisite service period of the underlying award. The company determines its estimated forfeiture rated based on an analysis of its actual forfeitures and will continue to evaluate the appropriateness of the forfeiture rate based on recent forfeiture activity and expected future employee turnover, if any. Changes in the estimated forfeiture rate can have a significant effect on reported stock-based compensation expense, as the cumulative effect of adjusting the rate for all expense is recognized in the period the forfeiture estimate is changed. No compensation cost is recorded for stock options that do not vest, and the compensation cost for vested stock options, whether forfeited or not, is not reversed. There were no exercises of stock options in 2019 and 2018. As of December 31, 2019 and 2018, there was $238 and $518, respectively, of unrecognized compensation cost, adjusted for estimated forfeitures, related to options, which is expected to be recognized over a weighted-average period of 1.6 and 1.8 years, respectively. RSUs As of December 31, 2019 and 2018, there was $3,552 and $4,852, respectively, of unrecognized compensation cost, adjusted for estimated forfeitures, related to RSUs, which is expected to be recognized over a weighted-average period of 2.5 years (for both periods). The Company uses the fair market value of the underlying common stock on the dates of grant to determine the fair value of RSUs. Employee Stock Purchase Plan The Company estimates the fair value of purchase rights under the 2013 ESPP using the Black-Scholes valuation model. The fair value of each purchase right under the 2013 ESPP is estimated on the date of grant using the Black-Scholes option valuation model and the straight-line attribution approach with assumptions substantially similar to those used for the valuation of stock option awards, with the exception of the expected life. The expected life is estimated to be six months, which is consistent with the purchase periods under the 2013 ESPP.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	13. Leases Operating and Finance Leases The Company has operating leases for corporate offices worldwide and for space at a data center. As of December 31, 2019, the Company had net operating lease ROU assets of $7,705. Operating lease costs, consisting primarily of rental expense, were approximately $7,838 and $8,420 for the years ended December 31, 2019, and 2018, respectively. Variable rent expense was not material for the year ended December 31, 2019. In 2019, the Company executed lease agreements for new office space in Paris, Dublin, Chicago and London, and exited its prior office space for each of those locations. There were no material costs incurred associated with the exits. As part of the new lease in Paris, the Company was required to enter into an irrevocable $109 letter of credit. The cash used to secure the letter of credit has been classified as restricted cash on the consolidated balance sheet. At various dates between August 2015 and October 2016, the Company entered into finance lease arrangements with two separate manufacturers for computer equipment. These finance leases are collateralized by the underlying computer equipment. As of December 31, 2019, the Company had net finance lease ROU assets of $536. Finance lease ROU assets are included in property and equipment on the consolidated balance sheets. Interest expense associated with finance leases is included within other income, net, on the consolidated statements of comprehensive loss. Finance lease costs for the year ended December 31, 2019 consisted of $729 in depreciation of the leased assets, and $64 in interest expense. Costs associated with capital leases for the year ended December 31, 2018 consisted of $858 in depreciation of the leased assets, and $147 in interest expense. As of December 31, 2019, the weighted-average rate used in discounting the lease liabilities for ROU operating and finance leases was 6.8% and 6.1%, respectively, and the weighted average remaining lease term for ROU operating and finance leases was 2.4 and 0.8 years, respectively. The maturities of operating and finance lease liabilities as of December 31, 2019 are as follows: Operating Leases Finance Leases 2020 $ 4,249 $ 618 2021 3,588 12 2022 1,844 — Total lease payments 9,681 630 Less: Amount representing imputed interest (714 ) (17 ) Present value of lease liabilities 8,967 613 Less: Current portion of lease liabilities (3,786 ) (601 ) Non-current portion of lease liabilities $ 5,181 $ 12 Subleases The Company subleases portions of its San Francisco and Portland office spaces. In August 2018, the Company entered into agreements to (a) extend its existing sublease for a portion of its San Francisco office space through July 2022, and (b) sublease an additional 14,380 square feet of its San Francisco office space to an unrelated third party through July 2020. The Company’s sublease for its Portland office space is with an unrelated third party and expires in May 2020. Income from these sublease agreements is included in other income, net, on the consolidated statements of comprehensive loss. Sublease income for the years ended December 31, 2019 and 2018 was $2,282 and $1,463, Future minimum amounts due under subleases as of December 31, 2019 are as follows: Operating Sublease Income 2020 $ 1,768 2021 1,105 2022 616 Total amounts due under subleases $ 3,489

