Magnite (MGNI) 10-Q 8 May 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
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	1250 Broadway,
Entity Address, Address Line Two	15th Floor
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10001
City Area Code	212
Local Phone Number	243-2769
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	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		140,023,657
Entity Central Index Key	0001595974
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 252,834	$ 326,219
Accounts receivable, net	999,848	1,176,276
Prepaid expenses and other current assets	20,772	20,508
TOTAL CURRENT ASSETS	1,273,454	1,523,003
Property and equipment, net	55,533	47,371
Right-of-use lease asset	64,001	60,549
Internal use software development costs, net	23,117	21,926
Intangible assets, net	43,422	51,011
Goodwill	978,217	978,217
Other assets, non-current	16,325	6,729
TOTAL ASSETS	2,454,069	2,688,806
Current liabilities:
Accounts payable and accrued expenses	1,123,407	1,372,176
Lease liabilities, current	19,905	20,402
Debt, current	3,650	3,600
Other current liabilities	7,729	5,957
TOTAL CURRENT LIABILITIES	1,154,691	1,402,135
Debt, non-current, net of debt discount and debt issuance costs	549,077	532,986
Lease liabilities, non-current	53,059	49,665
Deferred tax liability, net	288	680
Other liabilities, non-current	1,577	1,657
TOTAL LIABILITIES	1,758,692	1,987,123
Commitments and contingencies (Note 12)
STOCKHOLDERS' EQUITY
Preferred stock, $0.00001 par value, 10,000 shares authorized at March 31, 2024 and December 31, 2023; 0 shares issued and outstanding at March 31, 2024 and December 31, 2023	0	0
Common stock, $0.00001 par value; 500,000 shares authorized at March 31, 2024 and December 31, 2023; 140,024 and 138,577 shares issued and outstanding at March 31, 2024 and December 31, 2023	2	2
Additional paid-in capital	1,400,181	1,387,715
Accumulated other comprehensive loss	(3,091)	(2,076)
Accumulated deficit	(701,715)	(683,958)
TOTAL STOCKHOLDERS' EQUITY	695,377	701,683
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 2,454,069	$ 2,688,806

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	10,000	10,000
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	500,000
Common stock, shares, issued (in shares)	140,024	138,577
Common stock, shares, outstanding (in shares)	140,024	138,577

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 149,319	$ 130,150
Cost of revenue	65,902	124,828
Expenses:
Sales and marketing	43,689	53,049
Technology and development	26,891	24,215
General and administrative	26,665	21,088
Merger, acquisition, and restructuring costs	0	7,465
Total expenses	163,147	230,645
Loss from operations	(13,828)	(100,495)
Other (income) expense:
Interest expense, net	7,958	8,175
Foreign exchange (gain) loss, net	(2,315)	233
(Gain) loss on extinguishment of debt	7,387	(8,549)
Other income	(1,292)	(1,313)
Total other (income) expense, net	11,738	(1,454)
Loss before income taxes	(25,566)	(99,041)
Benefit for income taxes	(7,809)	(309)
Net loss	$ (17,757)	$ (98,732)
Net loss per share:
Basic (in dollars per share)	$ (0.13)	$ (0.73)
Diluted (in dollars per share)	$ (0.13)	$ (0.73)
Weighted average shares used to compute net loss per share:
Basic (in shares)	139,297	134,667
Diluted (in shares)	139,297	134,667

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (17,757)	$ (98,732)
Other comprehensive income (loss):
Foreign currency translation adjustments	(1,015)	367
Other comprehensive income (loss)	(1,015)	367
Comprehensive loss	$ (18,772)	$ (98,365)

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, 2022		134,006
Beginning Balance at Dec. 31, 2022	$ 791,298	$ 2	$ 1,319,221	$ (3,151)	$ (524,774)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		303
Exercise of common stock options	1,486		1,486
Issuance of common stock related to RSU and PSU vesting (in shares)		1,829
Shares withheld related to net share settlement (in shares)		(700)
Shares withheld related to net share settlement	(9,046)		(9,046)
Stock-based compensation	19,856		19,856
Other comprehensive income (loss)	367			367
Net loss	(98,732)				(98,732)
Ending Balance (in shares) at Mar. 31, 2023		135,438
Ending Balance at Mar. 31, 2023	$ 705,229	$ 2	1,331,517	(2,784)	(623,506)
Beginning Balance (in shares) at Dec. 31, 2023	138,577	138,577
Beginning Balance at Dec. 31, 2023	$ 701,683	$ 2	1,387,715	(2,076)	(683,958)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock related to RSU and PSU vesting (in shares)		2,363
Shares withheld related to net share settlement (in shares)		(916)
Shares withheld related to net share settlement	(8,941)		(8,941)
Stock-based compensation	21,407		21,407
Other comprehensive income (loss)	(1,015)			(1,015)
Net loss	$ (17,757)				(17,757)
Ending Balance (in shares) at Mar. 31, 2024	140,024	140,024
Ending Balance at Mar. 31, 2024	$ 695,377	$ 2	$ 1,400,181	$ (3,091)	$ (701,715)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING ACTIVITIES:
Net loss	$ (17,757)	$ (98,732)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	13,567	95,795
Stock-based compensation	20,831	19,287
(Gain) loss on extinguishment of debt	7,387	(8,549)
Gain on disposal of property and equipment	(10)	(26)
Provision for doubtful accounts	134	67
Amortization of debt discount and issuance costs	1,152	1,669
Non-cash lease expense	(546)	34
Deferred income taxes	(7,770)	(404)
Unrealized foreign currency gain, net	(3,910)	(1,463)
Other items, net	0	2,696
Changes in operating assets and liabilities:
Accounts receivable	175,313	100,142
Prepaid expenses and other assets	(812)	(2,063)
Accounts payable and accrued expenses	(249,742)	(141,068)
Other liabilities	1,752	1,722
Net cash used in operating activities	(60,411)	(30,893)
INVESTING ACTIVITIES:
Purchases of property and equipment	(5,873)	(4,404)
Capitalized internal use software development costs	(3,379)	(3,063)
Net cash used in investing activities	(9,252)	(7,467)
FINANCING ACTIVITIES:
Proceeds from issuance of 2024 Term Loan B Facility, net of debt discount	361,350	0
Repayment of 2021 Term Loan B Facility	(351,000)	0
Payment for debt issuance costs	(4,510)	0
Repayment of debt	0	(900)
Repurchase of Convertible Senior Notes	0	(40,828)
Proceeds from exercise of stock options	0	1,486
Repayment of financing lease	0	(208)
Taxes paid related to net share settlement	(8,941)	(9,046)
Payment of indemnification claims holdback	0	(2,313)
Net cash used in financing activities	(3,101)	(51,809)
EFFECT OF EXCHANGE RATE CHANGES ON CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(621)	265
CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(73,385)	(89,904)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period	326,219	326,502
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period	252,834	236,598
RECONCILIATION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH TO CONSOLIDATED BALANCE SHEETS
Cash and cash equivalents	252,834	236,550
Restricted cash included in prepaid expenses and other current assets	0	48
Total cash, cash equivalents and restricted cash	252,834	236,598
SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION:
Cash paid for income taxes	729	1,547
Cash paid for interest	7,182	8,987
Capitalized assets financed by accounts payable and accrued expenses and other liabilities	7,272	3,320
Capitalized stock-based compensation	576	569
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 8,255	$ 271

