Magnite (MGNI) 10-Q 10 May 21 2021 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2021	May 04, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-36384
Entity Registrant Name	MAGNITE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8881738
Entity Address, Address Line One	6080 Center Drive
Entity Address, Address Line Two	4th Floor
Entity Address, City or Town	Los Angeles,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90045
City Area Code	(310)
Local Phone Number	207-0272
Title of 12(b) Security	Common stock, par value $0.00001 per share
Trading Symbol	MGNI
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		128,859,048
Entity Central Index Key	0001595974
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 468,550	$ 117,676
Accounts receivable, net	401,836	471,666
Prepaid expenses and other current assets	17,368	17,729
TOTAL CURRENT ASSETS	887,754	607,071
Property and equipment, net	28,209	23,681
Right-of-use lease asset	38,033	39,599
Internal use software development costs, net	16,087	16,160
Intangible assets, net	82,293	89,884
Other assets, non-current	4,217	4,440
Goodwill	158,125	158,125
TOTAL ASSETS	1,214,718	938,960
Current liabilities:
Accounts payable and accrued expenses	436,590	509,315
Lease liabilities, current	8,255	9,813
Other current liabilities	4,114	3,070
TOTAL CURRENT LIABILITIES	448,959	522,198
Deferred tax liability, net	230	199
Debt, non-current, net of debt issuance costs	388,644	0
Lease liabilities, non-current	31,608	32,278
Other liabilities, non-current	2,921	2,672
TOTAL LIABILITIES	872,362	557,347
Commitments and contingencies (Note 12)
STOCKHOLDERS' EQUITY
Preferred stock, $0.00001 par value, 10,000 shares authorized at March 31, 2021 and December 31, 2020; 0 shares issued and outstanding at March 31, 2021 and December 31, 2020	0	0
Common stock, $0.00001 par value; 500,000 shares authorized at March 31, 2021 and December 31, 2020; 116,113 and 114,029 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively	2	2
Additional paid-in capital	751,017	777,084
Accumulated other comprehensive loss	(1,270)	(957)
Accumulated deficit	(407,393)	(394,516)
TOTAL STOCKHOLDERS' EQUITY	342,356	381,613
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 1,214,718	$ 938,960

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares, issued (in shares)	116,113,000	114,029,000
Common stock, shares, outstanding (in shares)	116,113,000	114,029,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue	$ 60,715	$ 36,295
Expenses:
Cost of revenue	20,756	14,003
Sales and marketing	22,589	11,269
Technology and development	14,266	10,693
General and administrative	14,158	9,127
Merger, acquisition, and restructuring costs	2,722	1,930
Total expenses	74,491	47,022
Loss from operations	(13,776)	(10,727)
Other (income) expense:
Interest (income) expense, net	143	(144)
Other income	(1,223)	(9)
Foreign exchange (gain) loss, net	15	(698)
Total other (income) expense, net	(1,065)	(851)
Loss before income taxes	(12,711)	(9,876)
Provision (benefit) for income taxes	166	(201)
Net loss	$ (12,877)	$ (9,675)
Net loss per share:
Basic and Diluted (usd per share)	$ (0.11)	$ (0.18)
Weighted average shares used to compute net loss per share:
Basic and Diluted (in shares)	115,296	54,866

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (12,877)	$ (9,675)
Other comprehensive income (loss):
Foreign currency translation adjustments	(313)	(789)
Other comprehensive loss	(313)	(789)
Comprehensive loss	$ (13,190)	$ (10,464)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - 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, 2019		53,888
Beginning Balance at Dec. 31, 2019	$ 111,936	$ 1	$ 453,064	$ (45)	$ (341,084)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		27
Exercise of common stock options	23		23
Issuance of common stock related to RSU vesting (in shares)		1,861
Shares withheld related to net share settlement (in shares)		(716)
Shares withheld related to net share settlement	(7,485)		(7,485)
Stock-based compensation	4,218		4,218
Other comprehensive income (loss)	(789)			(789)
Net loss	(9,675)				(9,675)
Ending Balance (in shares) at Mar. 31, 2020		55,060
Ending Balance at Mar. 31, 2020	$ 98,228	$ 1	449,820	(834)	(350,759)
Beginning Balance (in shares) at Dec. 31, 2020	114,029	114,029
Beginning Balance at Dec. 31, 2020	$ 381,613	$ 2	777,084	(957)	(394,516)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		733
Exercise of common stock options	5,785		5,785
Issuance of common stock related to RSU vesting (in shares)		1,351
Stock-based compensation	7,108		7,108
Capped call options	(38,960)
Other comprehensive income (loss)	(313)			(313)
Net loss	$ (12,877)				(12,877)
Ending Balance (in shares) at Mar. 31, 2021	116,113	116,113
Ending Balance at Mar. 31, 2021	$ 342,356	$ 2	$ 751,017	$ (1,270)	$ (407,393)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)
OPERATING ACTIVITIES:
Net loss	$ (12,877)	$ (9,675)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	12,485	7,524
Stock-based compensation	6,993	4,057
(Gain) loss on disposal of property and equipment	50	(6)
Provision for doubtful accounts	(159)	2
Amortization of debt issuance costs	99	0
Non-cash lease expense	(652)	23
Deferred income taxes	62	161
Unrealized foreign currency gain	(375)	(1,083)
Changes in operating assets and liabilities:
Accounts receivable	70,252	58,600
Prepaid expenses and other assets	1,578	(738)
Accounts payable and accrued expenses	(80,074)	(64,250)
Other liabilities	1,392	152
Net cash used in operating activities	(1,226)	(5,233)
INVESTING ACTIVITIES:
Purchases of property and equipment	(1,317)	(2,274)
Capitalized internal use software development costs	(1,955)	(2,337)
Net cash used in investing activities	(3,272)	(4,611)
FINANCING ACTIVITIES:
Proceeds from Convertible Notes offering, net of debt discount	389,000	0
Payment for capped call options	(38,960)	0
Payment for debt issuance costs	(198)	0
Proceeds from exercise of stock options	5,785	23
Taxes paid related to net share settlement	0	(7,485)
Net cash provided by (used in) financing activities	355,627	(7,462)
EFFECT OF EXCHANGE RATE CHANGES ON CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(256)	(299)
CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	350,873	(17,605)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period	117,731	88,888
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period	468,604	71,283
Cash and cash equivalents	468,550	71,283
Restricted cash included in other assets, non-current	54	0
SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION:
Cash paid for income taxes	226	50
Cash paid for interest	51	15
Capitalized assets financed by accounts payable and accrued expenses	6,050	338
Capitalized stock-based compensation	115	161
Debt issuance costs included in accrued expenses and other liabilities	1,349	0
Debt discount, non-cash	$ 11,000	$ 0

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	Organization and Summary of Significant Accounting Policies Company Overview Magnite, Inc. ("Magnite" or the "Company"), formerly known as The Rubicon Project, Inc., was formed in Delaware and began operations in April 2007. On April 1, 2020, Magnite completed a stock-for-stock merger with Telaria, Inc. ("Telaria" and such merger the "Telaria Merger"), a leading provider of connected television ("CTV") technology. On April 30, 2021, the Company completed its acquisition of SpotX, Inc. ("SpotX" and such acquisition the "SpotX Acquisition"), a leading platform shaping CTV and video advertising globally. The Company operates a sell side advertising platform that offers buyers and sellers of digital advertising a single partner for transacting globally across all channels, formats, and auction types. The Company is headquartered in Los Angeles, California and New York, New York. 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 sellers of digital advertising inventory, or publishers, that own or operate websites, applications, CTV channels, and other digital media properties, to manage and monetize their inventory; applications and services for buyers, including advertisers, agencies, agency trading desks, and demand side platforms, to buy digital advertising inventory; and a transparent, independent marketplace that brings buyers and sellers together and facilitates intelligent decision making and automated transaction execution at scale. The Company's clients include many of the world's leading sellers and buyers of digital advertising inventory. 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, 2021 are not necessarily indicative of the results that may be expected for any future interim period, the year ending December 31, 2021, or for any future year. The condensed consolidated balance sheet at March 31, 2021 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, 2020 included in its 2020 Annual Report on Form 10-K. Aside from the adoption of ASU 2020-06, as described below, 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, 2020 included in its Annual Report on Form 10-K. Reclassifications Amounts for merger, acquisition, and restructuring costs incurred in the three months ended March 31, 2020 have been reclassified to conform to the presentation for the three months ended March 31, 2021 condensed consolidated statements of operations. Reclassifications consist of $1.8 million from general and administrative expenses and $0.2 million from sales and marketing expenses to merger, acquisition, and restructuring costs in the condensed consolidated statement of operations for the three months ended March 31, 2020. These expenses were related to professional services associated with the Telaria Merger. The Company did not separately present the merger, acquisition, and restructuring expenses in the condensed consolidated statement of operations for the three months ended March 31, 2020. 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. Due to the economic uncertainty as a result of the COVID-19 pandemic, it has become more difficult to apply certain assumptions and judgments into these estimates. The extent of the impact of COVID-19 pandemic on the Company's operational and financial performance will depend on future developments, which are highly uncertain and cannot be predicted, including but not limited to, the duration and spread of the pandemic, its severity, including any resurgence, the actions to contain the virus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume. During the three months ended March 31, 2021, this uncertainty continued to result in a higher level of judgment related to its estimates and assumptions. As of the date of issuance of the condensed consolidated financial statements for the three months ended March 31, 2021, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, judgments, or revise the carrying value of its assets or liabilities. These estimates may change, as new events occur and additional information is obtained, and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ materially from these estimates. Recently Adopted Accounting Standards On January 1, 2021, the Company adopted ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (ASU "2020-06") on a prospective basis, which simplifies the accounting for convertible instruments by reducing the number of accounting models available for convertible debt instruments that require separating embedded conversion features from convertible instruments. This guidance also eliminates the treasury stock method to calculate diluted earnings per share for convertible instruments and requires the use of the if-converted method. The adoption of this standard is included in the financial statements as of March 31, 2021 and for the three ended March 31, 2021. Refer to Note 14—"Convertible Notes" for additional information related to accounting for convertible debt issued during the three months ended March 31, 2021. On January 1, 2021, the Company adopted ASU 2019-12— Simplifying the Accounting for Income Taxes ("ASU 2019-12"). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to general principles in Topic 740 and clarifies and amends existing guidance for clarity and consistent application. There was no material impact to the quarterly income tax provision. Recent Accounting Pronouncements In March 2020, the FASB issued Update No. 2020-04, Reference Rate Reform (Topic 848), which provides temporary optional guidance to companies impacted by the transition away from the LIBOR. The amendment provides certain expedients and exceptions to applying GAAP in order to lessen the potential accounting burden when contracts, hedging relationships, and other transactions that reference LIBOR as a benchmark rate are modified. Further, in January 2021, the FASB issued Update No. 2021-01, Reference Rate Reform (Topic 848), which clarifies the scope of Topic 848 so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions in Topic 848. These amendments are effective upon issuance and expire on December 31, 2022. The Company is currently assessing the impact of the LIBOR transition on the Company's condensed consolidated financial statements. The Company does not believe there are any other recently issued and effective or not yet effective pronouncements that would have or are expected to have any significant effect on the Company’s financial position, cash flows or results of operations.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share The following table presents the basic and diluted net loss per share: Three Months Ended March 31, 2021 March 31, 2020 (in thousands, except per share data) Basic and Diluted Income (Loss) Per Share: Net loss $ (12,877) $ (9,675) Weighted-average common shares outstanding 115,296 54,868 Weighted-average unvested restricted stock — (2) Weighted-average common shares outstanding used to compute net loss per share 115,296 54,866 Basic and diluted net loss per share $ (0.11) $ (0.18) 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, 2021 March 31, 2020 (in thousands) Options to purchase common stock 5,400 1,239 Unvested restricted stock awards — 1 Unvested restricted stock units 7,496 3,978 Unvested performance stock units 197 — ESPP 90 61 Total shares excluded from net loss per share 13,183 5,279