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes The components of the Company’s loss before benefit from or provision for income taxes are as follows: Years Ended December 31, 2019 2018 United States of America $ (2,589 ) $ (25,375 ) International (9,939 ) (15,283 ) Loss before (benefit from) provision for income taxes $ (12,528 ) $ (40,658 ) The components of the benefit from or provision for income taxes were as follows: Years Ended December 31, 2019 2018 Current income tax provision: Federal $ — $ — State 6 44 Foreign 175 940 Total current income tax provision 181 984 Deferred income tax benefit: Federal — — State — — Foreign (301 ) (398 ) Total deferred income tax benefit (301 ) (398 ) (Benefit from) provision for income taxes $ (120 ) $ 586 The differences in the total benefit from or provision for income taxes that would result from applying the 21% federal statutory rate in 2019 and 2018 to the loss before provision for income taxes and the reported provision for income taxes were as follows: Years Ended December 31, 2019 2018 Tax benefit at U.S. statutory rate $ (2,631 ) $ (8,538 ) Foreign income and withholding taxes 2,115 4,247 State income taxes, net of federal benefit (1,828 ) (1,766 ) Stock-based compensation 1,786 847 Impairment of goodwill 437 3,762 Change in valuation allowance (410 ) 1,402 Provision to return adjustments 336 658 Uncertain tax positions 154 224 Research and development credits 151 (822 ) Other permanent differences 48 45 Other (278 ) 527 (Benefit from) provision for income taxes $ (120 ) $ 586 Major components of the Company’s deferred tax assets and liabilities as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 Non-current deferred tax assets: Net operating loss $ 26,710 $ 27,192 Research and development credits 9,820 9,308 Other credits 4,164 3,237 Operating lease liabilities 1,843 — Stock-based compensation 945 2,519 Property and equipment and intangible assets 238 — Accruals and reserves 111 513 Other 2 35 Gross non-current deferred tax assets 43,833 42,804 Right-of-use assets, operating leases (1,515 ) — Property and equipment and intangible assets — (342 ) Total non-current deferred tax liabilities (1,515 ) (342 ) Total deferred tax assets 42,318 42,462 Valuation allowance (42,216 ) (42,626 ) Net deferred tax assets (liabilities) $ 102 $ (164 ) The Tax Reform Act of 1986, as amended, imposes restrictions on the utilization of net operating losses and tax credit carryforwards in certain situations where changes occur in the stock ownership of a corporation. Utilization of a domestic net operating loss or tax credit carryforward may be subject to a substantial limitation due to ownership changes that may have occurred or that could occur in the future, as required by Internal Revenue Code Section 382 (“IRC Section 382”), as well as similar state provisions. Accordingly, a company’s ability to use net operating losses may be limited as prescribed under IRC Section 382. Events which may cause limitations in the amount of the net operating losses that the Company may use in any one year include, but are not limited to, a cumulative ownership change of more than 50% over a three-year period. The Company last assessed the application of IRC Section 382 during the fourth quarter of 2017 and concluded that no such limitation currently applied. The Company has monitored equity transactions in the periods since the fourth quarter of 2017 and has found no circumstances which would result in a significant change in the Company’s stock ownership. These conclusions are monitored in future periods as circumstances dictate, such as significant changes in the Company's stock ownership. In the event the Company experiences any subsequent changes in ownership, the amount of net operating losses and research and development credit carryovers available in any taxable year could be limited and may expire unutilized. As of December 31, 2019, the Company had federal and state net operating loss carryforwards of approximately $112,724 and $96,395, respectively. The federal net operating loss carryforward will begin expiring in 2027 and the state net operating loss carryforward will begin expiring in 2022. As of December 31, 2019, the Company had federal and state research and development credits of approximately $6,123 and $6,451, respectively. The federal research and development credits will begin expiring in 2026. The state research and development credits are not currently subject to expiration. The Company has recorded a full valuation allowance against its otherwise recognizable deferred income tax assets as of December 31, 2019 and 2018 (except for the deferred income tax assets associated with certain of the Company’s foreign subsidiaries). The Company has determined, after evaluating all positive and negative historical and prospective evidence, that it is more likely than not that the deferred income tax assets will not be realized (except for those associated with certain of the Company's foreign subsidiaries). The valuation allowance decreased by $410 for the year ended December 31, 2019, and increased by $1,402 for the year ended December 31, 2018. The Company files federal, state and foreign income tax returns in jurisdictions with varying statutes of limitations. In the normal course of business, the Company is subject to examination by taxing authorities throughout the world. These audits include questioning the timing and amount of deduction, the nexus of income among various tax jurisdictions and compliance with state, local and foreign tax laws. The Company is not currently under any examination by any federal, state or foreign tax authorities. Because of net operating loss and credit carryforwards, all of the Company’s tax years dating to inception in 2006 remain open to examination. Uncertain Tax Positions As of December 31, 2019 and 2018, the Company had uncertain tax positions of $927 and $1,203, respectively, that if recognized would impact the annual effective tax rate. In 2019 and 2018, the Company did not have any material interest or penalties related to uncertain tax positions. The aggregate changes in the balance of gross uncertain tax positions were as follows: Ending balance as of December 31, 2017 $ 8,424 Increase in balances related to tax positions taken during the current period 778 Decrease in balances related to tax positions taken during the prior period (812 ) Ending balance as of December 31, 2018 8,390 Increase in balances related to tax positions taken during the current period 494 Increase in balances related to tax positions taken during the prior period 208 Decrease in balances related to tax positions taken during the prior period (166 ) Decrease in balances related to lapses in statutes of limitations (308 ) Ending balance as of December 31, 2019 $ 8,618 The Company does not anticipate that the amount of uncertain tax positions relating to tax positions existing at December 31, 2019 will materially increase or decrease within the next twelve months. The Tax Cuts and Jobs Act On December 22, 2017, the United States enacted the Tax Cuts and Jobs Act (“TCJA”), which instituted fundamental changes to the taxation of multinational corporations. Among other provisions, the TCJA imposes a U.S tax on Global Intangible Low Taxed Income (“GILTI”) that is earned by certain foreign subsidiaries, and requires U.S. corporations to elect an accounting policy to either recognize GILTI as a current period expense when incurred or to record deferred taxes for the temporary basis differences expected to reverse in the future as GILTI. The Company did not incur income tax associated with GILTI for the years ended December 31, 2019 and 2018, but elected to recognize GILTI tax as a period cost in the future, as applicable.

Net Loss Per Share Available to

Net Loss Per Share Available to Common Stockholders	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share Available to Common Stockholders	15. Net Loss Per Share Available to Common Stockholders Basic net loss of common stock is calculated by dividing the net loss available to common stockholders by the weighted-average number of shares of common stock outstanding for the period. Diluted net loss per share of common stock is computed by dividing the net loss using the weighted-average number of shares of common stock, excluding common stock subject to repurchase, and, if dilutive, potential shares of common stock outstanding during the period. Basic and diluted net loss per share was the same for all periods presented, as the impact of all potentially dilutive securities outstanding was anti-dilutive. The following table presents the calculation of basic and diluted net loss per share: Years Ended December 31, 2019 2018 Numerator: Net loss available to common stockholders $ (12,408 ) $ (41,244 ) Denominator: Weighted average number of shares, basic and diluted 6,373 5,783 Net loss per share available to common stockholders: Basic and diluted net loss per common share available to common stockholders $ (1.95 ) $ (7.13 ) The following table presents the potential shares of common stock outstanding that were excluded from the computation of diluted net loss per share available to common stockholders for the periods presented because including them would have been anti-dilutive: Years Ended December 31, 2019 2018 Options to purchase common stock 500 436 Unvested RSUs 1,104 834 Total 1,604 1,270

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Reporting	16. Segment Reporting The Company defines the term “chief operating decision maker” to be the Chief Executive Officer. The Chief Executive Officer reviews the financial information presented on a consolidated basis for purposes of allocating resources and evaluating of financial performance. Accordingly, the Company has determined that it operates as a single reporting and operating segment

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies Legal Matters From time to time, the Company may be involved in lawsuits, claims, investigations and proceedings, consisting of intellectual property, commercial, employment and other matters, which arise in the ordinary course of business. In accordance with GAAP, the Company records a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. These provisions are reviewed at least quarterly and adjusted to reflect the impact of negotiations, settlements, ruling, advice of legal counsel and other information and events pertaining to a particular case. Litigation is inherently unpredictable. If any unfavorable ruling was to occur in any specific period or if a loss becomes probable and estimable, there exists the possibility of a material adverse impact on the Company’s results of operations, financial position or cash flows. As of December 31, 2019, no material amounts are recorded related to legal proceedings on the consolidated balance sheet Indemnification The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to the agreements, each party may indemnify, defend and hold the other party harmless with respect to such claim, suit or proceeding brought against it by a third party alleging that the indemnifying party’s intellectual property infringes upon the intellectual property of the third party, or results from a breach of the indemnifying party’s representations and warranties or covenants, or that results from any acts of negligence or willful misconduct. The term of these indemnification agreements is generally perpetual any time after execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited. The Company also indemnifies its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company has a directors’ and officers’ insurance policy that enables the Company to recover a portion of any future amounts paid Other Contingencies The Company is subject to claims and assessments from time to time in the ordinary course of business. The Company’s management does not believe that any such matters, individually or in the aggregate, will have a material adverse effect on the Company’s financial position, results of operations or cash flows