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
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") was formed in Delaware and began operations on April 20, 2007. 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's common stock is listed on the Nasdaq Global Select Market of The Nasdaq Stock Market LLC ("Nasdaq") under the symbol "MGNI." Magnite has its principal offices in New York City, Los Angeles, Denver, London, and Sydney, and additional offices in Europe, Asia, North America, and South America. The Company’s platform features applications and services for sellers of digital advertising inventory, or publishers, that own or operate websites, applications, connected television ("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 accounting principles generally accepted in the United States of America, 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, 2024 are not necessarily indicative of the results that may be expected for any future interim period, the year ending December 31, 2024, or for any future year. The condensed consolidated balance sheet at December 31, 2023 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, 2023 included in its 2023 Annual Report on Form 10-K. There have been no significant changes in the Company's accounting policies from those disclosed in its audited consolidated financial statements and notes thereto for the year ended December 31, 2023 included in its Annual Report on Form 10-K. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed financial statements and accompanying footnotes. Actual results could differ materially from these estimates. In connection with the Company's periodic review of the estimated useful lives of its property and equipment, the Company extended the estimated useful lives of its network hardware assets from three years to five years effective January 1, 2024. The change in estimated useful lives were due to actual and expected longer refresh cycles for these assets. Based on the carrying value of network hardware assets as of December 31, 2023 and those placed in service during the three months ended March 31, 2024, the effect of this change in estimate was a decrease in loss from operations of $3.6 million and an increase in net loss of $2.0 million , or $0.01 per basic and diluted share, for the three months ended March 31, 2024. The updated policy reflecting the change in estimated useful lives is below. Property and Equipment, Net Property and equipment are recorded at historical cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method based upon the estimated useful lives of the assets. The estimated useful lives of the Company’s property and equipment are as follows: Years Computer equipment and network hardware 3 to 5 Furniture, fixtures, and office equipment 5 to 7 Leasehold improvements Shorter of useful life or life of lease Repair and maintenance costs are charged to expense as incurred, while renewals and improvements are capitalized. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any resulting gains or loss is reflected in the Company's results of operations. Recent Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280) – Improvements to Reportable Segment Disclosures ("ASU 2023-07"). ASU 2023-07 expands public entities’ segment disclosures by requiring disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss, an amount and description of its composition for other segment items, and interim disclosures of a reportable segment’s profit or loss and assets. ASU 2023-07 is effective for annual periods beginning after December 15, 2023 and for interim periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of adopting this new accounting guidance on its disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740) – Improvements to Income Tax Disclosures ("ASU 2023-09") to enhance income tax information primarily through changes in the rate reconciliation and income taxes paid information. ASU 2023-09 is effective for annual periods beginning after December 15, 2024 on a prospective basis. The Company is evaluating the impact of adopting this new accounting guidance on its disclosures. 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 a material impact on the Company’s present or future condensed consolidated financial statements.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share The following table presents the basic and diluted net loss per share: Three Months Ended March 31, 2024 March 31, 2023 (in thousands, except per share data) Basic and Diluted Loss Per Share: Net loss $ (17,757) $ (98,732) Weighted-average common shares outstanding used to compute net loss per share 139,297 134,667 Basic and diluted loss per share $ (0.13) $ (0.73) 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, 2024 March 31, 2023 (in thousands) Unvested restricted stock units 2,558 1,738 Options to purchase common stock 1,572 1,742 Unvested performance stock units 241 135 ESPP shares 65 17 Convertible Senior Notes 3,210 6,026 Total shares excluded from net loss per share 7,646 9,658 For the three months ended March 31, 2024 and 2023, the Company excluded outstanding performance stock units from the calculation of diluted net loss per share because they were anti-dilutive. As of March 31, 2024, the performance stock units granted during 2021, 2022, 2023, and 2024 had expected achievement levels of 0%, 80%, 93%, and 150%, respectively. As of March 31, 2023, the performance stock units granted in 2020, 2021, 2022, and 2023 had expected achievement levels of 94%, 0%, 54%, and 29%, respectively. Refer to Note 9—"Stock-Based Compensation" for additional information related to performance stock units. For the three months ended March 31, 2024 and 2023, shares that would be issuable assuming conversion of all of the Convertible Senior Notes (as defined in Note 13) were excluded from the calculation of diluted loss per share because they were anti-dilutive. The Convertible Senior Notes have an initial conversion rate of 15.6539 shares of common stock per $1,000 principal amount of the Convertible Senior Notes, which will be subject to anti-dilution adjustments in certain circumstances. As of March 31, 2024 and 2023, the number of shares that would be issuable assuming conversion of all of the Convertible Senior Notes is approximately 3,210,098 and 5,474,952, respectively.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue	Revenue For the majority of 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. 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. The following table presents the Company's revenue recognized on a net basis and on a gross basis for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands, except percentages) Revenue: Net basis $ 121,092 81 % $ 107,457 83 % Gross basis 28,227 19 22,693 17 Total $ 149,319 100 % $ 130,150 100 % The following table presents the Company's revenue by channel for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands, except percentages) Channel: CTV $ 72,592 49 % $ 59,050 45 % Mobile 53,953 36 48,184 37 Desktop 22,774 15 22,916 18 Total $ 149,319 100 % $ 130,150 100 % The following table presents the Company's revenue disaggregated by geographic location, based on the location of the Company's sellers for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands) United States $ 113,412 $ 97,156 International 35,907 32,994 Total $ 149,319 $ 130,150 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 are presented net of an allowance for doubtful accounts of $2.5 million at March 31, 2024, and $20.4 million at December 31, 2023. 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 $1.5 million and $1.1 million as of March 31, 2024 and December 31, 2023, respectively. The following is a summary of activity in the allowance for doubtful accounts for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands) Allowance for doubtful accounts, beginning balance $ 20,363 $ 1,092 Write-offs (18,511) (16) Increase in provision for expected credit losses 615 586 Allowance for doubtful accounts, ending balance $ 2,467 $ 1,662 During the three months ended March 31, 2024 the Company wrote off $18.5 million of allowance for doubtful accounts, which was primarily attributable to the outstanding accounts receivable from a buyer that had filed for bankruptcy during 2023. During the three months ended March 31, 2024, the provision for expected credit losses associated with accounts receivable increased by $0.6 million, offset by increases of contra seller payables related to recoveries of uncollected buyer receivables of $0.5 million, which resulted in $0.1 million of bad debt expense. During the three months ended March 31, 2023, the provision for expected credit losses associated with accounts receivable increased by $0.6 million, offset by increases of contra seller payables related to recoveries of uncollected buyer receivables of $0.5 million, which resulted in $0.1 million of bad debt expense.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
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, 2024: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 212,417 $ 212,417 $ — $ — The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at December 31, 2023: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 281,162 $ 281,162 $ — $ — At March 31, 2024 and December 31, 2023, cash equivalents of $212.4 million and $281.2 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, 2024 the Company had debt outstanding under its Convertible Senior Notes and loans under its 2024 Term Loan B Facility (as defined in Note 13), and at December 31, 2023, had debt outstanding under its Convertible Senior Notes and loans under its 2021 Term Loan B Facility (as defined in Note 13) included in its balance sheets, respectively. The estimated fair value of the Company's Convertible Senior Notes was $183.3 million and $174.3 million as of March 31, 2024 and December 31, 2023, respectively. The estimated fair value of Convertible Senior Notes is based on market rates and the closing trading price of the Convertible Senior Notes as of March 31, 2024 and December 31, 2023 and is classified as Level 2 in the fair value hierarchy. At March 31, 2024 and December 31, 2023, the estimated fair value of the Company's 2024 Term Loan B Facility and of the Company's 2021 Term Loan B Facility was $365.5 million and $352.3 million, respectively. The estimated fair value is based on borrowing rates currently available to the Company for financing with similar terms 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, 2024 and 2023.

Other Balance Sheet Amounts

Other Balance Sheet Amounts	3 Months Ended
	Mar. 31, 2024
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, 2024 December 31, 2023 (in thousands) Accounts payable—seller $ 1,072,080 $ 1,333,242 Accounts payable—trade 33,472 23,844 Accrued employee-related payables 17,855 15,090 Total $ 1,123,407 $ 1,372,176

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Major classes of property and equipment were as follows: March 31, 2024 December 31, 2023 (in thousands) Computer equipment and network hardware $ 164,546 $ 154,821 Furniture, fixtures, and office equipment 4,003 4,031 Leasehold improvements 3,809 3,893 Purchased software 1,124 1,124 Gross property and equipment 173,482 163,869 Accumulated depreciation (117,949) (116,498) Net property and equipment $ 55,533 $ 47,371 Depreciation expense on property and equipment totaled $3.2 million and $5.3 million for the three months ended March 31, 2024 and 2023, respectively. See Note 1 for information related to the change in estimated useful lives of network hardware assets. The Company's property and equipment, net by geographical region was as follows: March 31, 2024 December 31, 2023 (in thousands) United States $ 39,800 $ 32,161 International 15,733 15,210 Total $ 55,533 $ 47,371

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets The Company’s intangible assets as of March 31, 2024 and December 31, 2023 included the following: March 31, 2024 December 31, 2023 (in thousands) Amortizable intangible assets: Developed technology $ 109,736 $ 109,736 Customer relationships 37,300 37,300 In-process research and development 8,830 8,830 Trademarks 900 900 Non-compete agreements — 200 Total identifiable intangible assets, gross 156,766 156,966 Accumulated amortization—intangible assets: Developed technology (79,976) (75,321) Customer relationships (27,198) (24,867) In-process research and development (5,345) (4,832) Trademarks (825) (750) Non-compete agreements — (185) Total accumulated amortization—intangible assets (113,344) (105,955) Total identifiable intangible assets, net $ 43,422 $ 51,011 Amortization of intangible assets for the three months ended March 31, 2024 and 2023 was $7.6 million and $86.4 million, respectively. The estimated remaining amortization expense associated with the Company's intangible assets was as follows as of March 31, 2024: Fiscal Year Amount (in thousands) Remaining 2024 $ 22,545 2025 14,445 2026 6,001 2027 431 Total $ 43,422

