UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE

SECURITIES EXCHANGE ACT OF 1934

Filed by the Registrant x☒

Filed by a Party other than the Registrant ¨o

Check the appropriate box:

A10 NETWORKS, INC.

(Name of Registrant as Specified In Its Charter)

Payment of Filing Fee (Check the appropriate box):

A10 NETWORKS, INC.

3 WEST PLUMERIA DRIVE

SAN JOSE, CALIFORNIA 95134

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held at 10 a.m. Pacific Time on Wednesday, June 1, 2016

December 4, 2019

Dear Stockholders of A10 Networks, Inc.:

The 20162019 annual meeting of stockholders (the “Annual Meeting”) of A10 Networks, Inc., a Delaware corporation, will be held onWednesday, June 1, 2016December 4, 2019 at 10:00 a.m. Pacific Time,, at 3 West Plumeria Drive, San Jose, California, for the following purposes, as more fully described in the accompanying proxy statement:

Our board of directors has fixed the close of business on April 7, 2016October 10, 2019 as the record date for the Annual Meeting. Only stockholders of record on April 7, 2016October 10, 2019 are entitled to notice of and to vote at the Annual Meeting. Further information regarding voting rights and the matters to be voted upon is presented in the accompanying proxy statement. If you plan on attending this year’s annual meetingthe Annual Meeting as a stockholder, please follow the instructions on page 3 of the proxy statement.

This proxy statement and our annual report can be accessed directly at the following Internet address:website: http://www.proxyvote.com. All you have to do is enter the control number located on your proxy card.

YOUR VOTE IS IMPORTANT.ESPECIALLY IMPORTANT BECAUSE PROPOSAL 2 REQUIRES THE AFFIRMATIVE VOTE OF AT LEAST 66 2/3% OF THE OUTSTANDING SHARES ENTITLED TO VOTE ON THE RECORD DATE. Whether or not you plan to attend the Annual Meeting, we urge you to submit your vote via the Internet, telephone or mail.

We appreciate your continued support of A10 Networks, Inc. and look forward to either greeting you personally at the Annual Meeting or receiving your proxy.

TABLE OF CONTENTS

A10 NETWORKS, INC.

PROXY STATEMENT

FOR 20162019 ANNUAL MEETING OF STOCKHOLDERS

To Be Held at 10:00 a.m. Pacific Time on Wednesday, June 1, 2016

December 4, 2019

This proxy statement and the enclosed form of proxy are furnished in connection with the solicitation of proxies by our board of directors for use at the 20162019 annual meeting of stockholders of A10 Networks, Inc., a Delaware corporation (the “Company”), and any postponements, adjournments or continuations thereof (the “Annual Meeting”). The Annual Meeting will be held on Wednesday, June 1, 2016December 4, 2019 at 10:00 a.m. Pacific Time, at 3 West Plumeria Drive, San Jose, California. The Notice of Internet Availability of Proxy Materials (the “Notice”) containing instructions on how to access this proxy statement and our annual report is first being mailed on or about April 15, 2016October 23, 2019 to all stockholders entitled to vote at the Annual Meeting.

The information provided in the “question and answer” format below is for your convenience only and is merely a summary of the information contained in this proxy statement. You should read this entire proxy statement carefully. Information contained on, or that can be accessed through, our website is not intended to be incorporated by reference into this proxy statement and references to our website address in this proxy statement are inactive textual references only.

QUESTIONS AND ANSWERS ABOUT THE PROXY MATERIALS AND OUR ANNUAL MEETING

What matters am I voting on?

You will be voting on:

How does the board of directors recommend I vote on these proposals?

Our board of directors recommends a vote:

Who is entitled to vote?

Holders of our common stock as of the close of business on April 7, 2016,October 10, 2019, the record date, may vote at the Annual Meeting. As of the record date, there were 64,486,09076,815,472 shares of our common stock outstanding. In deciding all matters at the Annual Meeting, each stockholder will be entitled to one vote for each share of our common stock held by them on the record date. We do not have cumulative voting rights for the election of directors.

Registered Stockholders. If shares of our common stock are registered directly in your name with our transfer agent, you are considered the stockholder of record with respect to those shares, and the Notice was provided to you directly by us. As the stockholder of record, you have the right to grant your voting proxy directly to the individuals listed on the proxy card or to vote in person at the Annual Meeting.

Street Name Stockholders. If shares of our common stock are held on your behalf in a stock brokerage account or by a bank or other nominee, you are considered the beneficial owner of those shares held in “street name,” and the Notice was forwarded to you by your broker or nominee, who is considered the stockholder of record with respect to those shares. As the beneficial owner, you have the right to direct your broker or nominee how to vote your shares. Beneficial owners are also invited to attend the Annual Meeting. However, since a beneficial owner is not the stockholder of record, you may not vote your shares of our common stock in person at the Annual Meeting unless you follow your broker’s procedures for obtaining a legal proxy. If you request a printed copy of our proxy materials by mail, your broker or nominee will provide a voting instruction card for you to use. Throughout this proxy, we refer to stockholders who hold their shares through a broker, bank or other nominee as “street name stockholders.”

How many votes are needed for approval of each proposal?

What is a quorum?

A quorum is the minimum number of shares required to be present at the Annual Meeting for the Annual Meeting to be properly held under our amended and restated bylaws and Delaware law. The presence, in person or by proxy, of a majority of all issued and outstanding shares of our common stock entitled to vote at the Annual Meeting will constitute a quorum at the Annual Meeting. Abstentions, withhold votes and broker non-votes are counted as shares present and entitled to vote for purposes of determining a quorum.

How do I vote?

If you are a stockholder of record, there are four ways to vote:

If you are a street name stockholder, you will receive voting instructions from your broker, bank or other nominee. You must follow the voting instructions provided by your broker, bank or other nominee in order to instruct your broker, bank or other nominee on how to vote your shares. Street name stockholders should generally be able to vote by returning an instruction card, or by telephone or on the Internet. However, the availability of telephone and Internet voting will depend on the voting process of your broker, bank or other nominee. As discussed above, if you are a street name stockholder, you may not vote your shares in person at the Annual Meeting unless you obtain a legal proxy from your broker, bank or other nominee.

Can I change my vote?

Yes. If you are a stockholder of record, you can change your vote or revoke your proxy any time before the Annual Meeting by:

If you are a street name stockholder, your broker, bank or other nominee can provide you with instructions on how to change your vote.

What do I need to do to attend the Annual Meeting in person?