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans	18. Employee Benefit Plans The Company sponsors a 401(k) defined contribution plan covering all employees in the United States. The Board determines contributions made by the Company annually. The Company made no contributions under this plan for 2019 and 2018. The Company also sponsors a statutorily required defined contribution pension plan covering all employees in the United Kingdom. The Company made contributions to this plan of $110 and $87 for the years ended December 31, 2019 and 2018, respectively.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	19. Subsequent Events The recent global outbreak of COVID-19 has disrupted economic markets and the full economic impact, duration and spread of the COVID-19 virus is uncertain at this time and difficult to predict considering the rapidly evolving landscape. As a result, it is not possible to ascertain the overall impact of COVID-19 on the Company’s business. However, if the outbreak continues to evolve into a severe worldwide health crisis, the disease could have a material adverse effect on the Company’s business, results of operations, financial condition and cash flows.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Liquidity	Liquidity
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated upon consolidation.
Accounting Estimates	Accounting Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“GAAP”) requires management to make certain estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company is subject to uncertainties such as the impact of future events, economic and political factors and changes in the Company’s business environment; therefore, actual results could differ from these estimates. Accordingly, the accounting estimates used in the preparation of the Company’s financial statements will change as new events occur, as more experience is acquired, as additional information is obtained and as the Company’s operating environment changes. Changes in estimates are made when circumstances warrant. Such changes in estimates and refinements in estimation methodologies are reflected in reported results of operations and if material, the effects of changes in estimates are disclosed in the notes to the consolidated financial statements. Significant estimates and assumptions by management affect the allowances for doubtful accounts and customer revenue credits, the carrying value of long-lived assets (including goodwill and intangible assets), the useful lives of long-lived assets, the accounting for income taxes and stock-based compensation.
Certain Significant Risks and Uncertainties	Certain Significant Risks and Uncertainties The Company operates in a rapidly changing environment that involves a number of risks, some of which are beyond the Company’s control that could have a material adverse effect on the Company’s business, operating results and financial condition. These risks include, among others, the Company’s history of losses and negative cash flows; the highly competitive environment in which the Company operates; the ability to maintain and increase usage rates of the Company’s platform and the ability for the Company to increase demand for its solutions.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash, cash equivalents and accounts receivable. The Company’s cash and cash equivalents are placed with high-credit-quality financial institutions and issuers, and at times exceed federally insured limits. The Company has not experienced any loss relating to cash and cash equivalents in these accounts. The Company performs periodic credit evaluations of its customers and generally does not require collateral. As of December 31, 2019 and 2018, accounts receivable from one long-term strategic agreement with Google (see Note 3) accounted for 35% and 30%, respectively, of the Company's total accounts receivable, net. Revenues, net from the same long-term strategic agreement accounted for 25% of total revenues, net for the year ended December 31, 2019. No single customer accounted for 10% or more of total revenues, net for the year ended December 31, 2018.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with an original or remaining maturity from the Company’s date of purchase of 90 days or less to be cash equivalents. Deposits held with financial institutions are likely to exceed the amount of insurance on these deposits. Cash equivalents consist of money market funds which are readily convertible into cash and have original maturity dates of less than three months from the date of their respective purchases. Cash equivalents were $8,723 and $2,806 as of December 31, 2019 and 2018, respectively. Restricted cash consists of deposits held with a financial institution to secure the Company’s non-cancelable leases for its corporate headquarters in San Francisco and its office in Paris (see Note 13).
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments, including accounts receivable, accounts payable and accrued expenses are carried at cost, which approximates fair value because of the short-term nature of those instruments. The Company measures and reports certain financial assets at fair value on a recurring basis, including its investments in money market funds. The fair value hierarchy prioritizes the inputs into three broad levels: Level 1 Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 Inputs are unobservable inputs based on the Company’s assumptions. A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement.
Allowances for Doubtful Accounts and Revenue Credits	Allowances for Doubtful Accounts and Revenue Credits The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the Company’s receivables portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available evidence. The Company performs a regular review of its customers’ payment histories and associated credit risks and it does not require collateral from its customers. When collection of an outstanding balance is no longer probably, the Company will either partially or fully write-off the balance against the allowance for doubtful accounts. Certain contracts with advertising agencies contain sequential liability provisions, whereby the agency does not have an obligation to pay the Company until payment is received from the agency’s customers. In these circumstances, the Company evaluates the credit worthiness of the agency’s customers, in addition to the agency itself. The following are changes in the allowance for doubtful accounts for the periods presented. Years Ended December 31, 2019 2018 Balances at beginning of year $ 2,651 $ 4,028 (Reductions) additions to expense (249 ) 48 Write-offs and other deductions (843 ) (1,425 ) Balances at end of year $ 1,559 $ 2,651 From time to time, the Company provides revenue credits to customers. These typically relate to customer disputes and billing adjustments and are recorded as a reduction of revenues, net. Reserves for these revenues credits are accounted for as variable consideration under authoritative revenue recognition guidance (see Note 3) and are estimated based on historical credit activity. As of December 31, 2019 and 2018, the Company recorded an allowance for potential customer revenue credits in the amount of $319 and $353, respectively.
Property and Equipment	Property and Equipment Property and equipment are stated at historical cost less accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the related assets. Upon retirement or sale, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is reflected in operations. Major additions and improvements are capitalized while repairs and maintenance that do not extend the life of the asset are charged to operations as incurred. Depreciation and amortization expense is allocated to both cost of revenues and operating expenses.
Internally Developed Software	Internally Developed Software Costs incurred in the development phase are capitalized and amortized over the product’s estimated useful life, which is three years. The Company expenses all costs incurred that relate to planning and post implementation phases of development. Development phase costs generally include salaries and personnel costs and third-party contractor expenses associated with software development, configuration and coding. Capitalized costs related to internally developed software under development are treated as construction in progress until the program, feature or functionality is ready for its intended use, at which time amortization commences. For 2019 and 2018, the Company capitalized $2,056 and $2,129 of costs related to internally developed software, respectively. Amortization of capitalized costs related to internally developed software was $3,904 and $3,774 for 2019 and 2018, respectively. As of December 31, 2019 and 2018, unamortized internally developed software costs, including construction in progress, totaled $5,124 and $6,972, respectively. Amortization of internally developed software is reflected in cost of revenues. Costs associated with minor enhancements and maintenance are expensed as incurred.
Goodwill, Intangible Assets and Impairment Assessments	Goodwill, Intangible Assets and Impairment Assessments Goodwill represents the excess of the purchase price in a business combination over the fair value of net tangible and intangible assets acquired. Intangible assets that are not considered to have an indefinite useful life are amortized over their useful lives, which range from two to six years. Estimated remaining useful lives of purchased intangible assets are evaluated to assess whether events or changes in circumstances warrant a revision to the remaining periods of amortization. The Company evaluates goodwill for impairment in the fourth quarter of its fiscal year annually, or more frequently if events or changes in circumstances indicate that goodwill may be impaired. For the purposes of impairment testing, the Company has determined that it has one reporting unit. The Company performs its goodwill impairment test using the simplified method, whereby the fair value of this reporting unit is compared to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that reporting unit, goodwill is not considered impaired. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then goodwill is considered impaired by an amount equal to that difference. In November 2019, the Company performed an impairment assessment of goodwill in conjunction with the divestiture of its Perfect Audience business to SharpSpring, Inc., an unrelated third party. The assessment was performed utilizing the simplified method, and resulted in an impairment of goodwill of $1,910 at that time, reducing the goodwill balance to zero. Similarly, the Company performed an interim goodwill impairment test in the third quarter of 2018 due to a decline in the market capitalization of the Company’s common stock, which resulted in a charge for the impairment of $14,740 for the year ended December 31, 2018. Refer to Note 6 for further details on the Company’s goodwill impairment tests.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates long-lived assets, excluding goodwill, for potential impairment whenever adverse events or changes in circumstances or business climate indicate that expected undiscounted future cash flows related to such long-lived assets may not be sufficient to support the net book value of such assets. An impairment loss is recognized only if the carrying value of a long-lived asset or asset group is not recoverable and exceeds its fair value. The carrying value of a long-lived asset or asset group is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. There were no such impairment losses in 2019 and 2018.
Leases	Leases The Company has operating leases for corporate offices worldwide and for space at a data center. Additionally, the Company leases computer equipment through various finance leases. New contractual arrangements are evaluated at inception to determine if the contract is or contains a lease. For any contracts that are or contain a lease, the Company determines the appropriate classification of each identified lease as operating or finance. For all identified leases, the Company records the related lease liabilities and right-of-use (“ROU”) assets based on the future minimum lease payments over the lease term, which only includes options to renew the lease if it is reasonably certain that the Company will exercise that option. For leases with original terms of 12 months or less, the Company recognizes the lease expense as incurred and does not recognize lease liabilities and ROU assets. Lease liabilities are measured based on the future minimum lease payments discounted over the lease term. The Company uses the discount rate implicit in the lease whenever that rate is readily determinable. For leases where no such rate is determinable, the Company uses its incremental borrowing rate, or the rate of interest that Company would have to pay to borrow an amount equal to the lease payments, on a collateralized basis over a similar term and in a similar economic environment. Current and non-current operating lease liabilities are presented on the consolidated balance sheet beginning January 1, 2019, while current finance lease liabilities are included in accrued expenses and other current liabilities, and non-current finance lease liabilities are included in other long-term liabilities on the consolidated balance sheets. Balances classified as capital lease obligations under previous lease guidance are presented for all periods prior to 2019 to conform to the presentation of finance lease liabilities. ROU assets are measured based on the associated lease liabilities, adjusted for any lease incentives such as tenant improvement allowances. ROU assets for operating leases are presented as non-current assets on the condensed consolidated balance sheet beginning January 1, 2019, while ROU assets for finance leases are included within property and equipment, net. For operating leases, the Company recognizes the expense for lease payments on straight-line basis over the lease term. See Note 13 for further discussion on the Company’s leases.
Revenue Recognition	Revenue Recognition The Company generates revenues principally from subscriptions either directly with advertisers or with advertising agencies to its platform for the management of search, social and eCommerce advertising. The Company also generates revenues from strategic agreements with certain leading publishers. Under these strategic agreements, the Company receives consideration based on a percentage of the search advertising spend that customers manage on its platform. Revenues are recognized when control of these services is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those services. See Note 3 for further discussion on the Company's revenues.
Cost of Revenues	Cost of Revenues Cost of revenues primarily consists of costs related to hosting the Company’s cloud-based platform, providing implementation and ongoing customer support, data communications expenses, salaries and benefits of operations and support personnel, software license fees, costs associated with website development activities, indirect overhead, amortization expense associated with capitalized internally developed software and intangible assets and property and equipment depreciation.
Stock-Based Compensation Expense	Stock-Based Compensation Expense Stock-based compensation expense is measured at grant date based on the fair value of the award and is expensed on a straight-line basis over the requisite service period. Restricted stock units (“RSUs”) are measured based on the fair market values of the underlying common stock on the dates of grant. Shares of common stock are issued on the vesting dates. Fair values of stock option awards are determined on the date of grant using the Black-Scholes option-pricing model. In applying this option-pricing model, the Company’s determination of the fair value of the stock option award on the date of grant is affected by the Company’s fair value of its common stock, as well as assumptions regarding a number of subjective variables. These variables include, but are not limited to, the Company’s expected stock price volatility, actual and projected stock option exercise behaviors and risk-free interest rate. For stock option and RSU awards with time-based vesting, the Company recognizes stock-based compensation expense over the requisite service period using the straight-line method, based on awards ultimately expected to vest. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. See Note 11 and Note 12 for further information.
Research and Development	Research and Development Research and development costs are expensed as incurred, except for certain internal software development costs, which may be capitalized as noted above. Research and development costs consist of personnel costs, including salaries, stock-based compensation expense, benefits and bonuses, as well as non-personnel costs such as professional fees payable to third-party development resources, amortization of intangible assets and allocated overhead costs.
Advertising and Promotion	Advertising and Promotion Advertising and promotional costs are expensed as incurred and included in sales and marketing expense in the accompanying consolidated statements of comprehensive loss. Advertising and promotion expense totaled $463 and $494 for 2019 and 2018, respectively.
Sales Taxes	Sales Taxes Sales and other taxes collected from customers and remitted to governmental authorities are presented on a net basis and thus excluded from revenues.
Foreign Currency	Foreign Currency For international subsidiaries whose functional currency is not the U.S. Dollar, we re-measure the monetary assets and liabilities of these subsidiaries to U.S. Dollars using rates of exchange in effect at the balance sheet date. Nonmonetary assets and liabilities are re-measured to U.S. Dollars using historical exchange rates, and other accounts are re-measured using average exchange rates in effect during each period presented. The effects of foreign currency translation adjustments are included in stockholders’ equity as a component of accumulated other comprehensive loss on the accompanying consolidated balance sheets, and related periodic movements are summarized as a line item in the consolidated statements of comprehensive loss. The Company records net gains and losses resulting from foreign exchange transactions as a component of other income, net. Aggregate foreign currency (losses) gains included in determining net loss were $(31) and $205 for 2019 and 2018, respectively.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement and tax basis of assets and liabilities and net operating loss and credit carryforwards using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company accounts for uncertain tax positions using a more-likely-than-not threshold for financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. The Company establishes a liability for tax-related uncertainties based on estimates of whether, and the extent to which, additional taxes will be due. The Company records an income tax liability, if any, for the difference between the benefit recognized and measured and the tax position taken or expected to be taken on the Company’s tax returns. To the extent that the assessment of such tax positions changes, the change in estimate is recorded in the period in which the determination is made. The liability is adjusted in light of changing facts and circumstances, such as the outcome of a tax audit. The provision for income taxes includes changes to the liabilities that are considered appropriate. The Company would recognize interest and penalties related to uncertain tax positions as income tax expense, though such amounts were not material in 2019 or 2018. The Company does not expect that changes in the liability for uncertain tax positions for the next twelve months will have a material impact on the Company’s consolidated financial position or results of operations.
Recently Accounting Pronouncements Adopted	Recently Accounting Pronouncements Adopted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases As a result of the adoption, the Company recorded ROU assets of $14,589 and lease liabilities of $16,425 related to operating leases on January 1, 2019. ASC 842 did not have a material impact on the Company’s consolidated statement of comprehensive loss for the year ended December 31, 2019. Refer to Note 13 for further information on leases. In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income – Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
Recent Accounting Pronouncements Not Yet Effective	Recent Accounting Pronouncements Not Yet Effective In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses – Measurement of Credit Losses on Financial Instruments In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software In December 2019, the FASB issues ASU 2019-12, Income Taxes – Simplifying the Accounting for Income Taxes simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step up in the tax basis of goodwill, and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Changes in Allowance for Doubtful Accounts	The following are changes in the allowance for doubtful accounts for the periods presented. Years Ended December 31, 2019 2018 Balances at beginning of year $ 2,651 $ 4,028 (Reductions) additions to expense (249 ) 48 Write-offs and other deductions (843 ) (1,425 ) Balances at end of year $ 1,559 $ 2,651