Revenues

Revenues	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenues	Revenues For substantially all transactions on the Company's platform, the Company reports revenue on a net basis as it does not act as the principal in the purchase and sale of digital advertising inventory because it does not have control of the digital advertising inventory and does not set prices agreed upon within the auction marketplace. However, for certain advertising campaigns that are transacted through insertion orders, the Company reports revenue on a gross basis, based primarily on its determination that the Company acts as the primary obligor in the delivery of advertising campaigns for buyers with respect to such transactions. For the three months ended March 31, 2021, revenue reported on a gross basis was less than 3% of total revenue. The following table presents our revenue by channel for the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 March 31, 2020 (in thousands, except percentages) Channel: CTV $ 11,976 20 % $ — — % Desktop 20,851 34 15,296 42 Mobile 27,888 46 20,999 58 Total $ 60,715 100 % $ 36,295 100 % The following table presents the Company's revenue disaggregated by geographic location, based on the location of the Company's sellers: Three Months Ended March 31, 2021 March 31, 2020 (in thousands) United States $ 42,611 $ 25,533 International 18,104 10,762 Total $ 60,715 $ 36,295 Payment terms are specified in agreements between the Company and the buyers and sellers on its platform. The Company generally bills buyers at the end of each month for the full purchase price of impressions filled in that month. 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. Accounts receivable are recorded at the invoiced amount, are unsecured, and do not bear interest. The allowance for doubtful accounts is reviewed quarterly, requires judgment, and is based on the best estimate of the amount of probable credit losses in existing accounts receivable. The Company reviews the status of the then-outstanding accounts receivable on a customer-by-customer basis, taking into consideration the aging schedule of receivables, its historical collection experience, current information regarding the client, subsequent collection history, and other relevant data, in establishing the allowance for doubtful accounts. Accounts receivable is presented net of an allowance for doubtful accounts of $1.5 million at March 31, 2021, and $2.4 million at December 31, 2020. Accounts receivable are written off against the allowance for doubtful accounts when the Company determines amounts are no longer collectible. The Company reviews the associated payable to sellers for recovery of buyer receivable allowance and write-offs; in some cases, the Company can reduce the payable to sellers. The reduction of seller payables related to recovery of uncollected buyer receivables is netted against allowance expense. The contra seller payables related to recoveries were $0.8 million and $1.5 million as of March 31, 2021 and December 31, 2020, respectively. The following is a summary of activity in the allowance for doubtful accounts for the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 March 31, 2020 (in thousands) Allowance for doubtful accounts, Beginning Balance December 31 $ 2,360 $ 3,400 Write-offs (4) (740) Increase (decrease) in provision for expected credit losses (877) 413 Recoveries of previous write-offs 20 7 Allowance for doubtful accounts, March 31 $ 1,499 $ 3,080 During the three months ended March 31, 2021, the provision for expected credit losses associated with accounts receivable decreased by $0.9 million and was offset by decreases of contra seller payables related to recoveries of uncollected buyer receivables of $0.7 million, which resulted in $0.2 million of bad debt recoveries. During the three months ended March 31, 2020, the provision for expected credit losses associated with accounts receivable of $0.4 million was offset by increases of contra seller payables related to recoveries of uncollected buyer receivables of $0.4 million, which resulted in an immaterial amount of bad debt expense during the period.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Recurring 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, 2021: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 356,909 $ 356,909 $ — $ — The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at December 31, 2020: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 7,868 $ 7,868 $ — $ — At March 31, 2021 and December 31, 2020, cash equivalents of $356.9 million and $7.9 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. At March 31, 2021, the Company had Convertible Notes included in its balance sheet. The estimated fair value of the Company's Convertible Notes was $390.5 million as of March 31, 2021, which was approximate to its carrying value on the balance sheet as of March 31, 2021 due to the proximity of the Convertible Note offering to end of the period. The estimated fair value of Convertible Notes is based on market rates and the closing trading price of the Convertible Notes as of March 31, 2021 and is classified as Level 2 in the fair value hierarchy. There were no transfers between Level 1 and Level 2 fair value measurements during the three months ended March 31, 2021 and the year ended December 31, 2020.

Other Balance Sheet Amounts

Other Balance Sheet Amounts	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Balance Sheet Amounts	Other Balance Sheet Amounts Accounts payable and accrued expenses included the following: March 31, 2021 December 31, 2020 (in thousands) Accounts payable—seller $ 411,674 $ 492,605 Accounts payable—trade 15,058 4,268 Accrued employee-related payables 9,858 12,442 Total $ 436,590 $ 509,315

Goodwill, Intangible Assets, an

Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements	Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements The Company's goodwill balance as of December 31, 2020 was $158.1 million. There was no change for the three months ended March 31, 2021 (see Note 7). The Company’s intangible assets as of March 31, 2021 and December 31, 2020 included the following: March 31, 2021 December 31, 2020 (in thousands) Amortizable intangible assets: Developed technology $ 77,658 $ 77,658 Customer relationships 37,950 37,950 In-process research and development 8,030 8,030 Non-compete agreements 70 70 Total identifiable intangible assets, gross 123,708 123,708 Accumulated amortization—intangible assets: Developed technology (25,651) (21,905) Customer relationships (15,713) (11,877) Non-compete agreements (51) (42) Total accumulated amortization—intangible assets (41,415) (33,824) Total identifiable intangible assets, net $ 82,293 $ 89,884 Amortization of intangible assets for the three months ended March 31, 2021 and 2020 was $7.6 million and $1.1 million, respectively. The estimated remaining amortization expense associated with the Company's intangible assets was as follows as of March 31, 2021: Fiscal Year Amount (in thousands) Remaining 2021 $ 23,457 2022 26,342 2023 13,941 2024 13,757 2025 4,238 Thereafter 558 Total $ 82,293

Business Combinations

Business Combinations	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Business Combinations	Business Combinations On April 1, 2020 (the "Acquisition Date"), the Company completed the Telaria Merger. Management's purchase price allocation was finalized as of March 31, 2021, resulting in no changes from the purchase price and allocation as of December 31, 2020. Unaudited Pro Forma Information The following table provides unaudited pro forma information as if Telaria had been merged with the Company as of January 1, 2019. The unaudited pro forma information reflects adjustments for additional amortization resulting from the fair value adjustments to assets acquired and liabilities assumed, adjustments for alignment of accounting policies, and transaction expenses as if the Telaria Merger occurred on January 1, 2019. The pro forma results do not include any anticipated cost synergies or other effects of the integration merged companies. Accordingly, pro forma amounts are not necessarily indicative of the results that actually would have occurred had the acquisition been completed on the dates indicated, nor is it indicative of the future operating results of the combined company. Three Months Ended March 31, 2020 (in thousands) Pro Forma Revenue $ 51,333 Pro Forma Net Loss $ (21,537)

