Semrush (SEMR) 10-Q 11 May 21 2021 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2021	May 07, 2021
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-40276
Entity Registrant Name	Semrush Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-4053265
Entity Address, Address Line One	800 Boylston Street, Suite 2475
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02199
City Area Code	(800)
Local Phone Number	851-9959
Title of 12(b) Security	Class A Common Stock, $0.00001 par value per share
Trading Symbol	SEMR
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001831840
Current Fiscal Year End Date	--12-31
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		10,719,266
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		124,905,954

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 171,867	$ 35,531
Accounts receivable	2,383	1,399
Deferred contract costs, current portion	4,817	4,049
Prepaid expenses and other current assets	3,626	2,649
Total current assets	182,693	43,628
Property and equipment, net	3,876	2,968
Intangible assets, net	2,176	2,231
Goodwill	1,991	1,991
Deferred contract costs, net of current portion	2,000	1,670
Other long-term assets	1,130	2,470
Total assets	193,866	54,958
Current liabilities
Accounts payable	10,233	8,654
Accrued expenses	10,286	7,719
Deferred revenue	32,078	26,537
Total current liabilities	52,597	42,910
Long-term liabilities
Deferred revenue, net of current portion	181	123
Deferred tax liability	153	209
Other long-term liabilities	1,024	497
Total liabilities	53,955	43,739
Commitments and contingencies (Note 11)
Stockholders' equity (deficit)
Common stock	0	0
Additional paid-in capital	174,254	4,975
Accumulated deficit	(34,344)	(35,815)
Total stockholders’ equity (deficit)	139,911	(6,840)
Total liabilities, redeemable convertible preferred stock, and stockholders' deficit	193,866	54,958
Series A redeemable convertible preferred stock
Long-term liabilities
Redeemable convertible preferred stock	0	7,789
Series A-1 redeemable convertible preferred stock
Long-term liabilities
Redeemable convertible preferred stock	0	10,270
Series B convertible preferred stock
Stockholders' equity (deficit)
Preferred stock	0	24,000
Undesignated preferred stock
Stockholders' equity (deficit)
Preferred stock	0	0
Class A Common Stock
Stockholders' equity (deficit)
Common stock	0	0
Class B Common Stock
Stockholders' equity (deficit)
Common stock	$ 1	$ 0

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Redeemable convertible preferred stock, authorized (shares)		9,898,400
Preferred stock, par value (usd per share)	$ 0.00001
Preferred stock, authorized (shares)	100,000,000
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, authorized (shares)	0	300,000,000
Common stock, issued (shares)	0	95,206,893
Common stock, outstanding (shares)	0	95,050,041
Series A redeemable convertible preferred stock
Redeemable convertible preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Redeemable convertible preferred stock, authorized (shares)	0	3,379,400
Redeemable convertible preferred stock, issued (shares)	0	3,379,400
Redeemable convertible preferred stock, outstanding (shares)	0	3,379,400
Redeemable convertible preferred stock, liquidation value		$ 8,000
Series A-1 redeemable convertible preferred stock
Redeemable convertible preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Redeemable convertible preferred stock, authorized (shares)	0	1,837,600
Redeemable convertible preferred stock, issued (shares)	0	1,837,600
Redeemable convertible preferred stock, outstanding (shares)	0	1,837,600
Redeemable convertible preferred stock, liquidation value		$ 5,000
Series B convertible preferred stock
Redeemable convertible preferred stock, authorized (shares)		4,681,400
Preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, authorized (shares)	0	4,681,400
Preferred stock, issued (shares)	0	4,681,400
Preferred stock, outstanding (shares)	0	4,681,400
Preferred stock, liquidation value		$ 24,000
Undesignated preferred stock
Preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, authorized (shares)	100,000,000	0
Preferred stock, issued (shares)	0	0
Preferred stock, outstanding (shares)	0	0
Class A Common Stock
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, authorized (shares)	1,000,000,000	0
Common stock, issued (shares)	10,000,000	0
Common stock, outstanding (shares)	10,000,000	0
Class B Common Stock
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, authorized (shares)	160,000,000	0
Common stock, issued (shares)	124,905,954	0
Common stock, outstanding (shares)	124,749,102	0

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue	$ 39,998	$ 27,787
Cost of revenue	8,773	6,611
Gross profit	31,225	21,176
Operating expenses
Sales and marketing	16,457	12,877
Research and development	5,358	4,237
General and administrative	7,904	5,933
Total operating expenses	29,719	23,047
Income (loss) from operations	1,506	(1,871)
Other income, net	51	56
Income (loss) before income taxes	1,557	(1,815)
Provision for income taxes	86	116
Comprehensive income (loss)	1,471	(1,931)
Net income (loss)	$ 1,471	$ (1,931)
Net income (loss) per share attributable to common stockholders:
Basic (usd per share)	$ 0.02	$ (0.02)
Diluted (usd per share)	$ 0.01	$ (0.02)
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders:
Basic (shares)	96,375,531	94,592,700
Diluted (shares)	131,356,093	94,592,700

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Series A	Series A-1	Series BPreferred Stock	Class A Common StockCommon Stock	Class B Common StockCommon Stock
Beginning balance (in shares) at Dec. 31, 2019					3,379,400	1,837,600
Beginning balance at Dec. 31, 2019					$ 7,789	$ 10,270
Ending balance (in shares) at Mar. 31, 2020					3,379,400	1,837,600
Ending balance at Mar. 31, 2020					$ 7,789	$ 10,270
Beginning balance (in shares) at Dec. 31, 2019		94,592,700					4,681,400	0	0
Beginning balance at Dec. 31, 2019	$ (1,159)	$ 0	$ 3,644	$ (28,803)			$ 24,000	$ 0	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	205		205
Net (loss) income	(1,931)			(1,931)
Ending balance (in shares) at Mar. 31, 2020		94,592,700					4,681,400	0	0
Ending balance at Mar. 31, 2020	(2,885)	$ 0	3,849	(30,734)			$ 24,000	$ 0	$ 0
Beginning balance (in shares) at Dec. 31, 2020					3,379,400	1,837,600
Beginning balance at Dec. 31, 2020					$ 7,789	$ 10,270
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of Preferred Stock (in shares)					(3,379,400)	(1,837,600)
Conversion of Preferred Stock					$ (7,789)	$ (10,270)
Ending balance (in shares) at Mar. 31, 2021					0	0
Ending balance at Mar. 31, 2021					$ 0	$ 0
Beginning balance (in shares) at Dec. 31, 2020		95,050,041					4,681,400	0	0
Beginning balance at Dec. 31, 2020	(6,840)	$ 0	4,975	(35,815)			$ 24,000	$ 0	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Preferred Stock (in shares)		29,695,200					(4,681,400)
Conversion of Preferred Stock	18,058		42,058				$ (24,000)
Issuance of Class A Common Stock in connection with the Initial Public Offering, net of $13,378 in issuance costs (in shares)								10,000,000
Issuance of Class A Common Stock in connection with the initial public offering, net of $13,378 in issuance costs	126,622		126,622
Reclassification of Common Stock to Class B Common Stock in connection with the Initial Public Offering (in shares)		(124,745,241)							124,745,241
Reclassification of Common Stock to Class B Common Stock in connection with the initial public offering	$ 0		(1)						$ 1
Stock-based compensation expense (in shares)	3,861								3,861
Exercise of stock options	$ 7		7
Stock-based compensation expense	593		593
Net (loss) income	1,471			1,471
Ending balance (in shares) at Mar. 31, 2021		0					0	10,000,000	124,749,102
Ending balance at Mar. 31, 2021	$ 139,911	$ 0	$ 174,254	$ (34,344)			$ 0	$ 0	$ 1

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 0	$ 16

UNAUDITED CONDENSED CONSOLIDA_6

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities
Net income (loss)	$ 1,471	$ (1,931)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Depreciation and amortization expense	460	232
Amortization of deferred contract costs	1,322	1,104
Stock-based compensation expense	593	205
Deferred taxes	(56)	(57)
Changes in operating assets and liabilities
Accounts receivable	(985)	745
Deferred contract costs	(2,420)	(1,704)
Prepaid expenses and other current assets	(976)	(747)
Accounts payable	1,579	58
Accrued expenses	2,420	1,002
Deferred revenue	5,599	1,654
Net cash provided by operating activities	9,007	561
Investing Activities
Purchases of property and equipment	(166)	(1,084)
Purchases of convertible debt securities	(500)	0
Capitalization of internal-use software development costs	(123)	(297)
Cash paid for acquisition of business, net of cash acquired	(350)	0
Net cash used in investing activities	(1,139)	(1,381)
Financing Activities
Proceeds from exercise of stock options	7	0
Net proceeds from completing initial public offering	128,461	0
Payment of deferred offering costs	0	(16)
Net cash provided by (used in) financing activities	128,468	(16)
Increase in cash, cash equivalents and restricted cash	136,336	(836)
Cash, cash equivalents and restricted cash, at beginning of period	35,619	37,523
Cash, cash equivalents and restricted cash, at end of period	171,955	36,687
Supplemental cash flow disclosures
Cash paid for income taxes	158	154
Deferred offering costs incurred and not paid	1,839	0
Acquisition of fixed asset under capital lease	$ 1,024	$ 0