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Expected Future Revenue for Subscription Services Related to Performance Obligations Unsatisfied or Partially Unsatisfied	Expected future revenues for subscription services related to performance obligations that are unsatisfied (or partially unsatisfied) as of December 31, 2019 were as follows: Subscription Services Revenues 2020 $ 2,905 2021 777 2022 39 Total $ 3,721
Disaggregation of Revenues, Net	Revenues, net by geographic area, based on the billing location of the customer, were as follows for the periods presented: Years Ended December 31, 2019 2018 United States of America $ 36,718 $ 40,907 United Kingdom 5,489 7,664 Other (1) 6,829 10,060 Total revenues, net $ 49,036 $ 58,631 (1) No individual country within the “Other” category accounted for 10% or more of revenues, net for any period presented. Revenues, net by nature of services performed were as follows for the periods presented: Years Ended December 31, 2019 2018 Subscriptions $ 36,702 $ 54,532 Strategic agreements 12,334 4,099 Total revenues, net $ 49,036 $ 58,631
Changes in Balances of Deferred Costs to Obtain and Fulfill Contracts	Changes in the balances of deferred costs to obtain and fulfill contracts during the year ended December 31, 2019 were as follows: Deferred Costs to Obtain Contracts Deferred Costs to Fulfill Contracts Balances at December 31, 2018 $ 1,413 $ 606 Costs deferred 393 182 Amortization (1,027 ) (507 ) Balances at December 31, 2019 $ 779 $ 281

