0001595974-18-000040 | 10-Q | XBRL Viewer

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Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2018	Apr. 25, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	RUBICON PROJECT, INC.
Entity Central Index Key	0001595974
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		50,290,695

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 67,516	$ 76,642
Marketable securities	51,791	52,504
Accounts receivable, net	137,534	165,890
Prepaid expenses and other current assets	10,421	9,620
TOTAL CURRENT ASSETS	267,262	304,656
Property and equipment, net	41,334	47,393
Internal use software development costs, net	13,840	12,734
Other assets, non-current	2,415	5,493
Intangible assets, net	12,563	13,359
TOTAL ASSETS	337,414	383,635
Current liabilities:
Accounts payable and accrued expenses	191,239	214,103
Other current liabilities	2,975	3,141
TOTAL CURRENT LIABILITIES	194,214	217,244
Other liabilities, non-current	1,546	1,780
TOTAL LIABILITIES	195,760	219,024
Commitments and contingencies (Note 10)
STOCKHOLDERS' EQUITY
Preferred stock, $0.00001 par value, 10,000 shares authorized at March 31, 2018 and December 31, 2017; 0 shares issued and outstanding at March 31, 2018 and December 31, 2017	0	0
Common stock, $0.00001 par value; 500,000 shares authorized at March 31, 2018 and December 31, 2017; 50,280 and 50,239 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	423,009	418,354
Accumulated other comprehensive loss	245	41
Accumulated deficit	(281,600)	(253,784)
TOTAL STOCKHOLDERS' EQUITY	141,654	164,611
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 337,414	$ 383,635

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par or stated value per share (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par or stated value per share	$ 0.00001	$ 0.00001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares, issued	50,280,000	50,239,000
Common stock, shares, outstanding	50,280,000	50,239,000

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenue	$ 24,876	$ 46,015
Expenses:
Cost of revenue	14,783	14,688
Sales and marketing	12,257	14,628
Technology and development	10,494	12,753
General and administrative	12,544	15,080
Restructuring and other exit costs	2,466	4,338
Total expenses	52,544	61,487
Loss from operations	(27,668)	(15,472)
Other (income) expense:
Interest income, net	(271)	(167)
Other income	(210)	(212)
Foreign exchange loss, net	554	372
Total other (income) expense, net	73	(7)
Loss before income taxes	(27,741)	(15,465)
Provision for income taxes	75	375
Net loss	$ (27,816)	$ (15,840)
Net loss per share:
Basic (usd per share)	$ (0.56)	$ (0.33)
Diluted (usd per share)	$ (0.56)	$ (0.33)
Weighted-average shares used to compute net loss per share:
Weighted-average shares used to compute net income (loss) per share (in shares)	49,692	48,332
Weighted-average shares used to compute diluted net income (loss) per share (in shares)	49,692	48,332

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (27,816)	$ (15,840)
Other comprehensive income (loss):
Unrealized loss on investments	(10)	(4)
Foreign currency translation adjustments	214	97
Other comprehensive income	204	93
Comprehensive loss	$ (27,612)	$ (15,747)

Consolidated Statements of Stockholders' Equity (Deficit) - 3 months ended Mar. 31, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance (in shares) at Dec. 31, 2017	50,239	50,239
Beginning Balance at Dec. 31, 2017	$ 164,611	$ 0	$ 418,354	$ 41	$ (253,784)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		9
Exercise of common stock options	6		6
Issuance of common stock related to RSU vesting (in shares)		51
Shares withheld related to net share settlement (in shares)		(19)
Shares withheld related to net share settlement	(40)		(40)
Stock-based compensation	4,689		4,689
Other comprehensive income	204			204
Net loss	$ (27,816)				(27,816)
Ending Balance (in shares) at Mar. 31, 2018	50,280	50,280
Ending Balance at Mar. 31, 2018	$ 141,654	$ 0	$ 423,009	$ 245	$ (281,600)

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING ACTIVITIES:
Net loss	$ (27,816)	$ (15,840)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	8,710	10,121
Stock-based compensation	4,544	6,239
Loss on disposal of property and equipment	120	258
Provision for doubtful accounts	96	209
Accretion of available for sale securities	(154)	(57)
Unrealized foreign currency gains, net	227	119
Deferred income taxes	0	282
Changes in operating assets and liabilities, net of effect of business acquisitions:
Accounts receivable	28,259	58,292
Prepaid expenses and other assets	(170)	(1,449)
Accounts payable and accrued expenses	(23,158)	(54,794)
Other liabilities	(422)	(499)
Net cash provided by (used in) operating activities	(9,764)	2,881
INVESTING ACTIVITIES:
Purchases of property and equipment	(239)	(3,084)
Capitalized internal use software development costs	(2,573)	(2,285)
Investments in available-for-sale securities	(19,238)	(14,948)
Maturities of available-for-sale securities	22,600	16,950
Net cash provided by (used in) investing activities	550	(3,367)
FINANCING ACTIVITIES:
Proceeds from exercise of stock options	6	368
Taxes paid related to net share settlement	(40)	0
Net cash provided by (used in) financing activities	(34)	368
EFFECT OF EXCHANGE RATE CHANGES ON CASH, CASH EQUIVALENTS AND RESTRICTED CASH	122	62
CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(9,126)	(56)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period	76,642	149,498
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period	67,516	149,442
SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION:
Capitalized assets financed by accounts payable and accrued expenses	237	254
Capitalized stock-based compensation	$ 145	$ 166

Organization and Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Organization and Summary of Significant Accounting Policies

Company Overview

The Rubicon Project, Inc., or Rubicon Project (the "Company"), was formed on April 20, 2007 in Delaware and began operations in April 2007. The Company is headquartered in Los Angeles, California.

The Company is a global advertising exchange that helps websites and applications thrive by giving them tools and expertise to sell ads easily and safely. In addition, the world’s leading agencies and brands rely on the Company's technology to execute billions of advertising transactions each month.

The Company provides a technology solution to automate the purchase and sale of digital advertising inventory for buyers and sellers. The Company's platform features applications and services for digital advertising sellers, including websites, mobile applications and other digital media properties, to sell their advertising inventory; applications and services for buyers, including advertisers, agencies, agency trading desks, demand side platforms, or DSPs, to buy advertising inventory; and a marketplace over which such transactions are executed. Together, these features power and enhance a comprehensive, transparent, independent advertising marketplace that brings buyers and sellers together and facilitates intelligent decision making and automated transaction execution for the advertising inventory managed on the Company's platform. The Company's clients include many of the world's leading publishers of websites and mobile applications and buyers of digital advertising.

Advertising inventory takes different forms, referred to as advertising units, is purchased and sold through different transactional methodologies, and allows advertising content to be presented to users through different channels. The Company's solution enables buyers and sellers to purchase and sell:


•	a comprehensive range of advertising units, including display, audio and video;


•	that are transacted through real-time bidding ("RTB"), which includes (i) direct sale of premium inventory, which the Company refers to as private marketplace ("PMP"), and (ii) open auction bidding, which the Company refers to as open marketplace ("OMP"); and


•	that are displayed across digital channels, including mobile web, mobile application, and desktop, as well as across various out-of-home channels, such as digital billboards.