If you plan toTo attend the meeting, you must be a holder of Company shares as of the record date of April 7, 2016. Please contactOctober 10, 2019. If you plan to attend, please notify the Company to notify of your intention to attend no later than May 31, 2016December 3, 2019 at 6:5:00 p.m. PSTPacific Time by contacting Jaime Garcia (jgarcia@a10networks.com/408-643-8105).

On the day of the meeting, each stockholderyou may be required to present a valid picture identification such as a driver’s license or passport and you may be denied admission if you do not. Please note that seating is limited. Use of cameras, recording devices, computers and other personal electronic devices will not be permitted at the Annual Meeting. Photography and video are prohibited at the Annual Meeting. 

What is the effect of giving a proxy?

Proxies are solicited by and on behalf of our board of directors. Lee Chen, Greg StraughnTom Constantino and Robert Cochran have been designated as proxies by our board of directors. When proxies are properly dated, executed and returned, the shares represented by such proxies will be voted at the Annual Meeting in accordance with the instructions of the stockholder. If no specific instructions are given, however, the shares will be voted in accordance with the recommendations of our board of directors as described above. If any matters not described

in this proxy statement are properly presented at the Annual Meeting, the proxy holders will use their own judgment to determine how to vote the shares. If the Annual Meeting is adjourned, the proxy holders can vote the shares on the new Annual Meeting date as well, unless you have properly revoked your proxy instructions, as described above.

Why did I receive a Notice of Internet Availability of Proxy Materials instead of a full set of proxy materials?

In accordance with the rules of the Securities and Exchange Commission (“SEC”), we have elected to furnishprovide our proxy materials, including this proxy statement and our annual report, primarily via the Internet. The Notice containing instructions on how to access our proxy materials is first being mailed on or about April 15, 2016October 23, 2019 to all stockholders entitled to vote at the Annual Meeting. Stockholders may request to receive all future proxy materials in printed form by mail or electronically by e-mailemail by following the instructions contained in the Notice. We encourage stockholders to take advantage of the availability of our proxy materials on the Internet to help reduce the environmental impact of our annual meetings of stockholders.

stockholder meetings.

How are proxies solicited for the Annual Meeting?

Our board of directors is soliciting proxies for use at the Annual Meeting. All expenses associated with this solicitation will be borne by us. We will reimburse brokers or other nominees for reasonable expenses that they incur in sending our proxy materials to you if a broker or other nominee holds shares of our common stock on your behalf.

How may my brokerage firm or other intermediary vote my shares if I fail to provide timely directions?

Brokerage firms and other intermediaries holding shares of our common stock in street name for customers are generally required to vote such shares in the manner directed by their customers. In the absence of timely directions, your broker will have discretion to vote your shares on our sole “routine” matter: the proposal to ratify the appointment of Deloitte & ToucheArmanino LLP. Your broker will not have discretion to vote on the election of directors or the amendment of our 2014 Employee Stock Purchase Plan, each of which is a “non-routine” matter,any other proposal absent direction from you.

Where can I find the voting results of the Annual Meeting?

We will announce preliminary voting results at the Annual Meeting. We will also disclose voting results on a Current Report on Form 8-K that we will file with the SEC within four business days after the Annual Meeting. If final voting results are not available to us in time to file a Current Report on Form 8-K within four business days after the Annual Meeting, we will file a Current Report on Form 8-K to publish preliminary results and will provide the final results in an amendment to thissuch Current Report on Form 8-K as soon as they become available.

I share an address with another stockholder, and we received only one paper copy of the proxy materials. How may I obtain an additional copy of the proxy materials?

We have adopted aan SEC-approved procedure called “householding,” which the SEC has approved. Under this procedure, weallows us to deliver a single copy of the Notice and, if applicable, our proxy materials to multiple stockholders who share the same address unless we have received contrary instructions from one or more of the stockholders. This procedure reduces our printing costs, mailing costs, and fees. Stockholders who participate in householding will continue to be able to access and receive separate proxy cards. Upon written or oral request, we will deliver promptly a separate copy of the Notice and, if applicable, our proxy materials to any stockholder at a

shared address to which we delivered a single copy of any of these materials. To receive a separate copy, or, if a stockholder is receiving multiple copies, to request that we only send a single copy of the Notice and, if applicable, our proxy materials, such stockholder may contact us at the following address:

A10 Networks, Inc.
Attention: Investor Relations

3 West Plumeria Drive
San Jose, California 95134
(408) 325-8668

Stockholders who beneficially own shares of our common stock held in streetStreet name stockholders may contact their brokerage firm, bank, broker-dealer or other similar organization to request information about householding.

What is the deadline to propose actions for consideration at next year’s annual meeting of stockholders or to nominate individuals to serve as directors?

Stockholder Proposals

Stockholders may present proper proposals for inclusion in our proxy statement and for consideration at theour next annual meeting of stockholders by submitting their proposals in writing to our Secretary in a timely manner. For a stockholder proposal to be considered for inclusion inat our proxy statement for our 20172020 annual meeting of stockholders, our Secretary must receive the written proposal at our principal executive offices notprior to certain deadlines. Those deadlines vary based upon when we actually hold our 2020 annual meeting and also whether the stockholder intends the proposal to be included in our proxy statement for the meeting.

Proposals Intended to be Included in our Proxy Statement

If we hold the 2020 annual meeting no more than 30 days before or after the one-year anniversary of this year’s Annual Meeting, then, for a stockholder proposal to be considered for inclusion in our proxy statement for the 2020 annual meeting, our Secretary must receive the written proposal at our principal executive offices no later than December 16, 2016. June 25, 2020.

If we hold the 2020 annual meeting more than 30 days before or after the one-year anniversary of this year’s Annual Meeting, then our Secretary must receive the written proposal at our principal executive offices no earlier than the 120th day before the actual date of the 2020 annual meeting and no later than the close of business on the later of the following two dates:

In addition, stockholder proposals must comply with the requirements of SEC Rule 14a-8 regarding the inclusion of stockholder proposals in company-sponsored proxy materials. Stockholder proposals should be addressed to:

A10 Networks, Inc.
Attention: Secretary

3 West Plumeria Drive

San Jose, California 95134

Proposals Not Intended to be Included in our Proxy Statement

Our amended and restated bylaws also establish an advance notice procedure for stockholders who wish to present a proposal beforeat an annual meeting of stockholders but who do not intend for the proposal to be included in our proxy statement.statement for the meeting. Our amended and restated bylaws provide that the only business that may be conducted at an annual meeting is business that is (i) specified in our proxy materials with respect to such meeting, (ii) otherwise properly brought before the annual meeting by or at the direction of our board of directors, or (iii) properly brought before the annual meeting by a stockholder of record entitled to vote at the annual meeting who has delivered timely written notice to our Secretary, which notice must contain the information specified in our amended and restatedthe bylaws. To be timely for our 2017

If we hold the 2020 annual meeting no more than 30 days before or after the one-year anniversary of stockholders,this year’s Annual Meeting, then, for a stockholder proposal to be considered at the 2020 annual meeting, our Secretary must receive the written notice at our principal executive offices:

Inoffices at the event thatabove address:

If we hold our 2017the 2020 annual meeting of stockholders more than 30 days before or more than 30 days after the one-year anniversary of thethis year’s Annual Meeting, then notice of a stockholder proposal that is not intended to be included in our proxy statementSecretary must be receivedreceive the written notice no earlier than the close of business on the 120th day before suchthe actual date of the 2020 annual meeting and no later than the close of business on the latterlater of the following two dates:

If a stockholder who has notified us of his, her or its intention to present a proposal at an annual meeting does not appear to present his, her or its proposal at such annual meeting to present such proposal, we are not required to present the proposal for a vote at such annual meeting.