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2019
Balance Sheet Components [Abstract]
Components of Property and Equipment	The following table shows the components of property and equipment as of the dates presented: December 31, Estimated Useful Life 2019 2018 Software, including internally developed software 3 years $ 27,974 $ 25,518 Computer equipment 3 to 4 years 22,424 22,714 Finance lease ROU assets 4 years 5,067 5,067 Leasehold improvements Shorter of useful life or lease term 4,631 4,778 Office equipment, furniture and fixtures 3 to 5 years 1,986 2,140 Total property and equipment 62,082 60,217 Less: Accumulated depreciation and amortization (53,558 ) (48,402 ) Property and equipment, net $ 8,524 $ 11,815
Components of Accrued Expenses and Other Current Liabilities	The following table shows the components of accrued expenses and other current liabilities as of the dates presented: December 31, 2019 2018 Accrued salary and payroll-related expenses $ 3,204 $ 3,695 Deferred strategic agreement revenues 2,182 934 Accrued liabilities 1,165 866 Finance lease liabilities 601 1,249 Income taxes payable 480 883 Advanced billings 376 859 Sales and use tax payable 9 244 Deferred rent — 538 Customer advances — 432 Other 993 932 Total accrued expenses and other current liabilities $ 9,010 $ 10,632

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Activity of Goodwill	The goodwill activity for the year ended December 31, 2019 consisted of the following: Balance at December 31, 2018 $ 1,943 Impairment (1,910 ) Foreign currency translation adjustments (33 ) Balance at December 31, 2019 $ —
Summary of Intangible Assets	Intangible assets consisted of the following as of the dates presented: Estimated December 31, Useful Life 2019 2018 Developed technology 5 to 6 years $ 3,800 $ 9,910 Customer relationships 4 years — 2,080 Total intangible assets 3,800 11,990 Less: accumulated amortization (3,705 ) (10,052 ) Intangible assets, net $ 95 $ 1,938

Divestiture of Perfect Audien_2

Divestiture of Perfect Audience (Tables)	12 Months Ended
	Dec. 31, 2019
Discontinued Operations And Disposal Groups [Abstract]
Summary of Assets and Liabilities on Completion of this Divestiture	Perfect Audience assets and liabilities on completion of this divestiture were as follows: Accounts receivable $ 55 Prepaid expenses and other current assets 22 Intangible assets, net 28 Accounts payable (321 ) Accrued expenses and other current liabilities (307 ) Customer advances (274 ) Net liabilities transferred $ (797 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Account Balances Measured at Fair Value on Recurring Basis	Account balances measured at fair value on a recurring basis include the following as of the dates presented: December 31, 2019 2018 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash equivalents Money market funds $ 8,723 $ — $ — $ 2,806 $ — $ —

Equity Award Plans (Tables)

Equity Award Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Equity Award Plans [Abstract]
Summary of Stock Option Activity	A summary of stock option activity under the 2006 Plan and the 2013 Plan is as follows: Options Outstanding Number of Shares Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value Balance at December 31, 2017 436 $ 37.60 7.04 $ 65 Options granted 122 7.06 7.93 Options forfeited and cancelled (122 ) 37.55 — Balance at December 31, 2018 436 $ 29.01 6.79 $ — Options granted 128 4.00 9.37 Options forfeited and cancelled (64 ) 23.19 — Balance at December 31, 2019 500 $ 23.38 5.77 $ — Options exercisable as of December 31, 2019 363 30.35 4.49 — Options vested as of December 31, 2019 363 30.35 4.49 — Options vested and expected to vest as of December 31, 2019 486 23.91 5.68 —
Summary of RSU Activity	A summary of RSU activity under the 2013 Plan is as follows: RSUs Outstanding Number of Shares Weighted Average Grant Date Fair Value Per Unit Granted and unvested at December 31, 2017 568 $ 14.22 RSUs granted 709 6.34 RSUs vested (123 ) 14.87 RSUs cancelled and withheld to cover taxes (320 ) 12.75 Granted and unvested at December 31, 2018 834 $ 7.99 RSUs granted 934 3.49 RSUs vested (139 ) 9.57 RSUs cancelled and withheld to cover taxes (525 ) 6.80 Granted and unvested at December 31, 2019 1,104 $ 4.55

Stock-Based Compensation Expe_2

Stock-Based Compensation Expense (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Assumptions for Black-Scholes Option-Pricing Model	The Company used the following assumptions for its Black-Scholes option-pricing model for the periods presented: Years Ended December 31, 2019 2018 Dividend yield — — Expected volatility 66.4 % 55.9 % Risk-free interest rate 2.18 % 2.54 % Expected life of options (in years) 4.00 4.00 Weighted-average grant-date fair value $ 2.06 $ 3.20 Weighted-average grant-date exercise price $ 4.00 $ 7.06

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Maturities of Lease Liabilities	The maturities of operating and finance lease liabilities as of December 31, 2019 are as follows: Operating Leases Finance Leases 2020 $ 4,249 $ 618 2021 3,588 12 2022 1,844 — Total lease payments 9,681 630 Less: Amount representing imputed interest (714 ) (17 ) Present value of lease liabilities 8,967 613 Less: Current portion of lease liabilities (3,786 ) (601 ) Non-current portion of lease liabilities $ 5,181 $ 12
Future Minimum Amounts Due Under Subleases	Future minimum amounts due under subleases as of December 31, 2019 are as follows: Operating Sublease Income 2020 $ 1,768 2021 1,105 2022 616 Total amounts due under subleases $ 3,489