Merger, Acquisition, and Restru

Merger, Acquisition, and Restructuring Costs	3 Months Ended
	Mar. 31, 2021
Restructuring and Related Activities [Abstract]
Merger, Acquisition, and Restructuring Costs	Merger, Acquisition, and Restructuring Costs Merger, acquisition, and restructuring costs consist primarily of professional services fees and employee termination costs, including stock-based compensation charges, associated with the Telaria Merger, the SpotX Acquisition, and restructuring activities. The following table summarizes merger, acquisition, and restructuring cost activity (in thousands): Three Months Ended Three Months Ended March 31, 2021 March 31, 2020 (in thousands) Professional Services (investment banking advisory, legal and other professional services) $ 2,226 $ 1,827 Personnel related (severance and one-time termination benefit costs) 119 103 Non-cash stock-based compensation (double-trigger acceleration and severance) 377 — Total merger, acquisition, and restructuring costs $ 2,722 $ 1,930 Accrued merger, acquisition, and restructuring costs were $2.5 million and $2.9 million at March 31, 2021 and December 31, 2020, respectively, and were primarily related to the SpotX Acquisition and the Telaria Merger. Accrued restructuring costs associated with personnel costs are included within accounts payable and accrued expenses and accruals related to the Telaria Merger assumed loss contracts are included within other current liabilities and other liabilities, non-current on the Company's condensed consolidated balance sheet. (in thousands) Accrued merger, acquisition, and restructuring costs at December 31, 2020 2,935 Restructuring costs, personnel related and non-cash stock-based compensation 496 Cash paid for restructuring costs (531) Non-cash stock-based compensation (377) Accrued merger, acquisition, and restructuring costs at March 31, 2021 $ 2,523

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	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 awards ("RSAs"), and restricted stock units ("RSUs"), to the Company's employees, officers, directors, and consultants. The Company's board of directors administers the plans. Options outstanding 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. RSAs and RSUs vest at varying rates, typically approximately 25% vesting after approximately one year of service and the remainder vesting annually, semi-annually, or quarterly thereafter. The restricted stock units granted in 2020 included 0.7 million that vest 50% on each of the first and second anniversaries of the grant date. Options, RSAs, and RSUs granted under the plans accelerate under certain circumstances for certain participants upon a change in control, as defined in the governing plan or award agreement. An aggregate of 15,413,813 shares remained available for future grants at March 31, 2021 under the plans. Stock Options A summary of stock option activity for the three months ended March 31, 2021 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, 2020 6,695 $ 5.61 Exercised (733) $ 7.89 Forfeited (84) $ 8.09 Outstanding at March 31, 2021 5,878 $ 5.29 6.25 years $ 213,470 Exercisable at March 31, 2021 3,628 $ 5.52 4.97 years $ 130,947 The total intrinsic value of options exercised during the three months ended March 31, 2021 was $26.6 million. At March 31, 2021, the Company had unrecognized employee stock-based compensation expense relating to nonvested stock options of approximately $5.7 million, which is expected to be recognized over a weighted-average period of 2.3 years. Total fair value of options vested during the three months ended March 31, 2021 was $0.9 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, 2021 March 31, 2020 Expected term (in years) N/A 6.1 Risk-free interest rate N/A 2.51 % Expected volatility N/A 60 % Dividend yield N/A — % Restricted Stock Units A summary of restricted stock unit activity for the three months ended March 31, 2021 is as follows: Number of Shares Weighted-Average Grant Date Fair Value (in thousands) Nonvested restricted stock units outstanding at December 31, 2020 9,286 $ 5.30 Granted 210 $ 56.06 Canceled (133) $ 5.28 Vested (1,351) $ 5.03 Nonvested restricted stock units outstanding at March 31, 2021 8,012 $ 6.68 The weighted-average grant date fair value per share of restricted stock units granted during the three months ended March 31, 2021 was $56.06. The aggregate fair value of restricted stock units that vested during the three months ended March 31, 2021 was $53.8 million. At March 31, 2021, the intrinsic value of nonvested restricted stock units was $333.4 million. At March 31, 2021, the Company had unrecognized stock-based compensation expense relating to nonvested restricted stock units of approximately $42.2 million, which is expected to be recognized over a weighted-average period of 2.4 years. Performance Stock Units In April 2020, the Company granted the Company's CEO 146,341 restricted stock units that vest based on certain stock price performance metrics with a fair value of $0.9 million. The grant date fair value per share of restricted stock was $6.15, which was estimated using a Monte-Carlo lattice model. During the three months ended March 31, 2021, the Company recognized $0.3 million of stock-based compensation related to these performance stock units based on a performance measurement of 150%. At March 31, 2021, the Company had unrecognized employee stock-based compensation expense of approximately $0.6 million, which is expected to be recognized over the remaining 2 years. Between 0% and 150% of the performance stock units will vest on the third anniversary of its grant date. The compensation expense will not be reversed if the performance metrics are not met. 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, 2021, the Company has reserved 3,189,449 shares of its common stock for issuance under the ESPP. The ESPP has an evergreen provision pursuant to which the share reserve will automatically increase on January 1st of each year in an amount equal to 1% of the total number of shares of capital stock outstanding on December 31st of the preceding calendar year, although the Company’s board of directors may provide for a lesser increase, or no increase, in any year. 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, 2021 March 31, 2020 (in thousands) Cost of revenue $ 85 $ 101 Sales and marketing 2,461 1,085 Technology and development 1,826 1,183 General and administrative 2,244 1,688 Restructuring and other exit costs 377 — Total stock-based compensation expense $ 6,993 $ 4,057

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2021
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 adopted ASU2019-12, during the three months ended March 31, 2021. There was no material impact to the quarterly income tax provision. The Company recorded an income tax expense of $0.2 million and an income tax benefit of $0.2 million for the three months ended March 31, 2021 and 2020, respectively. The tax expense for the three months ended March 31, 2021 is primarily the result of the domestic valuation allowance and the change in unrecognized benefit. On March 27, 2020, President Trump signed into law the Coronavirus Aid, Relief, and Economic Security Act ("CARES Act"), in response to the COVID-19 pandemic. The CARES Act is meant to infuse negatively affected companies with various tax cash benefits to ease the impact of the COVID-19 pandemic. The CARES Act, among other things, includes provisions relating to refundable payroll tax credits, deferment of employer-side social security payments, and net operating loss carryback periods. The Company has determined the tax implications of the CARES Act will not be material. To date the Company has not taken advantage of any relief under the CARES Act. In addition, various foreign jurisdictions where the Company has activity have enacted or are considering enacting a variety of measures that could impact our tax liabilities. The Company is monitoring new legislation and evaluating the potential tax implications of these measures globally. 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. Due to the net operating loss carryforwards, all of the Company's United States federal and a majority of its state returns are open to examination by the Internal Revenue Service and state jurisdictions for all years since inception. The 2017 U.S. Income Tax Return for Telaria, Inc. is under examination by the IRS. There have been no issues identified through the period ending March 31, 2021. For the Netherlands and the United Kingdom, all tax years remain open for examination by the local country tax authorities, for France only 2018 forward are open for examination, for Singapore 2017 and forward are open for examination, for Australia, Brazil, Canada, Germany, Italy, New Zealand, and Malaysia 2016 and forward are open for examination, and for Japan 2014 and forward remain open for examination. Pursuant to Section 382 of the Internal Revenue Code, the Company and Telaria, Inc. both underwent ownership changes for tax purposes (i.e. a more than 50% change in stock ownership in aggregated 5% shareholders) on April 1, 2020 due to the Telaria Merger. As a result, the use of our total domestic NOL carryforwards and tax credits generated prior to the ownership change will be subject to annual use limitations under Section 382 and Section 383 of the Code and comparable state income tax laws. The Company believes that the ownership change will not impact our ability to utilize substantially all of our NOLs and state research and development carryforward tax credits to the extent it will generate taxable income that can be offset by such losses. The Company reasonably expects its federal research and development carryforward tax credits will not be recovered prior to expiration. There was no material change to the Company's unrecognized tax benefits in the three months ended March 31, 2021 and the Company does not expect to have any material changes to unrecognized tax benefits through the end of the fiscal year.

Lease Obligations

Lease Obligations	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Lease Obligations	Lease Obligations For the three months ended March 31, 2021 and 2020, the Company recognized $3.8 million and $2.1 million, respectively, of lease expense under ASC 842, which included operating lease expenses associated with leases included in the lease liability and ROU asset on the condensed consolidated balance sheet. In addition, for the three months ended March 31, 2021 and 2020, the Company recognized $0.3 million and $0.1 million, respectively, of lease expense related to short-term leases, and $6.4 million and $2.4 million during the three months ended March 31, 2021 and 2020, respectively, of variable and cloud-based services related to data centers that are not included in the ROU asset or lease liability balances. The Company also received rental income of $1.2 million for real estate leases for which it subleases the property to third parties during the three months ended March 31, 2021. The Company received insignificant amounts of rental income during the three months ended March 31, 2020. As of March 31, 2021, a weighted average discount rate of 4.94% has been applied to the remaining lease payments to calculate the lease liabilities included within the condensed consolidated balance sheet. The lease terms of the Company’s operating leases generally range from one year to ten years, and the weighted average remaining lease term of leases included in the lease liability is 6.13 years as of March 31, 2021. The maturity of the Company's lease liabilities associated with leases included in the lease liability and ROU asset were as follows as of March 31, 2021 (in thousands): Fiscal Year Remaining 2021 $ 7,575 2022 8,943 2023 7,978 2024 7,072 2025 3,551 Thereafter 11,403 Total lease payments (undiscounted) 46,522 Less: imputed interest (6,659) Lease liabilities—total (discounted) $ 39,863 In addition to the lease liabilities included in these condensed consolidated financial statements at March 31, 2021, during the three months ended December 31, 2020, the Company entered into agreements for an office lease in Los Angeles and a data center in Singapore which have not commenced as of March 31, 2021; therefore, they are not included in the lease liability on the balance sheet as of March 31, 2021. The Company has future commitments totaling $23.2 million over the course of 10 years for the office lease and $5.6 million over the course of four years for the data center in Singapore.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments The Company has commitments under non-cancelable operating leases for facilities, certain equipment, and its managed data center facilities (Note 11). As of March 31, 2021 and December 31, 2020, the Company had $6.0 million and $6.3 million, respectively, 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 the Company 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 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, 2021. However, based on management’s knowledge as of March 31, 2021, 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 consolidated financial position, results of operations or cash flows. Employment Contracts