Merger, Acquisition, and Restru

Merger, Acquisition, and Restructuring Costs	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Merger, Acquisition, and Restructuring Costs	Merger, Acquisition, and Restructuring Costs Merger, acquisition, and restructuring costs primarily consists of professional services fees and employee termination costs, including stock-based compensation charges, associated with historical acquisitions and restructuring activities. The following table summarizes merger, acquisition, and restructuring cost activity (in thousands): Three Months Ended March 31, 2023 (in thousands) Personnel related (severance and one-time termination benefit costs) $ 3,218 Loss contracts (facilities related) 2,190 Exit costs 1,408 Impairment of property and equipment, net 506 Non-cash stock-based compensation (double-trigger acceleration and severance) 143 Total merger, acquisition, and restructuring costs $ 7,465 During the three months ended March 31, 2024, the Company did not incur any merger, acquisition, and restructuring costs. During the three months ended March 31, 2023, the Company incurred merger, acquisition, and restructuring costs of $7.5 million, which included the Company's reduction of its global workforce primarily associated with the elimination of duplicative roles and other costs associated with the consolidation of its legacy CTV and SpotX CTV platforms following the 2021 acquisition of SpotX Inc., including loss contracts for office facilities the Company does not plan to continue to occupy and impairment charges related to certain assets it no longer plans to utilize.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock Options A summary of stock option activity for the three months ended March 31, 2024 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, 2023 4,262 $ 8.65 Granted 130 $ 9.20 Expired (7) $ 15.30 Outstanding at March 31, 2024 4,385 $ 8.66 5.3 years $ 18,357 Exercisable at March 31, 2024 3,781 $ 7.70 4.8 years $ 18,036 At March 31, 2024, the Company had unrecognized employee stock-based compensation expense relating to nonvested stock options of approximately $5.4 million, which is expected to be recognized over a weighted-average period of 2.3 years. Total grant date fair value of options vested during the three months ended March 31, 2024 was $1.1 million. The Company estimates the fair value of stock options that contain service conditions using the Black-Scholes option pricing model. The grant date fair value of options granted during the three months ended March 31, 2024 was $6.34 per share. The weighted-average input assumptions used by the Company were as follows: Three Months Ended March 31, 2024 March 31, 2023 Expected term (in years) 5.0 5.0 Risk-free interest rate 3.93 % 3.99 % Expected volatility 84 % 84 % Dividend yield — % — % Restricted Stock Units A summary of restricted stock unit ("RSU") activity for the three months ended March 31, 2024 is as follows: Number of Shares Weighted-Average Grant Date Fair Value (in thousands) Restricted stock units outstanding at December 31, 2023 11,450 $ 12.63 Granted 6,673 $ 9.20 Canceled (216) $ 10.30 Vested and released (2,363) $ 11.90 Restricted stock units outstanding and unvested at March 31, 2024 15,544 $ 11.30 The weighted-average grant date fair value per share of restricted stock units granted during the three months ended March 31, 2024 was $9.20. The intrinsic value of restricted stock units that vested during the three months ended March 31, 2024 was $23.2 million. At March 31, 2024, the intrinsic value of unvested restricted stock units was $167.1 million. At March 31, 2024, the Company had unrecognized stock-based compensation expense relating to unvested restricted stock units of approximately $161.2 million, which is expected to be recognized over a weighted-average period of 3.0 years. Performance Stock Units The Company grants performance stock units ("PSU") to select executive employees that vest based on share price metrics tied to total shareholder return relative ("TSR") to a peer group, subject to a time-based service component. Between 0% and 150% of the performance stock units will vest at the end of the performance period, which is generally on the third anniversary of the PSU grant date. During the three months ended March 31, 2024, the Company granted PSUs with an aggregate target of 486,431 shares, assuming a performance measurement of 100%. The amount of shares that will ultimately vest will be determined based on the Company's TSR relative to the TSRs of a peer group for the three year-period beginning January 1, 2024, as well as certain interim measurements based on relative TSR for the one-year and two-year periods beginning on January 1, 2024. A summary of PSU activity for the three months ended March 31, 2024 is as follows: Number of Shares Weighted-Average Grant Date Fair Value (in thousands) Outstanding at December 31, 2023 967 $ 18.17 Granted 486 $ 11.76 Outstanding at March 31, 2024 1,453 $ 16.03 The grant date fair value for the PSUs was estimated using a Monte-Carlo simulation model that incorporates option-pricing inputs covering the period from the grant date through the end of the performance period. Stock-based compensation expense for PSUs is based on the grant date fair value and the number of shares assuming a performance measurement of 100%. The compensation expense will not be reversed if the performance metrics are not met. The weighted-average input assumptions used by the Company were as follows: Three Months Ended March 31, 2024 March 31, 2023 Performance period (in years) 3.0 3.0 Risk-free interest rate 4.05 % 4.19 % Expected volatility of Magnite 87 % 94 % Expected volatility of selected peer companies 55 % 64 % Expected correlation coefficients of Magnite 0.59 0.62 Expected correlation coefficients of selected peer companies 0.47 0.54 Dividend yield — % — % At March 31, 2024, the intrinsic value of unvested performance stock units based on expected achievement levels was $13.3 million. As of March 31, 2024, the Company had unrecognized stock-based compensation expense relating to outstanding PSUs of approximately $12.0 million, which will be recognized over a weighted-average period of 2.2 years. 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, 2024 March 31, 2023 (in thousands) Cost of revenue $ 500 $ 468 Sales and marketing 8,236 7,405 Technology and development 5,416 5,446 General and administrative 6,679 5,825 Merger, acquisition, and restructuring costs — 143 Total stock-based compensation expense $ 20,831 $ 19,287 As of March 31, 2024, an aggregate of 16,787,890 shares remained available for future grants under the Magnite, Inc. Amended and Restated 2014 Equity Incentive Plan (the "Amended and Restated 2014 Equity Incentive Plan").

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
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, deductible stock option expenses, nondeductible executive compensation, and changes in the Company's valuation allowance. The Company recorded an income tax benefit of $7.8 million for the three months ended March 31, 2024, and an income tax benefit of $0.3 million for the three months ended March 31, 2023. The tax benefit for the three months ended March 31, 2024 was primarily the result of the Company's ability to recognize deferred tax assets ("DTAs") subject to the domestic valuation allowance, Base Erosion and Anti-Abuse Tax (“BEAT”), and the foreign income tax provision. The tax benefit for the three months ended March 31, 2023 was primarily the result of the Company's ability to recognize DTAs subject to the domestic valuation allowance and the foreign income tax provision. The Company continues to maintain a partial valuation allowance for the domestic DTAs. Due to uncertainty as to the realization of benefits from the Company's domestic and certain international DTAs, including net operating loss carryforwards and research and development tax credits, the Company has a partial valuation allowance reserved against such assets. The Company intends to continue to maintain a partial valuation allowance on the DTAs until there is sufficient evidence to support the reversal of all or some additional 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. For the Netherlands, India, Sweden, and the United Kingdom, all tax years remain open for examination by the local country tax authorities, for France, only 2021 and forward are open, for Singapore, only 2019 and forward are open for examination, for Australia, Brazil, Germany, and New Zealand, 2019 and forward are open for examination, for Canada, Italy, and Malaysia, 2018 and forward are open for examination, and for Japan, 2017 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 merger with Telaria Inc. As a result, the use of the Company's 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 its ability to utilize substantially all of its 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, 2024 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, 2024
Leases [Abstract]
Lease Obligations	Lease Obligations Operating lease expense was $5.7 million and $6.5 million for the three months ended March 31, 2024 and 2023, respectively, and variable lease expense was $0.9 million during each of the three months ended March 31, 2024 and 2023. The Company also received rental income of $1.3 million and $1.3 million for real estate leases for which it subleases the property to third parties during the three months ended March 31, 2024 and 2023, respectively. As of March 31, 2024 and December 31, 2023, a weighted average discount rate of 6.21% and 6.19%, respectively, 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 5.0 years and 5.2 years as of March 31, 2024 and December 31, 2023, respectively. 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, 2024 (in thousands): Fiscal Year Remaining 2024 $ 18,596 2025 18,265 2026 15,178 2027 10,119 2028 7,839 Thereafter 14,358 Total lease payments (undiscounted) 84,355 Less: imputed interest (11,391) Lease liabilities—total (discounted) $ 72,964

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
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, 2024 and December 31, 2023, the Company had $5.2 million and $5.3 million, respectively, of letters of credit associated with office leases available for borrowing, on which there were no outstanding borrowings as of either date. In the normal course of business, the Company enters into non-cancelable contractual obligations with various parties, primarily related to software services agreements and data center providers. As of March 31, 2024, the Company's outstanding non-cancelable contractual obligations with a remaining term of one year or longer consist of the following (in thousands): Fiscal Year Remaining 2024 $ 44,596 2025 21,990 2026 346 2027 241 2028 241 Total $ 67,414 The amounts above include commitments under a cloud-managed services agreement, under which the Company has a non-cancelable minimum spend commitment from July 2024 to June 2025 of $57.6 million. The minimum spend commitment reflected above approximates the manner in which the Company expects to fulfill the obligation. 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 condensed consolidated financial statements. Litigation The Company and its subsidiaries may from time to time be parties to legal or regulatory proceedings, lawsuits and other claims incident to their business activities and to the Company’s status as a public company. Such matters may include, among other things, assertions of contract breach or intellectual property infringement, claims for indemnity arising in the course of the Company’s business, regulatory investigations, audits by taxing authorities, 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, 2024. However, based on management’s knowledge as of March 31, 2024, management believes that the final resolution of these matters known at such date, individually and in the aggregate, will not have a material adverse effect upon the Company’s condensed consolidated financial position, results of operations or cash flows. Employment Contracts