Risks and Uncertainties

The Company has been negatively impacted by rapid changes in the ad tech industry including demand by ad tech buyers

for more efficiency and lower costs, changes in bidding technologies, and increased competition. In response to these challenges,

the Company made significant reductions in fees charged to buyers during 2017 and in November 2017 eliminated its buyer fees

altogether. The competitive pressures and reduced take rate resulted in the Company experiencing lower advertising spending on its platform in the first quarter of 2018 as compared to the first quarter of 2017 and also resulted in lower operating results and cash flows in the current quarter. In an effort to bring its costs into better alignment with reduced revenue trends, the Company has undertaken restructuring activities to reduce headcount and related operating costs, and has also reduced its capital expenditures, which may make execution against its strategic business plans more difficult. Unless and until the Company is able to compensate for the fee reductions and reduced gross margins by continuing to increase advertising spending on its platform, or sufficiently reducing costs, it may not be able to grow its business and may continue to operate at a loss, depleting its cash resources and liquidity. If the Company continues to experience significant operating losses in the future, the Company may require additional liquidity to fund its operations. The Company’s current credit facility expires in September 2018. There can be no guarantee that additional financing will be available on commercially reasonable terms, if at all.

Basis of Presentation and Summary of Significant Accounting Policies

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with United States Generally Accepted Accounting Principles, or GAAP, for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair statement of the results for the interim period presented have been included. Operating results for the three months ended March 31, 2018 are not necessarily indicative of the results that may be expected for any future interim period, the year ending December 31, 2018, or for any future year.

The condensed consolidated balance sheet at December 31, 2017 has been derived from the audited financial statements at that date, but does not include all of the disclosures required by GAAP. The accompanying condensed consolidated financial

statements should be read in conjunction with the Company's audited consolidated financial statements and notes thereto for the year ended December 31, 2017 included in its 2017 Annual Report on Form 10-K.

There have been no significant changes in the Company's accounting policies from those disclosed in its audited consolidated financial statements and notes thereto for the year ended December 31, 2017 included in its Annual Report on Form 10-K.

Reclassifications

Certain prior period amounts have been reclassified to conform to the current period presentation. Specifically, this includes amounts reclassified to conform to the current year presentation in the condensed consolidated statements of cash flows.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed financial statements and accompanying footnotes. Actual results could differ materially from these estimates.

Recently Adopted Accounting Pronouncements

On January 1, 2018, the Company adopted the following accounting pronouncements, using a prospective adoption method, which did not have an impact on the Company's condensed consolidated financial statements and did not result in any significant policy changes:


•	Accounting Standards Update ("ASU") 2017-01—Business Combinations (Topic 805): Clarifying the Definition of a Business; and


•	ASU 2017-09—Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting.

The Company has also adopted ASU 2016-15—Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, although the retrospective adoption method did not have an impact on periods presented. The Company will apply this guidance to applicable future transactions.

Recent Accounting Pronouncements

Under the Jumpstart Our Business Startups Act, or the JOBS Act, the Company meets the definition of an emerging growth company. The Company has irrevocably elected to opt out of the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act.

In February 2016, the FASB issued ASU 2016-02—Leases (Topic 842) ("ASU-2016-02"), which requires an entity to recognize right-of-use assets and lease liabilities on its balance sheet and disclose key information about leasing arrangements. ASU 2016-02 offers specific accounting guidance for a lessee, a lessor, and sale and leaseback transactions. Lessees and lessors are required to disclose qualitative and quantitative information about leasing arrangements to enable a user of the financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018, including interim periods within that reporting period, and requires a modified retrospective adoption, with early adoption permitted. The Company is currently evaluating the effect this guidance will have on its condensed consolidated financial statements and related disclosures, and anticipates the guidance to result in increases in its assets and liabilities as most of its operating lease commitments will be subject to the new standard and recognized as right-of-use assets and lease liabilities.

Net Income (Loss) Per Share

3 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Net Income (Loss) Per Share

The following table presents the basic and diluted net loss per share:



	Three Months Ended
	March 31, 2018			March 31, 2017
	(in thousands, except per share data)
Basic EPS:
Net loss	$	(27,816	)	$	(15,840	)
Weighted-average common shares outstanding	50,248			49,446
Weighted-average unvested restricted shares	(556		)	(1,114		)
Weighted-average common shares outstanding used to compute net loss per share	49,692			48,332
Basic net loss per share	$	(0.56	)	$	(0.33	)
Diluted EPS:
Net loss	$	(27,816	)	$	(15,840	)
Weighted-average shares used to compute diluted net loss per share	49,692			48,332
Diluted net loss per share	$	(0.56	)	$	(0.33	)

The following weighted-average shares have been excluded from the calculation of diluted net loss per share attributable to common stockholders for each period presented because they are anti-dilutive:



	Three Months Ended
	March 31, 2018	March 31, 2017
	(in thousands)
Options to purchase common stock	37	186
Unvested restricted stock awards	186	224
Unvested restricted stock units	1,369	661
ESPP	62	58
Total shares excluded from net loss per share	1,654	1,129

Revenues

3 Months Ended

Mar. 31, 2018

Revenue from Contract with Customer [Abstract]

Revenues

On January 1, 2018, the Company adopted Accounting Standards Update 2014-09—Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09") using a modified retrospective approach applied to all contracts that generated revenue in the preceding year. The adoption of this guidance did not have an impact on the amount or timing of revenue recognized by the Company.

The Company generates revenue from transactions where it provides a platform for the purchase and sale of advertising inventory. The Company’s advertising automation solution is a marketplace that includes sellers of advertising inventory (providers of websites, mobile applications and other digital media properties, and their representatives) and buyers of advertising inventory (including advertisers, agencies, agency trading desks, demand-side platforms, and ad networks). This solution incorporates proprietary machine-learning algorithms, sophisticated data processing, high-volume storage, detailed analytics capabilities, and a distributed infrastructure. Together, these features form the basis for the Company’s automated advertising solution that brings buyers and sellers together and facilitates intelligent decision-making and automated transaction execution for the advertising inventory managed on the Company's platform. Advertising inventory is created when users access sellers’ content. Sellers provide advertising inventory to the Company’s platform in the form of advertising requests, or ad requests. When the Company receives ad requests from sellers, it sends bid requests to buyers, which enable buyers to bid on sellers’ advertising inventory. Winning bids can create advertising, or paid impressions, for the seller to present to the user.