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Loss Before Benefit from or Provision for Income Taxes	The components of the Company’s loss before benefit from or provision for income taxes are as follows: Years Ended December 31, 2019 2018 United States of America $ (2,589 ) $ (25,375 ) International (9,939 ) (15,283 ) Loss before (benefit from) provision for income taxes $ (12,528 ) $ (40,658 )
Schedule of Components of Benefit from or Provision for Income Taxes	The components of the benefit from or provision for income taxes were as follows: Years Ended December 31, 2019 2018 Current income tax provision: Federal $ — $ — State 6 44 Foreign 175 940 Total current income tax provision 181 984 Deferred income tax benefit: Federal — — State — — Foreign (301 ) (398 ) Total deferred income tax benefit (301 ) (398 ) (Benefit from) provision for income taxes $ (120 ) $ 586
Differences in Total Benefit from or Provision for Income Taxes	The differences in the total benefit from or provision for income taxes that would result from applying the 21% federal statutory rate in 2019 and 2018 to the loss before provision for income taxes and the reported provision for income taxes were as follows: Years Ended December 31, 2019 2018 Tax benefit at U.S. statutory rate $ (2,631 ) $ (8,538 ) Foreign income and withholding taxes 2,115 4,247 State income taxes, net of federal benefit (1,828 ) (1,766 ) Stock-based compensation 1,786 847 Impairment of goodwill 437 3,762 Change in valuation allowance (410 ) 1,402 Provision to return adjustments 336 658 Uncertain tax positions 154 224 Research and development credits 151 (822 ) Other permanent differences 48 45 Other (278 ) 527 (Benefit from) provision for income taxes $ (120 ) $ 586
Schedule of Components of Deferred Tax Assets and Liabilities	Major components of the Company’s deferred tax assets and liabilities as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 Non-current deferred tax assets: Net operating loss $ 26,710 $ 27,192 Research and development credits 9,820 9,308 Other credits 4,164 3,237 Operating lease liabilities 1,843 — Stock-based compensation 945 2,519 Property and equipment and intangible assets 238 — Accruals and reserves 111 513 Other 2 35 Gross non-current deferred tax assets 43,833 42,804 Right-of-use assets, operating leases (1,515 ) — Property and equipment and intangible assets — (342 ) Total non-current deferred tax liabilities (1,515 ) (342 ) Total deferred tax assets 42,318 42,462 Valuation allowance (42,216 ) (42,626 ) Net deferred tax assets (liabilities) $ 102 $ (164 )
Schedule of Changes in Uncertain Tax Positions	The aggregate changes in the balance of gross uncertain tax positions were as follows: Ending balance as of December 31, 2017 $ 8,424 Increase in balances related to tax positions taken during the current period 778 Decrease in balances related to tax positions taken during the prior period (812 ) Ending balance as of December 31, 2018 8,390 Increase in balances related to tax positions taken during the current period 494 Increase in balances related to tax positions taken during the prior period 208 Decrease in balances related to tax positions taken during the prior period (166 ) Decrease in balances related to lapses in statutes of limitations (308 ) Ending balance as of December 31, 2019 $ 8,618

Net Loss Per Share Available _2

Net Loss Per Share Available to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Net Loss Per Share	The following table presents the calculation of basic and diluted net loss per share: Years Ended December 31, 2019 2018 Numerator: Net loss available to common stockholders $ (12,408 ) $ (41,244 ) Denominator: Weighted average number of shares, basic and diluted 6,373 5,783 Net loss per share available to common stockholders: Basic and diluted net loss per common share available to common stockholders $ (1.95 ) $ (7.13 )
Schedule of Potential Shares Common Stock Outstanding Excluded from Computation of Diluted Net Loss Per Share	The following table presents the potential shares of common stock outstanding that were excluded from the computation of diluted net loss per share available to common stockholders for the periods presented because including them would have been anti-dilutive: Years Ended December 31, 2019 2018 Options to purchase common stock 500 436 Unvested RSUs 1,104 834 Total 1,604 1,270

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Reportingunit	Dec. 31, 2018USD ($)	Jan. 01, 2019USD ($)	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Net loss	$ (12,408)	$ (41,244)
Accumulated deficit	(277,112)	(264,713)
Cash, cash equivalents and restricted cash	$ 12,105	11,503		$ 28,837
Percentage of reduction in expenses	30.00%
Allowance for potential customer revenue credits	$ 319	353
Payments to develop software	2,056	2,129
Amortization of capitalized costs	3,904	3,774
Unamortized internally developed software costs, including construction in progress	$ 5,124	6,972
Number of reporting unit | Reportingunit	1
Impairment of goodwill	$ 1,910	14,740
Goodwill	0	1,943
Impairment of long-lived assets held-for-use	0	0
Advertising and promotion expense	463	494
Aggregate foreign currency (losses) gains	(31)	205
Right-of-use assets, operating leases	7,705	0
Lease liability	$ 8,967
ASU 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Right-of-use assets, operating leases			$ 14,589
Lease liability			$ 16,425
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	2 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	6 years
Software and Software Development Costs [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents, fair value disclosure	$ 8,723	$ 2,806
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of major customers		0
Google [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk	35.00%	30.00%
Google [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk	25.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Balances	$ 2,651	$ 4,028
(Reductions) additions to expense	(249)	48
Write-offs and other deductions	(843)	(1,425)
Balances	$ 1,559	$ 2,651

Revenues - Additional Informati

Revenues - Additional Information (Details) - USD ($)	Jan. 01, 2018	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Accumulated deficit		$ (277,112,000)	$ (264,713,000)
Subscription contracts term		1 year
Unsatisfied performance obligation on subscription contract term		1 year
Revenues		$ 49,036,000	58,631,000
Remaining performance obligation		$ 3,721,000
Individual customer advances refund claim period		180 days
Breakage revenues	$ 1,445,000
Customer advances	558,000	$ 0	432,000
Breakage revenues recognized		203,000	213,000
Deferred strategic agreement revenues		$ 2,182,000	934,000
Deferred costs expected period of benefit		30 months
Impairment losses related to costs capitalized		$ 0	0
Google [Member]
Disaggregation Of Revenue [Line Items]
Strategic agreement term		3 years
Strategic agreement term, optional renewal term		1 year
Revenues		$ 12,203,000	2,933,000
Remaining performance obligation		94,000
Accounts receivable		$ 3,101,000	$ 3,867,000
Maximum [Member]
Disaggregation Of Revenue [Line Items]
Subscription contracts term		2 years
Advance advertiser invoicing period		12 months
Maximum [Member] | Google [Member]
Disaggregation Of Revenue [Line Items]
Strategic agreement term		2 years
Minimum [Member]
Disaggregation Of Revenue [Line Items]
Advance advertiser invoicing period		3 months
Subscription remaining performance obligations expected duration		1 year
ASC 606 [Member]
Disaggregation Of Revenue [Line Items]
Accumulated deficit	$ 4,235,000

Revenues - Expected Future Reve

Revenues - Expected Future Revenue for Subscription Services Related to Performance Obligations Unsatisfied or Partially Unsatisfied (Details) $ in Thousands	Dec. 31, 2019USD ($)
Disaggregation Of Revenue [Line Items]
Subscription Services Revenues	$ 3,721
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Disaggregation Of Revenue [Line Items]
Subscription Services Revenues	$ 2,905
Remaining performance obligation, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Disaggregation Of Revenue [Line Items]
Subscription Services Revenues	$ 777
Remaining performance obligation, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Disaggregation Of Revenue [Line Items]
Subscription Services Revenues	$ 39
Remaining performance obligation, satisfaction period	1 year

Revenues - Expected Future Re_2

Revenues - Expected Future Revenue for Subscription Services Related to Performance Obligations Unsatisfied or Partially Unsatisfied (Details1) $ in Thousands	Dec. 31, 2019USD ($)
Revenue From Contract With Customer [Abstract]
Subscription Services Revenues	$ 3,721

Revenues - Additional Informa_2

Revenues - Additional Information (Details1) $ in Thousands	Dec. 31, 2019USD ($)
Disaggregation Of Revenue [Line Items]
Remaining performance obligation	$ 3,721
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Disaggregation Of Revenue [Line Items]
Remaining performance obligation	$ 2,905
Remaining performance obligation, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Disaggregation Of Revenue [Line Items]
Remaining performance obligation	$ 777
Remaining performance obligation, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Disaggregation Of Revenue [Line Items]
Remaining performance obligation	$ 39
Remaining performance obligation, satisfaction period	1 year
Google [Member]
Disaggregation Of Revenue [Line Items]
Remaining performance obligation	$ 94
Google [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Disaggregation Of Revenue [Line Items]
Remaining performance obligation	$ 9,082
Remaining performance obligation, satisfaction period	1 year

Revenues - Revenues, Disaggrega

Revenues - Revenues, Disaggregation of Revenues, Net (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenues		$ 49,036	$ 58,631
Subscriptions [Member]
Disaggregation Of Revenue [Line Items]
Revenues		36,702	54,532
Strategic Agreements [Member]
Disaggregation Of Revenue [Line Items]
Revenues		12,334	4,099
United States of America [Member]
Disaggregation Of Revenue [Line Items]
Revenues		36,718	40,907
United Kingdom [Member]
Disaggregation Of Revenue [Line Items]
Revenues		5,489	7,664
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues	[1]	$ 6,829	$ 10,060
[1]	No individual country within the “Other” category accounted for 10% or more of revenues, net for any period presented.