Debt

Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt Long term debt as of March 31, 2024 and December 31, 2023 consisted of the following: March 31, 2024 December 31, 2023 (in thousands) Convertible Senior Notes $ 205,067 $ 205,067 Less: Unamortized debt issuance cost (2,304) (2,598) Net carrying value of Convertible Senior Notes 202,763 202,469 Term Loan B Facility* 365,000 351,000 Less: Unamortized discount and debt issuance cost (15,036) (16,883) Net carrying value of Term Loan B Facility* 349,964 334,117 Balance Sheet Presentation: Debt, current 3,650 3,600 Debt, non-current, net of debt discount and debt issuance costs 549,077 $ 532,986 Total debt $ 552,727 $ 536,586 * Term Loan B Facility as of March 31, 2024 and December 31, 2023 reflect the balances under the 2024 Term Loan B Facility and the 2021 Term Loan B Facility, respectively. Maturities of the principal amount of the Company's long-term debt as of March 31, 2024 are as follows (in thousands): Fiscal Year Remaining 2024 $ 2,737 2025 3,650 2026 208,717 2027 3,650 2028 3,650 Thereafter 347,663 Total $ 570,067 Amortization of debt discount and debt issuance cost is computed using the effective interest method and is included in interest expense in the condensed consolidated statement of operations. Amortization of the debt discount and debt issuance cost associated with the Company's indebtedness totaled $1.0 million for the three months ended March 31, 2024 and $1.6 million for the three months ended March 31, 2023. In addition, amortization of deferred financing costs was $0.1 million for the three months ended March 31, 2024 and $0.1 million for the three months ended March 31, 2023. Deferred financing costs are included in other assets, non-current assets. 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 Senior Notes"). The Convertible Senior Notes will mature on March 15, 2026, unless earlier repurchased, redeemed or converted. The total net proceeds from the offering, after deducting debt issuance costs, paid by the Company, were approximately $388.6 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 Senior Notes are senior, unsecured obligations and are (i) 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 Senior 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 the Loan Agreement or the new Credit Agreement (see section below); and (iv) structurally subordinated to all existing and future indebtedness and other liabilities, including trade payables, and (to the extent the Company is not a holder thereof) preferred equity, if any, of the Company’s subsidiaries that do not guarantee the Convertible Senior Notes. The Convertible Senior 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 Senior Notes will mature on March 15, 2026 unless they are redeemed, repurchased or converted prior to such date. The Convertible Senior Notes are convertible at the option of holders only during certain periods and upon satisfaction of certain conditions. Holders 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 Senior 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 Senior Notes may, at their option, convert all or a portion of their Convertible Senior 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 Senior 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 Senior Notes at their option at any time before March 20, 2024. Subject to the terms of the indenture agreement, 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 Senior 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 the Company sends 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 Senior Notes, which means that the Company is not required to redeem or retire the Convertible Senior 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 the Company distributes the related fundamental change notice. If an event of default, other than a reporting default remedied by special interest as defined in the indenture agreement, 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 a reporting event of default described above with respect to the Company 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, 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 the Company 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 Senior Notes have an initial conversion rate of 15.6539 shares of common stock per $1,000 principal amount of the Convertible Senior Notes, which will be subject to customary anti-dilution adjustments in certain circumstances. In connection with the pricing of the Convertible Senior 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 Senior 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 Senior 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 Senior 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. The Company incurred debt issuance costs of $11.4 million in March 2021. The Convertible Senior Notes are presented net of issuance costs on the Company's condensed consolidated balance sheets. The debt issuance costs are amortized on an effective interest basis over the term of the Convertible Senior Notes and are included in interest expense and amortization of debt discount in the accompanying condensed consolidated statements of operations. During the three months ended March 31, 2023, the Company repurchased its Convertible Senior Notes in the open market with cash on hand for $40.8 million. The Company recognized a gain on extinguishment of debt of $8.5 million related to the repurchase of $50.3 million of principal balance of Convertible Senior Notes and $0.9 million of unamortized debt issuance costs associated with the extinguished debt during the three months ended March 31, 2023. The gain on extinguishment is included in other (income) expense in the Company's condensed consolidated statement of operations. The following table sets forth interest expense related to the Convertible Senior Notes for the three months ended March 31, 2024 and 2023 (in thousands, except interest rates): Three Months Ended March 31, 2024 March 31, 2023 Contractual interest expense $ 128 $ 241 Amortization of debt issuance costs 293 551 Total interest expense $ 421 $ 792 Effective interest rate 0.82 % 0.82 % Amortization expense for the Company's debt issuance costs related to the Convertible Senior Notes for the fiscal years 2024 through 2026 is as follows (in thousands): Fiscal Year Debt Issuance Costs Remaining 2024 $ 879 2025 1,173 2026 252 Total $ 2,304 2021 and 2024 Credit Agreements On April 30, 2021, the Company entered into a credit agreement (the "2021 Credit Agreement") with Goldman Sachs Bank USA as administrative agent and collateral agent, and other lender parties thereto. The 2021 Credit Agreement provided for a $360.0 million seven-year senior secured term loan facility ("2021 Term Loan B Facility"), which had a maturity in April 2028, and a $65.0 million senior secured revolving credit facility (as amended in June 2021, the "2021 Revolving Credit Facility"), which had a maturity in December 2025. In June 2023, the Company amended the 2021 Credit Agreement (the "Amended 2021 Credit Agreement") to transition away from a variable interest rate based on the Eurodollar Rate towards a similar variable interest rate based on Adjusted Term SOFR, as defined in the Amended 2021 Credit Agreement, which is based on the secured overnight financing rate (“SOFR”). Amounts outstanding under the Amended 2021 Credit Agreement accrued interest at a rate equal to either, (1) for the 2021 Term Loan B Facility, at the Company’s election, the Adjusted Term SOFR plus a margin of 5.00% per annum, or ABR (as defined in the Amended 2021 Credit Agreement) plus a margin of 4.00%, and (2) for the 2021 Revolving Credit Facility, at the Company’s election, Adjusted Term SOFR 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. On February 6, 2024, the Company entered into a credit agreement (the “2024 Credit Agreement”) with Morgan Stanley Senior Funding, Inc. as the Company term loan administrative agent and Citibank, N.A. as the Company's revolving facility administrative agent and collateral agent, and other lender parties thereto. The 2024 Credit Agreement includes a $365.0 million seven-year senior secured term loan facility (the "2024 Term Loan B Facility"), whose loans will mature in February 2031 and a $175.0 million five-year senior secured revolving credit facility (the "2024 Revolving Credit Facility"), which matures in February 2029. The Company primarily used the proceeds from the 2024 Term Loan B Facility to repay in full all outstanding amounts owed under the Company's Amended 2021 Credit Agreement. Accordingly, the Amended 2021 Credit Agreement was terminated and replaced in its entirely. The obligations under the 2024 Credit Agreement are secured by substantially all of the assets of the Company. Amounts outstanding under the 2024 Credit Agreement accrue interest at a rate equal to either, (1) for the 2024 Term Loan B Facility, at the Company’s election, Term SOFR (as defined in the 2024 Credit Agreement) plus a margin of 4.50% per annum, or ABR (as defined in the 2024 Credit Agreement) plus a margin of 3.50%, and (2) for the 2024 Revolving Credit Facility, at the Company’s election, Term SOFR plus a margin of 3.50% to 4.00%, or ABR plus a margin of 2.50% to 3.00%, in each case, depending on the Company’s First Lien Net Leverage Ratio (as defined in the 2024 Credit Agreement). As of March 31, 2024, the contractual interest rate related to the Term Loan B Facility was 9.79%. In addition to having to pay contractual interest on the 2024 Term Loan B Facility, the Company is also required to pay certain other fees, primarily to the lenders under the 2024 Revolving Credit Facility, in order to maintain their revolving facility commitments. The covenants of the 2024 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 2024 Credit Agreement contains a springing financial covenant that is tested on the last day of any fiscal quarter only if utilization of the 2024 Revolving Credit Facility exceeds 35% of the total revolving commitments, whereby the Company is required to maintain a First Lien Net Leverage Ratio below 3.25 to 1.00. As of March 31, 2024, no amounts were outstanding under the 2024 Revolving Credit Facility and the Company was in compliance with its debt covenants. At March 31, 2024, amounts available under the 2024 Revolving Credit Facility were $169.8 million, net of letters of credit outstanding in the amount of $5.2 million. The 2024 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 2024 Credit Agreement. The 2024 Credit Agreement calls for customary scheduled loan amortization payments of 0.25% of the initial principal balance payable quarterly (i.e. 1% in aggregate per year) as well as a provision that requires the Company to prepay the 2024 Term Loan B Facility based on an annual calculation of free cash flow ("Excess Cash Flow") as defined by the 2024 Credit Agreement. The Company was not required to make any such mandatory prepayment required by the Excess Cash Flow provision for the period ended March 31, 2024. The following table summarizes the amount outstanding under the Company's 2024 Term Loan B Facility and 2021 Term Loan B Facility at March 31, 2024 and December 31, 2023, respectively: March 31, 2024 December 31, 2023 (in thousands) Term Loan B Facility* $ 365,000 $ 351,000 Unamortized debt discounts (7,146) (6,594) Unamortized debt issuance costs (7,890) (10,289) Debt, net of debt discount and debt issuance costs $ 349,964 $ 334,117 * Term Loan B Facility as of March 31, 2024 and December 31, 2023 reflect the balances under the 2024 Term Loan B Facility and the 2021 Term Loan B Facility, respectively. As part of the debt refinance on February 6, 2024, where lenders under the 2021 Credit Agreement continued to be lenders under the 2024 Credit Agreement, certain of their loans and revolving facility commitments were deemed to have been modified ("Modified Loans" and "Modified Commitments," respectively). The Company continued to defer debt discount costs of $3.7 million and debt issuance costs of $5.7 million from Modified Loans over the term of the new 2024 Term Loan B Facility. The Company continued to defer financing costs as of February 6, 2024 of $0.6 million from Modified Commitments over the term of the new 2024 Revolver Facility. For lenders of the 2021 Credit Agreement that did not continue to participate in the 2024 Credit Agreement, their pro-rata portion of the unamortized debt discount of $2.8 million, unamortized debt issuance cost of $4.3 million, and unamortized deferred financing costs of $0.3 million were deemed to be extinguished. The resulting loss on extinguishment of debt is included in other (income) expense in the Company's condensed consolidated statement of operations. The Company paid $7.7 million in third-party fees related to the closing of the 2024 Credit Agreement. Third-party fees attributed to new lenders of $2.4 million were capitalized as part of the debt issuance cost and will be amortized over the term of the 2024 Term Loan B Facility while third-party fees attributed to Modified Loans of $3.1 million were included in general and administrative expenses in the Company's condensed consolidated statement of operations for the three months ended March 31, 2024. In addition, third-party fees of $2.1 million attributed to new revolving lenders and Modified Commitments were capitalized as part of deferred financing costs and will be amortized over the term of the 2024 Revolving Facility. The Company also capitalized additional debt discount costs of $3.7 million associated with the closing of the 2024 Term Loan B Facility, which will be amortized over the term of the 2024 Term Loan B Facility. The following table sets forth interest expense related to the 2024 Term Loan B Facility and the 2021 Term Loan B Facility for the three months ended March 31, 2024 and related to the 2021 Term Loan B Facility for the three months ended March 31, 2023 (in thousands, except interest rates): Three Months Ended March 31, 2024 March 31, 2023 Contractual interest expense $ 9,166 $ 8,436 Amortization of debt discount 314 393 Amortization of debt issuance costs 418 612 Total interest expense $ 9,898 $ 9,441 Effective interest rate 11.03 % 10.65 % Amortization expense for the 2024 Term Loan B Facility debt discount and debt issuance costs for fiscal years 2024 through 2028 and thereafter is as follows (in thousands): Fiscal Year Debt Discount Debt Issuance Costs Remaining 2024 $ 807 $ 891 2025 1,067 1,178 2026 1,056 1,166 2027 1,045 1,154 2028 1,034 1,142 Thereafter 2,137 2,359 Total $ 7,146 $ 7,890