Overview and Basis of Presentat

Overview and Basis of Presentation	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Overview and Basis of Presentation	Overview and Basis of Presentation Description of Business Semrush Holdings, Inc. (“Semrush Holdings”) and its subsidiaries (together the “Group”, the “Company”, or “Semrush”) provide an online visibility management software-as-a-service (“SaaS”) platform. The Company’s platform enables its subscribers to improve their online visibility and drive traffic, including on their websites and social media pages, and distribute highly relevant content to their customers on a targeted basis across various channels to drive high-quality traffic and measure the effectiveness of their digital marketing campaigns. The Company is headquartered in Boston, Massachusetts, and has wholly owned subsidiaries in Cyprus, Russia, the Czech Republic, Poland, and the United States. The Company is subject to a number of risks and uncertainties common to companies in similar industries and stages of development that could affect future operations and financial performance. These risks include, but are not limited to, rapid technological change, competitive pressure from substitute products or larger companies, protection of proprietary technology, management of international activities, the need to obtain additional financing to support growth, and dependence on third parties and key individuals. 2019 Reorganization On December 19, 2019, Semrush Holdings was incorporated in the state of Delaware and entered into a Contribution and Exchange Agreement with SEMrush CY Ltd (“SEMrush CY”) (a private limited liability company organized under the Cyprus Companies Law, Cap 113), pursuant to which the holders of all outstanding shares of capital stock of SEMrush CY contributed those shares to Semrush Holdings in exchange for identical shares of capital stock of Semrush Holdings (the “2019 Share Exchange”). Upon the 2019 Share Exchange, Semrush Holdings became the holding company of SEMrush CY and its wholly owned subsidiaries and the historical consolidated financial statements of SEMrush CY became the historical consolidated financial statements of Semrush Holdings. The 2019 Share Exchange and related transactions were completed on December 27, 2019. Initial Public Offering On March 29, 2021, the Company closed its initial public offering (“IPO”) in which it sold 10,000,000 shares of its Class A common stock at a price to the public of $14.00 per share. The Company received $126.6 million in net proceeds after deducting approximately $13.4 million for underwriting discounts, commissions and offering expenses. Immediately prior to the completion of the IPO, all shares of common stock then outstanding were reclassified as Class B common stock, and all shares of redeemable convertible preferred stock and convertible preferred stock then outstanding were converted into shares of common stock on a one-to-one basis and then reclassified into Class B common stock. Effects of COVID-19 The Company considered the potential effects of the novel strain of coronavirus (“COVID-19”) pandemic on the Company. In March 2020, the World Health Organization declared the outbreak of COVID–19 a pandemic, and numerous new strains of COVID-19 have subsequently spread throughout the world. COVID–19 has continued to impact market and economic conditions globally. In an attempt to limit the spread of the virus, various governmental restrictions have been implemented, including restrictions with respect to business activities and travel restrictions, and “shelter–at–home” orders, that have had and may continue to have an adverse impact on the Company’s business and operations. In light of the evolving nature of COVID–19 and the uncertainty it has produced around the world, it is not possible to predict the COVID–19 pandemic’s cumulative and ultimate impact on the Company’s future business operations, results of operations, financial position, liquidity, and cash flows. The extent of the impact of the pandemic on the Company’s business and financial results will depend largely on future developments, including the duration of the spread of the outbreak both globally and within the U.S., the impact on capital, foreign currencies exchange and financial markets, and governmental or regulatory orders that impact the Company’s business, all of which are highly uncertain and cannot be predicted. The Company will continue to actively monitor the current international and domestic impacts of and responses to COVID-19 and its related risks. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual consolidated financial statements as of and for the year ended December 31, 2020, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of March 31, 2021, and the results of its operations and its cash flows for the three months ended March 31, 2021 and 2020. The consolidated balance sheet as of December 31, 2020 included herein was derived from the audited financial statements as of that date. The results for the three months ended March 31, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021, any other interim periods, or any future year or period. The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company’s final prospectus dated March 24, 2021 (the “Prospectus”) as filed with the SEC on March 25, 2021 pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the “Securities Act”). The accompanying unaudited condensed consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the unaudited condensed consolidated financial statements. As of March 31, 2021, there have been no material changes in the Company's significant accounting policies from those that were disclosed in the Prospectus except as discussed below.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting PoliciesPrinciples of Consolidation The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. Significant estimates relied upon in preparing these financial statements include, but are not limited to, revenue recognition, expected future cash flows used to evaluate the recoverability of long-lived assets, contingent liabilities, expensing and capitalization of research and development costs for internal-use software, the average period of benefit associated with costs capitalized to obtain revenue contracts, the determination of the fair value of stock-based awards issued, stock-based compensation expense, and the recoverability of the Company’s net deferred tax assets and related valuation allowance. Although the Company regularly assesses these estimates, actual results could differ materially from these estimates. Changes in estimates are recorded in the period in which they become known. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results may differ from management’s estimates if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. Subsequent Events Considerations The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated as required. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure, other than those disclosed in this Quarterly Report on Form 10-Q. Emerging Growth Company Status The Company is an "emerging growth company," as defined in the Jumpstart Our Business Startups Act, or JOBS Act, and may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not "emerging growth companies." The Company may take advantage of these exemptions until the Company is no longer an "emerging growth company." Section 107 of the JOBS Act provides that an "emerging growth company" can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. The Company has elected to use the extended transition period for complying with new or revised accounting standards and, as a result of this election, its financial statements may not be comparable to companies that comply with public company effective dates. The Company may take advantage of these exemptions up until the last day of the year following the fifth anniversary of an offering or such earlier time that it is no longer an emerging growth company. The Company would cease to be an emerging growth company if it has more than $1.07 billion in annual revenue, has more than $700.0 million in market value of its stock held by non-affiliates (and it has been a public company for at least 12 months, and has filed one annual report on Form 10-K), or it issues more than $1.0 billion of non-convertible debt securities over a three-year period. Revenue Recognition The Company derives revenue from two sources: (1) subscription revenues via the Semrush Online Visibility Management Platform and the Prowly Public Relations Platform, which are comprised of subscription fees from customers accessing the Company’s SaaS services and related customer support; and (2) the Semrush Marketplace, which allows customers to pay a set fee for services or products offered through the marketplace. The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”). Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration it expects to receive in exchange for those products or services. There were no changes to the Company’s revenue recognition policies since the filing of the Prospectus. For the three months ended March 31, 2021 and 2020, subscription revenue accounted for nearly all of the Company’s revenue. Revenue related to the Semrush Marketplace was not material for the three months ended March 31, 2021 and 2020. Amounts that have been invoiced are recorded in accounts receivable and in deferred revenue or revenue, depending on whether the revenue recognition criteria have been met. The Company primarily invoices and collects payments from customers for its services in advance on a monthly or annual basis. Deferred revenue represents amounts billed for which revenue has not yet been recognized. Deferred revenue that will be recognized during the succeeding 12-month period is recorded as current deferred revenue, and the remaining portion is recorded as long-term deferred revenue. Deferred revenue increased by $5,599 as of March 31, 2021 compared December 31, 2020. During the three months ended March 31, 2021 and 2020, $13,303 and $9,583 of revenue was recognized that was included in deferred revenue at the beginning of each respective period. The Company has elected to exclude amounts charged to customers for sales tax from the transaction price. Accordingly, revenue is presented net of any sales tax collected from customers. Transaction Price Allocated to Future Performance Obligations ASC 606 requires that the Company disclose the aggregate amount of the transaction price that is allocated to performance obligations that have not yet been satisfied as of the balance sheet dates reported. For contracts with an original expected duration greater than one year, the aggregate amount of the transaction price allocated to the performance obligations that were unsatisfied as of March 31, 2021 and December 31, 2020 was $866 and $1,280, respectively, which the Company expects to recognize over the next 12 months. For contracts with an original expected duration of one year or less, the Company has applied the practical expedient available under ASC 606 to not disclose the amount of transaction price allocated to unsatisfied performance obligations as of March 31, 2021 and December 31, 2020. For performance obligations not satisfied as of March 31, 2021 and December 31, 2020, and to which this expedient applies, the nature of the performance obligations is consistent with performance obligations satisfied as of December 31, 2019. The remaining durations are less than one year. Costs to Obtain a Contract The incremental direct costs of obtaining a contract, which primarily consist of sales commissions paid for new subscription contracts, are deferred and recorded as deferred contract costs in the consolidated balance sheet and are amortized over a period of approximately 24 months on a systematic basis, consistent with the pattern of transfer of the goods or services to which the asset relates. The 24-month period represents the estimated benefit period of the customer relationship and has been determined by taking into consideration the type of product sold, the commitment term of the customer contract, the nature of the Company’s technology development life-cycle, and an estimated customer relationship period based on historical experience and future expectations. Sales commissions for renewals and upgrade contracts are deferred and amortized on a straight-line basis over the remaining estimated customer relationship period of the related customer. Deferred contract costs that will be recorded as expense during the succeeding 12-month period are recorded as current deferred contract costs, and the remaining portion is recorded as deferred contract costs, net of current portion. Amortization of deferred contract costs is included in sales and marketing expense in the accompanying consolidated statement of operations and comprehensive loss. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid instruments purchased with an original maturity date of 90 days or less from the date of purchase to be cash equivalents. Management determines the appropriate classification of investments at the time of purchase and re-evaluates such determination at each balance sheet date. Cash and cash equivalents consist of cash on deposit with banks and amounts held in interest-bearing money market funds. Cash equivalents are carried at cost, which approximates their fair market value. At both March 31, 2021 and December 31, 2020, restricted cash was $88, and related to cash held at a financial institution in an interest-bearing cash account as collateral for a letter of credit related to the contractual provisions for one of the Company’s building leases. The following table is a reconciliation of cash, cash equivalents and restricted cash included in the accompanying condensed consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash included in the accompanying condensed consolidated statements of cash flows for the three months ended March 31, 2021 and 2020. March 31, 2021 March 31, 2020 Cash and cash equivalents $ 171,867 $ 36,599 Restricted cash included in “prepaid expenses and other current assets” and “other long-term assets,” respectively 88 88 $ 171,955 $ 36,687 Concentrations of Credit Risk and Significant Customers The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other hedging arrangements. Credit losses historically have not been significant and the Company generally has not experienced any material losses related to receivables from individual customers, or groups of customers. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company's accounts receivable. Credit risk with respect to accounts receivable is dispersed due to the large number of customers of the Company. The Company routinely assesses the creditworthiness of its customers and generally does not require its customers to provide collateral or other security to support accounts receivable. Credit losses historically have not been significant and the Company generally has not experienced any material losses related to receivables from individual customers, or groups of customers. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company's accounts receivable. As of March 31, 2021 and December 31, 2020, no individual customer represented more than 10% of the Company’s accounts receivable. During the three months ended March 31, 2021 and 2020, no individual customer represented more than 10% of the Company’s revenue. Disclosure of Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses, approximated their fair values at March 31, 2021 and December 31, 2020, due to the short-term nature of these instruments. The Company has evaluated the estimated fair value of financial instruments using available market information. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. See below for further discussion. Fair Value Measurements ASC 820, Fair Value Measurements and Disclosures (“ASC 820”), establishes a three-level valuation hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are those that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. This guidance further identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants based on the highest and best use of the asset or liability. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The Company uses valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs are prioritized as follows: Level 1 inputs—Unadjusted observable quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 inputs—Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 inputs—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company evaluates assets and liabilities subject to fair value measurements on a recurring and nonrecurring basis to determine the appropriate level to classify them for each reporting period. Cash equivalents include money market funds with original maturities of 90 days or less from the date of purchase. The fair value measurement of these assets is based on quoted market prices in active markets for identical assets and, therefore, these assets are recorded at fair value on a recurring basis and classified as Level 1 in the fair value hierarchy. As of March 31, 2021 and December 31, 2020, cash equivalents held in money market funds totaled $35,505 and $29,369, respectively. As of March 31, 2021, the Company measured its investments in convertible notes (see Note 4) and its contingent consideration associated with the acquisition of Prowly.com sp. z o.o (“Prowly”) on a recurring basis using significant unobservable inputs (Level 3) and did not have any assets or liabilities measured at fair value on a recurring basis using significant other observable inputs (Level 2). Changes in fair value of the convertible notes were not material for the three months ended March 31, 2021 due to the short time period between when the investment was made and the balance sheet date. Changes in fair value of the contingent consideration associated with the Prowly acquisition were not material for the three months ended March 31, 2021. As of December 31, 2020, the Company did not have any assets or liabilities measured at fair value on a recurring basis using significant other observable inputs (Level 2). Foreign Currency Translation The Group operates in a multi-currency environment having transactions in such currencies as the U.S. dollar, Russian rubles, Czech koruna, euros, and others. The reporting currency of the Company is the U.S. dollar. The functional currency of the Company’s foreign subsidiaries is the U.S. dollar, with the exception of Prowly, where the functional currency is the local currency, the Zloty. The foreign currency translation adjustment as it relates to Prowly was immaterial for the three months ended March 31, 2021 and 2020. For all other entities, foreign currency transactions are measured initially in the functional currency of the recording entity by use of the exchange rate in effect at that date. At each subsequent balance sheet date, foreign currency denominated assets and liabilities of these international subsidiaries are remeasured into U.S. dollars using the exchange rates in effect at the balance sheet date or historical rates, as appropriate. Any differences resulting from the remeasurement of foreign denominated assets and liabilities of the international subsidiaries to the U.S. dollar functional currency are recorded within other income (expense) in the unaudited condensed consolidated statement of operations and comprehensive loss. The foreign currency exchange gain (loss) included in other income for the three months ended March 31, 2021 and 2020 was $44 and $(107), respectively. Net Income (Loss) Per Share Net income (loss) per share information is determined using the two-class method, which includes the weighted-average number of shares of common stock outstanding during the period and other securities that participate in dividends (a participating security). Prior to the completion of the IPO, the Company considered the shares of Preferred Stock to be participating securities because they include rights to participate in dividends with the common stock. As of March 31, 2021, the Company did not have any participating securities outstanding. Under the two-class method, basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net income (loss) per share attributable to common stockholders is computed using the more dilutive of (1) the two-class method or (2) the if-converted method. The Company allocates net income first to preferred stockholders based on dividend rights under the Company’s certificate of incorporation and then to preferred and common stockholders based on ownership interests. Net losses are not allocated to preferred stockholders as they do not have an obligation to share in the Company’s net losses. During the three months ended March 31, 2021, the Company amended its certificate of incorporation to create two classes of common stock outstanding: Class A common stock and Class B common stock. As more fully described in Note 9, the rights of the holders of Class A and Class B common stock are identical, except with respect to voting and conversion. Each share of Class A common stock is entitled to one (1) vote per share and each share of Class B common stock is entitled to ten (10) votes per share. Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder at any time. Shares of Class B common stock are automatically converted into Class A common stock upon sale or transfer, subject to certain limited exceptions. Shares of Class A common stock are not convertible. See Note 9 to these unaudited condensed consolidated financial statements for additional information regarding the current conversion and transfer terms of the Company’s common stock. The Company allocates undistributed earnings attributable to common stock between the common stock classes on a one to one basis when computing net income (loss) per share. As a result, basic and diluted net income (loss) per share of Class A common stock and share of Class B common stock are equivalent. Diluted net income (loss) per share gives effect to all potentially dilutive securities. Potential dilutive securities consist of shares of common stock issuable upon the exercise of stock options, shares of common stock issuable upon the conversion of the outstanding shares of Preferred Stock, and shares of common stock issuable upon the vesting of restricted stock awards or restricted stock units. For the three months ended March 31, 2021, dilutive net income per share was calculated by dividing net income by the weighted-average number of shares of common stock outstanding during the period, the dilutive impact of stock options, shares of common stock issuable upon the vesting of RSUs, and the dilutive impact of shares issuable upon the conversion of the outstanding shares of Preferred Stock. For the three months ended March 31, 2020, the net loss attributable to common stockholders is divided by the weighted-average number of shares of common stock outstanding during the period to calculate diluted earnings per share. The dilutive effect of common stock equivalents has been excluded from the calculation for the three months ended March 31, 2020 as their effect would have been anti-dilutive due to the net losses incurred for the period. The following table presents a reconciliation of the weighted-average shares outstanding used in the calculation of basic and diluted net income (loss) per share: Three Months Ended March 31, 2021 2020 Weighted-average shares outstanding: Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—basic 96,375,531 94,592,700 Dilutive effect of share equivalents resulting from stock options 6,151,361 — Dilutive effect of share equivalents resulting from RSAs 123,841 — Dilutive effect of shares issuable upon conversion of preferred stock 28,705,360 — Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—diluted 131,356,093 94,592,700 The following potentially dilutive common stock equivalents have been excluded from the calculation of diluted weighted-average shares outstanding for the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 2020 Stock options outstanding — 6,286,357 Shares of Preferred Stock — 29,695,200 Restricted stock units outstanding 1,733 — Comprehensive income (loss) Comprehensive income (loss) is comprised of two components: net income (loss) and other comprehensive income (loss), which includes other changes in stockholders’ deficit that result from transactions and economic events other than those with stockholders. The Company had no items qualifying as other comprehensive income (loss) with the exception of an immaterial cumulative translation adjustment related to the Prowly entity and an immaterial fair-value adjustment related to the convertible note investments; accordingly, comprehensive income (loss) equaled total net loss for the three months ended March 31, 2021 and 2020. Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) . ASU 2016-02 requires a lessee to recognize most leases on the balance sheet but recognize expenses on the income statement in a manner similar to current practice. The update states that a lessee will recognize a lease liability for the obligation to make lease payments and a right-to-use asset for the right to use the underlying assets for the lease term. Leases will continue to be classified as either financing or operating, with classification affecting the recognition, measurement, and presentation of expenses and cash flows arising from a lease. For public entities, ASU 2016-02 is effective for years beginning after December 15, 2019. For non-public companies, ASU 2016-02 is effective for fiscal years beginning after December 15, 2021 and interim periods in annual periods beginning after December 15, 2022. Early adoption is permitted. The Company plans to adopt this guidance in the year ended December 31, 2022. The Company is currently assessing the impact that adopting this guidance will have on its consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . ASU 2016-13 requires that credit losses be reported as an allowance using an expected losses model, representing the entity's current estimate of credit losses expected to be incurred. The accounting guidance currently in effect is based on an incurred loss model. ASU 2016-13 affect loans, debt securities, trade receivables, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. ASU 2016-13 is effective for public entities for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years. For non-public companies, ASU 2016-13 is effective for fiscal years beginning after December 15, 2020, and interim periods within fiscal years beginning after December 15, 2021. The Company plans to adopt this guidance in the year ended December 31, 2021. The Company is currently evaluating ASU 2016-13 and the potential impact on its condensed consolidated financial statements and financial statement disclosures. In August 2018, the FASB issued ASU No. 2018-15, Intangible-Goodwill and Other Internal-Use Software (Subtopic 350-40) . ASU 2018-15 updates guidance regarding accounting for implementation costs associated with a cloud computing arrangement that is a service contract. The amendments under ASU 2018-15 are effective for public entities for years beginning after December 15, 2019, and interim periods within those years. For non-public companies, ASU 2081-15 is effective for annual reporting periods beginning after December 15, 2020, and interim periods within annual periods beginning after December 15, 2021, with early adoption permitted. The Company plans to adopt this guidance in the year ended December 31, 2021. The Company is currently assessing the impact that adopting this guidance will have on its condensed consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, Income Taxes – Simplifying the Accounting for Income Taxes . The new guidance simplifies the accounting for income taxes by removing several exceptions in the current standard and adding guidance to reduce complexity in certain areas, such as requiring that an entity reflect the effect of an enacted change in tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. For public companies, the ASU is effective for years beginning after December 15, 2020, and interim periods within those years,