The total volume of spending between buyers and sellers on the Company’s platform is referred to as advertising spend. The Company keeps a percentage of that advertising spend as a fee, and remits the remainder to the seller. The fee or “take rate” that the Company retains from the gross advertising spend on its platform is recognized as revenue. The fee earned on each transaction is based on the pre-existing agreement between the Company and the seller and the clearing price of the winning bid. The Company recognizes revenue upon fulfillment of its performance obligation to a customer, which occurs at the point in time an ad renders and is counted as a paid impression, subject to an underlying agreement existing with the customer and a fixed or determinable transaction price. Performance obligations for all transactions are satisfied, and the corresponding revenue is recognized, at a distinct point in time, the Company has no arrangements with multiple performance obligations. The Company considers the

following when determining if a contract exists under which the performance obligations have been satisfied; (i) contract approval by all parties, (ii) identification of each party’s rights regarding the goods or services to be transferred, (iii) specified payment terms, (iv) commercial substance of the contract, and (v) collectability of substantially all of the consideration is probable, although in some cases, payments are handled directly between buyers and sellers or third parties making seller inventory available.

The Company has determined that it does not act as the principal in the purchase and sale of advertising inventory because it does not have control of the advertising inventory and does not set prices agreed upon within the auction marketplace, and therefore reports revenue on a net basis. In periods prior to the second quarter of 2017, the Company reported revenue on a gross basis for revenue associated with its intent marketing solution, as the Company determined that it acted as the principal in the purchase and sale of advertising inventory. The Company ceased offering its intent marketing solution after the first quarter of 2017, after which time, all of the Company’s revenues have been recorded on a net basis. Revenue generated by the Company’s intent marketing solution during the period ended March 31, 2017 was $1.3 million.

Payment terms are specified in agreements between the Company and the buyers and sellers on its exchange platform. The Company generally bills buyers at the end of each month for the full purchase price of impressions filled in that month, together with other fees, if applicable. The Company recognizes volume discounts as a reduction of revenue as they are incurred. Specific payment terms may vary by agreement, but are generally seventy five days or less. The Company's accounts receivable are recorded at the amount of gross billings to buyers, net of allowances for the amounts the company is responsible to collect. The Company's accounts payable related to amounts due to sellers are recorded at the net amount payable to sellers (see Note 5). Accordingly, both accounts receivable and accounts payable appear large in relation to revenue reported on a net basis.

The following table presents our revenue disaggregated by geographic location, based on the location of the Company's sellers:



	Three Months Ended
	March 31, 2018		March 31, 2017
	(in thousands)
United States	$	15,504	$	27,661
United Kingdom	1,971		4,277
Other international	7,401		14,077
Total	$	24,876	$	46,015

Fair Value Measurements

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair value represents the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Observable inputs are based on market data obtained from independent sources. The fair value hierarchy is based on the following three levels of inputs, of which the first two are considered observable and the last one is considered unobservable:


•	Level 1 – Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.


•	Level 2 – Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly.


•	Level 3 – Unobservable inputs.

The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at March 31, 2018:



	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents	$	5,195	$	403	$	4,792	$	—
Corporate debt securities	$	21,904	$	—	$	21,904	$	—
U.S. Treasury, government and agency debt securities	$	29,887	$	29,887	$	—	$	—

The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at December 31, 2017:



	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents	$	1,807	$	210	$	1,597	$	—
Corporate debt securities	$	25,098	$	—	$	25,098	$	—
U.S. Treasury, government and agency debt securities	$	29,901	$	29,901	$	—	$	—

At March 31, 2018 and December 31, 2017, cash equivalents of $5.2 million and $1.8 million, respectively, consisted of money market funds and commercial paper, with original maturities of three months or less. The carrying amounts of cash equivalents are classified as Level 1 or Level 2 depending on whether or not their fair values are based on quoted market prices for identical securities that are traded in an active market. The commercial paper included in cash equivalents is classified as Level 2 since its fair value is not based on quoted market prices for identical securities that are traded in an active market, but rather is derived from similar securities. Corporate debt securities (which are included in marketable securities on the balance sheet) with fair values derived from similar securities rather than based on quoted market prices for identical securities, are classified as Level 2 as well. The fair values of the Company's U.S. treasury, government and agency debt securities are based on quoted market prices and classified as Level 1, and are included within marketable securities.

There were no transfers between Level 1 and Level 2 fair value measurements during the three months ended March 31, 2018 and 2017.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Other Balance Sheet Amounts

3 Months Ended

Mar. 31, 2018

Balance Sheet Related Disclosures [Abstract]

Other Balance Sheet Amounts

Investments in marketable securities as of March 31, 2018 consisted of the following:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sale—short-term:
U.S. Treasury, government and agency debt securities	$	29,926	$	—	$	(39	)	$	29,887
Corporate debt securities	21,904		—		—			21,904
Total	$	51,830	$	—	$	(39	)	$	51,791

Investments in marketable securities as of December 31, 2017 consisted of the following:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sale—short-term:
U.S. Treasury, government and agency debt securities	$	27,426	$	—	$	(20	)	$	27,406
Corporate debt securities	25,098		—		—			25,098
Total	$	52,524	$	—	$	(20	)	$	52,504
Available-for-sale—long-term:
U.S. Treasury, government and agency debt securities	$	2,504	$	—	$	(9	)	$	2,495

The Company's available-for-sale securities had a weighted remaining contractual maturity of 0.4 years as of March 31, 2018. For the three months ended March 31, 2018, there were no realized gains (losses) and there were no unrealized holding gains (losses) reclassified out of accumulated other comprehensive loss into the condensed consolidated statements of operations for the sale of available-for-sale investments.

Accounts payable and accrued expenses included the following:



	March 31, 2018		December 31, 2017
	(in thousands)
Accounts payable—seller	$	177,850	$	203,694
Accounts payable—trade	6,435		3,764
Accrued employee-related payables	6,954		6,645
Total	$	191,239	$	214,103

As of December 31, 2016, the Company had $0.1 million of restricted cash, which is included in the beginning balance of cash, cash equivalents and restricted cash in the condensed consolidated statement of cash flows for the three months ended March 31, 2017. There was no restricted cash as of March 31, 2018 and December 31, 2017.