Nomination of Director Candidates

You may propose director candidates for consideration by our nominating and corporate governance committee. Any such recommendations should include the nominee’s name and qualifications for membership on our board of directors and should be directed to our Secretary at the address set forth above. For additional information regarding stockholder recommendations for director candidates, see “Board of Directors and Corporate Governance—Stockholder Recommendations for Nominations to the Board of Directors.”

In addition, our amended and restated bylaws permit stockholders to nominate directors for election at an annual meeting of stockholders. To nominate a director, thea stockholder must provide the information required by our amendedbylaws and restated bylaws. In addition, the stockholder must give timely notice to our Secretary in accordance with our amended and restated bylaws, which, in general, require that the notice be received by our Secretary within the time period described above under “Stockholder Proposals” for stockholder proposals that are not intended“—Proposals Not Intended to be includedIncluded in a proxy statement.

our Proxy Statement.”

Availability of Bylaws

You may contact our Secretary at our principal executive offices for a copy of the relevant bylaw provisions regarding the requirements for making stockholder proposals and nominating director candidates.

BOARD OF DIRECTORS AND CORPORATE GOVERNANCE

Our business affairs are managed under the direction of our board of directors, which is currently composed of fivesix members. ThreeFive of our directors are independent within the meaning of the listing standards of the New York Stock Exchange. Our board of directors is divided into three staggered classes of directors. At eachour 2018 annual meeting of stockholders, our stockholders approved a classphased-in declassification of our board of directors. Accordingly, our directors in Class III will continue in office until their terms expire at our 2020 annual meeting of stockholders, at which point our board of directors will be electedcompletely declassified and all director nominees will be subject to election for a three-year termone-year term.

In July 2019, we entered into a letter agreement with VIEX Capital Advisors, LLC, VIEX Opportunities Fund, LP – Series One, VIEX Opportunities Fund, LP – Series Two, VIEX GP, LLC, VIEX Special Opportunities Fund II, LP, VIEX Special Opportunities GP II, LLC, VIEX Special Opportunities Fund III, LP, VIEX Special Opportunities GP III, LLC and Eric Singer (collectively, the “VIEX Group”), pursuant to succeedwhich we agreed, among other things, to nominate and support Mr. Singer and Tor. R. Braham for election as directors at the same class whose term is then expiring.

Annual Meeting. Subject to certain exceptions set forth in the letter agreement, the VIEX Group agreed to vote all of its shares at the Annual Meeting in a manner consistent with the recommendation of our board of directors. The Viex Group also agreed to customary standstill restrictions.

The following table sets forth the names, ages as of April 7, 2016,September 30, 2019, and certain other information for each of the directors with terms expiring at the annual meetingAnnual Meeting (who are also nominees for election as a director at the annual meeting)Annual Meeting) and for each of the continuing Class III members of our board of directors:

Peter Y. Chung has served as a member of our board of directors since June 2013. Mr. Chung is a managing directorManaging Director and the chief executive officerChief Executive Officer of Summit Partners, L.P., where he has been employed since 1994. He is currently a director of M/A-COMAcacia Communications and MACOM Technology Solutions Holdings, Inc., a provider of semiconductor solutions for use in radio frequency, microwave and millimeter wave applications, as well as several privately-held companies. Previously, Mr. Chung served as a director of Ubiquiti Networks, Inc., a company that develops networking technology. Mr. Chung has an M.B.A. from the Stanford University Graduate School of Business and an A.B. in Economics from Harvard University. Mr. Chung has specific attributes that qualify him to serve as a member of our board of directors, including his experience in investment banking, private equity and venture capital investing and in the communications technology sector, as well as his prior service on public and private company boards.

Robert CochranDr. Phillip J. Salsbury has served as our Vice President, Legal and Corporate Collaboration since January 2012 and as a member of our board of directors since May 2013. Dr. Salsbury is also our lead independent director. From 2005 to April 2012. Mr. Cochran has served as our Secretary since August 2004, and previously served on our board of directors from August 2004 to October 2004. From January 1993 to January 2012, Mr. Cochran was an attorney in private practice in Woodside, California, where he had served as our outside legal counsel since our incorporation. From 2004 to 2010, Mr. CochranDr. Salsbury served as a director of Techwell, Inc., a fabless semiconductor public company that was acquired by Intersil Corporation. Mr. Cochran also serves asDr. Salsbury was a directorfounder, the Chief Technology Officer, and later the president and Chief Executive Officer of two privately-held companies. Mr. Cochran hasSEEQ Technology, Inc., a J.D.non-volatile memory and Ethernet communications semiconductor company, from Harvard Law SchoolJanuary 1981 until its acquisition by LSI Logic Corporation, a large semiconductor company, in June 1999. He holds a Ph.D. and an A.B.M.S. in EconomicsElectrical Engineering from Harvard University. Mr. CochranStanford University and a B.S. in Electrical Engineering from the University of Michigan. Dr. Salsbury has specific attributes that qualify him to serve as a member of our board of directors, including the perspectivehis strong technical background and management experience he has acquired from counseling growth companies over the last thirty years,as chief executive officer of a public company, and his prior service as a director of a public company.

Eric Singer has served as a member of our board of directors since July 2019. Mr. Singer is a founder and Managing Member of VIEX Capital Advisors. In addition to a long track record as a successful investor in technology companies, Mr. Singer has substantial experience serving on public boards and in assisting them in creating and expanding shareholder value. Mr. Singer is currently a director of Quantum Corporation and previously served on the boards of directors of Numerex Corp., YuMe, Inc., Support.com, Meru Networks, PLX Technology, Inc., and Sigma Designs, Inc., among other companies. Mr. Singer has a B.A. from Brandeis University. Mr. Singer has specific attributes that qualify him to serve as a member of our board of directors, including his extensive financial and operating experience and knowledge of the technology industry gained through his service on public and private company boards.