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net Property and equipment consists of the following (in thousands): As of March 31, December 31, Computer equipment $ 3,383 $ 3,513 Furniture and office equipment 877 1,041 Leasehold improvements 1,142 667 Capital leases 1,024 — Total property and equipment 6,426 5,221 Less: accumulated depreciation and amortization (2,550) (2,253) Property and equipment, net $ 3,876 $ 2,968 Depreciation and amortization expense related to property and equipment was $344 and $203 for the three months ended March 31, 2021 and 2020, respectively.

Other Long-Term Assets

Other Long-Term Assets	3 Months Ended
	Mar. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Long-Term Assets	Other Long-Term Assets Deferred Offering Costs Deferred offering costs, which primarily consist of direct incremental legal and accounting fees relating to the IPO and to a credit facility, are deferred. The deferred issuance costs relating to the IPO were offset against IPO proceeds upon the consummation of the Company’s offering. The deferred costs relating to the credit facility are being amortized to interest expense up through the maturity date of the facility. As of March 31, 2021 and December 31, 2020, the Company had deferred offering costs relating to the IPO of $0 and $1,839. As of March 31, 2021 and December 31, 2020, the Company had $578 and $630, respectively, in issuance costs relating to the credit facility. The issuance costs for the IPO and credit facility are classified in other long-term assets in the accompanying unaudited condensed consolidated balance sheets. Investments in Convertible Debt In January 2021, the Company purchased two convertible debt securities for a total aggregate investment of $500. Both investments mature on January 1, 2023 and receive interest at an annual rate of 6%. Interest accrues and becomes payable upon conversion of the convertible notes, or will be paid in connection with the repayment in full of the principal amount of such convertible notes. These convertible note investments are classified as available-for-sale securities with changes in fair value reported in other comprehensive income (loss). Changes in fair value were not material for the three months ended March 31, 2021 due to the short time period between when the investment was made and the balance sheet date. These investments are classified in other long-term assets in the accompanying unaudited condensed consolidated balance sheets based on the maturity date.