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net loss	$ (17,757)	$ (98,732)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Trading Plans In the first quarter of 2024, the following trading plans were adopted or terminated by our Section 16 officers or directors: Officer Name Officer Title Date Plan Adopted/Terminated Duration of Plan Shares to be Purchased or Sold Intended to Satisfy Rule 10b5-1(c)? James Rossman Director Adopted March 8, 2024 June 10, 2024 - March 7, 2025 Sell up to 224,936, subject to certain conditions Yes Katheryn Evans Chief Operating Officer Adopted March 14, 2024 June 13, 2024 - March 14, 2025 Sell up to 49,888, subject to certain conditions Yes Aaron Saltz Chief Legal Officer Adopted March 15, 2024 June 14, 2024 - March 14, 2025 Sell up to 51,521, subject to certain conditions Yes
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
James Rossman [Member]
Trading Arrangements, by Individual
Name	James Rossman
Title	Director
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	Adopted March 8, 2024
Arrangement Duration	200 days
Aggregate Available	224,936
Katheryn Evans [Member]
Trading Arrangements, by Individual
Name	Katheryn Evans
Title	Chief Operating Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	Adopted March 14, 2024
Arrangement Duration	274 days
Aggregate Available	49,888
Aaron Saltz [Member]
Trading Arrangements, by Individual
Name	Aaron Saltz
Title	Chief Legal Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	Adopted March 15, 2024
Arrangement Duration	273 days
Aggregate Available	51,521

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
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 accounting principles generally accepted in the United States of America, 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, 2024 are not necessarily indicative of the results that may be expected for any future interim period, the year ending December 31, 2024, or for any future year. The condensed consolidated balance sheet at December 31, 2023 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, 2023 included in its 2023 Annual Report on Form 10-K. There have been no significant changes in the Company's accounting policies from those disclosed in its audited consolidated financial statements and notes thereto for the year ended December 31, 2023 included in its Annual Report on Form 10-K.
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. Actual results could differ materially from these estimates. In connection with the Company's periodic review of the estimated useful lives of its property and equipment, the Company extended the estimated useful lives of its network hardware assets from three years to five years effective January 1, 2024. The change in estimated useful lives were due to actual and expected longer refresh cycles for these assets. Based on the carrying value of network hardware assets as of December 31, 2023 and those placed in service during the three months ended March 31, 2024, the effect of this change in estimate was a decrease in loss from operations of $3.6 million and an increase in net loss of $2.0 million , or $0.01 per basic and diluted share, for the three months ended March 31, 2024. The updated policy reflecting the change in estimated useful lives is below.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are recorded at historical cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method based upon the estimated useful lives of the assets. The estimated useful lives of the Company’s property and equipment are as follows: Years Computer equipment and network hardware 3 to 5 Furniture, fixtures, and office equipment 5 to 7 Leasehold improvements Shorter of useful life or life of lease Repair and maintenance costs are charged to expense as incurred, while renewals and improvements are capitalized. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any resulting gains or loss is reflected in the Company's results of operations.
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280) – Improvements to Reportable Segment Disclosures ("ASU 2023-07"). ASU 2023-07 expands public entities’ segment disclosures by requiring disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss, an amount and description of its composition for other segment items, and interim disclosures of a reportable segment’s profit or loss and assets. ASU 2023-07 is effective for annual periods beginning after December 15, 2023 and for interim periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of adopting this new accounting guidance on its disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740) – Improvements to Income Tax Disclosures ("ASU 2023-09") to enhance income tax information primarily through changes in the rate reconciliation and income taxes paid information. ASU 2023-09 is effective for annual periods beginning after December 15, 2024 on a prospective basis. The Company is evaluating the impact of adopting this new accounting guidance on its disclosures. 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 a material impact on the Company’s present or future condensed consolidated financial statements.

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Property, Plant and Equipment	The estimated useful lives of the Company’s property and equipment are as follows: Years Computer equipment and network hardware 3 to 5 Furniture, fixtures, and office equipment 5 to 7 Leasehold improvements Shorter of useful life or life of lease Major classes of property and equipment were as follows: March 31, 2024 December 31, 2023 (in thousands) Computer equipment and network hardware $ 164,546 $ 154,821 Furniture, fixtures, and office equipment 4,003 4,031 Leasehold improvements 3,809 3,893 Purchased software 1,124 1,124 Gross property and equipment 173,482 163,869 Accumulated depreciation (117,949) (116,498) Net property and equipment $ 55,533 $ 47,371 The Company's property and equipment, net by geographical region was as follows: March 31, 2024 December 31, 2023 (in thousands) United States $ 39,800 $ 32,161 International 15,733 15,210 Total $ 55,533 $ 47,371

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 March 31, 2023 (in thousands, except per share data) Basic and Diluted Loss Per Share: Net loss $ (17,757) $ (98,732) Weighted-average common shares outstanding used to compute net loss per share 139,297 134,667 Basic and diluted loss per share $ (0.13) $ (0.73)
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, 2024 March 31, 2023 (in thousands) Unvested restricted stock units 2,558 1,738 Options to purchase common stock 1,572 1,742 Unvested performance stock units 241 135 ESPP shares 65 17 Convertible Senior Notes 3,210 6,026 Total shares excluded from net loss per share 7,646 9,658

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Revenue Recognized on a Net Basis and on a Gross Basis	The following table presents the Company's revenue recognized on a net basis and on a gross basis for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands, except percentages) Revenue: Net basis $ 121,092 81 % $ 107,457 83 % Gross basis 28,227 19 22,693 17 Total $ 149,319 100 % $ 130,150 100 %
Summary of Disaggregation of Revenue	The following table presents the Company's revenue by channel for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands, except percentages) Channel: CTV $ 72,592 49 % $ 59,050 45 % Mobile 53,953 36 48,184 37 Desktop 22,774 15 22,916 18 Total $ 149,319 100 % $ 130,150 100 % The following table presents the Company's revenue disaggregated by geographic location, based on the location of the Company's sellers for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands) United States $ 113,412 $ 97,156 International 35,907 32,994 Total $ 149,319 $ 130,150
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, 2024 and 2023: Three Months Ended March 31, 2024 March 31, 2023 (in thousands) Allowance for doubtful accounts, beginning balance $ 20,363 $ 1,092 Write-offs (18,511) (16) Increase in provision for expected credit losses 615 586 Allowance for doubtful accounts, ending balance $ 2,467 $ 1,662

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 212,417 $ 212,417 $ — $ — The table below sets forth a summary of financial instruments that are measured at fair value on a recurring basis at December 31, 2023: Total Quoted Prices in Significant Other Significant (in thousands) Cash equivalents $ 281,162 $ 281,162 $ — $ —

Other Balance Sheet Amounts (Ta

Other Balance Sheet Amounts (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 December 31, 2023 (in thousands) Accounts payable—seller $ 1,072,080 $ 1,333,242 Accounts payable—trade 33,472 23,844 Accrued employee-related payables 17,855 15,090 Total $ 1,123,407 $ 1,372,176

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The estimated useful lives of the Company’s property and equipment are as follows: Years Computer equipment and network hardware 3 to 5 Furniture, fixtures, and office equipment 5 to 7 Leasehold improvements Shorter of useful life or life of lease Major classes of property and equipment were as follows: March 31, 2024 December 31, 2023 (in thousands) Computer equipment and network hardware $ 164,546 $ 154,821 Furniture, fixtures, and office equipment 4,003 4,031 Leasehold improvements 3,809 3,893 Purchased software 1,124 1,124 Gross property and equipment 173,482 163,869 Accumulated depreciation (117,949) (116,498) Net property and equipment $ 55,533 $ 47,371 The Company's property and equipment, net by geographical region was as follows: March 31, 2024 December 31, 2023 (in thousands) United States $ 39,800 $ 32,161 International 15,733 15,210 Total $ 55,533 $ 47,371

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The Company’s intangible assets as of March 31, 2024 and December 31, 2023 included the following: March 31, 2024 December 31, 2023 (in thousands) Amortizable intangible assets: Developed technology $ 109,736 $ 109,736 Customer relationships 37,300 37,300 In-process research and development 8,830 8,830 Trademarks 900 900 Non-compete agreements — 200 Total identifiable intangible assets, gross 156,766 156,966 Accumulated amortization—intangible assets: Developed technology (79,976) (75,321) Customer relationships (27,198) (24,867) In-process research and development (5,345) (4,832) Trademarks (825) (750) Non-compete agreements — (185) Total accumulated amortization—intangible assets (113,344) (105,955) Total identifiable intangible assets, net $ 43,422 $ 51,011
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, 2024: Fiscal Year Amount (in thousands) Remaining 2024 $ 22,545 2025 14,445 2026 6,001 2027 431 Total $ 43,422

Merger, Acquisition, and Rest_2

Merger, Acquisition, and Restructuring Costs (Tables)	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Merger, Acquisition, and Restructuring Costs	The following table summarizes merger, acquisition, and restructuring cost activity (in thousands): Three Months Ended March 31, 2023 (in thousands) Personnel related (severance and one-time termination benefit costs) $ 3,218 Loss contracts (facilities related) 2,190 Exit costs 1,408 Impairment of property and equipment, net 506 Non-cash stock-based compensation (double-trigger acceleration and severance) 143 Total merger, acquisition, and restructuring costs $ 7,465