Intangible Assets

3 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

The Company’s intangible assets as of March 31, 2018 and December 31, 2017 included the following:



	March 31, 2018			December 31, 2017
	(in thousands)
Amortizable intangible assets:
Developed technology	$	16,878		$	16,878
Non-compete agreements	690			690
Trademarks	20			20
Total identifiable intangible assets, gross	17,588			17,588
Accumulated amortization—intangible assets:
Developed technology	(4,768		)	(4,062		)
Non-compete agreements	(247		)	(161		)
Trademarks	(10		)	(6		)
Total accumulated amortization—intangible assets	(5,025		)	(4,229		)
Total identifiable intangible assets, net	$	12,563		$	13,359

Amortization of intangible assets for the three months ended March 31, 2018 and 2017 were $0.8 million and $1.6 million, respectively. The estimated remaining amortization expense associated with the Company's intangible assets was as follows as of March 31, 2018:



Fiscal Year	Amount
	(in thousands)
Remaining 2018	$	2,389
2019	3,010
2020	2,826
2021	2,826
2022	1,512
Thereafter	—
Total	$	12,563

Stock-Based Compensation

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

The Company’s equity incentive plans provide for the grant of equity awards, including non-statutory or incentive stock options, restricted stock, and restricted stock units, to the Company's employees, officers, directors, and consultants. The Company's board of directors administers the plans. Outstanding options vest based upon continued service at varying rates, but generally over four years from issuance with 25% vesting after one year of service and the remainder vesting monthly thereafter. Restricted stock and restricted stock units vest at varying rates, typically approximately 25% vesting after approximately one year of service and the remainder vesting semi-annually thereafter. In the first quarter of 2018, the Company granted 2,650,000 restricted stock units that vest 50% on each of the first and second anniversaries of the grant date. Options, restricted stock, and restricted stock units granted

under the plans accelerate under certain circumstances for certain participants upon a change in control, as defined in the governing plan. An aggregate of 4,505,735 shares remained available for future grants at March 31, 2018 under the plans.

Stock Options

A summary of stock option activity for the three months ended March 31, 2018 is as follows:



	Shares Under Option		Weighted- Average Exercise Price		Weighted- Average Contractual Life	Aggregate Intrinsic Value
	(in thousands)					(in thousands)
Outstanding at December 31, 2017	4,363		$	8.75
Granted	658		$	1.97
Exercised	(9	)	$	0.60
Expired	(191	)	$	14.93
Forfeited	(45	)	$	3.77
Outstanding at March 31, 2018	4,776		$	7.63	6.16 years	$	511
Exercisable at March 31, 2018	2,899		$	9.71	4.23 years	$	140

The total intrinsic values of options exercised during the three months ended March 31, 2018 was $11.9 thousand. At March 31, 2018, the Company had unrecognized employee stock-based compensation expense relating to nonvested stock options of approximately $5.2 million, which is expected to be recognized over a weighted-average period of 3.0 years. The weighted-average grant date fair value per share of stock options granted during the three months ended March 31, 2018 was $1.09. Total fair value of options vested during the three months ended March 31, 2018 was $1.2 million.

The Company estimates the fair value of stock options that contain service and/or performance conditions using the Black-Scholes option pricing model. The weighted-average input assumptions used by the Company were as follows:



	Three Months Ended
	March 31, 2018		March 31, 2017
Expected term (in years)	6.1		6.1
Risk-free interest rate	2.66	%	2.17	%
Expected volatility	57	%	55	%
Dividend yield	—	%	—	%

Restricted Stock

A summary of restricted stock activity for the three months ended March 31, 2018 is as follows:



	Number of Shares		Weighted-Average Grant Date Fair Value
	(in thousands)
Nonvested shares of restricted stock outstanding at December 31, 2017	558		$	12.60
Granted	—		$	—
Canceled	—		$	—
Vested	(9	)	$	5.62
Nonvested shares of restricted stock outstanding at March 31, 2018	549		$	12.71

The aggregate fair value of restricted stock with service conditions that vested during the three months ended March 31, 2018 was $17.0 thousand. At March 31, 2018, the Company had unrecognized stock-based compensation expense for restricted stock with service conditions of $2.0 million, which is expected to be recognized over a weighted-average period of 1.4 years.

Restricted Stock Units

A summary of restricted stock unit activity for the three months ended March 31, 2018 is as follows:



	Number of Shares		Weighted-Average Grant Date Fair Value
	(in thousands)
Nonvested restricted stock units outstanding at December 31, 2017	3,609		$	7.55
Granted	4,499		$	2.19
Canceled	(343	)	$	6.25
Vested	(51	)	$	8.48
Nonvested restricted stock units outstanding at March 31, 2018	7,714		$	4.48

The weighted-average grant date fair value per share of restricted stock units granted during the three months ended March 31, 2018 was $2.19. The aggregate fair value of restricted stock units that vested during three months ended March 31, 2018 was $0.1 million. At March 31, 2018, the intrinsic value of nonvested restricted stock units was $13.9 million. At March 31, 2018, the Company had unrecognized stock-based compensation expense relating to nonvested restricted stock units of approximately $28.3 million, which is expected to be recognized over a weighted-average period of 2.65 years.

Employee Stock Purchase Plan

In November 2013, the Company adopted the Company's 2014 Employee Stock Purchase Plan ("ESPP"). The ESPP is designed to enable eligible employees to periodically purchase shares of the Company's common stock at a discount through payroll deductions of up to 10% of their eligible compensation, subject to any plan limitations. At the end of each six-month offering period, employees are able to purchase shares at a price per share equal to 85% of the lower of the fair market value of the Company's common stock on the first trading day of the offering period or on the last trading day of the offering period. Offering periods generally commence and end in May and November of each year.

As of March 31, 2018, the Company has reserved 1,781,853 shares of its common stock for issuance under the ESPP.

Stock-Based Compensation Expense

Total stock-based compensation expense recorded in the condensed consolidated statements of operations was as follows:



	Three Months Ended
	March 31, 2018		March 31, 2017
	(in thousands)
Cost of revenue	$	107	$	84
Sales and marketing	1,185		1,435
Technology and development	849		1,075
General and administrative	2,357		2,709
Restructuring and other exit costs	46		936
Total stock-based compensation expense	$	4,544	$	6,239

Restructuring and Other Exit Costs

3 Months Ended

Mar. 31, 2018

Restructuring and Related Activities [Abstract]

Restructuring and Other Exit Costs

As part of its on-going efforts to control costs and create efficiencies, the Company has undergone restructuring events throughout 2017 and in the first quarter of 2018. The objective of these restructuring activities was to streamline operations, prioritize resources for growth initiatives and increase profitability.

In January 2017, the Company announced that it would cease providing intent marketing services and would close its Toronto, Canada office as a result (the "2017 Restructuring Events"). In the first quarter of 2017, the Company recognized expenses of $4.3 million as restructuring and other exit costs related to the cessation of our intent marketing solution, including the closure of the Toronto office, as well as the realignment of the management team to a more cost efficient structure. A majority of the costs incurred in the first quarter of 2017 were severance and one-time termination benefit costs, of which $0.9 million related to non-cash stock-based compensation, the remainder of which related to facility closure costs.

In the first quarter of 2018, the Company announced its restructuring plan to reduce headcount to bring the Company's general and administrative operations into better alignment with the current size of the business and de-layer certain functions, and

to reduce its investment in unprofitable projects (the "2018 Restructuring Events"). During three months ended March 31, 2018, the Company incurred restructuring and other exit costs of $2.5 million for severance and one-time termination benefits.