Acquisitions, Acquired Intangib

Acquisitions, Acquired Intangible Assets, and Goodwill	3 Months Ended
	Mar. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions, Acquired Intangible Assets, and Goodwill	Acquisitions, Acquired Intangible Assets, and Goodwill Acquisitions On August 27, 2020, the Company acquired 100% of the outstanding capital of Prowly for cash consideration of $3,317. In addition to the purchase consideration, the founders of Prowly are eligible to earn up to a maximum of $2,750 in aggregate additional consideration based on the satisfaction of certain earnings targets as defined in the purchase agreement. For the three months ended March 31, 2021, the Company recognized compensation expense of $56 as compensation expense related to the additional consideration. Intangible Assets Intangible assets consisted of intangible assets resulting from the acquisition of Prowly and capitalized internal-use software development costs. Intangible assets consists of the following: As of March 31, 2021 Gross Net Carrying Accumulated Carrying Amount Amortization Amount Developed technology 1,194 (109) 1,085 Trade name 68 (9) 59 Capitalized internal-use software 1,684 (652) 1,032 Total as of March 31, 2021 $ 2,946 $ (770) $ 2,176 As of December 31, 2020 Gross Net Carrying Accumulated Carrying Amount Amortization Amount Developed technology 1,194 (66) 1,128 Trade name 68 (3) 65 Capitalized internal-use software 1,561 (523) 1,038 Total as of December 31, 2020 $ 2,823 $ (592) $ 2,231 During the three months ended March 31, 2021 and 2020, the Company capitalized $123 and $200, respectively, of software development costs, which are classified as intangible assets on the accompanying consolidated balance sheets. The Company recorded amortization expense associated with its capitalized development costs of $129 and $52 for the three months ended March 31, 2021 and 2020, respectively. As of March 31, 2021 and December 31, 2020, the capitalized internal-use software asset balances totaled $1,032 and $1,038, respectively. Amortization expense for acquired intangible assets was $55 for the three months ended March 31, 2021. As of March 31, 2021, future amortization expense is expected to be as follows: Amount Remainder of 2021 $ 519 2022 559 2023 428 2024 199 2025 and thereafter 471 Total $ 2,176 Goodwill The was no change in the carrying value of goodwill of $1,991 from December 31, 2020 through March 31, 2021.

Accrued expenses

Accrued expenses	3 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Accrued expenses	Accrued expenses Accrued expenses consist of the following: As of March 31, December 31, Employee compensation $ 4,776 $ 4,478 Vacation reserves 464 465 Other current liabilities 5,046 2,776 Total accrued expenses $ 10,286 $ 7,719

Revolving Credit Facility

Revolving Credit Facility	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Revolving Credit Facility	Revolving Credit Facility Senior Secured Revolving Credit Facility On January 12, 2021, the Company executed a credit agreement with JPMorgan Chase Bank, N.A., in the form of a revolving credit facility, that consists of a $45.0 million revolving credit facility and a letter of credit sub-facility with an aggregate limit equal to the lesser of $5.0 million and the aggregate unused amount of the revolving commitments then in effect. The availability of the credit facility is subject to the borrowing base based on an advance rate of 400% multiplied by annualized retention applied to monthly recurring revenue. The credit facility has a maturity of three years and will mature on January 12, 2024. Borrowings under the credit facility bear interest at the Company’s option at (i) LIBOR, subject to a 0.50% floor, plus a margin, or (ii) the alternate base rate, subject to a 3.25% floor (or 1.50% prior to positive consolidated adjusted earnings before interest, taxes, depreciation, and amortization (“adjusted EBITDA”) for the twelve months most recently ended), plus a margin. For LIBOR borrowings, the applicable rate margin is 2.75% (or 3.50% prior to positive consolidated adjusted EBITDA as of the twelve months most recently ended). For base rate borrowings, the applicable margin is 0.00% (or 2.50% prior to positive consolidated adjusted EBITDA as of the twelve months most recently ended). The Company is also required to pay a 0.25% per annum fee on undrawn amounts under the Company’s revolving credit facility, payable quarterly in arrears.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We are subject to U.S. federal, state, and foreign income taxes. For the three months ended March 31, 2021 and 2020, we recorded provisions for income taxes of $86 and $116, respectively. Our effective tax rate for the three months ended March 31, 2021 and 2020 was lower than the U.S. statutory rate primarily due to the valuation allowance. We recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. These differences are measured using the enacted statutory tax rates that are expected to be in effect for the years in which differences are expected to reverse. On a periodic basis, we reassess any valuation allowances that we maintain on our deferred tax assets, weighing positive and negative evidence to assess the recoverability of the deferred tax assets. We will maintain a valuation allowance on certain federal, state, and foreign tax attributes that we expect will expire prior to the utilization. In March 2020, the Coronavirus Aid, Relief and Economic Security Act (the “CARES Act”) was signed into law. The CARES Act includes provisions relating to several aspects of corporate income taxes. We do not currently expect the CARES Act to have a significant impact on our provision for income taxes.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Stockholders’ Equity	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Redeemable Convertible Preferred Stock and Stockholders’ Equity	Redeemable Convertible Preferred Stock and Stockholders’ Equity Prior to the IPO, the authorized capital stock of the Company included 9,898,400 shares of preferred stock, of which 3,379,400 shares have been designated as Series A Redeemable Convertible Preferred Stock, 1,837,600 shares have been designated as Series A-1 Redeemable Convertible Preferred Stock and 4,681,400 shares have been designated as Series B Convertible Preferred Stock (collectively the “Preferred Stock”). Immediately prior to the closing of the IPO, the outstanding shares of Preferred Stock were converted on a three-for-one basis into 29,695,200 shares of common stock. The holders of the Company’s Preferred Stock had certain voting, dividend, and redemption rights, as well as liquidation preferences and conversion privileges. All rights, preferences, and privileges associated with the preferred stock were terminated at the time of the Company’s IPO in conjunction with the conversion of all outstanding shares of Preferred Stock into shares of common stock. As of March 31, 2021, the total number of shares of all classes of stock which the Company shall have authority to issue was (i) 1,000,000,000 shares of Class A common stock, par value $0.00001 per share, and (ii) 160,000,000 shares of Class B common stock, par value $0.00001 per share, and (iii) 100,000,000 undesignated shares of Preferred Stock, par value $0.00001 per share. Each share of Class A common stock entitles the holder to one vote for each share on all matters submitted to a vote of the Company's stockholders at all meetings of stockholders and written actions in lieu of meetings. Each share of Class B common stock entitles the holder to ten votes for each share on all matters submitted to a vote of the Company's stockholders at all meetings of stockholders and written actions in lieu of meetings. Holders of Class A common stock and Class B common stock are entitled to receive dividends, when and if declared by the board of directors (the “Board”). Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder at any time. Automatic conversion shall occur upon the occurrence of (i) a Transfer, as defined in the amended and restated certificate of incorporation, of such share of Class B common stock, (ii) the affirmative vote of at least two-thirds of the outstanding shares of Class B common stock, voting as a single class, or (iii) on or after the earlier to occur of (a) the seven Stock Split On March 15, 2021, the Board approved a 3-for-1 stock-split of the Company’s common stock. The stock split was approved by the stockholders on March 15, 2021 and became effective on March 15, 2021. Upon the effectiveness of the stock split, (i) every one share of common stock outstanding was increased to 3 shares of common stock, (ii) the number of shares of common stock into which each outstanding option to purchase common stock is exercisable was proportionally increased on a 3-for-1 basis, and (iii) the exercise price of each outstanding option to purchase common stock was proportionately decreased on a 3-for-1 basis. Additionally, shares of common stock reserved for issuance upon the conversion of the Company’s Preferred Stock were proportionately increased on a 3-for-1 basis and the respective conversion prices of the Preferred Stock were proportionately reduced. All share and per share data shown in the accompanying consolidated financial statements and related notes have been retroactively revised to reflect the stock split. Common Stock Reserved for Future Issuance As of March 31, 2021, the Company had reserved the following shares of common stock for future issuance: Options outstanding 7,591,554 Options reserved for future issuance 13,483,501 Restricted stock outstanding 156,852 Restricted stock units 19,500 Total authorized shares of common stock reserved for future issuance 21,251,407