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 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, 2023 4,262 $ 8.65 Granted 130 $ 9.20 Expired (7) $ 15.30 Outstanding at March 31, 2024 4,385 $ 8.66 5.3 years $ 18,357 Exercisable at March 31, 2024 3,781 $ 7.70 4.8 years $ 18,036
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, 2024 March 31, 2023 Expected term (in years) 5.0 5.0 Risk-free interest rate 3.93 % 3.99 % Expected volatility 84 % 84 % Dividend yield — % — % Three Months Ended March 31, 2024 March 31, 2023 Performance period (in years) 3.0 3.0 Risk-free interest rate 4.05 % 4.19 % Expected volatility of Magnite 87 % 94 % Expected volatility of selected peer companies 55 % 64 % Expected correlation coefficients of Magnite 0.59 0.62 Expected correlation coefficients of selected peer companies 0.47 0.54 Dividend yield — % — %
Schedule of Nonvested Restricted Stock Units Activity	A summary of restricted stock unit ("RSU") activity for the three months ended March 31, 2024 is as follows: Number of Shares Weighted-Average Grant Date Fair Value (in thousands) Restricted stock units outstanding at December 31, 2023 11,450 $ 12.63 Granted 6,673 $ 9.20 Canceled (216) $ 10.30 Vested and released (2,363) $ 11.90 Restricted stock units outstanding and unvested at March 31, 2024 15,544 $ 11.30
Schedule of Nonvested Performance-Based Units Activity	A summary of PSU activity for the three months ended March 31, 2024 is as follows: Number of Shares Weighted-Average Grant Date Fair Value (in thousands) Outstanding at December 31, 2023 967 $ 18.17 Granted 486 $ 11.76 Outstanding at March 31, 2024 1,453 $ 16.03
Schedule of 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, 2024 March 31, 2023 (in thousands) Cost of revenue $ 500 $ 468 Sales and marketing 8,236 7,405 Technology and development 5,416 5,446 General and administrative 6,679 5,825 Merger, acquisition, and restructuring costs — 143 Total stock-based compensation expense $ 20,831 $ 19,287

Lease Obligations (Tables)

Lease Obligations (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 (in thousands): Fiscal Year Remaining 2024 $ 18,596 2025 18,265 2026 15,178 2027 10,119 2028 7,839 Thereafter 14,358 Total lease payments (undiscounted) 84,355 Less: imputed interest (11,391) Lease liabilities—total (discounted) $ 72,964

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contractual Obligation, Fiscal Year Maturity	As of March 31, 2024, the Company's outstanding non-cancelable contractual obligations with a remaining term of one year or longer consist of the following (in thousands): Fiscal Year Remaining 2024 $ 44,596 2025 21,990 2026 346 2027 241 2028 241 Total $ 67,414

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long term debt as of March 31, 2024 and December 31, 2023 consisted of the following: March 31, 2024 December 31, 2023 (in thousands) Convertible Senior Notes $ 205,067 $ 205,067 Less: Unamortized debt issuance cost (2,304) (2,598) Net carrying value of Convertible Senior Notes 202,763 202,469 Term Loan B Facility* 365,000 351,000 Less: Unamortized discount and debt issuance cost (15,036) (16,883) Net carrying value of Term Loan B Facility* 349,964 334,117 Balance Sheet Presentation: Debt, current 3,650 3,600 Debt, non-current, net of debt discount and debt issuance costs 549,077 $ 532,986 Total debt $ 552,727 $ 536,586 * Term Loan B Facility as of March 31, 2024 and December 31, 2023 reflect the balances under the 2024 Term Loan B Facility and the 2021 Term Loan B Facility, respectively.
Schedule of Maturities of Long-term Debt	Maturities of the principal amount of the Company's long-term debt as of March 31, 2024 are as follows (in thousands): Fiscal Year Remaining 2024 $ 2,737 2025 3,650 2026 208,717 2027 3,650 2028 3,650 Thereafter 347,663 Total $ 570,067 Amortization expense for the Company's debt issuance costs related to the Convertible Senior Notes for the fiscal years 2024 through 2026 is as follows (in thousands): Fiscal Year Debt Issuance Costs Remaining 2024 $ 879 2025 1,173 2026 252 Total $ 2,304 Amortization expense for the 2024 Term Loan B Facility debt discount and debt issuance costs for fiscal years 2024 through 2028 and thereafter is as follows (in thousands): Fiscal Year Debt Discount Debt Issuance Costs Remaining 2024 $ 807 $ 891 2025 1,067 1,178 2026 1,056 1,166 2027 1,045 1,154 2028 1,034 1,142 Thereafter 2,137 2,359 Total $ 7,146 $ 7,890
Interest Income and Interest Expense Disclosure	The following table sets forth interest expense related to the Convertible Senior Notes for the three months ended March 31, 2024 and 2023 (in thousands, except interest rates): Three Months Ended March 31, 2024 March 31, 2023 Contractual interest expense $ 128 $ 241 Amortization of debt issuance costs 293 551 Total interest expense $ 421 $ 792 Effective interest rate 0.82 % 0.82 % The following table sets forth interest expense related to the 2024 Term Loan B Facility and the 2021 Term Loan B Facility for the three months ended March 31, 2024 and related to the 2021 Term Loan B Facility for the three months ended March 31, 2023 (in thousands, except interest rates): Three Months Ended March 31, 2024 March 31, 2023 Contractual interest expense $ 9,166 $ 8,436 Amortization of debt discount 314 393 Amortization of debt issuance costs 418 612 Total interest expense $ 9,898 $ 9,441 Effective interest rate 11.03 % 10.65 %
Schedule of Debt	The following table summarizes the amount outstanding under the Company's 2024 Term Loan B Facility and 2021 Term Loan B Facility at March 31, 2024 and December 31, 2023, respectively: March 31, 2024 December 31, 2023 (in thousands) Term Loan B Facility* $ 365,000 $ 351,000 Unamortized debt discounts (7,146) (6,594) Unamortized debt issuance costs (7,890) (10,289) Debt, net of debt discount and debt issuance costs $ 349,964 $ 334,117 * Term Loan B Facility as of March 31, 2024 and December 31, 2023 reflect the balances under the 2024 Term Loan B Facility and the 2021 Term Loan B Facility, respectively.

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Jan. 01, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Decrease in loss from operations	$ (13,828)	$ (100,495)
Increase in net loss	$ 17,757	$ 98,732
Basic (in dollars per share)	$ 0.13	$ 0.73
Diluted (in dollars per share)	$ 0.13	$ 0.73
Change in Accounting Method Accounted for as Change in Estimate
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life			5 years	3 years
Decrease in loss from operations	$ 3,600
Increase in net loss	$ 2,000
Basic (in dollars per share)	$ 0.01
Diluted (in dollars per share)	$ 0.01

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies - Property and Equipment (Details)	Mar. 31, 2024
Computer equipment and network hardware | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Computer equipment and network hardware | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Furniture, fixtures, and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Furniture, fixtures, and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	7 years

Net Loss Per Share - Basic and

Net 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, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net loss	$ (17,757)	$ (98,732)
Weighted-average common shares outstanding, basic (in shares)	139,297	134,667
Weighted average number of shares outstanding, diluted (in shares)	139,297	134,667
Basic loss per share (in dollars per share)	$ (0.13)	$ (0.73)
Diluted loss per share (in dollars per share)	$ (0.13)	$ (0.73)

Net Loss Per Share - Shares Exc

Net Loss Per Share - Shares Excluded From Calculation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	7,646	9,658
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)	2,558	1,738
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)	1,572	1,742
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)	241	135
ESPP shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	65	17
Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded from net loss per share (in shares)	3,210	6,026

Net Loss Per Share - Narrative

Net Loss Per Share - Narrative (Details) - equityInstrument	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares issuable assuming conversion (in shares)	3,210,098	5,474,952
Unvested performance stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance measurement percentage	100%
Performance Shares, Granted in 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance measurement percentage		94%
Performance Shares, Granted in 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance measurement percentage	0%	0%
Performance Shares, Granted in 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance measurement percentage	80%	54%
Performance Shares, Granted in 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance measurement percentage	93%	29%
Performance Shares, Granted in 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance measurement percentage	150%

Revenue - Revenue Recognized on

Revenue - Revenue Recognized on a Gross and Net Basis (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 149,319	$ 130,150
Net basis
Disaggregation of Revenue [Line Items]
Revenue	121,092	107,457
Gross basis
Disaggregation of Revenue [Line Items]
Revenue	$ 28,227	$ 22,693
Revenue from Contract with Customer Benchmark | Concentration of Basis of Revenue Recognition
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	100%	100%
Revenue from Contract with Customer Benchmark | Concentration of Basis of Revenue Recognition | Net basis
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	81%	83%
Revenue from Contract with Customer Benchmark | Concentration of Basis of Revenue Recognition | Gross basis
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	19%	17%

Revenue - Revenue Disaggregated

Revenue - Revenue Disaggregated by Sales Distribution Channel (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 149,319	$ 130,150
CTV
Disaggregation of Revenue [Line Items]
Revenue	72,592	59,050
Mobile
Disaggregation of Revenue [Line Items]
Revenue	53,953	48,184
Desktop
Disaggregation of Revenue [Line Items]
Revenue	$ 22,774	$ 22,916
Product Concentration Risk | Revenue from Contract with Customer Benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	100%	100%
Product Concentration Risk | Revenue from Contract with Customer Benchmark | CTV
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	49%	45%
Product Concentration Risk | Revenue from Contract with Customer Benchmark | Mobile
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	36%	37%
Product Concentration Risk | Revenue from Contract with Customer Benchmark | Desktop
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	15%	18%

Revenue - Revenue Disaggregat_2

Revenue - Revenue Disaggregated by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 149,319	$ 130,150
United States
Disaggregation of Revenue [Line Items]
Revenue	113,412	97,156
International
Disaggregation of Revenue [Line Items]
Revenue	$ 35,907	$ 32,994