SVB Loan Agreement

SVB Loan Agreement	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
SVB Loan Agreement	SVB Loan Agreement On September 25, 2020, the Company amended and restated its loan and security agreement with Silicon Valley Bank ("SVB") (the "Loan Agreement"), which was scheduled to expire on September 26, 2020. The Loan Agreement provides a senior secured revolving credit facility of up to the lesser of $60.0 million and 85% of eligible accounts receivable, with a maturity date of September 25, 2022. The Loan Agreement includes a letter of credit, foreign exchange and cash management facility with a sublimit up to $10.0 million, of which $6.0 million was utilized for letters of credit related to leases as of March 31, 2021 (see Note 12). As of March 31, 2021, the amount available for borrowing is $54.0 million. The Company incurred $0.1 million of debt issuance fees that were capitalized and are being amortized over the term of the Loan Agreement. An unused revolver fee in the amount of 0.15% per annum of the average unused portion of the revolver line is charged and is payable monthly in arrears. The Company may elect for advances to bear interest calculated by reference to prime or LIBOR. If the Company elects LIBOR, amounts outstanding under the amended credit facility bear interest at a rate per annum equal to LIBOR plus 2.25%, with LIBOR having a floor of 3.5%. If the Company elects prime, advances bear interest at a rate of prime plus 0.25%, with prime having a floor of 3.5%. The Loan Agreement is collateralized by security interests in substantially all of the Company's assets. Subject to certain exceptions, the Loan Agreement restricts the Company's ability to, among other things, pay dividends, sell assets, make changes to the nature of the business, engage in mergers or acquisitions, incur, assume or permit to exist, additional indebtedness and guarantees, create or permit to exist, liens, make distributions or redeem or repurchase capital stock, or make other investments, engage in transactions with affiliates, make payments with respect to subordinated debt, and enter into certain transactions without the consent of the financial institution. The Company is required to maintain a lockbox arrangement where clients payments received in the lockbox will be deposited daily into the Company's operating bank accounts. The Loan Agreement requires the Company to comply with financial covenants, measured quarterly, with respect to a minimum liquidity ratio and maximum quarterly cash burn. The Company is required to maintain a minimum liquidity ratio of at least 1.25 on the last day of each quarter and not exceed, on an absolute basis, a maximum quarterly cash burn for specific periods, as defined in the Loan Agreement. The Liquidity Ratio is defined as Cash and Cash Equivalents, plus Accounts Receivable, less Accounts Payable - Seller, divided by all obligations the Company has to pay to SVB, including all debt balances, interest, service fees, and unused credit line fees, net of outstanding letters of credit as of the balance sheet date. Cash Burn is defined as Adjusted EBITDA less Capital Expenditures during the trailing periods as outlined in the Loan Agreement. The Loan Agreement defines Capital Expenditures as the current period unfinanced cash expenditures that are capitalized and amortized, including but not limited to property and equipment and capitalized labor costs as they relate to internal use software development costs. As of March 31, 2021, the Company was in compliance with its financial covenants. The Loan Agreement also includes customary representations and warranties, affirmative covenants, and events of default, including events of default upon a change of control and material adverse change (as defined in the Loan Agreement). Following an event of default, SVB would be entitled to, among other things, accelerate payment of amounts due under the credit facility and exercise all rights of a secured creditor. As of March 31, 2021, there were no amounts outstanding under the Loan Agreement (other than with respect to the letters of credit). Future availability under the credit facility is dependent on several factors including the available borrowing base and compliance with future covenant requirements.

Convertible Senior Notes and Ca

Convertible Senior Notes and Capped Call Transactions	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Convertible Senior Notes and Capped Call Transactions	Convertible Senior Notes and Capped Call Transactions In March 2021, the Company issued $400.0 million aggregate principal amount of 0.25% convertible senior notes in a private placement, including $50.0 million aggregate principal amount of such notes pursuant to the exercise in full of the over-allotment options of the initial purchasers (collectively, the ("Convertible Notes")). The Convertible Notes will mature on March 15, 2026, unless earlier repurchased, redeemed or converted. The total net proceeds from the offering, after deducting initial purchaser discounts and debt issuance costs, paid or payable by us, were approximately $389.0 million. The Company used approximately $39.0 million of the net proceeds from the offering to pay for the Capped Call Transactions (as described below). The Convertible Notes are senior, unsecured obligations and (i) will be equal in right of payment with the existing and future senior, unsecured indebtedness; (ii) senior in right of payment to any of the Company’s future indebtedness that is expressly subordinated to the Convertible Notes; (iii) effectively subordinated to the Company’s existing and future secured indebtedness, to the extent of the value of the collateral securing that indebtedness, including amounts outstanding under our Existing Loan Agreement or our New Credit Facilities (see Note 15); and (iv) structurally subordinated to all existing and future indebtedness and other liabilities, including trade payables, and (to the extent we are not a holder thereof) preferred equity, if any, of the Company’s subsidiaries that do not guarantee the Convertible Notes. The Convertible Notes accrue interest at 0.25% per annum payable semi-annually in arrears on March 15 and September 15 of each year, beginning on September 15, 2021. The Convertible Notes will mature on March 15, 2026 unless they are redeemed, repurchased or converted prior to such date. The Convertible Notes are convertible at the option of holders only during certain periods and upon satisfaction of certain conditions. Holders will have the right to convert their notes (or any portion of a note in an authorized denomination), in the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending on June 30, 2021, if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price for each of at least 20 trading days during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (ii) during the five consecutive business days immediately after any ten consecutive trading day period (such ten consecutive trading day period, the "measurement period") in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (iii) upon the occurrence of certain corporate events or distributions on the Company’s common stock; (iv) if the Company calls such Convertible Notes for redemption; and (v) on or after September 15, 2025, until the close of business on the second scheduled trading day immediately before the maturity date, holders of the Convertible Notes may, at their option, convert all or a portion of their Convertible Notes regardless of the foregoing conditions.at any time from, and including, September 15, 2025 until the close of business on the second scheduled trading day immediately before the maturity date. Upon conversion, the Convertible Notes may be settled in shares of the Company’s common stock, cash or a combination of cash and shares of the Company’s common stock, at the Company’s election. All conversions with a conversion date that occurs on or after September 15, 2025 will be settled using the same settlement method, and the Company will send notice of such settlement method to noteholders no later than the open of business on September 15, 2025. The Company may not redeem the Convertible Notes at their option at any time before March 20, 2024. Subject to the terms of the indenture, the Company has the right, at its election, to redeem all, or any portion (subject to the partial redemption limitation) in an authorized denomination, of the Convertible Notes, at any time, and from time to time, on a redemption date on or after March 20, 2024 and on or before the 40th scheduled trading day immediately before the maturity date, for cash, but only if the "last reported sale price," as defined under the Offering Memorandum, per share of common stock exceeds 130% of the “conversion price” on (i) each of at least 20 trading days, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (ii) the trading day immediately before the date we send such notice. In addition, calling any note for redemption will constitute a "make-whole fundamental change" (as defined below) with respect to that note, in which case the conversion rate applicable to the conversion of that note will be increased in certain circumstances if it is converted after it is called for redemption. If the Company elects to redeem less than all of the outstanding notes, then the redemption will not constitute a make-whole fundamental change with respect to the notes not called for redemption, and holders of the notes not called for redemption will not be entitled to an increased conversion rate for such notes as described above on account of the redemption, except to the limited extent described further below. No sinking fund is provided for the Convertible Notes, which means that the Company is not required to redeem or retire the Convertible Notes periodically. If a fundamental change occurs, then each noteholder will have the right to require the Company to repurchase its notes (or any portion thereof in an authorized denomination) for cash on a date (the "fundamental change repurchase date") of the Company’s choosing, which must be a business day that is no more than 45, nor less than 20, business days after the date Magnite sends the related fundamental change notice. If an event of default occurs with respect to the Company or any guarantor, then the principal amount of, and all accrued and unpaid interest on, all of the notes then outstanding will immediately become due and payable without any further action or notice by any person. If an event of default (other than an event of default described below with respect to Magnite or any guarantor and not solely with respect to a significant subsidiary of the Company’s or a guarantor, other than the Company or such guarantor) occurs and is continuing, then, except as described below under the caption —Special interest as sole remedy for certain reporting defaults, the trustee, by notice to the Company, or noteholders of at least 25% of the aggregate principal amount of notes then outstanding, by written notice to us and the trustee, may declare the principal amount of, and all accrued and unpaid interest on, all of the notes then outstanding to become due and payable immediately. The Convertible Notes have an initial conversion rate of 15.6539 shares of common stock per $1,000 principal amount of the Convertible Notes, which will be subject to customary anti-dilution adjustments in certain circumstances. In connection with the pricing of the Convertible Notes, the Company entered into privately negotiated capped call transactions with various financial institutions (the "Capped Call Transactions"). The Capped Call Transactions were entered into with third party broker-dealers to limit the potential dilution that would occur if the Company has to settle the conversion value in excess of the principal in shares. This exposure will be covered (i.e., the Company will receive as many shares as are required to be issued between the conversion price of $63.8818 and the maximum price of $91.2600). Any shares required to be issued by the Company over this amount would have net earnings per share dilution impact. By entering into the Capped Call Transactions, the Company expects to reduce the potential dilution to its common stock (or, in the event the conversion is settled in cash, to reduce its cash payment obligation) in the event that at the time of conversion its stock price exceeds the conversion price under the Convertible Notes. The Company paid $39.0 million for the Capped Call Transactions, which was recorded as additional paid-in capital, using a portion of the gross proceeds from the sale of the Convertible Notes. The cost of the Capped Call Transactions is not expected to be tax deductible as the Company did not elect to integrate the capped call into the Convertible Notes for tax purposes. The cost of the Capped Call Transaction was recorded as a reduction of the Company’s additional paid-in capital in the accompanying condensed consolidated financial statements. As noted in Note 1, the Company early adopted ASU 2020-06 effective January 1, 2021. The Company has not elected the fair value option, the embedded conversion features are not required to be bifurcated under the accounting guidance, and the convertible debt was not issued with a substantial premium. As such, the Company accounted for the Convertible Notes as a liability in its entirety. Under the guidance, all the embedded features of the Convertible Notes met the definition of a derivative. These features included a contingent call option, contingent put options, and conversion features. The contingent call option and contingent put options are clearly and closely related to the debt host and, therefore, do not require bifurcation. As the conversion features are indexed to the Company’s own equity and would be equity classified if they were freestanding instruments, the scope exception in ASC 815-10-15-74(a) applies and these conversion features will not be bifurcated under ASC 815. The new accounting guidance also eliminated the bifurcation models of ASC 470-20 and eliminated the treasury method approach to earnings per share. Accordingly, earnings per share on convertible debt instruments should only be calculated under the If-Converted method. Under the guidance above, the Company will assume settlement in shares. The Company will assess at each period end whether the impact of the contingent conversion (e.g., stock price exceeding 130% of the conversion price for 20 days) is dilutive, regardless of whether the stock price contingency has been met. A determination must be made each quarter, if a contingency has been overcome to trigger potential conversion election, whether the conversion option is out of the money or in the money (i.e., is the current share price above or below the conversion price). If the current share price exceeds the conversion price, then the conversion will be dilutive to the Company’s earnings per share. At issuance and at March 31, 2021, the share price did not exceed the conversion prices, and as such, the conversion was anti-dilutive. The following table summarizes the Convertible Notes at March 31, 2021: March 31, 2021 (in thousands) Convertible Notes $ 400,000 Unamortized debt discounts (10,920) Unamortized debt issuance costs (436) Debt, non-current, net of debt issuance costs $ 388,644 Fees and other amounts paid to the creditor were treated as an increase to debt discount. The Company incurred debt issuance costs of $11.4 million in March 2021, of which $11.0 million were associated with issuance fees netted against the proceeds and $0.4 million were associated with other deferred financing costs associated with the Convertible Notes. The Convertible Notes are presented net of issuance costs on the Company's condensed consolidated balance sheet. The debt issuance costs are amortized on an effective interest basis over the term of the Convertible Notes and are included in interest expense and amortization of debt discount in the accompanying condensed consolidated statements of operations. The following table sets forth interest expense related to the Convertible Notes for the three months ended March 31, 2021: March 31, 2021 (in thousands) Contractual interest expense $ 36 Amortization of debt discount 80 Amortization of debt issuance costs 3 Total interest expense $ 119 Effective interest rate 0.82 % Amortization expense for the Company's debt discount and debt issuance costs for the remainder of 2021 and for fiscal years 2022 through 2026 is as follows: Fiscal Year Debt Discount Debt Issuance Costs Remaining 2021 $ 1,650 $ 66 2022 2,200 88 2023 2,200 88 2024 2,200 88 2025 2,200 88 2026 470 18 Total $ 10,920 $ 436