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation In 2019, the Board adopted the Semrush Holdings, Inc. 2019 Stock Option and Grant Plan (the “2019 Plan”), which provides for the grant of qualified incentive stock options and nonqualified stock options or other awards, including restricted stock unit awards, to the Company’s employees, officers, directors, advisors, and outside consultants for the purchase of up to 8,682,600 shares of the Company’s common stock. In July 2020, the Plan was amended to provide for the grant of qualified incentive stock options and nonqualified stock options or other awards to the Company’s employees, officers, directors, advisors, and outside consultants for the purchase of up to 10,163,772 shares of the Company’s common stock. Stock options generally vest over a 4 year period and expire 10 years from the date of grant. Certain options provide for accelerated vesting if there is a change in control (as defined in the Plan). The Semrush Holdings, Inc. 2021 Stock Option and Incentive Plan (the “2021 Plan”) was adopted by the Board March 3, 2021 and approved by stockholders on March 15, 2021 and became effective immediately prior to the effectiveness of the Company’s registration statement in connection with its IPO. The 2021 Plan replaced the 2019 Plan as the Board determined not to make additional awards under the 2019 Plan following the pricing of the Company’s IPO. The 2021 Plan allows the compensation committee of the Board to make equity-based and cash-based incentive awards to the Company’s officers, employees, directors and other key persons (including consultants). The Company initially reserved 13,503,001 shares of Class A common stock for the issuance of awards under the 2021 Plan. The 2021 Plan provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning on January 1, 2022, by the lesser of 5% of the outstanding number of shares of Class A and Class B common stock on the immediately preceding December 31, or such lesser number of shares as determined by the compensation committee. This number is subject to adjustment in the event of a stock split, stock dividend or other change in our capitalization. The Company accounts for stock-based compensation in accordance with the provisions of ASC 718, which requires the recognition of expense related to the fair value of stock-based compensation awards in the statements of operations. For stock-based awards issued under the Company’s stock-based compensation plans to employees and members of the Board for their services on the Board, the fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model as discussed further below. For service-based awards, the Company recognizes compensation expense on a straight-line basis over the requisite service period of the award with actual forfeitures recognized as they occur. Given the absence of an active market for the Company’s common stock prior to the completion of the IPO, the Board, the members of which the Company believes have extensive business, finance, and venture capital experience, were required to estimate the fair value of the Company’s common stock at the time of each grant of a stock-based award. The Company and the Board utilized various valuation methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation, to estimate the fair value of its common stock. Each valuation methodology included estimates and assumptions that require the Company’s judgment. These estimates and assumptions include a number of objective and subjective factors, in determining the value of the Company’s common stock at each grant date, including the following factors: (1) prices paid for the Company’s Preferred Stock, which the Company had sold to outside investors in arm’s-length transactions, and the rights, preferences, and privileges of the Company’s Preferred Stock and common stock; (2) valuations performed by an independent valuation specialist; (3) the Company’s stage of development and revenue growth; (4) the fact that the grants of stock-based awards involved illiquid securities in a private company; and (5) the likelihood of achieving a liquidity event for the common stock underlying the stock-based awards, such as an IPO or sale of the Company, given prevailing market conditions. The Company believes this methodology to be reasonable based upon the Company’s internal peer company analyses, and further supported by several arm’s-length transactions involving the Company’s Preferred Stock. As the Company’s common stock is not actively traded, the determination of fair value involves assumptions, judgments, and estimates. If different assumptions were made, stock-based compensation expense, consolidated net income (loss) and consolidated net income (loss) per share could have been significantly different. The Company has recorded stock-based compensation expense for stock options of $593 and $205 during the three months ended March 31, 2021 and 2020, respectively. The following table shows stock- based compensation expense by where the stock-based compensation expense is recorded in the Company’s unaudited condensed consolidated statement of operations: For the Three Months Ended 2021 2020 Cost of revenue $ 7 $ 5 Sales and marketing 190 27 Research and development 67 29 General and administrative 329 144 Total stock-based compensation $ 593 $ 205 As of March 31, 2021, there was $5,024 of unrecognized compensation cost related to unvested common stock option arrangements granted under the 2021 Plan, which is expected to be recognized over a weighted-average period of 3.12 years. The fair value of each option award was estimated on the date of grant using the Black-Scholes option-pricing model. As there was no public market for its common stock prior to March 25, 2021, which was the first day of trading, and as the trading history of the Company’s common stock was limited through March 31, 2021, the Company determined the expected volatility for options granted based on an analysis of reported data for a peer group of companies that issued options with substantially similar terms. The expected volatility of options granted has been determined using an average of the historical volatility measures of this peer group of companies. The expected life of options granted to employees was calculated using the simplified method, which represents the average of the contractual term of the option and the weighted-average vesting period of the option. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate expected term. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected life of the share option. The Company has not paid, nor anticipates paying, cash dividends on its ordinary shares; therefore, the expected dividend yield is assumed to be zero. The weighted-average assumptions utilized to determine the fair value of options granted to employees are presented in the following table: Three Months Ended March 31, 2021 2020 Expected volatility 52.0 % 46.7 % Weighted-average risk-free interest rate 0.58 % 1.46 % Expected dividend yield — — Expected life – in years 6 6 A summary of the Company’s option activity as of March 31, 2021, which all occurred under the Semrush Holdings, Inc. Amended and Restated 2019 Stock Option and Grant Plan (the “2019 Plan”), and changes during the three months then ended are as follows: Number of Options Weighted-Average Exercise Price (per share) Weighted-Average Remaining Contractual Term (in years) Outstanding at December 31, 2020 7,611,258 $ 1.37 8.40 Granted 34,500 6.21 Exercised (3,861) 1.35 Forfeited (50,343) 2.00 Outstanding at March 31, 2021 7,591,554 1.39 8.28 Options exercisable at March 31, 2021 3,309,264 0.94 7.60 The weighted-average grant-date fair value of options granted during the three months ended March 31, 2021 and 2020 was $9.09 and $1.70 per share, respectively. No tax benefits were realized from options during the three months ended March 31, 2021. The aggregate intrinsic value of options outstanding as of March 31, 2021 and December 31, 2020 was $79,858 and $36,816, respectively. The aggregate intrinsic value for options exercised during the three months ended March 31, 2021 was $19. No options were exercised for the three months ended March 31,2020. The aggregate intrinsic value for options exercisable as of March 31, 2021 was $36,313. The aggregate intrinsic value was calculated based on the positive difference, if any, between the estimated fair value of the Company’s common stock on March 31, 2021 and December 31, 2020, respectively, or the date of exercise, as appropriate, and the exercise price of the underlying options. On July 28, 2020, the Company issued 156,852 shares of its restricted common stock (“Restricted Stock Issuance”) to the founders of Prowly for a total fair value of $291 under the 2019 Plan. This Restricted Stock Issuance vests over a three-year service period, applicable to both founders. On March 3, 2021, the Company granted, to an employee, a restricted stock unit award for 19,500 shares of Class A common stock under the 2021 Plan. 2021 Employee Stock Purchase Plan The Semrush Holdings, Inc. 2021 Employee Stock Purchase Plan (the “ESPP”) was adopted by the Board on March 3, 2021 and approved by stockholders on March 15, 2021 and became effective

Commitment and Contingencies

Commitment and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company leases office facilities under noncancelable operating leases that expire at various dates through 2024. In addition, the Company has multi-year commitments with data centers. Some of these lease agreements contain escalating rent payments. Rent expense is recorded on a straight-line basis. Rent expense was $928 and $1,086 for the three months ended March 31, 2021 and 2020, respectively. The Company also has non-cancelable commitments related to its data centers. Future minimum amounts payable as of March 31, 2021, under the office facilities operating leases and data center agreements are as follows: Operating Leases Remainder of 2021 $ 3,070 2022 3,109 2023 1,515 2024 459 2025 and thereafter — Total minimum lease payments $ 8,153 During the year ended December 31, 2020, the Company entered into leasing arrangements for certain data center equipment under non-cancelable capital leases. The leasing arrangements have terms of 36 months beginning on the date the Company accepts the installation of the equipment subject to the lease. As of December 31, 2020, the equipment had not been installed and the Company had not accepted the equipment under these leases, and as such the lease commencement date had not begun. During the three months ended March 31, 2021, a portion of the equipment was installed and the related lease commenced. The Company is required to make total payments of $6,045 over the term of the leases which is excluded from the table above. The Company recorded $1,024 in capital leases to property and equipment, net, as of March 31, 2021 (see Note 3), which is being depreciated over the lease term of 36 months. The $1,024 of capital leases represents the total balance of other-long term liabilities on the unaudited condensed consolidated balance sheet as of March 31, 2021. In addition to the lease commitments above, the Company also has multi-year commitments with certain data providers. The Company is committed to spend approximately $4,124, $6,776, and $1,933 for the remainder of the year ending December 31, 2021, and for the years ending December 31, 2022, and 2023, respectively, for data services. Litigation The Company, from time to time, may be party to litigation arising in the ordinary course of its business. The Company was not subject to any material legal proceedings during the three months ended March 31, 2021, and, to the best of its knowledge, no material legal proceedings are currently pending or threatened. Indemnification The Company typically enters into indemnification agreements with customers in the ordinary course of business. Pursuant to these agreements, the Company indemnifies and agrees to reimburse the indemnified party for losses suffered or incurred as a result of claims of intellectual property infringement. These indemnification agreements are provisions of the applicable customer agreement. Based on when clients first sign an agreement for the Company’s service, the maximum potential amount of future payments the Company could be required to make under certain of these indemnification agreements is unlimited. Based on historical experience and information known as of March 31, 2021, the Company has not incurred any costs for the above guarantees and indemnities. In certain circumstances, the Company warrants that its services will perform in all material respects in accordance with its standard published specification documentation in effect at the time of delivery of the services to the customer for the term of the agreement. To date, the Company has not incurred significant expense under its warranties and, as a result, the Company believes the estimated fair value of these agreements is immaterial.

Components of Other Income, Net

Components of Other Income, Net	3 Months Ended
	Mar. 31, 2021
Other Income and Expenses [Abstract]
Components of Other Income, Net	Components of Other Income, Net The components of other income, net, are as follows: For the Three Months Ended 2021 2020 Foreign currency exchange gain (loss) 44 (107) Other, net 7 163 Other income, net $ 51 $ 56

Employee Benefit Plan

Employee Benefit Plan	3 Months Ended
	Mar. 31, 2021
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit PlanThe Company maintains a defined contribution savings plan under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”) covering all U.S. employees who satisfy certain eligibility requirements. The 401(k) Plan allows each participant to defer a percentage of their eligible compensation subject to applicable annual limits pursuant to the limits established by the Internal Revenue Service. The Company may, at the discretion of the Board, make contributions in the form of matching contributions or profit-sharing contributions. For the three months ended March 31, 2021 and 2020, the Company made matching contributions of $90 and $34, respectively, to the 401(k) Plan.

Segment and Geographic Informat

Segment and Geographic Information	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment and Geographic Information	Segment and Geographic InformationDisclosure requirements about segments of an enterprise and related information establishes standards for reporting information regarding operating segments in annual financial statements and requires selected information of those segments to be presented in interim financial reports issued to shareholders. Operating segments are defined as components of an enterprise about which separate discrete financial information is available that is evaluated regularly by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the chief executive officer. The Company and the chief executive officer view the Company’s operations and manage its business as one operating segment. Geographic Data The Company allocates, for the purpose of geographic data reporting, its revenue based upon the location of the customer. Total revenue by geographic area was as follows: For the Three Months Ended 2021 2020 Revenue: United States $ 18,132 $ 12,886 United Kingdom 4,195 2,994 Other 17,671 11,907 Total revenue $ 39,998 $ 27,787 Property and equipment, net by geographic location consists of the following: As of March 31, December 31, Property and equipment, net: United States $ 2,020 $ 1,023 Russia 1,360 1,450 Czech Republic 440 439 Other 56 56 Total assets $ 3,876 $ 2,968