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Payment terms in days (or less)	75 days
Accounts receivable, allowance for credit loss	$ 2,467	$ 1,662	$ 20,363	$ 1,092
Contra seller payable	1,500		$ 1,100
Allowance for doubtful accounts, writeoff	18,511	16
Increase in provision for expected credit losses	615	586
Increase (decrease) in contra seller payable	500	500
Accounts receivable, credit loss expense (recovery)	$ 134	$ 67

Revenue - Schedule of Allowance

Revenue - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts, beginning balance	$ 20,363	$ 1,092
Write-offs	(18,511)	(16)
Increase in provision for expected credit losses	615	586
Allowance for doubtful accounts, ending balance	$ 2,467	$ 1,662

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 212,417	$ 281,162
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	212,417	281,162
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) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Credit Agreements, 2021 and 2024 | Line of Credit | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Term loan fair value	$ 365,500	$ 352,300
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	212,417	281,162
Recurring | 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	$ 183,300	$ 174,300

Other Balance Sheet Amounts (De

Other Balance Sheet Amounts (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable—seller	$ 1,072,080	$ 1,333,242
Accounts payable—trade	33,472	23,844
Accrued employee-related payables	17,855	15,090
Total	$ 1,123,407	$ 1,372,176

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment by Major Class (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 173,482	$ 163,869
Accumulated depreciation	(117,949)	(116,498)
Net property and equipment	55,533	47,371
Computer equipment and network hardware
Property, Plant and Equipment [Line Items]
Gross property and equipment	164,546	154,821
Furniture, fixtures, and office equipment
Property, Plant and Equipment [Line Items]
Gross property and equipment	4,003	4,031
Leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property and equipment	3,809	3,893
Purchased software
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 1,124	$ 1,124

Property and Equipment - Narrat

Property and Equipment - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense on property and equipment	$ 3.2	$ 5.3

Property and Equipment - Summ_2

Property and Equipment - Summary of Property and Equipment by Geographical Region (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total	$ 55,533	$ 47,371
United States
Property, Plant and Equipment [Line Items]
Total	39,800	32,161
International
Property, Plant and Equipment [Line Items]
Total	$ 15,733	$ 15,210

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 7.6	$ 86.4

Intangible Assets - Finite-Live

Intangible Assets - Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	$ 156,766	$ 156,966
Total accumulated amortization—intangible assets	(113,344)	(105,955)
Total	43,422	51,011
Developed technology
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	109,736	109,736
Total accumulated amortization—intangible assets	(79,976)	(75,321)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	37,300	37,300
Total accumulated amortization—intangible assets	(27,198)	(24,867)
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	8,830	8,830
Total accumulated amortization—intangible assets	(5,345)	(4,832)
Trademarks
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	900	900
Total accumulated amortization—intangible assets	(825)	(750)
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, gross	0	200
Total accumulated amortization—intangible assets	$ 0	$ (185)

Intangible Assets - Finite-Li_2

Intangible Assets - Finite-Lived Intangible Assets, Future Amortization Expense (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fiscal Year
Remaining 2024	$ 22,545
2025	14,445
2026	6,001
2027	431
Total	$ 43,422	$ 51,011

Merger, Acquisition, and Rest_3

Merger, Acquisition, and Restructuring Costs - Merger and Restructuring Cost Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restructuring Cost and Reserve [Line Items]
Loss contracts (facilities related)		$ 2,190
Impairment of property and equipment, net		506
Non-cash stock-based compensation (double-trigger acceleration and severance)		143
Total merger, acquisition, and restructuring costs	$ 0	7,465
Personnel related (severance and one-time termination benefit costs)
Restructuring Cost and Reserve [Line Items]
Restructuring charges		3,218
Exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 1,408

Merger, Acquisition, and Rest_4

Merger, Acquisition, and Restructuring Costs - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restructuring and Related Activities [Abstract]
Acquisition related costs	$ 0	$ 7,465

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Options Outstanding (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares
Shares Under Option
Beginning balance (in shares) | shares	4,262
Granted (in shares) | shares	130
Expired (in shares) | shares	(7)
Ending balance (in shares) | shares	4,385
Exercisable (in shares) | shares	3,781
Weighted- Average Exercise Price
Beginning balance (usd per share) | $ / shares	$ 8.65
Granted (usd per share) | $ / shares	9.20
Expired (usd per share) | $ / shares	15.30
Ending balance (usd per share) | $ / shares	8.66
Exercisable (usd per share) | $ / shares	$ 7.70
Weighted- Average Contractual Life
Outstanding	5 years 3 months 18 days
Exercisable	4 years 9 months 18 days
Aggregate Intrinsic Value
Outstanding | $	$ 18,357
Exercisable | $	$ 18,036

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Options Narrative (Details) - Stock Option $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares
Number of Shares
Unrecognized employee stock-based compensation	$ 5.4
Unrecognized employee stock-based compensation, period for recognition	2 years 3 months 18 days
Fair value of options vested in period	$ 1.1
Grant date fair value of options granted (usd per share) | $ / shares	$ 6.34

Stock-Based Compensation - Valu

Stock-Based Compensation - Valuation Assumptions (Details) - Stock Option	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years	5 years
Risk-free interest rate	3.93%	3.99%
Expected volatility	84%	84%
Dividend yield	0%	0%

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) shares in Thousands	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	11,450
Granted (in shares) | shares	6,673
Canceled (in shares) | shares	(216)
Vested and released (in shares) | shares	(2,363)
Ending balance (in shares) | shares	15,544
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 12.63
Granted (in dollars per share) | $ / shares	9.20
Canceled (in dollars per share) | $ / shares	10.30
Vested and released (in dollars per share) | $ / shares	11.90
Ending balance (in dollars per share) | $ / shares	$ 11.30

Stock-Based Compensation - Re_2

Stock-Based Compensation - Restricted Stock Units Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of nonvested unit	$ 13.3
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share) | $ / shares	$ 9.20
Fair value of restricted stock vested	$ 23.2
Intrinsic value of nonvested unit	167.1
Unrecognized employee stock-based compensation	$ 161.2
Unrecognized employee stock-based compensation, period for recognition	3 years

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance Stock Units Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Aug. 31, 2021	Mar. 31, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of nonvested unit		$ 13.3
Performance Shares Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		486,000
Performance measurement percentage		100%
Unrecognized employee stock-based compensation, period for recognition		2 years 2 months 12 days
Unrecognized employee stock-based compensation		$ 12
Performance Shares Units | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		486,431
Performance Shares Units | Tranche one | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years	3 years
Performance Shares Units | Tranche two | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years	1 year
Performance Shares Units | Tranche three | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years	2 years
Performance Shares Units | Minimum | Tranche four | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage		0%
Performance Shares Units | Maximum | Tranche four | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage		150%

Stock-Based Compensation - Pe_2

Stock-Based Compensation - Performance Stock Units Activity (Details) - Unvested performance stock units shares in Thousands	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	967
Granted (in shares) | shares	486
Ending balance (in shares) | shares	1,453
Weighted-Average Grant Date Fair Value
Beginning balance, nonvested (in dollars per share) | $ / shares	$ 18.17
Granted (in dollars per share) | $ / shares	11.76
Ending balance, nonvested (in dollars per share) | $ / shares	$ 16.03

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions (Details) - Unvested performance stock units - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	3 years	3 years
Risk-free interest rate	4.05%	4.19%
Expected volatility of Magnite	87%	94%
Expected volatility of selected peer companies	55%	64%
Expected correlation coefficients of Magnite	59%	62%
Expected correlation coefficients of selected peer companies	47%	54%
Dividend yield	$ 0	$ 0

Stock-Based Compensation - St_3

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 20,831	$ 19,287
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	500	468
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	8,236	7,405
Technology and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	5,416	5,446
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	6,679	5,825
Merger, acquisition, and restructuring costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 0	$ 143

Stock-Based Compensation - St_4

Stock-Based Compensation - Stock Based Compensation Expense Narrative (Details)	Mar. 31, 2024 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved (in shares)	16,787,890
2014 Employee Stock Purchase Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved (in shares)	4,730,838

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Benefit for income taxes	$ (7,809)	$ (309)

Lease Obligations - Narrative (

Lease Obligations - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Lease expense	$ 5.7	$ 6.5
Lease cost	0.9	0.9
Sublease income	$ 1.3	$ 1.3
Weighted average discount rate	6.21%		6.19%
Weighted average remaining lease term	5 years		5 years 2 months 12 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

Lease Obligations - Schedule of

Lease Obligations - Schedule of Lease Liability Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Fiscal Year
Remaining 2024	$ 18,596
2025	18,265
2026	15,178
2027	10,119
2028	7,839
Thereafter	14,358
Total lease payments (undiscounted)	84,355
Less: imputed interest	(11,391)
Lease liabilities—total (discounted)	$ 72,964

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Non Cancelable Inventory And Other Services Purchase Commitments Member
Other Commitments [Line Items]
Non-cancelable purchase commitments	$ 57.6
Financial Standby Letter of Credit
Other Commitments [Line Items]
Letters of credit outstanding, amount	$ 5.2	$ 5.3

Commitments and Contingencies -

Commitments and Contingencies - Contractual Obligations (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining 2024	$ 44,596
2025	21,990
2026	346
2027	241
2028	241
Total	$ 67,414

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total	$ 570,067
Debt, current	3,650	$ 3,600
Debt, non-current, net of debt discount and debt issuance costs	549,077	532,986
Total	552,727	536,586
Convertible Senior Notes | Convertible Debt
Debt Instrument [Line Items]
Total	205,067	205,067
Less: Unamortized discount and debt issuance costs	(2,304)	(2,598)
Total	202,763	202,469
Credit Agreements, 2021 and 2024 | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Total	365,000	351,000
Less: Unamortized discount and debt issuance costs	(15,036)	(16,883)
Debt, non-current, net of debt discount and debt issuance costs	349,964	334,117
Total	$ 349,964	$ 334,117