The following table summarizes restructuring and other exit cost activity for the 2018 Restructuring Events (in thousands):



Accrued restructuring and other exit costs at December 31, 2017	$	—
Restructuring and other exit costs	2,466
Cash paid for restructuring and other exit costs	(1,797		)
Non-cash stock-based compensation for restructuring and other exit costs	(46		)
Accrued restructuring and other exit costs at March 31, 2018	$	623

Accrued restructuring costs related to the 2017 Restructuring Events were $0.1 million at December 31, 2017 and were substantially paid in the first quarter of 2018. The remaining liabilities are included within other liabilities on the Company's condensed consolidated balance sheets. The Company expects to pay the majority of the remaining expenses during the second quarter of 2018.

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes In determining quarterly provisions for income taxes, the Company uses the annual estimated effective tax rate applied to the actual year-to-date income. The Company's annual estimated effective tax rate differs from the statutory rate primarily as a result of state taxes, foreign taxes, nondeductible stock option expenses, and changes in the Company's valuation allowance. The Company recorded income tax expenses of $0.1 million and $0.4 million for the three months ended March 31, 2018 and 2017, respectively. The tax provision for the three months ended March 31, 2018 is primarily the result of the domestic valuation allowance and the tax liability associated with the foreign subsidiaries. On December 22, 2017, the U.S. government enacted the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act includes significant changes to the U.S. corporate income tax system including: a federal corporate rate reduction from 34% to 21%; limitations on the deductibility of executive compensation and research and development (“R&D”) expenditures, immediate expensing of qualified property; the creation of new minimum taxes such as the base erosion anti-abuse tax (“BEAT”) and Global Intangible Low Taxed Income (“GILTI”) tax; and the transition of U.S. international taxation from a worldwide tax system to a modified territorial tax system, which will result in a one time U.S. tax liability on those earning which have not previously been repatriated to the U.S. (the “Transition Tax”). The Tax Act imposes a Transition Tax on previously untaxed accumulated and current earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, the Company determined, among other things, the amount of post-1986 E&P of the relevant subsidiaries. The Company recorded a provisional Transition Tax of $0.6 million which reduced its U.S. net deferred tax assets for the year ended December 31, 2017. For the three months ended March 31, 2018, there was no change to the provisional Transaction Tax recorded in the prior period. The SEC staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared or analyzed in reasonable detail to complete the accounting for certain income tax effects of the Tax Act and allows the registrant to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. The Company has recognized the actual impact of the revaluation of deferred tax balances and the provisional impact related to the one-time Transition Tax. The Company included these amounts in its consolidated financial statements for the year ended December 31, 2017. The ultimate impact may materially differ from these provisional amounts, due to, among other things, additional analysis, changes in interpretations and assumptions that have been made, additional regulatory guidance that may be issued, and actions may be taken as a result of the Tax Act. The Company expects to complete its analysis within the measurement period in accordance with SAB 118. In addition, it is unclear how many U.S. states will incorporate the federal law changes, or portions thereof, into their tax codes and foreign governments may enact tax laws in response to the Tax Act that could result in further changes to global taxation and materially affect the Company's financial position and results of operations. Finally, the Tax Act imposes a new BEAT, essentially a 10% minimum tax (5% for tax years beginning after December 31, 2017, increasing to 10% for years beginning after December 31, 2018) calculated on a base equal to taxpayer’s income determined without tax benefits arising from base erosion payments. BEAT does not apply to corporations whose annual gross receipts for the three-taxable-year period ending with the preceding taxable year are less than $500 million. BEAT does not apply to the Company for the year ending December 31, 2018. Also, the Tax Act requires certain GILTI income earned by controlled foreign corporations (“CFCs”) to be included in the gross income of the CFCs’ U.S. shareholder (for tax years beginning after December 31, 2017). For the three months ended March 31, 2018, the Company has included a provisional GILTI inclusion of $1.4 million for purposes of Accounting Standards Codification Topic 740. GAAP allows the Company to either (i) treat taxes due on future U.S. inclusions in taxable income related to BEAT and GILTI as current-period expense when incurred (the “period cost method”); or (ii) factor such amounts into the measurement of deferred taxes (the “deferred method”). The Company elected the period cost method. Due to uncertainty as to the realization of benefits from the Company's domestic and certain international deferred tax assets, including net operating loss carryforwards and research and development tax credits, the Company has a full valuation allowance reserved against such assets. The Company intends to continue to maintain a full valuation allowance on the deferred tax assets until there is sufficient evidence to support the reversal of all or some portion of these allowances. There were no material changes to the Company's unrecognized tax benefits in the three months ended March 31, 2018, and the Company does not expect to have any significant changes to unrecognized tax benefits through the end of the fiscal year. Because of the Company's history of tax losses, all years remain open to tax audit. During the first quarter of 2017, the Internal Revenue Service commenced an examination of the 2015 tax year. The Company has not received any income tax Notice of Proposed Adjustments (NOPAs) and the IRS has indicated during that conversation that they do not intend to make any income tax related adjustments.

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases The Company has commitments under non-cancelable operating leases for facilities, certain equipment, and its managed data center facilities. Total rental expenses were $3.3 million and $4.0 million for the three months ended March 31, 2018 and 2017, respectively. Additionally, expenses for cloud-based services related to data centers were $1.9 million and $0.9 million for the three months ended March 31, 2018 and 2017, respectively. As of March 31, 2018 and December 31, 2017, the Company had $2.9 million of letters of credit associated with office leases available for borrowing, on which there were no outstanding borrowings as of either date. Guarantees and Indemnification The Company’s agreements with sellers, buyers, and other third parties typically obligate it to provide indemnity and defense for losses resulting from claims of intellectual property infringement, damages to property or persons, business losses, or other liabilities. Generally, these indemnity and defense obligations relate to the Company’s own business operations, obligations, and acts or omissions. However, under some circumstances, the Company agrees to indemnify and defend contract counterparties against losses resulting from their own business operations, obligations, and acts or omissions, or the business operations, obligations, and acts or omissions of third parties. For example, because the Company’s business interposes the Company between buyers and sellers in various ways, buyers often require the Company to indemnify them against acts and omissions of sellers, and sellers often require the Company to indemnify them against acts and omissions of buyers. In addition, the Company’s agreements with sellers, buyers, and other third parties typically include provisions limiting the Company’s liability to the counterparty, and the counterparty’s liability to the Company. These limits sometimes do not apply to certain liabilities, including indemnity obligations. These indemnity and limitation of liability provisions generally survive termination or expiration of the agreements in which they appear. The Company has also entered into indemnification agreements with its directors, executive officers and certain other officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors, officers or employees. No material demands have been made upon the Company to provide indemnification under such agreements and there are no claims that the Company is aware of that could have a material effect on the Company’s condensed consolidated financial statements. Litigation The Company and its subsidiaries may from time to time be parties to legal or regulatory proceedings, lawsuits and other claims incident to their business activities and to the Company’s status as a public company. Such matters may include, among other things, assertions of contract breach or intellectual property infringement, claims for indemnity arising in the course of the Company’s business, regulatory investigations or enforcement proceedings, and claims by persons whose employment has been terminated. Such matters are subject to many uncertainties, and outcomes are not predictable with assurance. Consequently, management is unable to ascertain the ultimate aggregate amount of monetary liability, amounts which may be covered by insurance or recoverable from third parties, or the financial impact with respect to such matters as of March 31, 2018. However, based on management’s knowledge as of March 31, 2018, management believes that the final resolution of these matters known at such date, individually and in the aggregate, will not have a material adverse effect upon the Company’s condensed consolidated financial position, results of operations or cash flows. On March 31, 2017, Guardian News & Media Limited ("Guardian") issued proceedings (the "Complaint") against the Company in the Chancery Division of the High Court of Justice in England & Wales. The Complaint alleges that the Company underpaid Guardian for advertising inventory sold by Guardian through the Company's platform as a result of the fact that the Company charged fees to buyers of that inventory. Guardian claims the Company was precluded from charging buyer fees as a result of the contractual arrangements with Guardian and English agency law principles, as well as representations it allegedly made to Guardian. The Complaint claims damages including loss of revenue, interest, and costs, without specifying the amount of damages sought. The Company disputes Guardian’s claims and is defending them vigorously, but the Complaint involves disputed facts and complex legal questions, and its outcome is therefore uncertain. Even if Guardian were to prevail in this action, the Company does not believe the payment of the damages it thinks could be recoverable by Guardian would have a material adverse effect upon its condensed consolidated financial position, results of operations, or cash flows. However, pending or in response to the outcome of this action, if the Company faces similar claims from other clients or as a preventative measure, it might decide to provide concessions or make other changes to its business practices that could have such material adverse effects. Employment Contracts The Company has entered into severance agreements with certain employees and officers. The Company may be required to pay severance and accelerate the vesting of certain equity awards in the event of involuntary terminations.