Revenues - Changes in Balances

Revenues - Changes in Balances of Deferred Costs to Obtain and Fulfill (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Deferred Costs to Obtain Contracts [Member]
Capitalized Contract Cost [Line Items]
Balance at beginning of period	$ 1,413
Costs deferred	393
Amortization	(1,027)
Balance at end of period	779
Deferred Costs to Fulfill Contracts [Member]
Capitalized Contract Cost [Line Items]
Balance at beginning of period	606
Costs deferred	182
Amortization	(507)
Balance at end of period	$ 281

Restructuring Activities - Addi

Restructuring Activities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
2019 Restructuring Plan [Member]
Restructuring Cost And Reserve [Line Items]
Percentage headcount reduction	6.00%
Restructuring related expenses	$ 268,000
Unpaid remained associated cost amount	$ 208,000
2018 Restructuring Plan [Member]
Restructuring Cost And Reserve [Line Items]
Percentage headcount reduction	13.00%
Restructuring related expenses	$ 229,000	$ 1,276,000
Unpaid remained associated cost amount	$ 0

Balance Sheet Components - Comp

Balance Sheet Components - Components of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 62,082	$ 60,217
Less: Accumulated depreciation and amortization	(53,558)	(48,402)
Property and equipment, net	8,524	11,815
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 22,424	22,714
Computer Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	3 years
Computer Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	4 years
Software, Including Internally Developed Software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 27,974	25,518
Estimated useful life	3 years
Finance Lease ROU Assets [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 5,067	5,067
Estimated useful life	4 years
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,631	4,778
Office Equipment, Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,986	$ 2,140
Office Equipment, Furniture and Fixtures [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	3 years
Office Equipment, Furniture and Fixtures [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	5 years

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Components [Abstract]
Depreciation and amortization	$ 5,838	$ 6,432

Balance Sheet Components - Co_2

Balance Sheet Components - Components of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Balance Sheet Components [Abstract]
Accrued salary and payroll-related expenses	$ 3,204	$ 3,695
Deferred strategic agreement revenues	2,182	934
Accrued liabilities	1,165	866
Finance lease liabilities	601	1,249
Income taxes payable	480	883
Advanced billings	376	859
Sales and use tax payable	9	244
Deferred rent	0	538
Customer advances	0	432	$ 558
Other	993	932
Total accrued expenses and other current liabilities	$ 9,010	$ 10,632

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill, Impairment Loss	$ 1,910	$ 14,740
Goodwill	0	1,943
Amortization of intangible assets	$ 1,814	$ 2,537

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Activity of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Balance at beginning of period	$ 1,943
Impairment	(1,910)	$ (14,740)
Foreign currency translation adjustments	(33)
Balance at end of period	$ 0	$ 1,943

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 3,800	$ 11,990
Less: accumulated amortization	(3,705)	(10,052)
Intangible assets, net	$ 95	1,938
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	2 years
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	6 years
Developed Technology [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 3,800	9,910
Developed Technology [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	5 years
Developed Technology [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	6 years
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 0	$ 2,080
Estimated useful life	4 years

Divesture of Perfect Audience -

Divesture of Perfect Audience - Additional Information (Details) - USD ($) $ in Thousands	Nov. 21, 2019	Dec. 31, 2019	Dec. 31, 2018
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net consideration from Divestiture		$ 4,267	$ 0
Gain on divestiture		$ 5,064	$ 0
Perfect Audience [Member] | Disposed by Sale [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net consideration from Divestiture	$ 4,267
Cash proceeds from divestiture	4,566
Transaction costs	299
Net liabilities transferred	(797)
Gain on divestiture	$ 5,064

Divesture of Perfect Audience_2

Divesture of Perfect Audience - Summary of Assets and Liabilities on Completion of this Divestiture (Details) - Perfect Audience [Member] - Disposed by Sale [Member] $ in Thousands	Nov. 21, 2019USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Accounts receivable	$ 55
Prepaid expenses and other current assets	22
Intangible assets, net	28
Accounts payable	(321)
Accrued expenses and other current liabilities	(307)
Customer advances	(274)
Net liabilities transferred	$ (797)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Account Balances Measured at Fair Value on Recurring Basis (Details) - Money Market Funds [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 8,723	$ 2,806
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	8,723	2,806
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Unrealized gains (losses) on money market funds	$ 0	$ 0

Common and Preferred Stock- Add

Common and Preferred Stock- Additional Information (Details) - $ / shares shares in Thousands	Dec. 31, 2019	Dec. 31, 2018
Class Of Stock Disclosures [Abstract]
Common stock, shares authorized	142,857	142,857
Common stock, par value	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized	10,000	10,000
Convertible preferred stock, par value	$ 0.001	$ 0.001

Shelf Registration and At-the_2

Shelf Registration and At-the-Market Offering - Additional Information (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)$ / sharesshares
Registration Payment Arrangement [Line Items]
Issuance of common stock (in shares) | shares	658
Proceeds from sales	$ 1,643
Offering costs	$ 210
Weighted average sales price (in dollars per share) | $ / shares	$ 2.82
Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 50,000
Compensation percentage	5.00%
Common stock aggregate offering price available for issuance	$ 11,147
JMP Securities [Member] | Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 13,000

Equity Award Plans - Additional

Equity Award Plans - Additional Information (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 28, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, vested in period, fair value		$ 410	$ 778
2013 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)		718,000		643,000
Percentage of increase in outstanding common shares		5.00%
2013 Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, expiration period		10 years
2013 Plan [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in shares available for issuance (in shares)	341,000
2006 Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, expiration period		10 years
2013 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)		138,000		143,000
Percentage of lesser of fair market value of common stock		85.00%
Percentage of increase in outstanding shares		1.00%
Stock issued during period (in shares)		75,000	86,000
2013 Employee Stock Purchase Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in shares available for issuance, authorized (in shares)		100,000
2013 Employee Stock Purchase Plan [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in shares available for issuance (in shares)	68,000

Equity Award Plans - Summary of

Equity Award Plans - Summary of Stock Option Activity (Details) - 2006 and 2013 Plan [Member] - Stock Options [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Balance at beginning of period	436	436
Options granted	128	122
Options forfeited and cancelled	(64)	(122)
Balance at end of period	500	436	436
Options exercisable as of December 31, 2019	363
Options vested as of December 31, 2019	363
Options vested and expected to vest as of December 31, 2019	486
Weighted Average Exercise Price Per Share
Balance at beginning of period	$ 29.01	$ 37.60
Options granted	4	7.06
Options forfeited and cancelled	23.19	37.55
Balance at end of period	23.38	$ 29.01	$ 37.60
Options exercisable as of December 31, 2019	30.35
Options vested as of December 31, 2019	30.35
Options vested and expected to vest as of December 31, 2019	$ 23.91
Weighted Average Remaining Contractual Term (in Years)
Options outstanding	5 years 9 months 7 days	6 years 9 months 14 days	7 years 14 days
Options granted	9 years 4 months 13 days	7 years 11 months 4 days
Options exercisable	4 years 5 months 26 days
Options vested	4 years 5 months 26 days
Options vested and expected to vest	5 years 8 months 4 days
Aggregate Intrinsic Value
Options outstanding	$ 0	$ 0	$ 65