Continuing Directors

Lee Chen has served as our President, Chief Executive Officer and as a member of our board of directors since July 2004, and as the Chairmanchairman of our board of directors since March 2014. From 1996 to August 2004, Mr. Chen served in a variety of positions, including as Vice President of Software Engineering and Quality Assurance at Foundry Networks, Inc., a company that designed, manufactured and sold high-end enterprise and service provider switches and routers, as well as wireless, security, and traffic management solutions. Mr. Chen has previously held management and senior technical positions at OTS, Apple Computer, Convergent Technologies, Inc. and InSync Group, and was a co-founder of Centillion Networks, Inc. Mr. Chen has an M.S.E.E. from San Jose State University and a B.S. in Electrophysics from National Chiao-Tung University in Taiwan. Mr. Chen is a technology pioneer, especially in the area of Internet Protocol Multicast and System & System Security, and holds numerous patents. Mr. Chen has specific attributes that qualify him to serve as a member of our board of directors, including his extensive knowledge of the perspectiveCompany’s business and experience he brings as our Chief Executive Officerin executive and President, one of our founders and a significant stockholder.technical positions at technology companies.

Alan S. Henricks has served as a member of our board of directors since March 2014. Since May 2012 he has served as a member of the board of directors and audit committee chairman of Roku, Inc. (NASDAQ: ROKU), a streaming media company. Since May 2015 he has served as a member of the board of directors and audit committee of Model N, Inc. (NYSE: MODN), a provider of cloud-based Revenue Management solutions. From November 2014 to May 2015solutions, and since February 2017, he has served as a member of the board of directors and audit committee chairman of APT Software Holdings.its compensation committee. From April 2010 to June 2015 he served as a member of the board of directors and audit committee of Ellie Mae, Inc. (NYSE: ELLI), a SaaS Company,company, and as its lead independent director from November 2012 to May 2014. Since May 2012 he has served as a member of the board of directors and audit committee chairman of Roku, Inc., a consumer electronics company. From May 2009 to the present, Mr. Henricks has also been a board member, advisor and consultant to a variety of private technology companies. His consulting CFO roles includedcompanies including Tile, Inc.,Ring, Percolate, Livescribe, Inc. and Santur Corporation. From September 2006Santur. Prior to May 2009, Mr. Henricks served as Chief Financial Officer of Pure Digital Technologies, Inc. Prior to September 2006, Mr. Henricks served as Chief Financial Officer of several private and public companies including Pure Digital Technologies, Inc., Traiana Inc., Informix Software, Inc., Documentum, Inc., Borland International, Inc., Cornish & Carey and Maxim Integrated Products, Inc. Mr. Henricks holds a Bachelor of Science in Engineering from the Massachusetts Institute of Technology and a Master of Business Administration from Stanford University.

Mr. Henricks has specific attributes that qualify him to serve as a member of our board of directors, including his extensive experience serving as chief financial officer of both public and private companies, as well as his prior service on public and private company boards.

Dr. Phillip J. Salsbury has served as a member of our board of directors since May 2013. Dr. Salsbury is also our Lead Independent Director. From 2005 to April 2010, Dr. Salsbury served as a director of Techwell, Inc., a fabless semiconductor public company that was acquired by Intersil Corporation. Dr. Salsbury was a founder, the Chief Technology Officer, and later the president and Chief Executive Officer of SEEQ Technology, Inc., a non-volatile memory and Ethernet communications semiconductor company, from January 1981 until its acquisition by LSI Logic Corporation, a large semiconductor company, in June 1999. He holds a Ph.D. and an M.S. in Electrical Engineering from Stanford University and a B.S. in Electrical Engineering from the

University of Michigan. Dr. Salsbury has specific attributes that qualify him to serve as a member of our board of directors, including his strong technical background and management experience as chief executive officer of a public company, and his prior service as a director of a public company.

Director Independence

Our common stock is listed on the New York Stock Exchange. Under the listing standards of the New York Stock Exchange, independent directors must comprise a majority of a listed company’s board of directors. In addition, the listing standards of the New York Stock Exchange require that, subject to specified exceptions, each member of a listed company’s audit, compensation, and nominating and corporate governance committees be independent. Under the listing standards of the New York Stock Exchange, a director will only qualify as an “independent director” if, in the opinion of that listed company’s board of directors, that director does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director.

Audit committee members must also satisfy the independence criteria set forth in Rule 10A-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the listing standards of the New York Stock Exchange. In addition, Compensationcompensation committee members must also satisfy the independence criteria set forth under the listing standards of the New York Stock Exchange.

Our board of directors has undertaken a review of the independence of each director. Based on information provided by each director concerning his background, employment and affiliations, our board of directors has determined that Messrs. Braham, Chung, Henricks, Salsbury and SalsburySinger do not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director and that each of these directors is “independent” as that term is defined under the listing standards of the New York Stock Exchange. In making these determinations, our board of directors considered the current and prior relationships that each non-employee director has with our company and all other facts and circumstances our board of directors deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director, and the transactions involving them described in the section titled “Related PartyPerson Transactions.”

Board Leadership Structure

Mr. Chen currently serves as both chairchairman of our Boardboard of Directorsdirectors and our chief executive officer.Chief Executive Officer. Our Boardboard believes that the current Boardboard leadership structure provides effective independent oversight of management while allowing our Board of Directorsboard and management to benefit from Mr. Chen’s leadership and years of experience as an executive in the networking industry. Mr. Chen is best positioned to identify strategic priorities, lead critical discussion and execute our strategy and business plans. Mr. Chen possesses detailed in-depth knowledge of the issues, opportunities, and challenges facing us.

Lead Independent Director

Our BoardBecause the chairman of our board of directors is not an independent director, our board determined that it would be beneficial to have a Lead Independent Directorlead independent director to, among other things, preside over executive sessions of the independent directors, which provides the Boardour board with the benefit of having the perspective of entirely independent directors. Independent directors and management sometimes have different perspectives and roles in strategy development.

Our Board appointed Phillip J.Dr. Salsbury Ph.D. to serveserves as our lead independent director. As lead independent director,In this role, Dr. Salsbury presides over periodic meetings of our independent directors, serves as a liaison between our Chairmanchairman of the board of directors and the independent directors, and performs such additional duties as our board of directors may otherwise determine and delegate.