Organization and Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

Reclassifications

Reclassifications Certain prior period amounts have been reclassified to conform to the current period presentation. Specifically, this includes amounts reclassified to conform to the current year presentation in the condensed consolidated statements of cash flows.

Use of Estimates

Use of EstimatesThe preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed financial statements and accompanying footnotes. Actual results could differ materially from these estimates.

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements


•	Accounting Standards Update ("ASU") 2017-01—Business Combinations (Topic 805): Clarifying the Definition of a Business; and


•	ASU 2017-09—Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting.

Recent Accounting Pronouncements

Net Income (Loss) Per Share (Tables)

3 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table presents the basic and diluted net loss per share:



	Three Months Ended
	March 31, 2018			March 31, 2017
	(in thousands, except per share data)
Basic EPS:
Net loss	$	(27,816	)	$	(15,840	)
Weighted-average common shares outstanding	50,248			49,446
Weighted-average unvested restricted shares	(556		)	(1,114		)
Weighted-average common shares outstanding used to compute net loss per share	49,692			48,332
Basic net loss per share	$	(0.56	)	$	(0.33	)
Diluted EPS:
Net loss	$	(27,816	)	$	(15,840	)
Weighted-average shares used to compute diluted net loss per share	49,692			48,332
Diluted net loss per share	$	(0.56	)	$	(0.33	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share



	Three Months Ended
	March 31, 2018	March 31, 2017
	(in thousands)
Options to purchase common stock	37	186
Unvested restricted stock awards	186	224
Unvested restricted stock units	1,369	661
ESPP	62	58
Total shares excluded from net loss per share	1,654	1,129

Revenues (Tables)

3 Months Ended

Mar. 31, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The following table presents our revenue disaggregated by geographic location, based on the location of the Company's sellers:



	Three Months Ended
	March 31, 2018		March 31, 2017
	(in thousands)
United States	$	15,504	$	27,661
United Kingdom	1,971		4,277
Other international	7,401		14,077
Total	$	24,876	$	46,015

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value, Assets Measured on Recurring Basis

The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at March 31, 2018:



	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents	$	5,195	$	403	$	4,792	$	—
Corporate debt securities	$	21,904	$	—	$	21,904	$	—
U.S. Treasury, government and agency debt securities	$	29,887	$	29,887	$	—	$	—

The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at December 31, 2017:



	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents	$	1,807	$	210	$	1,597	$	—
Corporate debt securities	$	25,098	$	—	$	25,098	$	—
U.S. Treasury, government and agency debt securities	$	29,901	$	29,901	$	—	$	—

Other Balance Sheet Amounts (Tables)

3 Months Ended

Mar. 31, 2018

Balance Sheet Related Disclosures [Abstract]

Investments in Marketable Securities

Investments in marketable securities as of March 31, 2018 consisted of the following:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sale—short-term:
U.S. Treasury, government and agency debt securities	$	29,926	$	—	$	(39	)	$	29,887
Corporate debt securities	21,904		—		—			21,904
Total	$	51,830	$	—	$	(39	)	$	51,791

Investments in marketable securities as of December 31, 2017 consisted of the following:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sale—short-term:
U.S. Treasury, government and agency debt securities	$	27,426	$	—	$	(20	)	$	27,406
Corporate debt securities	25,098		—		—			25,098
Total	$	52,524	$	—	$	(20	)	$	52,504
Available-for-sale—long-term:
U.S. Treasury, government and agency debt securities	$	2,504	$	—	$	(9	)	$	2,495

Schedule of Accounts Payable and Accrued Liabilities

Accounts payable and accrued expenses included the following:



	March 31, 2018		December 31, 2017
	(in thousands)
Accounts payable—seller	$	177,850	$	203,694
Accounts payable—trade	6,435		3,764
Accrued employee-related payables	6,954		6,645
Total	$	191,239	$	214,103

Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets

The Company’s intangible assets as of March 31, 2018 and December 31, 2017 included the following:



	March 31, 2018			December 31, 2017
	(in thousands)
Amortizable intangible assets:
Developed technology	$	16,878		$	16,878
Non-compete agreements	690			690
Trademarks	20			20
Total identifiable intangible assets, gross	17,588			17,588
Accumulated amortization—intangible assets:
Developed technology	(4,768		)	(4,062		)
Non-compete agreements	(247		)	(161		)
Trademarks	(10		)	(6		)
Total accumulated amortization—intangible assets	(5,025		)	(4,229		)
Total identifiable intangible assets, net	$	12,563		$	13,359

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

The estimated remaining amortization expense associated with the Company's intangible assets was as follows as of March 31, 2018:



Fiscal Year	Amount
	(in thousands)
Remaining 2018	$	2,389
2019	3,010
2020	2,826
2021	2,826
2022	1,512
Thereafter	—
Total	$	12,563

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity

A summary of stock option activity for the three months ended March 31, 2018 is as follows:



	Shares Under Option		Weighted- Average Exercise Price		Weighted- Average Contractual Life	Aggregate Intrinsic Value
	(in thousands)					(in thousands)
Outstanding at December 31, 2017	4,363		$	8.75
Granted	658		$	1.97
Exercised	(9	)	$	0.60
Expired	(191	)	$	14.93
Forfeited	(45	)	$	3.77
Outstanding at March 31, 2018	4,776		$	7.63	6.16 years	$	511
Exercisable at March 31, 2018	2,899		$	9.71	4.23 years	$	140

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions



	Three Months Ended
	March 31, 2018		March 31, 2017
Expected term (in years)	6.1		6.1
Risk-free interest rate	2.66	%	2.17	%
Expected volatility	57	%	55	%
Dividend yield	—	%	—	%

Nonvested Restricted Stock Shares Activity

A summary of restricted stock activity for the three months ended March 31, 2018 is as follows:



	Number of Shares		Weighted-Average Grant Date Fair Value
	(in thousands)
Nonvested shares of restricted stock outstanding at December 31, 2017	558		$	12.60
Granted	—		$	—
Canceled	—		$	—
Vested	(9	)	$	5.62
Nonvested shares of restricted stock outstanding at March 31, 2018	549		$	12.71

Schedule of Nonvested Restricted Stock Units Activity

A summary of restricted stock unit activity for the three months ended March 31, 2018 is as follows:



	Number of Shares		Weighted-Average Grant Date Fair Value
	(in thousands)
Nonvested restricted stock units outstanding at December 31, 2017	3,609		$	7.55
Granted	4,499		$	2.19
Canceled	(343	)	$	6.25
Vested	(51	)	$	8.48
Nonvested restricted stock units outstanding at March 31, 2018	7,714		$	4.48

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs for all Plans

Total stock-based compensation expense recorded in the condensed consolidated statements of operations was as follows:



	Three Months Ended
	March 31, 2018		March 31, 2017
	(in thousands)
Cost of revenue	$	107	$	84
Sales and marketing	1,185		1,435
Technology and development	849		1,075
General and administrative	2,357		2,709
Restructuring and other exit costs	46		936
Total stock-based compensation expense	$	4,544	$	6,239

Restructuring and Other Exit Costs (Tables)

3 Months Ended

Mar. 31, 2018

Restructuring and Related Activities [Abstract]

Schedule of Restructuring and Other Exit Costs

The following table summarizes restructuring and other exit cost activity for the 2018 Restructuring Events (in thousands):



Accrued restructuring and other exit costs at December 31, 2017	$	—
Restructuring and other exit costs	2,466
Cash paid for restructuring and other exit costs	(1,797		)
Non-cash stock-based compensation for restructuring and other exit costs	(46		)
Accrued restructuring and other exit costs at March 31, 2018	$	623

Net Income (Loss) Per Share (Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic EPS:
Net loss	$ (27,816)	$ (15,840)
Weighted-average common shares outstanding (in shares)	50,248	49,446
Weighted-average unvested restricted shares (in shares)	(556)	(1,114)
Weighted-average shares used to compute net income (loss) per share (in shares)	49,692	48,332
Basic net income (loss) per share (usd per share)	$ (0.56)	$ (0.33)
Diluted EPS:
Net loss	$ (27,816)	$ (15,840)
Weighted-average shares used to compute diluted net income (loss) per share (in shares)	49,692	48,332
Diluted net income (loss) per share (usd per share)	$ (0.56)	$ (0.33)

Net Income (Loss) Per Share (Shares Excluded and Included in Calculation of Diluted Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net income (loss) per share (in shares)	1,654	1,129
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net income (loss) per share (in shares)	37	186
Unvested restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net income (loss) per share (in shares)	186	224
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net income (loss) per share (in shares)	1,369	661
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net income (loss) per share (in shares)	62	58

Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
Revenues (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 24,876	$ 46,015
Intent Marketing Solution
Disaggregation of Revenue [Line Items]
Revenue		$ 1,300

Revenues (Revenue Disaggregated by Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 24,876	$ 46,015
United States
Disaggregation of Revenue [Line Items]
Revenue	15,504	27,661
United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	1,971	4,277
Other international
Disaggregation of Revenue [Line Items]
Revenue	$ 7,401	$ 14,077

Fair Value Measurements (Financial Instruments) (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 5,195	$ 1,807
Cash equivalents \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	403	210
Cash equivalents \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	4,792	1,597
Cash equivalents \| Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	21,904	25,098
Corporate debt securities \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Corporate debt securities \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	21,904	25,098
Corporate debt securities \| Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
U.S. Treasury, government and agency debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,887	29,901
U.S. Treasury, government and agency debt securities \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,887	29,901
U.S. Treasury, government and agency debt securities \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
U.S. Treasury, government and agency debt securities \| Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 0	$ 0

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Cash equivalents \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 5,195	$ 1,807

Other Balance Sheet Amounts (Investments in Marketable Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Available-for-sale—short-term
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 51,830	$ 52,524
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(39)	(20)
Fair Value	51,791	52,504
Available-for-sale—short-term \| U.S. Treasury, government and agency debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,926	27,426
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(39)	(20)
Fair Value	29,887	27,406
Available-for-sale—short-term \| Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,904	25,098
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 21,904	25,098
Available-for-sale — long-term \| U.S. Treasury, government and agency debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,504
Gross Unrealized Gains		0
Gross Unrealized Losses		(9)
Fair Value		$ 2,495

Other Balance Sheet Amounts (Narrative) (Details)	3 Months Ended
Other Balance Sheet Amounts (Narrative) (Details)	Mar. 31, 2018 USD ($)
Balance Sheet Related Disclosures [Abstract]
Weighted remaining contractual maturity	4 months 24 days
Realized gains (losses) on available-for-sale securities	$ 0
Unrealized holding gains (losses) reclassified out of AOCI into the statements of operations for the sale of AFS investments	$ 0

Other Balance Sheet Amounts (Accounts Payable and Accrued Expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Accounts payable—seller	$ 177,850	$ 203,694
Accounts payable—trade	6,435	3,764
Accrued employee-related payables	6,954	6,645
Accounts payable and accrued expenses	$ 191,239	$ 214,103

Other Balance Sheet Amounts (Restricted Cash) (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Restricted cash	$ 0	$ 0	$ 100,000

Intangible Assets (Finite-Lived Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 17,588	$ 17,588
Total accumulated amortization—intangible assets	(5,025)	(4,229)
Total	12,563	13,359
Developed technology
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	16,878	16,878
Total accumulated amortization—intangible assets	(4,768)	(4,062)
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	690	690
Total accumulated amortization—intangible assets	(247)	(161)
Trademarks
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	20	20
Total accumulated amortization—intangible assets	$ (10)	$ (6)

Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 0.8	$ 1.6

Intangible Assets (Finite-Lived Intangible Assets, Future Amortization Expense) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Remaining 2018	$ 2,389
2019	3,010
2020	2,826
2021	2,826
2022	1,512
Thereafter	0
Total	$ 12,563	$ 13,359