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has completed an evaluation of all subsequent events after the balance sheet date of March 31, 2021 through the date this Quarterly Report on Form 10-Q was filed with the SEC, to ensure that this filing includes appropriate disclosure of events both recognized in the financial statements as of March 31, 2021, and events which occurred subsequently but were not recognized in the financial statements. The Company has concluded that no subsequent events have occurred that require disclosure, except as disclosed within these financial statements and except as disclosed below. Exercise of Overallotment Option On April 20, 2021, the underwriters of the Company’s IPO partially exercised their option to purchase additional shares of Class A common stock. In connection with the closing of the partial exercise on April 23, 2021, the underwriters purchased 719,266 shares of the Company’s Class A common stock for net proceeds to the Company of $9.4 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual consolidated financial statements as of and for the year ended December 31, 2020, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of March 31, 2021, and the results of its operations and its cash flows for the three months ended March 31, 2021 and 2020. The consolidated balance sheet as of December 31, 2020 included herein was derived from the audited financial statements as of that date. The results for the three months ended March 31, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021, any other interim periods, or any future year or period. The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company’s final prospectus dated March 24, 2021 (the “Prospectus”) as filed with the SEC on March 25, 2021 pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the “Securities Act”). The accompanying unaudited condensed consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the unaudited condensed consolidated financial statements. As of March 31, 2021, there have been no material changes in the Company's significant accounting policies from those that were disclosed in the Prospectus except as discussed below.
Principles of Consolidation	Principles of ConsolidationThe unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. Significant estimates relied upon in preparing these financial statements include, but are not limited to, revenue recognition, expected future cash flows used to evaluate the recoverability of long-lived assets, contingent liabilities, expensing and capitalization of research and development costs for internal-use software, the average period of benefit associated with costs capitalized to obtain revenue contracts, the determination of the fair value of stock-based awards issued, stock-based compensation expense, and the recoverability of the Company’s net deferred tax assets and related valuation allowance. Although the Company regularly assesses these estimates, actual results could differ materially from these estimates. Changes in estimates are recorded in the period in which they become known. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results may differ from management’s estimates if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made.
Subsequent Events Considerations	Subsequent Events Considerations The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated as required. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure, other than those disclosed in this Quarterly Report on Form 10-Q.
Revenue Recognition	Revenue Recognition The Company derives revenue from two sources: (1) subscription revenues via the Semrush Online Visibility Management Platform and the Prowly Public Relations Platform, which are comprised of subscription fees from customers accessing the Company’s SaaS services and related customer support; and (2) the Semrush Marketplace, which allows customers to pay a set fee for services or products offered through the marketplace. The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”). Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration it expects to receive in exchange for those products or services. There were no changes to the Company’s revenue recognition policies since the filing of the Prospectus. For the three months ended March 31, 2021 and 2020, subscription revenue accounted for nearly all of the Company’s revenue. Revenue related to the Semrush Marketplace was not material for the three months ended March 31, 2021 and 2020. Amounts that have been invoiced are recorded in accounts receivable and in deferred revenue or revenue, depending on whether the revenue recognition criteria have been met. The Company primarily invoices and collects payments from customers for its services in advance on a monthly or annual basis. Deferred revenue represents amounts billed for which revenue has not yet been recognized. Deferred revenue that will be recognized during the succeeding 12-month period is recorded as current deferred revenue, and the remaining portion is recorded as long-term deferred revenue. Deferred revenue increased by $5,599 as of March 31, 2021 compared December 31, 2020. During the three months ended March 31, 2021 and 2020, $13,303 and $9,583 of revenue was recognized that was included in deferred revenue at the beginning of each respective period. The Company has elected to exclude amounts charged to customers for sales tax from the transaction price. Accordingly, revenue is presented net of any sales tax collected from customers. Transaction Price Allocated to Future Performance Obligations ASC 606 requires that the Company disclose the aggregate amount of the transaction price that is allocated to performance obligations that have not yet been satisfied as of the balance sheet dates reported. For contracts with an original expected duration greater than one year, the aggregate amount of the transaction price allocated to the performance obligations that were unsatisfied as of March 31, 2021 and December 31, 2020 was $866 and $1,280, respectively, which the Company expects to recognize over the next 12 months. For contracts with an original expected duration of one year or less, the Company has applied the practical expedient available under ASC 606 to not disclose the amount of transaction price allocated to unsatisfied performance obligations as of March 31, 2021 and December 31, 2020. For performance obligations not satisfied as of March 31, 2021 and December 31, 2020, and to which this expedient applies, the nature of the performance obligations is consistent with performance obligations satisfied as of December 31, 2019. The remaining durations are less than one year. Costs to Obtain a Contract The incremental direct costs of obtaining a contract, which primarily consist of sales commissions paid for new subscription contracts, are deferred and recorded as deferred contract costs in the
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid instruments purchased with an original maturity date of 90 days or less from the date of purchase to be cash equivalents. Management determines the appropriate classification of investments at the time of purchase and re-evaluates such determination at each balance sheet date.
Concentrations of Credit Risk and Significant Customers	Concentrations of Credit Risk and Significant Customers The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other hedging arrangements. Credit losses historically have not been significant and the Company generally has not experienced any material losses related to receivables from individual customers, or groups of customers. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company's accounts receivable. Credit risk with respect to accounts receivable is dispersed due to the large number of customers of the Company. The Company routinely assesses the creditworthiness of its customers and generally does not require its customers to provide collateral or other security to support accounts receivable. Credit losses historically have not been significant and the Company generally has not experienced any material losses related to receivables from individual customers, or groups of customers. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company's accounts receivable.
Disclosure of Fair Value of Financial Instruments and Fair Value Measurements	Disclosure of Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses, approximated their fair values at March 31, 2021 and December 31, 2020, due to the short-term nature of these instruments. The Company has evaluated the estimated fair value of financial instruments using available market information. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. See below for further discussion. Fair Value Measurements ASC 820, Fair Value Measurements and Disclosures (“ASC 820”), establishes a three-level valuation hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are those that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. This guidance further identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants based on the highest and best use of the asset or liability. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The Company uses valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs are prioritized as follows: Level 1 inputs—Unadjusted observable quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 inputs—Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 inputs—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company evaluates assets and liabilities subject to fair value measurements on a recurring and nonrecurring basis to determine the appropriate level to classify them for each reporting period. Cash equivalents include money market funds with original maturities of 90 days or less from the date of purchase. The fair value measurement of these assets is based on quoted market prices in active markets for identical assets and, therefore, these assets are recorded at fair value on a recurring basis and classified as Level 1 in the fair value hierarchy. As of March 31, 2021 and December 31, 2020, cash equivalents held in money market funds totaled $35,505 and $29,369, respectively. As of March 31, 2021, the Company measured its investments in convertible notes (see Note 4) and its contingent consideration associated with the acquisition of Prowly.com sp. z o.o (“Prowly”) on a recurring basis using significant unobservable inputs (Level 3) and did not have any assets or liabilities measured at fair value on a recurring basis using significant other observable inputs (Level 2). Changes in fair value of the convertible notes were not material for the three months ended March 31, 2021 due to the short time period between when the investment was made and the balance sheet date. Changes in fair value of the contingent consideration associated with the Prowly acquisition were not material for the three months ended March 31, 2021. As of December 31, 2020, the Company did not have any assets or liabilities measured at fair value on a recurring basis using significant other observable inputs (Level 2).
Foreign Currency Translation	Foreign Currency TranslationThe Group operates in a multi-currency environment having transactions in such currencies as the U.S. dollar, Russian rubles, Czech koruna, euros, and others. The reporting currency of the Company is the U.S. dollar. The functional currency of the Company’s foreign subsidiaries is the U.S. dollar, with the exception of Prowly, where the functional currency is the local currency, the Zloty. The foreign currency translation adjustment as it relates to Prowly was immaterial for the three months ended March 31, 2021 and 2020. For all other entities, foreign currency transactions are measured initially in the functional currency of the recording entity by use of the exchange rate in effect at that date. At each subsequent balance sheet date, foreign currency denominated assets and liabilities of these international subsidiaries are remeasured into U.S. dollars using the exchange rates in effect at the balance sheet date or historical rates, as appropriate. Any differences resulting from the remeasurement of foreign denominated assets and liabilities of the international subsidiaries to the U.S. dollar functional currency are recorded within other income (expense) in the unaudited condensed consolidated statement of operations and comprehensive loss.
Net Income (Loss) Per Share	Net Income (Loss) Per Share Net income (loss) per share information is determined using the two-class method, which includes the weighted-average number of shares of common stock outstanding during the period and other securities that participate in dividends (a participating security). Prior to the completion of the IPO, the Company considered the shares of Preferred Stock to be participating securities because they include rights to participate in dividends with the common stock. As of March 31, 2021, the Company did not have any participating securities outstanding. Under the two-class method, basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net income (loss) per share attributable to common stockholders is computed using the more dilutive of (1) the two-class method or (2) the if-converted method. The Company allocates net income first to preferred stockholders based on dividend rights under the Company’s certificate of incorporation and then to preferred and common stockholders based on ownership interests. Net losses are not allocated to preferred stockholders as they do not have an obligation to share in the Company’s net losses. During the three months ended March 31, 2021, the Company amended its certificate of incorporation to create two classes of common stock outstanding: Class A common stock and Class B common stock. As more fully described in Note 9, the rights of the holders of Class A and Class B common stock are identical, except with respect to voting and conversion. Each share of Class A common stock is entitled to one (1) vote per share and each share of Class B common stock is entitled to ten (10) votes per share. Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder at any time. Shares of Class B common stock are automatically converted into Class A common stock upon sale or transfer, subject to certain limited exceptions. Shares of Class A common stock are not convertible. See Note 9 to these unaudited condensed consolidated financial statements for additional information regarding the current conversion and transfer terms of the Company’s common stock. The Company allocates undistributed earnings attributable to common stock between the common stock classes on a one to one basis when computing net income (loss) per share. As a result, basic and diluted net income (loss) per share of Class A common stock and share of Class B common stock are equivalent. Diluted net income (loss) per share gives effect to all potentially dilutive securities. Potential dilutive securities consist of shares of common stock issuable upon the exercise of stock options, shares of common stock issuable upon the conversion of the outstanding shares of Preferred Stock, and shares of common stock issuable upon the vesting of restricted stock awards or restricted stock units. For the three months ended March 31, 2021, dilutive net income per share was calculated by dividing net income by the weighted-average number of shares of common stock outstanding during the period, the dilutive impact of stock options, shares of common stock issuable upon the vesting of RSUs, and the dilutive impact of shares issuable upon the conversion of the outstanding shares of Preferred Stock. For the three months ended March 31, 2020, the net loss attributable to common stockholders is divided by the weighted-average number of shares of common stock outstanding during the period to calculate diluted earnings per share. The dilutive effect of common stock equivalents has been excluded from the calculation for the three months ended March 31, 2020 as their effect would have been anti-dilutive due to the net losses incurred for the period.
Comprehensive income (loss)	Comprehensive income (loss)Comprehensive income (loss) is comprised of two components: net income (loss) and other comprehensive income (loss), which includes other changes in stockholders’ deficit that result from transactions and economic events other than those with stockholders. The Company had no items qualifying as other comprehensive income (loss) with the exception of an immaterial cumulative translation adjustment related to the Prowly entity and an immaterial fair-value adjustment related to the convertible note investments; accordingly, comprehensive income (loss) equaled total net loss for the three months ended March 31, 2021 and 2020.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) . ASU 2016-02 requires a lessee to recognize most leases on the balance sheet but recognize expenses on the income statement in a manner similar to current practice. The update states that a lessee will recognize a lease liability for the obligation to make lease payments and a right-to-use asset for the right to use the underlying assets for the lease term. Leases will continue to be classified as either financing or operating, with classification affecting the recognition, measurement, and presentation of expenses and cash flows arising from a lease. For public entities, ASU 2016-02 is effective for years beginning after December 15, 2019. For non-public companies, ASU 2016-02 is effective for fiscal years beginning after December 15, 2021 and interim periods in annual periods beginning after December 15, 2022. Early adoption is permitted. The Company plans to adopt this guidance in the year ended December 31, 2022. The Company is currently assessing the impact that adopting this guidance will have on its consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . ASU 2016-13 requires that credit losses be reported as an allowance using an expected losses model, representing the entity's current estimate of credit losses expected to be incurred. The accounting guidance currently in effect is based on an incurred loss model. ASU 2016-13 affect loans, debt securities, trade receivables, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. ASU 2016-13 is effective for public entities for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years. For non-public companies, ASU 2016-13 is effective for fiscal years beginning after December 15, 2020, and interim periods within fiscal years beginning after December 15, 2021. The Company plans to adopt this guidance in the year ended December 31, 2021. The Company is currently evaluating ASU 2016-13 and the potential impact on its condensed consolidated financial statements and financial statement disclosures. In August 2018, the FASB issued ASU No. 2018-15, Intangible-Goodwill and Other Internal-Use Software (Subtopic 350-40) . ASU 2018-15 updates guidance regarding accounting for implementation costs associated with a cloud computing arrangement that is a service contract. The amendments under ASU 2018-15 are effective for public entities for years beginning after December 15, 2019, and interim periods within those years. For non-public companies, ASU 2081-15 is effective for annual reporting periods beginning after December 15, 2020, and interim periods within annual periods beginning after December 15, 2021, with early adoption permitted. The Company plans to adopt this guidance in the year ended December 31, 2021. The Company is currently assessing the impact that adopting this guidance will have on its condensed consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, Income Taxes – Simplifying the Accounting for Income Taxes . The new guidance simplifies the accounting for income taxes by removing several exceptions in the current standard and adding guidance to reduce complexity in certain areas, such as requiring that an entity reflect the effect of an enacted change in tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. For public companies, the ASU is effective for years beginning after December 15, 2020, and interim periods within those years,