Board Meetings and Committees

During our fiscal year ended December 31, 2015,2018, the board of directors held five (5)nineteen (19) meetings (including regularly scheduled and special meetings) and acted by written consent one (1) time. Eachthree (3) times. No director attended at least 85%fewer than 75% of the aggregate of (i) the total number of meetings of our board of directors held during the period for which he or she has been a director and (ii) the total number of meetings held by all committees of our board of directors on which he or she served during the periods that he or she served.

Although we do not have a formal policy regarding attendance by members of our board of directors at annual meetings of stockholders, we encourage, but do not require, our directors to attend. Four (4) of our directors attended our 20152018 annual meeting of stockholders. Our board of directors has established three standing committees: an audit committee, a compensation committee and a nominating and corporate governance committee. The composition and responsibilities of each of thethese committees of our board of directors is described below. Members will serve on these committees until their resignation or until as otherwise determined by our board of directors.

Audit Committee

OurThe audit committee is comprised of Messrs. Chung,Braham, Henricks and Salsbury, each of whom is a non-employee member of our board of directors.Salsbury. Mr. Henricks is the chair of ourthe audit committee. Our board of directors has determined that each of the members of our auditthis committee satisfies the requirements for independence and financial literacy under the applicable rules and regulations of the New York Stock Exchange and the SEC. Our board of directors has also determined that Mr. Henricks qualifies as an “audit committee financial expert” as defined in the SEC rules and satisfies the financial sophistication requirements of the New York Stock Exchange.

The audit committee is responsible for, among other things:

The audit committee operates under a written charter that satisfies the applicable standards of the SEC and the New York Stock Exchange. A copy of the charter of ourthe audit committee is available on our website at http://investors.a10networks.com. During 2015, our2018, the audit committee held seven (7)twenty (20) meetings and did not actacted by written/electronic consent.written consent one (1) time.

Compensation Committee

OurThe compensation committee consists of Messrs. Braham, Chung, Henricks, Salsbury and Salsbury.Singer. Mr. Chung is the chairmanchair of ourthe compensation committee. Our board of directors has determined that each member of this committee is independent under the applicable rules and regulations of the New York Stock Exchange and the SEC, a non-employee director, as defined pursuant to Rule 16b-3 promulgated under the Exchange Act, and an outside director, as defined under Section 162(m) of the Internal Revenue Code of 1986, as amended, or Section 162(m).

amended.

The compensation committee is responsible for, among other things:

The compensation committee operates under a written charter that satisfies the applicable rules and regulations of the SEC and the listing standards of the New York Stock Exchange. A copy of the charter of ourthe compensation committee is available on our website at http://investors.a10networks.com. During 2015, our2018, the compensation committee held six (6) meetings and acted by written/electronicwritten consent one (1) time.two (2) times.

Nominating and Corporate Governance Committee

OurThe nominating and corporate governance committee consists of Messrs. Chung, Henricks, Salsbury and Salsbury, each of whom is a non-employee member of our board of directors.Singer. Dr. Salsbury is the chairmanchair of ourthe nominating and corporate governance committee. Our board of directors has determined that each member of our nominating and corporate governancethis committee meets the requirements for independence under the rules of the New York Stock Exchange.

The nominating and corporate governance committee is responsible for, among other things:

OurThe nominating and corporate governance committee operates under a written charter that satisfies the applicable listing standards of the New York Stock Exchange. A copy of the charter of ourthe nominating and corporate governance committee is available on our website at http://investors.a10networks.com. During 2015, our2018, the nominating and corporate governance committee held two meetings and did not act by written/electronic consent. Our nominating and corporate governance committee held aone (1) meeting in the first quarter of 2016 and acted by written consent in April of 2016 in connection with its recommendation of Messrs. Chung and Cochran as nominees for election as the Class II directors at the Annual Meeting.one (1) time.

Compensation Committee Interlocks and Insider Participation

Messrs. Braham, Chung, Henricks, Salsbury and SalsburySinger are the members of our compensation committee. None of the members of our compensation committee is or has been one of our officers or employees. None of our executive officers currently serves, or in the past year has served, as a member of the compensation committee or director (or other board committee performing equivalent functions or, in the absence of any such committee, the entire board of directors) of any entity that has one or more executive officers serving on our compensation committee or our board of directors.

Considerations in Evaluating Director Nominees

Our nominating and corporate governance committee uses a variety of methods for identifying and evaluating director nominees. In its evaluation of director candidates, our nominating and corporate governance committee will consider the current size and composition of our board of directors and the needs of our board of directors and the respective committees of our board of directors. Some of the qualifications that our nominating and corporate governance committee considers include, without limitation, issues of character, integrity, judgment, diversity (including, but not limited to, diversity of experience,gender, ethnicity, race, international background and life experience), independence, area of expertise, corporate experience, length of service, potential conflicts of interest and other commitments. Nominees must also have the ability to offer advice and guidance to our Chief Executive Officer based on past experience in positions with a high degree of responsibility and be leaders in the companies or institutions with which they are affiliated. Director candidates must have sufficient time available in the judgment of our nominating and corporate governance committee to perform all board of director and committee responsibilities. Members of our board of directors are expected to prepare for, attend, and participate in all board of director and applicable committee meetings. Other than the foregoing, there are no stated minimum criteria for director nominees, although our nominating and corporate governance committee may also consider such other factors as it may deem, from time to time, are in our and our stockholders’ best interests.

Although our board of directors does not maintain a specific policy with respect to board diversity, our board of directors believes that our board of directors should be a diverse body, and our nominating and corporate governance

committee considers a broad range of backgrounds and experiences. In making determinations regarding nominations of directors, our nominating and corporate governance committee may take into account the benefits of diverse viewpoints. Our nominating and corporate governance committee also considers these and other factors as it oversees the annual board of director and committee evaluations. After completing its review and evaluation of director candidates, our nominating and corporate governance committee recommends to our full board of directors the director nominees for selection.

Stockholder Recommendations for Nominations to the Board of Directors

Our nominating and corporate governance committee will consider candidates for director recommended by stockholders holding at least one percent (1%) of the fully diluted capitalization of the company continuously for at least twelve (12) months prior to the date of the submission of the recommendation, so long as such recommendations comply with our amended and restated certificate of incorporation currently in effect and amended and restated bylaws and applicable laws, rules and regulations, including those promulgated by the SEC. The nominating and corporate governance committee will evaluate such recommendations in accordance with its charter, our amended and restated bylaws, our policies and procedures for director candidates, as well as the regular director nominee criteria described above. This process is designed to ensure that our board of directors includes members with diverse backgrounds, skills and experience, including appropriate financial and other expertise relevant to our business. Eligible stockholders wishing to recommend a candidate for nomination should contact our General Counsel or our Legal DepartmentSecretary in writing. Such recommendations must include information about the candidate, a statement of support by the recommending stockholder, evidence of the recommending stockholder’s ownership of our common stock and a signed letter from the candidate confirming willingness to serve on our board of directors. Our nominating and corporate governance committee has discretion to decide which individuals to recommend for nomination as directors.