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On April 1, 2021, the Company granted 969,941 restricted stock units, 200,299 stock options, and 26,291 performance stock units to the Company's employees. The options granted will vest over four years from grant date, with 25% vesting after one year and the remainder vesting monthly thereafter. The RSUs granted will vest over four years from issuance with 25% after one year, and the remainder vesting quarterly thereafter. Between 0% and 150% of the performance stock units will vest on the third anniversary of its grant date based on certain stock price performance metrics. On April 30, 2021, the Company completed the SpotX Acquisition, pursuant to a Stock Purchase Agreement, dated as of February 4, 2021 (the "Purchase Agreement"), by and between the Company and RTL US Holdings, Inc. ("RTL"). The initial purchase price for the SpotX Acquisition was $560 million in cash ("Cash Consideration") and 14,000,000 shares of the Company's common stock. Per the terms of the Purchase Agreement, at the completion of the Company’s offering of its Convertible Notes, RTL elected to increase the Cash Consideration by an amount equal to 20% of the gross proceeds of the Convertible Notes (which amount was equal to $80 million) and to reduce the number of shares of common stock it would otherwise receive by a number of shares of common stock equal to 20% of the gross proceeds of the proposed offering of notes ($80 million) divided by the closing price of a share of our common stock on the trading day immediately prior to the date of pricing of the proposed offering of notes ($49.21). As a result of this election, the adjusted purchase price was $1,135.6 million, consisting of $640 million in cash plus 12,374,315 shares of common stock (based on the fair value of the Company's common stock on April 30, 2021). The Cash Consideration is subject to customary working capital and other adjustments. The Company is currently evaluating the allocation of the purchase price to the acquired assets and assumed liabilities. It is not practicable to disclose the preliminary purchase price allocation or the unaudited combined financial information given the short period of time between the acquisition and the issuance of these unaudited interim condensed consolidated financial statements. On April 30, 2021, the Company entered into a credit agreement (the "Credit Agreement") with Goldman Sachs Bank USA as administrative agent and collateral agent, and other lender parties thereto. The Credit Agreement provides for a $360.0 million seven-year senior secured term loan facility ("Term Loan B Facility") and a $52.5 million senior secured revolving credit facility (the "Revolving Credit Facility"). As part of the Term Loan B Facility, the Company received $325 million in proceeds, net of fees, which were used to finance the SpotX Acquisition and related transactions, and for general corporate purposes. Loans, if any, under the Revolving Credit Facility will generally be used for general corporate purposes. The obligations under the Credit Agreement are secured by substantially all of the assets of the Company and those of its subsidiaries that are guarantors under the Credit Agreement. Amounts outstanding under the Credit Agreement accrue interest at a rate equal to either, (1) for the Term Loan B Facility, at the Company’s election, the Eurodollar Rate (as defined in the Credit Agreement) plus a margin of 5.00% per annum, or ABR (as defined in the Credit Agreement) plus a margin of 4.00%, and (2) for the Revolving Credit Facility, at the Company’s election, the Eurodollar Rate plus a margin of 4.25% to 4.75%, or ABR plus a margin of 3.25% to 3.75%, in each case, depending on the Company’s first lien net leverage ratio. The covenants of the Credit Agreement include customary negative covenants that, among other things, restrict the Company’s ability to incur additional indebtedness, grant liens and make certain acquisitions, investments, asset dispositions and restricted payments. In addition, the Credit Agreement contains a financial covenant, tested on the last day of any fiscal quarter if utilization of the Revolving Credit Facility exceeds 35% of the total revolving commitments, that requires the Company to maintain a first lien net leverage ratio not greater than 3.25 to 1.00. The Credit Agreement includes customary events of default, and customary rights and remedies upon the occurrence of any event of default thereunder, including rights to accelerate the loans, terminate the commitments thereunder and realize upon the collateral securing the obligations under the Credit Agreement. In connection with entering into the Credit Agreement, the Loan Agreement with SVB was terminated on April 30, 2021.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	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, 2021 are not necessarily indicative of the results that may be expected for any future interim period, the year ending December 31, 2021, or for any future year. The condensed consolidated balance sheet at March 31, 2021 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, 2020 included in its 2020 Annual Report on Form 10-K. Aside from the adoption of ASU 2020-06, as described below, 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, 2020 included in its Annual Report on Form 10-K.
Reclassifications	Reclassifications Amounts for merger, acquisition, and restructuring costs incurred in the three months ended March 31, 2020 have been reclassified to conform to the presentation for the three months ended March 31, 2021 condensed consolidated statements of operations. Reclassifications consist of $1.8 million from general and administrative expenses and $0.2 million from sales and marketing expenses to merger, acquisition, and restructuring costs in the condensed consolidated statement of operations for the three months ended March 31, 2020. These expenses were related to professional services associated with the Telaria Merger. The Company did not separately present the merger, acquisition, and restructuring expenses in the condensed consolidated statement of operations for the three months ended March 31, 2020.
Use of Estimates	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. Due to the economic uncertainty as a result of the COVID-19 pandemic, it has become more difficult to apply certain assumptions and judgments into these estimates. The extent of the impact of COVID-19 pandemic on the Company's operational and financial performance will depend on future developments, which are highly uncertain and cannot be predicted, including but not limited to, the duration and spread of the pandemic, its severity, including any resurgence, the actions to contain the virus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume. During the three months ended March 31, 2021, this uncertainty continued to result in a higher level of judgment related to its estimates and assumptions. As of the date of issuance of the condensed consolidated financial statements for the three months ended March 31, 2021, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, judgments, or revise the carrying value of its assets or liabilities. These estimates may change, as new events occur and additional information is obtained, and are
Recently Adopted and Recent Accounting Pronouncements	Recently Adopted Accounting Standards On January 1, 2021, the Company adopted ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (ASU "2020-06") on a prospective basis, which simplifies the accounting for convertible instruments by reducing the number of accounting models available for convertible debt instruments that require separating embedded conversion features from convertible instruments. This guidance also eliminates the treasury stock method to calculate diluted earnings per share for convertible instruments and requires the use of the if-converted method. The adoption of this standard is included in the financial statements as of March 31, 2021 and for the three ended March 31, 2021. Refer to Note 14—"Convertible Notes" for additional information related to accounting for convertible debt issued during the three months ended March 31, 2021. On January 1, 2021, the Company adopted ASU 2019-12— Simplifying the Accounting for Income Taxes ("ASU 2019-12"). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to general principles in Topic 740 and clarifies and amends existing guidance for clarity and consistent application. There was no material impact to the quarterly income tax provision. Recent Accounting Pronouncements In March 2020, the FASB issued Update No. 2020-04, Reference Rate Reform (Topic 848), which provides temporary optional guidance to companies impacted by the transition away from the LIBOR. The amendment provides certain expedients and exceptions to applying GAAP in order to lessen the potential accounting burden when contracts, hedging relationships, and other transactions that reference LIBOR as a benchmark rate are modified. Further, in January 2021, the FASB issued Update No. 2021-01, Reference Rate Reform (Topic 848), which clarifies the scope of Topic 848 so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions in Topic 848. These amendments are effective upon issuance and expire on December 31, 2022. The Company is currently assessing the impact of the LIBOR transition on the Company's condensed consolidated financial statements. The Company does not believe there are any other recently issued and effective or not yet effective pronouncements that would have or are expected to have any significant effect on the Company’s financial position, cash flows or results of operations.