Stock-Based Compensation (Details)	3 Months Ended
Stock-Based Compensation (Details)	Mar. 31, 2018 shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of shares available for grant	4,505,735
Restricted awards
Number of Shares
Award vesting rights, percentage	25.00%
Stock Option
Number of Shares
Vesting period	4 years
Award vesting rights, percentage	25.00%
Restricted Stock Units (RSUs) \| Two Year RSUs
Number of Shares
Award vesting rights, percentage	50.00%
Number of awards granted	2,650,000

Stock-Based Compensation (Stock Options Outstanding) (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (in shares) \| shares	4,363
Granted (in shares) \| shares	658
Exercised (in shares) \| shares	(9)
Expired (in shares) \| shares	(191)
Forfeited (in shares) \| shares	(45)
Ending balance (in shares) \| shares	4,776
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning balance (usd per share) \| $ / shares	$ 8.75
Granted (usd per share) \| $ / shares	1.97
Exercised (usd per share) \| $ / shares	0.60
Expired (usd per share) \| $ / shares	14.93
Forfeited (usd per share) \| $ / shares	3.77
Ending balance (usd per share) \| $ / shares	$ 7.63
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding	6 years 1 month 28 days
Outstanding, aggregate intrinsic value \| $	$ 511
Exercisable (in shares) \| shares	2,899
Exercisable (usd per share) \| $ / shares	$ 9.71
Exercisable	4 years 2 months 23 days
Exercisable, aggregate intrinsic value \| $	$ 140

Stock-Based Compensation (Stock Options Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Number of Shares
Intrinsic values of options exercised	$ 11,900
Unrecognized employee stock-based compensation	$ 5,200,000
Weighted average grant date fair value	$ 1.09
Options outstanding (in shares)	4,776		4,363
Beginning balance (usd per share)	$ 8.75
Stock-based compensation expense	$ 4,544,000	$ 6,239,000
Fair value of options vested in period	$ 1,200,000
Stock Option
Number of Shares
Unrecognized employee stock-based compensation, period for recognition	3 years

Stock-Based Compensation (Valuation Assumptions) (Details) - Stock Option	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Number of Shares
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate	2.66%	2.17%
Expected volatility	57.00%	55.00%
Dividend yield	0.00%	0.00%

Stock-Based Compensation (Restricted Stock Activity) (Details) - Restricted Stock Awards shares in Thousands	3 Months Ended
	Mar. 31, 2018 $ / shares shares
Number of Shares
Beginning balance \| shares	558
Granted \| shares	0
Canceled \| shares	0
Vested \| shares	(9)
Ending balance \| shares	549
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share) \| $ / shares	$ 12.60
Granted (in dollars per share) \| $ / shares	0
Canceled (in dollars per share) \| $ / shares	0
Vested (in dollars per share) \| $ / shares	5.62
Ending balance (in dollars per share) \| $ / shares	$ 12.71

Stock-Based Compensation (Restricted Stock Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Number of Shares
Stock-based compensation expense	$ 4,544	$ 6,239
Unvested restricted stock awards
Number of Shares
Granted	0
Unrecognized employee stock-based compensation	$ 2,000
Unrecognized employee stock-based compensation, period for recognition	1 year 4 months 24 days
Granted (in dollars per share)	$ 0
Fair value of restricted stock unit	$ 17

Stock-Based Compensation (Restricted Stock Units Activity) (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2018 $ / shares shares
Number of Shares
Granted (usd per share)	$ 1.97
Restricted Stock Units (RSUs)
Number of Shares
Beginning balance \| shares	3,609
Granted \| shares	4,499
Canceled \| shares	(343)
Vested \| shares	(51)
Ending balance \| shares	7,714
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 7.55
Granted (in dollars per share)	2.19
Canceled (in dollars per share)	6.25
Vested (in dollars per share)	8.48
Ending balance (in dollars per share)	$ 4.48

Stock-Based Compensation (Restricted Stock Units Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares
Unvested restricted stock awards
Number of Shares
Unrecognized employee stock-based compensation	$ 2,000
Unrecognized employee stock-based compensation, period for recognition	1 year 4 months 24 days
Grant date fair value \| $ / shares	$ 0
Fair value of restricted stock unit	$ 17
Restricted Stock Units (RSUs)
Number of Shares
Unrecognized employee stock-based compensation	$ 28,300
Grant date fair value \| $ / shares	$ 2.19
Fair value of restricted stock unit	$ 100
Intrinsic value of nonvested unit	$ 13,900
Employee Service Share-Based Compensation, Non-Vested Restricted Stock Units, Compensation Cost Not Yet Recognized, Period for Recognition	2 years 7 months 24 days

Stock-Based Compensation (Employee Stock Purchase Plan Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Number of Shares
Stock-based compensation expense	$ 4,544	$ 6,239
2014 Employee Stock Purchase Plan \| Employee Stock
Number of Shares
Maximum employee subscription rate	10.00%
Purchase price of common stock, percent	85.00%
Number of shares reserved	1,781,853

(Employee Stock Purchase Plan Using the Black-Scholes Model) (Details) - Stock Option	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Number of Shares
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate (in percentage)	2.66%	2.17%
Expected volatility (in percentage)	57.00%	55.00%
Dividend yield (in percentage)	0.00%	0.00%

Stock-Based Compensation (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,544	$ 6,239
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	107	84
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,185	1,435
Technology and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	849	1,075
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,357	2,709
Restructuring and other exit costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 46	$ 936

Restructuring and Other Exit Costs - Schedule of Restructuring and Other Exit Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit costs	$ 2,466	$ 4,338
Restructuring Reserve [Roll Forward]
Restructuring and other exit costs	2,466	4,338
The 2017 Restructuring Events
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit costs		4,300
Accrued restructuring costs	100
Restructuring Reserve [Roll Forward]
Accrued restructuring and other exit costs at December 31, 2017	100
Restructuring and other exit costs		4,300
The 2018 Restructuring Events
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit costs	2,466
Accrued restructuring costs	623
Restructuring Reserve [Roll Forward]
Accrued restructuring and other exit costs at December 31, 2017	0
Restructuring and other exit costs	2,466
Cash paid for restructuring and other exit costs	(1,797)
Non-cash stock-based compensation for restructuring and other exit costs	(46)
Accrued restructuring and other exit costs at March 31, 2018	$ 623
Non-cash stock-based compensation \| The 2017 Restructuring Events
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit costs		900
Restructuring Reserve [Roll Forward]
Restructuring and other exit costs		$ 900

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 75	$ 375
Provisional Transition Tax recorded due to Tax Act			$ 600
Provisional GILTI inclusion for ASC Topic 740	$ 1,400

Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Other Commitments [Line Items]
Rental expense	$ 3.3	$ 4.0
Data Centers For Cloud-Based Services
Other Commitments [Line Items]
Rental expense	1.9	$ 0.9
Office Lease \| Financial Standby Letter of Credit
Other Commitments [Line Items]
Letters of credit outstanding, amount	$ 2.9		$ 2.9