Any nomination should be sent in writing to our General Counsel or our Legal DepartmentSecretary at A10 Networks, Inc., 3 West Plumeria Drive, San Jose, CA 95134. To be timely for our 2017If we hold the 2020 annual meeting of stockholders no more than 30 days before or after the one-year anniversary of this year’s Annual Meeting, then our General Counsel or Legal DepartmentSecretary must receive the written nomination;

If we hold the 2020 annual meeting more than 30 days before or after the one-year anniversary of this year’s Annual Meeting, then our Secretary must receive the written nomination no earlier than January 30, 2017the close of business on the 120th day before the actual date of the 2020 annual meeting and no later than March 1, 2017.the close of business on the later of the following two dates:

Communications with the Board of Directors

Interested parties wishing to communicate with our board of directors or with an individual member or members of our board of directors may do so by writing to our board of directors or to the particular member or members of our board of directors, and mailing the correspondence to our General Counsel at A10 Networks, Inc., 3 West Plumeria Drive, San Jose, CA 95134, Attn: General Counsel. Each communication should set forth (i) the name and address of the stockholder, as it appears on our books, and if the shares of our common stock are held by a nominee, the name and address of the beneficial owner of such shares, and (ii) the number of shares of our common stock that are owned of record by the record holder and beneficially by the beneficial owner.

Our General Counsel, in consultation with appropriate members of our board of directors as necessary, will review all incoming communications and, if appropriate, forward such communications will be forwarded to the member or members of our board of directors to whom such communication wascommunications were directed, or if none is specified, to the Chairman of our board of directors.

Corporate Governance Guidelines and Code of Business Conduct and Ethics

Our board of directors has adopted Corporate Governance Guidelines that address items such as the qualifications and responsibilities of our directors and director candidates and corporate governance policies and standards applicable to us in general. In addition, our board of directors has adopted a Code of Business Conduct and

Ethics that applies to all of our employees, officers and directors, including our Chief Executive Officer, Chief Financial Officer, and other executive and senior financial officers. The full text of our Corporate Governance Guidelines and our Code of Business Conduct and Ethics is posted on the Corporate Governance portion of our website at http://investors.a10networks.com. We will post amendments to our Code of Business Conduct and Ethics or waivers of our Code of Business Conduct and Ethics for directors and executive officers on the same website.

Risk Management

Risk is inherent with every business, and we face a number of risks, including strategic, financial, business and operational, legal and compliance, and reputational. We have designed and implemented processes to manage risk in our operations. Management is responsible for the day-to-day management of risks the company faces, while our board of directors, as a whole and assisted by its committees, has responsibility for the oversight of risk management. In its risk oversight role, our board of directors has the responsibility to satisfy itself that the risk management processes designed and implemented by management are appropriate and functioning as designed.

Our board of directors believes that open communication between management and our board of directors is essential for effective risk management and oversight. Our board of directors meets with our Chief Executive Officer and other members of the senior management team at quarterly meetings of our board of directors, where, among other topics, they discuss strategy and risks facing the company, as well as at such other times as they deemed appropriate.

While our board of directors is ultimately responsible for risk oversight, our board committees assist our board of directors in fulfilling its oversight responsibilities in certain areas of risk. Our audit committee assists our board of directors in fulfilling its oversight responsibilities with respect to risk management in the areas of internal control over financial reporting, and disclosure controls and procedures, and legal and regulatory compliance, and discusses with management and the independent auditor guidelines and policies with respect

to risk assessment and risk management. Our audit committee also reviews our major financial risk exposures and the steps management has taken to monitor and control these exposures. Our audit committee also monitors certain key risks on a regular basis throughout the fiscal year, such as riskrisks associated with internal control over financial reporting and liquidity risk. Our nominating and corporate governance committee assists our board of directors in fulfilling its oversight responsibilities with respect to the management of risk associated with board organization, membership and structure, and corporate governance. Our compensation committee assesses risks created by the incentives inherent in our compensation policies. Finally, our full board of directors reviews strategic and operational risk in the context of reports from the management team, receives reports on all significant committee activities at each regular meeting, and evaluates the risks inherent in significant transactions.

Director Compensation

Equity Compensation.Compensation

Each non-employee director who first joins usour board of directors will be granted an initial equity award with a value of $225,000 and$225,000. On the date of each annual meeting of stockholders, each continuing non-employee director will be granted an annual equity award with a value of $150,000 on each of our annual stockholder meetings.$150,000. However, a continuing non-employee director who, as of the date of our annual stockholder meeting, has not served as a board member for the entire 12-month period prior to the annual stockholder meeting will receive an annual award with a value that is prorated based on the number of months the director served during the prior year. The initial and annual equity awards will be granted in the form of restricted stock units, and the number of shares to be granted pursuant to such equity awards will be determined by the closing price of a share of our sharescommon stock on the New York Stock Exchange on the grant date. However, aA non-employee director who is not continuing as a director following an annual stockholder meeting will not receive an annual equity award at such meeting.

The initial equity award will be scheduled to vest in three, equal, annual installments from the date the non-employee director joins our board of directors, subject to continued service as a board memberwith us through each such date. Each annual equity award will vest as to 100% of the underlying shares on the earlier of the one yearone-year anniversary of the award’s grant date or the date of our next annual stockholder meeting, subject to continued service as a board memberwith us through such date.

Cash Compensation.Compensation

Our board of directors approved the following annual compensation package for our non-employee directors:

PROPOSAL NO. 1

ELECTION OF DIRECTORS

Our board of directors is currently composed of fivesix members. In accordance with our amended and restated certificate of incorporation currently in effect, our board of directors, iswhich was previously divided into three staggered classes of directors, was declassified after our 2018 annual meeting as to the Class I directors and, at the Annual Meeting will be declassified as to the Class II directors. At our 2020 annual meeting, the Class III directors will be declassified such that all elected directors will serve for one-year terms. At the Annual Meeting, two Class II directorseach of the recommended nominees, if elected, will be electedserve for a three-year term to succeed the same class whose term is then expiring.

one-year term.

Each director’s term continues until the election and qualification of his or her successor, or such director’s earlier death, resignation, or removal. Any increase or decrease in the number of directors will be distributed among the three classes so that, as nearly as possible, each class will consist of one-third of our directors. This classification of our board of directors may have the effect of delaying or preventing changes in control of our company.