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Net Loss Per Share, Basic and Diluted	The following table presents the basic and diluted net loss per share: Three Months Ended March 31, 2021 March 31, 2020 (in thousands, except per share data) Basic and Diluted Income (Loss) Per Share: Net loss $ (12,877) $ (9,675) Weighted-average common shares outstanding 115,296 54,868 Weighted-average unvested restricted stock — (2) Weighted-average common shares outstanding used to compute net loss per share 115,296 54,866 Basic and diluted net loss per share $ (0.11) $ (0.18)
Schedule of Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share	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, 2021 March 31, 2020 (in thousands) Options to purchase common stock 5,400 1,239 Unvested restricted stock awards — 1 Unvested restricted stock units 7,496 3,978 Unvested performance stock units 197 — ESPP 90 61 Total shares excluded from net loss per share 13,183 5,279

Revenues (Tables)

Revenues (Tables)	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Summary of Disaggregation of Revenue	The following table presents our revenue by channel for the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 March 31, 2020 (in thousands, except percentages) Channel: CTV $ 11,976 20 % $ — — % Desktop 20,851 34 15,296 42 Mobile 27,888 46 20,999 58 Total $ 60,715 100 % $ 36,295 100 % The following table presents the Company's revenue disaggregated by geographic location, based on the location of the Company's sellers: Three Months Ended March 31, 2021 March 31, 2020 (in thousands) United States $ 42,611 $ 25,533 International 18,104 10,762 Total $ 60,715 $ 36,295
Accounts Receivable, Allowance for Credit Loss	The following is a summary of activity in the allowance for doubtful accounts for the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 March 31, 2020 (in thousands) Allowance for doubtful accounts, Beginning Balance December 31 $ 2,360 $ 3,400 Write-offs (4) (740) Increase (decrease) in provision for expected credit losses (877) 413 Recoveries of previous write-offs 20 7 Allowance for doubtful accounts, March 31 $ 1,499 $ 3,080

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
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, 2021: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 356,909 $ 356,909 $ — $ — The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at December 31, 2020: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 7,868 $ 7,868 $ — $ —

Other Balance Sheet Amounts (Ta

Other Balance Sheet Amounts (Tables)	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses included the following: March 31, 2021 December 31, 2020 (in thousands) Accounts payable—seller $ 411,674 $ 492,605 Accounts payable—trade 15,058 4,268 Accrued employee-related payables 9,858 12,442 Total $ 436,590 $ 509,315

Goodwill, Intangible Assets, _2

Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements (Tables)	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The Company’s intangible assets as of March 31, 2021 and December 31, 2020 included the following: March 31, 2021 December 31, 2020 (in thousands) Amortizable intangible assets: Developed technology $ 77,658 $ 77,658 Customer relationships 37,950 37,950 In-process research and development 8,030 8,030 Non-compete agreements 70 70 Total identifiable intangible assets, gross 123,708 123,708 Accumulated amortization—intangible assets: Developed technology (25,651) (21,905) Customer relationships (15,713) (11,877) Non-compete agreements (51) (42) Total accumulated amortization—intangible assets (41,415) (33,824) Total identifiable intangible assets, net $ 82,293 $ 89,884
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, 2021: Fiscal Year Amount (in thousands) Remaining 2021 $ 23,457 2022 26,342 2023 13,941 2024 13,757 2025 4,238 Thereafter 558 Total $ 82,293

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Unaudited Pro Forma Information	The following table provides unaudited pro forma information as if Telaria had been merged with the Company as of January 1, 2019. The unaudited pro forma information reflects adjustments for additional amortization resulting from the fair value adjustments to assets acquired and liabilities assumed, adjustments for alignment of accounting policies, and transaction expenses as if the Telaria Merger occurred on January 1, 2019. The pro forma results do not include any anticipated cost synergies or other effects of the integration merged companies. Accordingly, pro forma amounts are not necessarily indicative of the results that actually would have occurred had the acquisition been completed on the dates indicated, nor is it indicative of the future operating results of the combined company. Three Months Ended March 31, 2020 (in thousands) Pro Forma Revenue $ 51,333 Pro Forma Net Loss $ (21,537)

Merger, Acquisition, and Rest_2

Merger, Acquisition, and Restructuring Costs (Tables)	3 Months Ended
	Mar. 31, 2021
Restructuring and Related Activities [Abstract]
Merger and Restructuring Costs	The following table summarizes merger, acquisition, and restructuring cost activity (in thousands): Three Months Ended Three Months Ended March 31, 2021 March 31, 2020 (in thousands) Professional Services (investment banking advisory, legal and other professional services) $ 2,226 $ 1,827 Personnel related (severance and one-time termination benefit costs) 119 103 Non-cash stock-based compensation (double-trigger acceleration and severance) 377 — Total merger, acquisition, and restructuring costs $ 2,722 $ 1,930 (in thousands) Accrued merger, acquisition, and restructuring costs at December 31, 2020 2,935 Restructuring costs, personnel related and non-cash stock-based compensation 496 Cash paid for restructuring costs (531) Non-cash stock-based compensation (377) Accrued merger, acquisition, and restructuring costs at March 31, 2021 $ 2,523

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity	A summary of stock option activity for the three months ended March 31, 2021 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, 2020 6,695 $ 5.61 Exercised (733) $ 7.89 Forfeited (84) $ 8.09 Outstanding at March 31, 2021 5,878 $ 5.29 6.25 years $ 213,470 Exercisable at March 31, 2021 3,628 $ 5.52 4.97 years $ 130,947
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The weighted-average input assumptions used by the Company were as follows: Three Months Ended March 31, 2021 March 31, 2020 Expected term (in years) N/A 6.1 Risk-free interest rate N/A 2.51 % Expected volatility N/A 60 % Dividend yield N/A — %
Schedule of Nonvested Restricted Stock Units Activity	A summary of restricted stock unit activity for the three months ended March 31, 2021 is as follows: Number of Shares Weighted-Average Grant Date Fair Value (in thousands) Nonvested restricted stock units outstanding at December 31, 2020 9,286 $ 5.30 Granted 210 $ 56.06 Canceled (133) $ 5.28 Vested (1,351) $ 5.03 Nonvested restricted stock units outstanding at March 31, 2021 8,012 $ 6.68
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, 2021 March 31, 2020 (in thousands) Cost of revenue $ 85 $ 101 Sales and marketing 2,461 1,085 Technology and development 1,826 1,183 General and administrative 2,244 1,688 Restructuring and other exit costs 377 — Total stock-based compensation expense $ 6,993 $ 4,057

Lease Obligations (Tables)

Lease Obligations (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Schedule of Maturity of Lease Liabilities	The maturity of the Company's lease liabilities associated with leases included in the lease liability and ROU asset were as follows as of March 31, 2021 (in thousands): Fiscal Year Remaining 2021 $ 7,575 2022 8,943 2023 7,978 2024 7,072 2025 3,551 Thereafter 11,403 Total lease payments (undiscounted) 46,522 Less: imputed interest (6,659) Lease liabilities—total (discounted) $ 39,863

Convertible Senior Notes and _2

Convertible Senior Notes and Capped Call Transactions (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule of Debt	The following table summarizes the Convertible Notes at March 31, 2021: March 31, 2021 (in thousands) Convertible Notes $ 400,000 Unamortized debt discounts (10,920) Unamortized debt issuance costs (436) Debt, non-current, net of debt issuance costs $ 388,644
Interest Income and Interest Expense Disclosure	The following table sets forth interest expense related to the Convertible Notes for the three months ended March 31, 2021: March 31, 2021 (in thousands) Contractual interest expense $ 36 Amortization of debt discount 80 Amortization of debt issuance costs 3 Total interest expense $ 119 Effective interest rate 0.82 %
Schedule of Maturities of Long-term Debt	Amortization expense for the Company's debt discount and debt issuance costs for the remainder of 2021 and for fiscal years 2022 through 2026 is as follows: Fiscal Year Debt Discount Debt Issuance Costs Remaining 2021 $ 1,650 $ 66 2022 2,200 88 2023 2,200 88 2024 2,200 88 2025 2,200 88 2026 470 18 Total $ 10,920 $ 436

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Merger, acquisition, and restructuring costs	$ 2,722	$ 1,930
General and administrative	(14,158)	(9,127)
Sales and marketing	(22,589)	(11,269)
Revision of Prior Period, Reclassification, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Merger, acquisition, and restructuring costs	200
Revision of Prior Period, Reclassification, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Merger, acquisition, and restructuring costs	1,800
General and administrative		$ 1,800
Sales and marketing	$ 200