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Reconciliation of Cash, Equivalents and Restricted Cash	The following table is a reconciliation of cash, cash equivalents and restricted cash included in the accompanying condensed consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash included in the accompanying condensed consolidated statements of cash flows for the three months ended March 31, 2021 and 2020. March 31, 2021 March 31, 2020 Cash and cash equivalents $ 171,867 $ 36,599 Restricted cash included in “prepaid expenses and other current assets” and “other long-term assets,” respectively 88 88 $ 171,955 $ 36,687
Reconciliation of Cash, Equivalents and Restricted Cash	The following table is a reconciliation of cash, cash equivalents and restricted cash included in the accompanying condensed consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash included in the accompanying condensed consolidated statements of cash flows for the three months ended March 31, 2021 and 2020. March 31, 2021 March 31, 2020 Cash and cash equivalents $ 171,867 $ 36,599 Restricted cash included in “prepaid expenses and other current assets” and “other long-term assets,” respectively 88 88 $ 171,955 $ 36,687
Schedule of Earnings Per Share, Basic and Diluted	The following table presents a reconciliation of the weighted-average shares outstanding used in the calculation of basic and diluted net income (loss) per share: Three Months Ended March 31, 2021 2020 Weighted-average shares outstanding: Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—basic 96,375,531 94,592,700 Dilutive effect of share equivalents resulting from stock options 6,151,361 — Dilutive effect of share equivalents resulting from RSAs 123,841 — Dilutive effect of shares issuable upon conversion of preferred stock 28,705,360 — Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—diluted 131,356,093 94,592,700
Schedule of Potentially Dilutive Common Stock Equivalents	The following potentially dilutive common stock equivalents have been excluded from the calculation of diluted weighted-average shares outstanding for the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 2020 Stock options outstanding — 6,286,357 Shares of Preferred Stock — 29,695,200 Restricted stock units outstanding 1,733 —

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consists of the following (in thousands): As of March 31, December 31, Computer equipment $ 3,383 $ 3,513 Furniture and office equipment 877 1,041 Leasehold improvements 1,142 667 Capital leases 1,024 — Total property and equipment 6,426 5,221 Less: accumulated depreciation and amortization (2,550) (2,253) Property and equipment, net $ 3,876 $ 2,968

Acquisitions, Acquired Intang_2

Acquisitions, Acquired Intangible Assets, and Goodwill (Tables)	3 Months Ended
	Mar. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Schedule of Intangible Assets	Intangible assets consists of the following: As of March 31, 2021 Gross Net Carrying Accumulated Carrying Amount Amortization Amount Developed technology 1,194 (109) 1,085 Trade name 68 (9) 59 Capitalized internal-use software 1,684 (652) 1,032 Total as of March 31, 2021 $ 2,946 $ (770) $ 2,176 As of December 31, 2020 Gross Net Carrying Accumulated Carrying Amount Amortization Amount Developed technology 1,194 (66) 1,128 Trade name 68 (3) 65 Capitalized internal-use software 1,561 (523) 1,038 Total as of December 31, 2020 $ 2,823 $ (592) $ 2,231
Schedule of Future Amortization Expense	As of March 31, 2021, future amortization expense is expected to be as follows: Amount Remainder of 2021 $ 519 2022 559 2023 428 2024 199 2025 and thereafter 471 Total $ 2,176

Payables and Accruals (Tables)

Payables and Accruals (Tables)	3 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued expenses	Accrued expenses consist of the following: As of March 31, December 31, Employee compensation $ 4,776 $ 4,478 Vacation reserves 464 465 Other current liabilities 5,046 2,776 Total accrued expenses $ 10,286 $ 7,719

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Tables)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Common Stock Reserved For Future Issuance	As of March 31, 2021, the Company had reserved the following shares of common stock for future issuance: Options outstanding 7,591,554 Options reserved for future issuance 13,483,501 Restricted stock outstanding 156,852 Restricted stock units 19,500 Total authorized shares of common stock reserved for future issuance 21,251,407

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-based Compensation Expense	The following table shows stock- based compensation expense by where the stock-based compensation expense is recorded in the Company’s unaudited condensed consolidated statement of operations: For the Three Months Ended 2021 2020 Cost of revenue $ 7 $ 5 Sales and marketing 190 27 Research and development 67 29 General and administrative 329 144 Total stock-based compensation $ 593 $ 205
Weighted-Average Assumptions to Determine Fair Value	The weighted-average assumptions utilized to determine the fair value of options granted to employees are presented in the following table: Three Months Ended March 31, 2021 2020 Expected volatility 52.0 % 46.7 % Weighted-average risk-free interest rate 0.58 % 1.46 % Expected dividend yield — — Expected life – in years 6 6
Summary of Option Activity	A summary of the Company’s option activity as of March 31, 2021, which all occurred under the Semrush Holdings, Inc. Amended and Restated 2019 Stock Option and Grant Plan (the “2019 Plan”), and changes during the three months then ended are as follows: Number of Options Weighted-Average Exercise Price (per share) Weighted-Average Remaining Contractual Term (in years) Outstanding at December 31, 2020 7,611,258 $ 1.37 8.40 Granted 34,500 6.21 Exercised (3,861) 1.35 Forfeited (50,343) 2.00 Outstanding at March 31, 2021 7,591,554 1.39 8.28 Options exercisable at March 31, 2021 3,309,264 0.94 7.60

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Amounts Payable Under Operating Leases	Future minimum amounts payable as of March 31, 2021, under the office facilities operating leases and data center agreements are as follows: Operating Leases Remainder of 2021 $ 3,070 2022 3,109 2023 1,515 2024 459 2025 and thereafter — Total minimum lease payments $ 8,153

Components of Other Income, N_2

Components of Other Income, Net (Tables)	3 Months Ended
	Mar. 31, 2021
Other Income and Expenses [Abstract]
Summary of Components of Other Income, Net	The components of other income, net, are as follows: For the Three Months Ended 2021 2020 Foreign currency exchange gain (loss) 44 (107) Other, net 7 163 Other income, net $ 51 $ 56

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Total Revenue by Geographic Area	Total revenue by geographic area was as follows: For the Three Months Ended 2021 2020 Revenue: United States $ 18,132 $ 12,886 United Kingdom 4,195 2,994 Other 17,671 11,907 Total revenue $ 39,998 $ 27,787
Property and Equipment, Net by Geographic Location	Property and equipment, net by geographic location consists of the following: As of March 31, December 31, Property and equipment, net: United States $ 2,020 $ 1,023 Russia 1,360 1,450 Czech Republic 440 439 Other 56 56 Total assets $ 3,876 $ 2,968

Overview and Basis of Present_2

Overview and Basis of Presentation (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 29, 2021	Mar. 31, 2021	Mar. 31, 2020
Sale of Stock [Line Items]
Issuance costs		$ 0	$ 16
Class A Common Stock
Sale of Stock [Line Items]
Issuance costs		$ 13,378
Number of shares issued in conversion (in shares)		1
Class B Common Stock
Sale of Stock [Line Items]
Number of shares issued in conversion (in shares)		1
IPO | Class A Common Stock
Sale of Stock [Line Items]
Stock sold (shares)	10,000,000
Price per share (usd per share)	$ 14
Net proceeds	$ 126,600
Issuance costs	$ 13,400

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)voteshares	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Increase in deferred revenue	$ 5,599	$ 1,654
Revenue recognized that was included in deferred revenue at the beginning of each period	$ 13,303	9,583
Amortization period of deferred contract costs	24 months
Restricted cash	$ 88	88	$ 88
Money market funds	35,505		29,369
Foreign currency exchange gain (loss)	$ 44	$ (107)
Allocable basis to compute net income (loss) per share | shares	1
Class A Common Stock
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Number of votes per share of common stock held | vote	1
Number of shares issued in conversion (in shares) | shares	1
Class B Common Stock
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Number of votes per share of common stock held | vote	10
Number of shares issued in conversion (in shares) | shares	1
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Aggregate amount of transaction price			$ 1,280
Remaining performance obligation, expected timing of satisfaction			12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Aggregate amount of transaction price	$ 866
Remaining performance obligation, expected timing of satisfaction		12 months

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 171,867	$ 35,531	$ 36,599
Restricted cash included in “prepaid expenses and other current assets” and “other long-term assets,” respectively	88	88	88
Cash, cash equivalents and restricted cash	$ 171,955	$ 35,619	$ 36,687	$ 37,523

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Reconciliation of the Numerator and Denominator Used in the Calculation of Basic and Diluted Net Income (Loss) Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Weighted-average shares outstanding:
Weighted-average number of shares of common stock used in computing net income per share attributable to common stockholders—basic (in shares)	96,375,531	94,592,700
Dilutive effect of shares issuable upon conversion of preferred stock	28,705,360	0
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—diluted (in shares)	131,356,093	94,592,700
Stock options outstanding
Weighted-average shares outstanding:
Dilutive effect of share equivalents resulting (in shares)	6,151,361	0
Restricted stock units
Weighted-average shares outstanding:
Dilutive effect of share equivalents resulting (in shares)	123,841	0