Nominees

OurAs recommended by the nominating and corporate governance committee, has recommended, and ourthe board’s nominees for election to the board are the following current members of directors has approved,the board: Tor R. Braham, Peter Y. Chung, Phillip J. Salsbury and Robert Cochran as nominees for election asEric Singer. Mr. Braham joined the Class II directorsboard in March 2018, Mr. Chung was most recently elected by the stockholders at the Annual Meeting.2017 annual meeting, Dr. Salsbury was most recently elected by the stockholders at the 2018 annual meeting and Mr. Singer joined the board in July 2019. If elected, Messrs. Chung and Cochran will serve as Class II directorseach nominee would hold office until the 2019 annual meeting of stockholdersto be held in 2020 and until their successors are dulyhis successor is elected and qualified. The nominees are currently directors of our company.qualified or until his earlier death, resignation or removal. For information concerning the nominees,nominee, please see the section titled “Board of Directors and Corporate Governance.”

In July 2019, we entered into a letter agreement with VIEX Capital Advisors, LLC, VIEX Opportunities Fund, LP – Series One, VIEX Opportunities Fund, LP – Series Two, VIEX GP, LLC, VIEX Special Opportunities Fund II, LP, VIEX Special Opportunities GP II, LLC, VIEX Special Opportunities Fund III, LP, VIEX Special Opportunities GP III, LLC and Eric Singer (collectively, the “VIEX Group”), pursuant to which we agreed, among other things, to nominate and support Mr. Singer and Tor. R. Braham for election as directors at the Annual Meeting. Subject to certain exceptions set forth in the letter agreement, the VIEX Group agreed to vote all of its shares at the Annual Meeting in a manner consistent with the recommendation of our board of directors. The Viex Group also agreed to customary standstill restrictions.

If you are a stockholder of record and you sign your proxy card or vote by telephone or over the Internet but do not give instructions with respect to the voting of directors, your shares will be voted “FOR” the re-electionelection of Messrs. Chung and Cochran.the four nominees listed above. We expect that Messrs. Chung and Cochraneach nominee will accept suchtheir nomination; however, in the event that a director nominee is unable or declines to serve as a director at the time of the Annual Meeting, the proxies will be voted for any nominee who shall be designated by our board of directors to fill such vacancy. If you are a street name stockholder and you do not give voting instructions to your broker or nominee, your broker will leave your shares unvoted on this matter.

Vote Required

The election of directorseach director requires a plurality vote of the shares of our common stock present in person or by proxy at the Annual Meeting and entitled to vote thereon to be approved. Broker non-votes will have no effect on this proposal.

THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR”

EACH OF THE NOMINEES NAMED ABOVE.

PROPOSAL NO. 2
AMENDMENT AND RESTATEMENT OF THE COMPANY’S
CERTIFICATE OF INCORPORATION

APPROVAL OF AN AMENDMENT TO OUR 2014 EMPLOYEE STOCK PURCHASE PLAN TOWe are seeking stockholder approval to amend and restate the Company’s Amended and Restated Certificate of Incorporation (the “Certificate”) to eliminate the supermajority voting provisions from the Certificate and to replace such provisions with a majority voting standard (the “Proposed Certificate Amendment”). As discussed further below, the Certificate currently requires a two-thirds supermajority vote for stockholders to (i) amend the Company’s Amended and Restated Bylaws (the “Bylaws”) and certain provisions in the Certificate (see Proposal 2(a)), and (ii) remove directors from office (see Proposal 2(b)). In light of the differing nature of the provisions affected, this matter is presented as two separate voting items. Approval of either of Proposal 2(a) or Proposal 2(b) is not conditioned upon approval of the other.

REMOVE THE AUTOMATIC ANNUAL SHARE INCREASE THEREUNDER AND INCREASE THEPurpose and Effect of the Proposed Amendment

NUMBER OF SHARES AVAILABLE FOR ISSUANCE THEREUNDER BY 4,000,000 SHARES

Our 2014 Employee Stock Purchase Plan, or ESPP,The Proposed Certificate Amendment is a benefitresult of our board of directors’ ongoing review of our corporate governance guidelines. In developing the Proposed Certificate Amendment, our board of directors (including all members of the nominating and corporate governance committee) carefully considered the implications of amending our Certificate to eliminate supermajority voting provisions. Our board of directors recognizes that wesupermajority voting requirements are intended to protect against self-interested action on the part of large stockholders by requiring broad stockholder support for certain types of governance changes. In this regard, the Proposed Certificate Amendment may make available on a broad basisit easier for one or more stockholders to remove directors or effect other corporate governance changes in the employeesfuture and may make it more difficult for our board of directors to protect stockholders’ interests if presented with an acquisition proposal that undervalues the Company. Nevertheless, our board of directors also recognizes that many investors and others now view supermajority voting provisions as unduly limiting the board’s accountability to stockholders or stockholder participation in the corporate governance of the Company. After considering stockholder input, as well as consulting with management and outside advisors, our board of directors believes that the Proposed Certificate Amendment is in the best interest of the Company and our participating subsidiary corporations and other participating affiliates, and allows employeesstockholders.

Proposal 2(a): Eliminate Supermajority Voting Provisions to purchaseAmend Our Governance Documents

Currently, the Certificate states that stockholders can alter, amend or repeal the Bylaws only if that action is approved by at least a two-thirds supermajority vote (see Article VI of the Certificate). This Proposal 2(a) proposes to amend this provision by replacing the reference to “66-2/3%” with “a majority.” As a result, stockholders would be able to amend the Bylaws by the affirmative vote of the holders of at least a majority of the voting power of all then outstanding shares of our commoncapital stock at a discount from fair market value. The ESPP assists us in recruiting, retaining and motivating our employees, which helps us achieve our business goals, including creating long-term value for our stockholders.

We are asking our stockholdersentitled to approve an amendment to our ESPP that (i) removes the automatic annual increasevote generally in the share reserveelection of directors, voting together as a single class.

Likewise, Article X of the Certificate currently requires a two-thirds supermajority vote to amend or repeal, or adopt a provision inconsistent with, the provisions in the Certificate relating to:

This Proposal 2(a) proposes to delete the supermajority voting requirement for amending these provisions. As a result, if approved and implemented, the standard for stockholder approval of any future amendments to the Certificate, including with respect to any of these provisions, would be the affirmative vote of the holders of at least a majority of the voting power of all then outstanding shares of capital stock entitled to vote generally in the election of directors, voting together as a single class, which is the default voting standard under the ESPP (the “Annual Share Increase”),Delaware General Corporation Law.