Net Income (Loss) Per Share - B

Net Income (Loss) Per Share - Basic and Diluted Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic and Diluted Income (Loss) Per Share:
Net loss	$ (12,877)	$ (9,675)
Weighted-average common shares outstanding (in shares)	115,296	54,868
Weighted-average unvested restricted stock (in shares)	0	(2)
Weighted-average common shares outstanding used to compute net loss per share (in shares)	115,296	54,866
Basic and diluted net loss per share (usd per share)	$ (0.11)	$ (0.18)

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Shares Excluded From Calculation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	13,183	5,279
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	5,400	1,239
Unvested restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	0	1
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	7,496	3,978
Unvested performance stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	197	0
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	90	61

Net Income (Loss) Per Share - N

Net Income (Loss) Per Share - Narrative (Details)	1 Months Ended	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2021shares	Mar. 31, 2020shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		13,183,000	5,279,000
Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		6,261,560
Convertible Notes | Convertible Debt
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion ratio	0.0156539

Revenues - Narrative (Details)

Revenues - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Percent of revenue (less than)	3.00%
Payment terms	75 days
Accounts receivable, allowance for credit loss	$ 1,499	$ 3,080	$ 2,360	$ 3,400
Contra seller payable	800		$ 1,500
Increase (decrease) in provision for expected credit losses	(877)	413
Increase in contra seller payable	(700)	400
Provision for doubtful accounts	$ (159)	$ 2

Revenues - Revenue Disaggregate

Revenues - Revenue Disaggregated by Sales Distribution Channel (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 60,715	$ 36,295
Concentration risk, percentage	100.00%	100.00%
CTV
Disaggregation of Revenue [Line Items]
Revenue	$ 11,976	$ 0
Concentration risk, percentage	20.00%	0.00%
Desktop
Disaggregation of Revenue [Line Items]
Revenue	$ 20,851	$ 15,296
Concentration risk, percentage	34.00%	42.00%
Mobile
Disaggregation of Revenue [Line Items]
Revenue	$ 27,888	$ 20,999
Concentration risk, percentage	46.00%	58.00%

Revenues - Revenue Disaggrega_2

Revenues - Revenue Disaggregated by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 60,715	$ 36,295
United States
Disaggregation of Revenue [Line Items]
Revenue	42,611	25,533
International
Disaggregation of Revenue [Line Items]
Revenue	$ 18,104	$ 10,762

Revenues - Schedule of Allowanc

Revenues - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts, Beginning Balance December 31	$ 2,360	$ 3,400
Write-offs	(4)	(740)
Increase (decrease) in provision for expected credit losses	(877)	413
Recoveries of previous write-offs	20	7
Allowance for doubtful accounts, March 31	$ 1,499	$ 3,080

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 356,909	$ 7,868
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	356,909	7,868
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Significant Unobservable Inputs  (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 356,909	$ 7,868
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Convertible notes	390,500
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 356,900	$ 7,900

Other Balance Sheet Amounts - A

Other Balance Sheet Amounts - Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable—seller	$ 411,674	$ 492,605
Accounts payable—trade	15,058	4,268
Accrued employee-related payables	9,858	12,442
Total	$ 436,590	$ 509,315

Other Balance Sheet Amounts - N

Other Balance Sheet Amounts - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted cash	$ 0.1	$ 0.1

Goodwill, Intangible Assets, _3

Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 158,125		$ 158,125
Amortization expense of intangible assets	7,600	$ 1,100
Prepaid Expenses and Other Current Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Capitalized cloud computing software, net	300		200
Other Noncurrent Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Capitalized cloud computing software, net	800		$ 700
Computer Software, Intangible Asset
Acquired Finite-Lived Intangible Assets [Line Items]
Capitalized computer software, additions	$ 300

Goodwill, Intangible Assets, _4

Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements - Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	$ 123,708	$ 123,708
Total accumulated amortization—intangible assets	(41,415)	(33,824)
Total	82,293	89,884
Developed technology
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	77,658	77,658
Total accumulated amortization—intangible assets	(25,651)	(21,905)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	37,950	37,950
Total accumulated amortization—intangible assets	(15,713)	(11,877)
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	8,030	8,030
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	70	70
Total accumulated amortization—intangible assets	$ (51)	$ (42)

Goodwill, Intangible Assets, _5

Goodwill, Intangible Assets, and Capitalized Costs Incurred in Cloud Computing Arrangements - Finite-Lived Intangible Assets, Future Amortization Expense (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fiscal Year
Remaining 2021	$ 23,457
2022	26,342
2023	13,941
2024	13,757
2025	4,238
Thereafter	558
Total	$ 82,293	$ 89,884

Business Combinations - Unaudit

Business Combinations - Unaudited Pro forma Information (Details) - Telaria $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Business Acquisition [Line Items]
Pro Forma Revenue	$ 51,333
Pro Forma Net Loss	$ (21,537)

Merger, Acquisition, and Rest_3

Merger, Acquisition, and Restructuring Costs - Merger and Restructuring Cost Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Restructuring Cost and Reserve [Line Items]
Total merger, acquisition, and restructuring costs	$ 2,722	$ 1,930
Telaria
Restructuring Cost and Reserve [Line Items]
Professional Services (investment banking advisory, legal and other professional services)	2,226	1,827
Personnel related (severance and one-time termination benefit costs)	119	103
Non-cash stock-based compensation (double-trigger acceleration and severance)	377	0
Total merger, acquisition, and restructuring costs	$ 2,722	$ 1,930

Merger, Acquisition, and Rest_4

Merger, Acquisition, and Restructuring Costs - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
SpotX and Telaria
Business Acquisition [Line Items]
Accrued restructuring costs related to the merger	$ 2,523	$ 2,935

Merger, Acquisition, and Rest_5

Merger, Acquisition, and Restructuring Costs - Accrued Merger and Restructuring Cost Activity (Details) - SpotX and Telaria $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Restructuring Reserve [Roll Forward]
Restructuring Reserve And Business Combination, Acquisition Related Costs	$ 2,935
Restructuring costs, personnel related and non-cash stock-based compensation	496
Cash paid for restructuring costs	(531)
Non-cash stock-based compensation	(377)
Accrued merger, acquisition, and restructuring costs at March 31, 2021	$ 2,523

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)	15,413,813
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Stock Option | Vesting After One Year of Service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Award vesting rights, percentage	25.00%
RSAs and RSUs | Vesting After One Year of Service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Award vesting rights, percentage	25.00%
Restricted Stock Units (RSUs) | Vesting on First and Second Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage		50.00%
RSUs granted (in shares)		700,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Options Outstanding (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)$ / sharesshares
Shares Under Option
Beginning balance (in shares) | shares	6,695
Exercised (in shares) | shares	(733)
Forfeited (in shares) | shares	(84)
Ending balance (in shares) | shares	5,878
Exercisable (in shares) | shares	3,628
Weighted- Average Exercise Price
Beginning balance (usd per share) | $ / shares	$ 5.61
Exercised (usd per share) | $ / shares	7.89
Forfeited (usd per share) | $ / shares	8.09
Ending balance (usd per share) | $ / shares	5.29
Exercisable (usd per share) | $ / shares	$ 5.52
Weighted- Average Contractual Life
Outstanding	6 years 3 months
Exercisable	4 years 11 months 19 days
Aggregate Intrinsic Value
Outstanding | $	$ 213,470
Exercisable | $	$ 130,947

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Options Narrative (Details) - Stock Option $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)
Number of Shares
Intrinsic values of options exercised	$ 26.6
Unrecognized employee stock-based compensation	$ 5.7
Unrecognized employee stock-based compensation, period for recognition	2 years 3 months 18 days
Fair value of options vested in period	$ 0.9

Stock-Based Compensation - Valu

Stock-Based Compensation - Valuation Assumptions (Details) - Stock Option	3 Months Ended
	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days
Risk-free interest rate	2.51%
Expected volatility	60.00%
Dividend yield	0.00%

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) - $ / shares	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2021
Number of Shares
Beginning balance (in shares)		9,286,000
Granted (in shares)	146,341	210,000
Canceled (in shares)		(133,000)
Vested (in shares)		(1,351,000)
Ending balance (in shares)		8,012,000
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)		$ 5.30
Granted (in dollars per share)		56.06
Canceled (in dollars per share)		5.28
Vested (in dollars per share)	$ 6.15	5.03
Ending balance (in dollars per share)		$ 6.68

Stock-Based Compensation - Re_2

Stock-Based Compensation - Restricted Stock Units Narrative (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share)		$ 56.06
Fair value of restricted stock vested	$ 0.9	$ 53.8
Intrinsic value of nonvested unit		333.4
Unrecognized employee stock-based compensation		$ 42.2
Unrecognized employee stock-based compensation, period for recognition		2 years 4 months 24 days

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance Stock Units Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 6,993	$ 4,057
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	146,341	210,000
Fair value of restricted stock vested	$ 900	$ 53,800
Vested (in dollars per share)	$ 6.15	$ 5.03
Unrecognized employee stock-based compensation		$ 42,200
Unrecognized employee stock-based compensation, period for recognition		2 years 4 months 24 days
Performance Shares Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 300
Performance measurement percentage		150.00%
Unrecognized employee stock-based compensation		$ 600
Unrecognized employee stock-based compensation, period for recognition		2 years
Performance Shares Units | Minimum | Vesting on third anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage		0.00%
Performance Shares Units | Maximum | Vesting on third anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage		150.00%

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Purchase Plan Narrative (Details) - shares	1 Months Ended	3 Months Ended
	Nov. 30, 2013	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved		15,413,813
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual percentage increase		1.00%
2014 Employee Stock Purchase Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum employee subscription rate	10.00%
Offering period	6 months
Purchase price of common stock, percent	85.00%
Number of shares reserved		3,189,449