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Potentially Dilutive Common Stock Equivalents (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock options outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents	0	6,286,357
Shares of Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents	0	29,695,200
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents	1,733	0

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment	$ 6,426		$ 5,221
Less: accumulated depreciation and amortization	(2,550)		(2,253)
Property and equipment, net	3,876		2,968
Depreciation	344	$ 203
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	3,383		3,513
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	877		1,041
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	1,142		667
Capital leases
Property, Plant and Equipment [Line Items]
Property and equipment	$ 1,024		$ 0

Other Long-Term Assets - Debt O

Other Long-Term Assets - Debt Offering Costs (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred offering costs, IPO	$ 0	$ 1,839
Deferred offering costs, credit facility	$ 578	$ 630

Other Long-Term Assets - Invest

Other Long-Term Assets - Investments in Convertible Debt (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2021USD ($)investment	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Number of convertible debt securities purchased | investment	2
Investment in convertible debt securities | $	$ 500	$ 500	$ 0
Investment interest rate	6.00%

Acquisitions, Acquired Intang_3

Acquisitions, Acquired Intangible Assets, and Goodwill - Acquisition (Details) - USD ($) $ in Thousands	Aug. 27, 2020	Mar. 31, 2021
Business Acquisition [Line Items]
Compensation expense related to the acquisition		$ 56
Prowly
Business Acquisition [Line Items]
Outstanding capital acquired	100.00%
Cash consideration for acquisition	$ 3,317
Maximum additional consideration payable	$ 2,750

Acquisitions, Acquired Intang_4

Acquisitions, Acquired Intangible Assets, and Goodwill - Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 2,946	$ 2,823
Accumulated amortization	(770)	(592)
Net carrying amount	2,176	2,231
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,194	1,194
Accumulated amortization	(109)	(66)
Net carrying amount	1,085	1,128
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	68	68
Accumulated amortization	(9)	(3)
Net carrying amount	59	65
Capitalized internal-use software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,684	1,561
Accumulated amortization	(652)	(523)
Net carrying amount	$ 1,032	$ 1,038

Acquisitions, Acquired Intang_5

Acquisitions, Acquired Intangible Assets, and Goodwill - Intangible Assets Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Net carrying amount	$ 2,176		$ 2,231
Amortization expense	55
Software development
Acquired Finite-Lived Intangible Assets [Line Items]
Capitalized software development costs	123	$ 200
Amortization expense associated with capitalized development costs	129	$ 52
Net carrying amount	$ 1,032		$ 1,038

Acquisitions, Acquired Intang_6

Acquisitions, Acquired Intangible Assets, and Goodwill - Amortization (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Business Combination and Asset Acquisition [Abstract]
Amortization expense	$ 55
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2021	519
2022	559
2023	428
2024	199
2025 and thereafter	471
Net carrying amount	$ 2,176	$ 2,231

Acquisitions, Acquired Intang_7

Acquisitions, Acquired Intangible Assets, and Goodwill - Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Business Combination and Asset Acquisition [Abstract]
Change in carrying value of goodwill	$ 0
Goodwill	$ 1,991	$ 1,991

Payables and Accruals (Details)

Payables and Accruals (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Employee compensation	$ 4,776	$ 4,478
Vacation reserves	464	465
Other current liabilities	5,046	2,776
Total accrued expenses	$ 10,286	$ 7,719

Revolving Credit Facility (Deta

Revolving Credit Facility (Details) - JPMorgan Chase Bank, N.A. - USD ($)	Jan. 12, 2021	Mar. 31, 2021
Revolving credit facility
Line of Credit Facility [Line Items]
Fee on undrawn amounts	0.25%
Interest expense		$ 53,000
Revolving credit facility | JP Morgan Chase Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 45,000,000
Advance rate	400.00%
Term	3 years
Revolving credit facility | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Variable interest rate floor	0.50%
Margin on variable interest rate	2.75%
Margin on variable interest rate, prior to initial public offering or positive adjusted EBITDA	3.50%
Revolving credit facility | Base Rate
Line of Credit Facility [Line Items]
Variable interest rate floor	3.25%
Variable interest rate floor, prior to initial public offering or positive adjusted EBITDA	1.50%
Margin on variable interest rate	0.00%
Margin on variable interest rate, prior to initial public offering or positive adjusted EBITDA	2.50%
Letter of credit sub-facility | JP Morgan Chase Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 5,000,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 86	$ 116

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock and Stockholders’ Equity - Additional Information (Details)	Mar. 28, 2021shares	Mar. 31, 2021vote$ / sharesshares	Dec. 31, 2020$ / sharesshares
Class of Stock [Line Items]
Redeemable convertible preferred stock, authorized (shares)			9,898,400
Preferred stock, conversion ratio	3
Conversion of Preferred Stock (in shares)	29,695,200
Common stock, authorized (shares)		0	300,000,000
Common stock, par value (usd per share) | $ / shares		$ 0.00001	$ 0.00001
Preferred stock, authorized (shares)		100,000,000
Preferred stock, par value (usd per share) | $ / shares		$ 0.00001
Percentage of votes required		0.6666
Anniversary of effectiveness		7 years
Percentage of outstanding shares		0.10
Conversion ratio	3
Series A redeemable convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock, authorized (shares)		0	3,379,400
Series A-1 redeemable convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock, authorized (shares)		0	1,837,600
Series B convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock, authorized (shares)			4,681,400
Preferred stock, authorized (shares)		0	4,681,400
Preferred stock, par value (usd per share) | $ / shares		$ 0.00001	$ 0.00001
Class A Common Stock
Class of Stock [Line Items]
Common stock, authorized (shares)		1,000,000,000	0
Common stock, par value (usd per share) | $ / shares		$ 0.00001	$ 0.00001
Number of votes per share of common stock held | vote		1
Number of shares issued in conversion (in shares)		1
Class B Common Stock
Class of Stock [Line Items]
Common stock, authorized (shares)		160,000,000	0
Common stock, par value (usd per share) | $ / shares		$ 0.00001	$ 0.00001
Number of votes per share of common stock held | vote		10
Number of shares issued in conversion (in shares)		1

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock and Stockholders’ Equity - Common Stock Reserved for Future Issuance (Details)	Mar. 31, 2021shares
Class of Stock [Line Items]
Total authorized shares of common stock reserved for future issuance	21,251,407
Options outstanding
Class of Stock [Line Items]
Total authorized shares of common stock reserved for future issuance	7,591,554
Options reserved for future issuance
Class of Stock [Line Items]
Total authorized shares of common stock reserved for future issuance	13,483,501
Restricted stock units outstanding
Class of Stock [Line Items]
Total authorized shares of common stock reserved for future issuance	156,852
Restricted stock units
Class of Stock [Line Items]
Total authorized shares of common stock reserved for future issuance	19,500

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	Mar. 03, 2021	Jul. 28, 2020	Jul. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-based compensation				$ 593,000	$ 205,000
Unrecognized compensation cost				$ 5,024,000
Unrecognized compensation cost, period of recognition				3 years 1 month 13 days
Expected dividend yield				0.00%	0.00%
Weighted-average grant date fair value of options granted (usd per share)				$ 9.09	$ 1.70
Aggregate intrinsic value of options outstanding				$ 79,858,000		$ 36,816,000
Aggregate intrinsic value of options exercised				19,000	$ 0
Aggregate intrinsic value of options exercisable				$ 36,313,000
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (shares)	19,500	156,852
Fair value of awards granted		$ 291,000
Service period		3 years
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved and authorized (shares)				3,000,667
Percent of outstanding shares				1.00%
2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved and authorized (shares)			10,163,772				8,682,600
Award vesting period			4 years
Award expiration period			10 years
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved and authorized (shares)				13,503,001
Percent of outstanding shares				5.00%

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 593	$ 205
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	7	5
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	190	27
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	67	29
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 329	$ 144

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value Assumptions (Details)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Expected volatility	52.00%	46.70%
Weighted-average risk-free interest rate	0.58%	1.46%
Expected dividend yield	0.00%	0.00%
Expected life – in years	6 years	6 years

Stock-Based Compensation - Opti

Stock-Based Compensation - Options Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Number of Options
Outstanding (shares)	7,611,258
Granted (shares)	34,500
Exercised (shares)	(3,861)
Forfeited (shares)	(50,343)
Outstanding (shares)	7,591,554	7,611,258
Options exercisable (shares)	3,309,264
Weighted-Average Exercise Price
Outstanding (usd per share)	$ 1.37
Granted (usd per share)	6.21
Exercised (usd per share)	1.35
Forfeited (usd per share)	2
Outstanding (usd per share)	1.39	$ 1.37
Options exercisable (usd per share)	$ 0.94
Weighted-Average Remaining Contractual Term
Outstanding	8 years 3 months 10 days	8 years 4 months 24 days
Options exercisable	7 years 7 months 6 days

Commitment and Contingencies -

Commitment and Contingencies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Other Commitments [Line Items]
Rent expense	$ 928	$ 1,086
Total required lease payments	8,153
Property and equipment	6,426		$ 5,221
Data provider
Other Commitments [Line Items]
Committed spending amount for the remainder of the year	4,124
Committed spending amount for year two	6,776
Committed spending amount for year three	$ 1,933
Data center equipment
Other Commitments [Line Items]
Lease arrangement term	36 months
Total required lease payments	$ 6,045
Capital leases
Other Commitments [Line Items]
Property and equipment	$ 1,024		$ 0
Depreciation period	36 months

Commitment and Contingencies _2

Commitment and Contingencies - Future Minimum Amounts Payable Under Operating Leases (Details) $ in Thousands	Mar. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2021	$ 3,070
2022	3,109
2023	1,515
2024	459
2025 and thereafter	0
Total minimum lease payments	$ 8,153

Components of Other Income, N_3

Components of Other Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Income and Expenses [Abstract]
Foreign currency exchange gain (loss)	$ 44	$ (107)
Other, net	7	163
Other income, net	$ 51	$ 56

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Retirement Benefits [Abstract]
Matching contributions	$ 90	$ 34

Segment and Geographic Inform_3

Segment and Geographic Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)segment	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments | segment	1
Total revenue	$ 39,998	$ 27,787
Property and equipment, net	3,876		$ 2,968
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	18,132	12,886
Property and equipment, net	2,020		1,023
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	4,195	2,994
Russia
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	1,360		1,450
Czech Republic
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	440		439
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	17,671	$ 11,907
Property and equipment, net	$ 56		$ 56

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent event - Class A Common Stock - Underwriters' option $ in Millions	1 Months Ended
	May 12, 2021USD ($)shares
Subsequent Event [Line Items]
Stock sold (shares) | shares	719,266
Net proceeds | $	$ 9.4