Equity Award Plans - Summary _2

Equity Award Plans - Summary of RSU Activity (Details) - 2013 Plan [Member] - RSUs [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Granted and unvested at beginning of period	834	568
RSUs granted	934	709
RSUs vested	(139)	(123)
RSUs cancelled and withheld to cover taxes	(525)	(320)
Granted and unvested at end of period	1,104	834
Weighted Average Grant Date Fair Value Per Unit
Granted and unvested at beginning of period	$ 7.99	$ 14.22
RSUs granted	3.49	6.34
RSUs vested	9.57	14.87
RSUs cancelled and withheld to cover taxes	6.80	12.75
Granted and unvested at end of period	$ 4.55	$ 7.99

Stock-Based Compensation Expe_3

Stock-Based Compensation Expense - Additional Information (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 2,664	$ 3,971
Expected life	6 months
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options exercised (in shares)	0	0
Unrecognized compensation cost related to options	$ 238	$ 518
Share-based compensation, weighted average recognized period	1 year 7 months 6 days	1 year 9 months 18 days
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, weighted average recognized period	2 years 6 months	2 years 6 months
Unrecognized compensation cost related to RSUs	$ 3,552	$ 4,852

Stock-Based Compensation Expe_4

Stock-Based Compensation Expense - Assumptions for Black-Scholes Option-Pricing Model (Details) - Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Assumptions for Black-Scholes Option Pricing Model [Abstract]
Dividend yield	0.00%	0.00%
Expected volatility	66.40%	55.90%
Risk-free interest rate	2.18%	2.54%
Expected life of options (in years)	4 years	4 years
Weighted-average grant-date fair value	$ 2.06	$ 3.20
Weighted-average grant-date exercise price	$ 4	$ 7.06

Leases - Additional Information

Leases - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)ft²Manufacturer	Dec. 31, 2018USD ($)
Lessee Lease Description [Line Items]
Right-of-use assets, operating leases	$ 7,705,000	$ 0
Operating leases, rent expense	$ 7,838,000	8,420,000
Number of manufacturers entered into finance lease arrangements | Manufacturer	2
Finance lease, right-of-use asset	$ 536,000
Depreciation of finance lease assets	729,000	858,000
Finance lease, interest expense	$ 64,000	147,000
Weighted average discount rate, operating lease	6.80%
Weighted average discount rate, finance lease	6.10%
Weighted average remaining lease term, operating lease	2 years 4 months 24 days
Weighted average remaining lease term, finance lease	9 months 18 days
Additional area subleased | ft²	14,380
Sublease income	$ 2,282,000	$ 1,463,000
Letter of Credit [Member]
Lessee Lease Description [Line Items]
Maximum borrowing capacity	$ 109,000

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Maturities of Operating Lease Liabilities [Abstract]
2020	$ 4,249
2021	3,588
2022	1,844
Total lease payments	9,681
Less: Amount representing imputed interest	(714)
Present value of lease liabilities	8,967
Less: Current portion of lease liabilities	(3,786)	$ 0
Non-current portion of lease liabilities	5,181	0
Maturities of Finance Lease Liabilities [Abstract]
2020	618
2021	12
2022	0
Total lease payments	630
Less: Amount representing imputed interest	(17)
Present value of lease liabilities	613
Less: Current portion of lease liabilities	(601)	$ (1,249)
Non-current portion of lease liabilities	$ 12

Leases - Future Minimum Amounts

Leases - Future Minimum Amounts Due Under Subleases (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 1,768
2021	1,105
2022	616
Total amounts due under subleases	$ 3,489

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Loss Before Benefit from or Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States of America	$ (2,589)	$ (25,375)
International	(9,939)	(15,283)
Loss before (benefit from) provision for income taxes	$ (12,528)	$ (40,658)

Income Taxes - Schedule of Co_2

Income Taxes - Schedule of Components of Benefit from or Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal, Current income tax provision	$ 0	$ 0
State, Current income tax provision	6	44
Foreign, Current income tax provision	175	940
Total, Current income tax provision	181	984
Federal, Deferred income tax benefit	0	0
State, Deferred income tax benefit	0	0
Foreign, Deferred income tax benefit	(301)	(398)
Total, Deferred income tax benefit	(301)	(398)
(Benefit from) provision for income taxes	$ (120)	$ 586

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Cumulative Change in Ownership, Percentage	50.00%
Cumulative Change in Ownership, Period	3 years
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ (410)	$ 1,402
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	927	1,203
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total	0	$ 0
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 112,724
Operating Loss Carry Forwards, Expiration Year	2027
Domestic Tax Authority [Member] | Federal Research and Development [Member]
Tax Credit Carryforward, Amount	$ 6,123
Tax Credit Carryforward, Expiration Year	2026
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	$ 96,395
Operating Loss Carry Forwards, Expiration Year	2022
State and Local Jurisdiction [Member] | Federal Research and Development [Member]
Tax Credit Carryforward, Amount	$ 6,451

Income Taxes - Differences in T

Income Taxes - Differences in Total Benefit from or Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax benefit at U.S. statutory rate	$ (2,631)	$ (8,538)
Foreign income and withholding taxes	2,115	4,247
State income taxes, net of federal benefit	(1,828)	(1,766)
Stock-based compensation	1,786	847
Impairment of goodwill	437	3,762
Change in valuation allowance	(410)	1,402
Provision to return adjustments	336	658
Uncertain tax positions	154	224
Research and development credits	151	(822)
Other permanent differences	48	45
Other	(278)	527
(Benefit from) provision for income taxes	$ (120)	$ 586

Income Taxes - Schedule of Co_3

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Non-current deferred tax assets:
Net operating loss	$ 26,710	$ 27,192
Research and development credits	9,820	9,308
Other credits	4,164	3,237
Operating lease liabilities	1,843	0
Stock-based compensation	945	2,519
Property and equipment and intangible assets	238	0
Accruals and reserves	111	513
Other	2	35
Gross non-current deferred tax assets	43,833	42,804
Right-of-use assets, operating leases	(1,515)	0
Property and equipment and intangible assets	0	(342)
Total non-current deferred tax liabilities	(1,515)	(342)
Total deferred tax assets	42,318	42,462
Valuation allowance	(42,216)	(42,626)
Net deferred tax assets	$ 102
Net deferred tax liabilities		$ (164)

Income Taxes - Changes in Uncer

Income Taxes - Changes in Uncertain Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Balance	$ 8,390	$ 8,424
Increase in balances related to tax positions taken during the current period	494	778
Increase in balances related to tax positions taken during the prior period	208
Decrease in balances related to tax positions taken during the prior period	(166)	(812)
Decrease in balances related to lapses in statutes of limitations	(308)
Balance	$ 8,618	$ 8,390

Net Loss Per Share Available _3

Net Loss Per Share Available to Common Stockholders - Schedule of Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss available to common stockholders	$ (12,408)	$ (41,244)
Denominator:
Weighted average number of shares, basic and diluted	6,373	5,783
Net loss per share available to common stockholders:
Basic and diluted net loss per common share available to common stockholders	$ (1.95)	$ (7.13)

Net Loss Per Share Available _4

Net Loss Per Share Available to Common Stockholders - Schedule of Potential Shares of Common Shares Outstanding (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	1,604	1,270
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	500	436
Unvested RSUs [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	1,104	834

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
United States
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 0	$ 0
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 110,000	$ 87,000