Stock-Based Compensation - St_3

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,993	$ 4,057
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	85	101
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,461	1,085
Technology and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,826	1,183
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,244	1,688
Restructuring and other exit costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 377	$ 0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes	$ 166	$ (201)

Lease Obligations - Narrative (

Lease Obligations - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Lease expense	$ 3,800	$ 2,100
Short-term lease expense	300	100
Sublease income	$ 1,200
Weighted average discount rate	4.94%
Weighted average remaining lease term	6 years 1 month 17 days
Minimum
Lessee, Lease, Description [Line Items]
Term of lease contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Term of lease contract	10 years
Data centers for cloud-based services
Lessee, Lease, Description [Line Items]
Variable lease cost	$ 6,400	$ 2,400
Operating lease not yet commenced, amount	$ 5,600
Operating lease not yet commenced, term of contract	4 years
Office, Los Angeles CA
Lessee, Lease, Description [Line Items]
Operating lease not yet commenced, amount	$ 23,200
Operating lease not yet commenced, term of contract	10 years

Lease Obligations - Schedule of

Lease Obligations - Schedule of Lease Liability Maturities (Details) $ in Thousands	Mar. 31, 2021USD ($)
Fiscal Year
Remaining 2021	$ 7,575
2022	8,943
2023	7,978
2024	7,072
2025	3,551
Thereafter	11,403
Total lease payments (undiscounted)	46,522
Less: imputed interest	(6,659)
Lease liabilities—total (discounted)	$ 39,863

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Financial Standby Letter of Credit
Other Commitments [Line Items]
Letters of credit outstanding, amount	$ 6	$ 6.3

SVB Loan Agreement (Details)

SVB Loan Agreement (Details) - USD ($)	Sep. 25, 2020	Mar. 31, 2021	Dec. 31, 2020
Financial Standby Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount		$ 6,000,000	$ 6,300,000
Revolving Credit Facility | Loan Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 60,000,000
Eligible accounts receivable	85.00%
Available borrowing capacity		54,000,000
Capitalized debt issuance costs		100,000
Unused capacity fee, percentage	0.15%
Minimum liquidity ratio	1.25
Debt outstanding amount		0
Revolving Credit Facility | Loan Agreement | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate	2.25%
Debt instrument, variable rate floor	3.50%
Revolving Credit Facility | Loan Agreement | Prime Rate
Debt Instrument [Line Items]
Variable interest rate	0.25%
Debt instrument, variable rate floor	3.50%
Revolving Credit Facility | Loan Agreement Sublimit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 10,000,000

Convertible Senior Notes and _3

Convertible Senior Notes and Capped Call Transactions - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2021USD ($)project$ / shares	Mar. 31, 2021USD ($)$ / shares	Mar. 31, 2020USD ($)
Debt Instrument [Line Items]
Net proceeds		$ 389,000	$ 0
Capped calls, transaction costs	$ 39,000
Percent of outstanding balance holders able to call debt in the event of default	25.00%	25.00%
debt issuance costs, gross	$ 11,400	$ 11,400
Minimum
Debt Instrument [Line Items]
Conversion price | $ / shares	$ 63.8818	$ 63.8818
Maximum
Debt Instrument [Line Items]
Conversion price | $ / shares	$ 91.2600	$ 91.2600
Convertible Notes | Convertible Debt
Debt Instrument [Line Items]
Aggregate principle amount	$ 400,000	$ 400,000
Interest rate	0.25%	0.25%
Over-allotment options	$ 50,000	$ 50,000
Net proceeds	$ 389,000
Conversion ratio	0.0156539
Convertible Notes | Convertible Debt | Issuance Fees
Debt Instrument [Line Items]
debt issuance costs, gross	$ 11,000	11,000
Convertible Notes | Convertible Debt | Deferred Financing Costs
Debt Instrument [Line Items]
debt issuance costs, gross	$ 400	$ 400
Convertible Notes | Convertible Debt | Minimum
Debt Instrument [Line Items]
Make-whole fundamental change period	20 days
Convertible Notes | Convertible Debt | Maximum
Debt Instrument [Line Items]
Make-whole fundamental change period	45 days
Convertible Notes | Convertible Debt | Conversion Term (i)
Debt Instrument [Line Items]
Threshold percent of stock price trigger	130.00%
Threshold trading days | project	20
Threshold consecutive trading days | project	30
Convertible Notes | Convertible Debt | Conversion Term (ii)
Debt Instrument [Line Items]
Threshold percent of stock price trigger	98.00%
Threshold trading days | project	5
Threshold consecutive trading days | project	10
Convertible Notes | Convertible Debt | Conversion Term (iv)
Debt Instrument [Line Items]
Threshold percent of stock price trigger	130.00%
Threshold trading days | project	20
Threshold consecutive trading days | project	30

Convertible Senior Notes and _4

Convertible Senior Notes and Capped Call Transactions - Summary of Convertible Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Unamortized debt discounts	$ (10,920)
Debt, non-current, net of debt issuance costs	388,644	$ 0
Convertible Debt | Convertible Notes
Debt Instrument [Line Items]
Convertible Notes	400,000
Unamortized debt discounts	(10,920)
Unamortized debt issuance costs	(436)
Debt, non-current, net of debt issuance costs	$ 388,644

Convertible Senior Notes and _5

Convertible Senior Notes and Capped Call Transactions - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Amortization of debt issuance costs	$ 99	$ 0
Convertible Debt | Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense	36
Amortization of debt discount	80
Amortization of debt issuance costs	3
Total interest expense	$ 119
Effective interest rate	0.82%

Convertible Senior Notes and _6

Convertible Senior Notes and Capped Call Transactions - Amortization of Debt Discount and Issuance Costs (Details) $ in Thousands	Mar. 31, 2021USD ($)
Debt Discount
Total	$ 10,920
Convertible Debt | Convertible Notes
Debt Discount
Remaining 2021	1,650
2022	2,200
2023	2,200
2024	2,200
2025	2,200
2026	470
Total	10,920
Debt Issuance Costs
Remaining 2021	66
2022	88
2023	88
2024	88
2025	88
2026	18
Total	$ 436

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 30, 2021	Apr. 01, 2021	Feb. 04, 2021	Apr. 30, 2020	Mar. 31, 2021	Apr. 29, 2021
SpotX, Inc
Subsequent Event [Line Items]
Cash consideration			$ 560
Issued in merger (in shares)			14,000,000
Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
Granted (in shares)				146,341	210,000
Stock Option
Subsequent Event [Line Items]
Vesting period					4 years
Stock Option | Vesting After One Year of Service
Subsequent Event [Line Items]
Vesting period					1 year
Award vesting rights, percentage					25.00%
Subsequent Events
Subsequent Event [Line Items]
Granted (in shares)		200,299
Share Price						$ 49.21
Subsequent Events | Term Loan B Facility | Secured Debt
Subsequent Event [Line Items]
Aggregate principle amount	$ 360
Long-term debt, term	7 years
Net proceeds	$ 325
Subsequent Events | Term Loan B Facility | Secured Debt | Eurodollar
Subsequent Event [Line Items]
Variable interest rate	5.00%
Subsequent Events | Term Loan B Facility | Secured Debt | Alternate Base Rate
Subsequent Event [Line Items]
Variable interest rate	4.00%
Subsequent Events | Senior Secured Revolving Credit Facility | Revolving Credit Facility
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 52.5
Debt utilization triggering leverage ratio compliance, percent	35.00%
Leverage ratio maximum	3.25
Subsequent Events | SpotX, Inc
Subsequent Event [Line Items]
Cash consideration	$ 640
Issued in merger (in shares)	12,374,315
Cash consideration, elected increase, percent	20.00%
Cash consideration, elected increase, amount	$ 80
Shares issued, elected decrease, percent	20.00%
Shares issued, elected decrease, value	$ 80
Purchase price	$ 1,135.6
Subsequent Events | Minimum | Senior Secured Revolving Credit Facility | Revolving Credit Facility | Eurodollar
Subsequent Event [Line Items]
Variable interest rate	4.25%
Subsequent Events | Minimum | Senior Secured Revolving Credit Facility | Revolving Credit Facility | Alternate Base Rate
Subsequent Event [Line Items]
Variable interest rate	3.25%
Subsequent Events | Maximum | Senior Secured Revolving Credit Facility | Revolving Credit Facility | Eurodollar
Subsequent Event [Line Items]
Variable interest rate	4.75%
Subsequent Events | Maximum | Senior Secured Revolving Credit Facility | Revolving Credit Facility | Alternate Base Rate
Subsequent Event [Line Items]
Variable interest rate	3.75%
Subsequent Events | Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
Granted (in shares)		969,941
Vesting period		4 years
Award vesting rights, percentage		25.00%
Subsequent Events | Restricted Stock Units (RSUs) | Vesting After One Year of Service
Subsequent Event [Line Items]
Vesting period		1 year
Subsequent Events | Performance Shares Units
Subsequent Event [Line Items]
Granted (in shares)		26,291
Subsequent Events | Performance Shares Units | Vesting on third anniversary | Minimum
Subsequent Event [Line Items]
Award vesting rights, percentage		0.00%
Subsequent Events | Performance Shares Units | Vesting on third anniversary | Maximum
Subsequent Event [Line Items]
Award vesting rights, percentage		150.00%
Subsequent Events | Stock Option
Subsequent Event [Line Items]
Vesting period		4 years
Award vesting rights, percentage		25.00%
Subsequent Events | Stock Option | Vesting After One Year of Service
Subsequent Event [Line Items]
Vesting period		1 year