Debt - Long-term Debt (Narrativ

Debt - Long-term Debt (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Disclosure [Abstract]
Amortization of debt discount and issuance costs	$ 1	$ 1.6
Amortization of deferred financing costs	$ 0.1	$ 0.1

Debt - Maturities of Principle

Debt - Maturities of Principle Amount of Long-Term Debt (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Debt Disclosure [Abstract]
Remaining 2024	$ 2,737
2025	3,650
2026	208,717
2027	3,650
2028	3,650
Thereafter	347,663
Total	$ 570,067

Debt - Convertible Senior Notes

Debt - Convertible Senior Notes and Capped Call Transactions (Narrative) (Details)	1 Months Ended	3 Months Ended
	Mar. 31, 2021 USD ($) day $ / shares	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
Capped calls, transaction costs	$ 39,000,000
Repayments of convertible debt		$ 0	$ 40,828,000
(Gain) loss on extinguishment of debt		(7,387,000)	8,549,000
Unamortized debt issuance costs associated with debt extinguishment		$ 0	900,000
Convertible Senior Notes
Debt Instrument [Line Items]
Capped calls, transaction costs	$ 39,000,000
Percent of outstanding balance holders able to call debt in the event of default	25%
Debt issuance costs, gross	$ 11,400,000
Convertible Senior Notes | Minimum
Debt Instrument [Line Items]
Conversion price (in USD per share) | $ / shares	$ 63.8818
Convertible Senior Notes | Maximum
Debt Instrument [Line Items]
Conversion price (in USD per share) | $ / shares	$ 91.2600
Convertible Senior Notes | Convertible Debt
Debt Instrument [Line Items]
Aggregate principle amount	$ 400,000,000
Interest rate	0.25%
Over-allotment options	$ 50,000,000
Net proceeds	$ 388,600,000
Conversion ratio		0.0156539
Repayments of convertible debt			40,800,000
(Gain) loss on extinguishment of debt			8,500,000
Debt instrument, repurchased during period, face amount			50,300,000
Unamortized debt issuance costs associated with debt extinguishment			$ 900,000
Convertible Senior Notes | Convertible Debt | Minimum
Debt Instrument [Line Items]
Make-whole fundamental change period	20 days
Convertible Senior Notes | Convertible Debt | Maximum
Debt Instrument [Line Items]
Make-whole fundamental change period	45 days
Convertible Senior Notes | Convertible Debt | Conversion Term (i)
Debt Instrument [Line Items]
Threshold percent of stock price trigger	130%
Threshold trading days | day	20
Threshold consecutive trading days | day	30
Convertible Senior Notes | Convertible Debt | Conversion Term (ii)
Debt Instrument [Line Items]
Threshold percent of stock price trigger	98%
Threshold trading days | day	5
Threshold consecutive trading days | day	10
Convertible Senior Notes | Convertible Debt | Conversion Term (iv)
Debt Instrument [Line Items]
Threshold percent of stock price trigger	130%
Threshold trading days | day	20
Threshold consecutive trading days | day	30
Convertible Senior Notes | Convertible Debt | Conversion Term (v)
Debt Instrument [Line Items]
Threshold trading days | day	40

Debt - Interest Expense Related

Debt - Interest Expense Related to the Convertible Senior Notes (Details) - Convertible Debt - Convertible Senior Notes - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Contractual interest expense	$ 128	$ 241
Amortization of debt issuance costs	293	551
Total interest expense	$ 421	$ 792
Effective interest rate	0.82%	0.82%

Debt - Amortization Expense for

Debt - Amortization Expense for Debt Issuance Costs (Details) - Convertible Debt - Convertible Senior Notes $ in Thousands	Mar. 31, 2024 USD ($)
Debt Issuance Costs
Remaining 2024	$ 879
2025	1,173
2026	252
Total	$ 2,304

Debt - Credit Agreements (Narra

Debt - Credit Agreements (Narrative) (Details) - USD ($) $ in Thousands	Feb. 06, 2024	Apr. 30, 2021	Mar. 31, 2024	Dec. 31, 2023
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount			$ 552,727	$ 536,586
Credit Agreements, 2021 and 2024 | Line of Credit | Secured Debt
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount			349,964	334,117
Debt discount costs			7,146	$ 6,594
Credit Agreements, 2021 and 2024 | Line of Credit | Revolving Credit Facility | New Lenders
Line of Credit Facility [Line Items]
Debt issuance costs	$ 2,100
2021 Credit Agreement | Secured Overnight Financing Rate (SOFR) | Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate		4.25%
2021 Credit Agreement | Secured Overnight Financing Rate (SOFR) | Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate		4.75%
2021 Credit Agreement | Alternate Base Rate | Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate		3.25%
2021 Credit Agreement | Alternate Base Rate | Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate		3.75%
2021 Credit Agreement | Line of Credit | Secured Debt
Line of Credit Facility [Line Items]
Aggregate principle amount		$ 360,000
Long-term debt, term		7 years
2021 Credit Agreement | Line of Credit | Secured Debt | Debt Discount
Line of Credit Facility [Line Items]
Unamortized debt issuance costs associated with debt extinguishment	2,800
2021 Credit Agreement | Line of Credit | Secured Debt | Debt Refinance Cost
Line of Credit Facility [Line Items]
Unamortized debt issuance costs associated with debt extinguishment	4,300
2021 Credit Agreement | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 65,000
2021 Credit Agreement | Line of Credit | Revolving Credit Facility | Deferred Financing Costs
Line of Credit Facility [Line Items]
Unamortized debt issuance costs associated with debt extinguishment	300
2021 Credit Agreement | Line of Credit | Secured Overnight Financing Rate (SOFR) | Secured Debt
Line of Credit Facility [Line Items]
Variable interest rate		5%
2021 Credit Agreement | Line of Credit | Alternate Base Rate | Secured Debt
Line of Credit Facility [Line Items]
Variable interest rate		4%
2024 Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Debt fees	7,700
2024 Credit Agreement | Line of Credit | Secured Debt
Line of Credit Facility [Line Items]
Aggregate principle amount	$ 365,000
Long-term debt, term	7 years
Interest rate	9.79%
Quarterly payments of principle balance (percent)	0.25%
Aggregate annual payments of principle balance (percent)	1%
2024 Credit Agreement | Line of Credit | Secured Debt | Existing Lenders
Line of Credit Facility [Line Items]
Debt fees			3,100
2024 Credit Agreement | Line of Credit | Secured Debt | Existing Lenders | Debt Discount
Line of Credit Facility [Line Items]
Debt issuance costs	$ 3,700
2024 Credit Agreement | Line of Credit | Secured Debt | Existing Lenders | Deferred Financing Costs
Line of Credit Facility [Line Items]
Debt issuance costs	5,700
2024 Credit Agreement | Line of Credit | Secured Debt | New Lenders
Line of Credit Facility [Line Items]
Debt issuance costs	2,400
Debt discount costs	$ 3,700
2024 Credit Agreement | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term debt, term	5 years
Maximum borrowing capacity	$ 175,000
Debt utilization triggering leverage ratio compliance, percent	35%
Leverage ratio maximum	3.25
Debt outstanding			0
Available borrowing capacity			169,800
2024 Credit Agreement | Line of Credit | Revolving Credit Facility | Existing Lenders
Line of Credit Facility [Line Items]
Debt issuance costs	$ 600
2024 Credit Agreement | Line of Credit | Letter of Credit
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount			$ 5,200
2024 Credit Agreement | Line of Credit | Secured Overnight Financing Rate (SOFR) | Secured Debt
Line of Credit Facility [Line Items]
Variable interest rate	4.50%
2024 Credit Agreement | Line of Credit | Secured Overnight Financing Rate (SOFR) | Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate	3.50%
2024 Credit Agreement | Line of Credit | Secured Overnight Financing Rate (SOFR) | Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate	4%
2024 Credit Agreement | Line of Credit | Alternate Base Rate | Secured Debt
Line of Credit Facility [Line Items]
Variable interest rate	3.50%
2024 Credit Agreement | Line of Credit | Alternate Base Rate | Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate	2.50%
2024 Credit Agreement | Line of Credit | Alternate Base Rate | Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable interest rate	3%

Debt - Summary of Term Loan B F

Debt - Summary of Term Loan B Facility (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Term Loan B Facility	$ 570,067
Debt, net of debt discount and debt issuance costs	549,077	$ 532,986
Line of Credit | Credit Agreements, 2021 and 2024 | Secured Debt
Debt Instrument [Line Items]
Term Loan B Facility	365,000	351,000
Unamortized debt discounts	(7,146)	(6,594)
Unamortized debt issuance costs	(7,890)	(10,289)
Debt, net of debt discount and debt issuance costs	$ 349,964	$ 334,117

Debt - Interest Expense Relat_2

Debt - Interest Expense Related to the Term Loan B Facility (Details) - Line of Credit - Credit Agreements, 2021 and 2024 - Secured Debt - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Contractual interest expense	$ 9,166	$ 8,436
Amortization of debt discount	314	393
Amortization of debt issuance costs	418	612
Total interest expense	$ 9,898	$ 9,441
Effective interest rate	11.03%	10.65%

Debt - Amortization Expense f_2

Debt - Amortization Expense for the Term Loan B Facility Debt Discount and Issuance Costs (Details) - Line of Credit - Credit Agreements, 2021 and 2024 - Secured Debt - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Discount
Remaining 2024	$ 807
2025	1,067
2026	1,056
2027	1,045
2028	1,034
Thereafter	2,137
Total	7,146	$ 6,594
Debt Issuance Costs
Remaining 2024	891
2025	1,178
2026	1,166
2027	1,154
2027	1,142
Thereafter	2,359
Total	$ 7,890	$ 10,289