Proposal 2(b): Eliminate Supermajority Voting Provision to Remove Directors

Currently, the Certificate states that stockholders can remove a director from office only if that action is approved by at least a two-thirds supermajority vote (see Article V, Section 5.3 of the Certificate). This Proposal 2(b) proposes to amend this provision by replacing the reference to “66-2/3%” with “a majority.” As a result, if approved and (ii) increasesimplemented, stockholders would be able to remove any director from office by 4,000,000 shares the maximum numberaffirmative vote of the holders of at least a majority of the voting power of all then outstanding shares of our commoncapital stock that will be made available for saleentitled to vote on the matter, voting together as a single class, which is the default voting standard under the ESPP (collectively referred to as the “Amendment”). As such, following the effectiveness of the Amendment, any additional increasesDelaware General Corporation Law.

Related Changes to the ESPP’s share reserve in future years will require additional stockholder approval. Our compensation committee andBylaws

In connection with the Proposed Certificate Amendment, our board of directors havehas approved the Amendment, subjectconforming amendments to the Bylaws, contingent upon stockholder approval and implementation of our stockholders at the Annual Meeting.

Ourrelated portion of the Proposed Certificate Amendment. Specifically, our board of directors adopted,has approved amendments to the Bylaws to: (i) replace the two-thirds supermajority voting provision to amend the Bylaws set forth in Article X with the majority voting standard described above under Proposal 2(a) and (ii) make certain other changes as set forth therein.

Additional Information

The general description of the Proposed Certificate Amendment set forth above is qualified in its entirety by reference to the text of the Proposed Certificate Amendment, which is attached as Appendix A to these proxy materials. In addition, the text of the related and other amendments to the Bylaws, which can be amended from time to time by our stockholdersboard of directors, is attached as Appendix B to these proxy materials. Additions to the Certificate and the Bylaws are indicated by double underlining. Deletions to the Certificate and the Bylaws are indicated by strikeouts.

The Proposed Certificate Amendment is binding. If either Proposal 2(a) or Proposal 2(b) is approved, the ESPP in March 2014. Currently,Company intends to file a maximumCertificate of 2,857,971 shares of our common stock have been reserved for issuance under the ESPP, which includes the initial 1,600,000 shares that were reserved under the ESPP plus a total of 1,257,971 shares of our common stock that were addedAmendment to the ESPP pursuantCertificate with the Secretary of State of the State of Delaware, and the portion of the Proposed Certificate Amendment relating to such proposal will become effective at the Annual Share Increasestime of that occurred onfiling. If neither Proposal 2(a) nor Proposal 2(b) is approved by the first dayrequisite vote, then a Certificate of eachAmendment will not be filed with the Secretary of our fiscal years 2015State of the State of Delaware, the supermajority voting provisions in both the Certificate and 2016. BeforeBylaws will remain in place, and the Amendment,related Bylaw amendments will not become effective.

Vote Required

Under the ESPP limits each Annual Share Increase toexisting supermajority voting provisions set forth in the Certificate, the affirmative vote of the holders of at least of (i) 3,500,000 shares of our common stock, (ii) onesixty-six and two-thirds percent (1%(66-2/3%) of the voting power of all outstanding shares of our common stock on the last day of our immediately preceding fiscal year, or (iii) an amount determined by the administrator of the ESPP. As of April 1, 2016, 1,184,272 shares of our common stock remained available for issuance under the ESPP. We currently expect that approximately 590,000 shares will be purchased in our May 2016 purchase leaving approximately 594,272 shares remaining available for issuance under the ESPP.

If stockholdersis required to approve this Amendment, the number of shares of our common stock issuable under the ESPP would increase by 4,000,000, bringing the maximum number of shares of our common stock under the ESPP’s share reserve to 6,857,971, of which an aggregate of 1,673,699 shares have been issued since March 2014 through April 1, 2016. We have not made any other material amendments to the ESPP since it became effective in March 2014. Following the next scheduled purchase of shares under the ESPP in May 2016, the number of shares of our common stock remaining available for sale under the ESPP, if stockholders approve this Amendment, is expected to be approximately 4,594,272 shares.

Without stockholder approval of the Amendment, we believe our ability to use the ESPP as a tool to assist us to attractProposal 2(a) and retain the individuals necessary to drive our performance and increase long-term stockholder value will be limited. We believe that the approval of the Amendment is important to our continued success. If stockholders do not approve the Amendment, the ESPP will continue without any increase in the share reserve and the Annual Share Increases will remain in effect. In that case, it is likely that the shares reserved for issuance under the ESPP may be insufficient to cover full grants under the ESPP during fiscal year 2016 and each fiscal year thereafter while the ESPP remains in effect, and enrollments under the ESPP may need to be reduced annually to eliminate overenrollment. If the shares available for issuance under the ESPP run out, it will be more difficult for us to meet our goals of recruiting, retaining and motivating talented employees.

In approving the Amendment and recommending that our board of directors approve the Amendment, our compensation committee reviewed: (1) current and anticipated employee participation, expected levels of contribution and pricing available under the ESPP to purchase shares of our common stock, (2) the period of time the current balance would last based on the number of shares of our common stock currently available under the ESPP, (3) the historical number of shares actually purchased under the ESPP since its adoption, (4) the

percent of eligible participants who participated, (5) the expected period of time that the increased share reserve will last, (6) the percent of our common stock outstanding that the 4,000,000 share increase proposed by the Amendment would represent, which was approximately 6.2 percent, (7) the analysis and recommendations of the independent compensation consultant retained by our compensation committee, (8) key components of the ESPP design, and (9) the recommendations of management.

Description of the ESPP

The following paragraphs provide a summary of the principal features of the ESPP and its operation. However, this summary is not a complete description of all of the provisions of the ESPP and is qualified in its entirety by the specific language of the ESPP. A copy of the ESPP as amended is provided as Appendix A to this proxy statement.

PurposeProposal 2(b). The purpose of the ESPP is to provide our employees and employees of our participating subsidiaries with an opportunity to purchase shares of our common stock through accumulated payroll deductions or other contributions that we may permit. The ESPP is intended to qualify as an employee stock purchase plan under Section 423 (“Section 423”) of the Internal Revenue Code of 1986, as amended (the “423 component”). In addition, the ESPP authorizes the grant of purchase rights that do not qualify under Section 423 pursuant to rules, procedures or sub-plans adopted by the Administrator (as defined below) designed to achieve desired tax, securities laws or other objectives (the “non-423 component”).

Authorized Shares.Initially, a maximum of 1,600,000 shares of our common stock were made available for sale under the ESPP. In addition, our ESPP provides for an Annual Share Increase that makes available an additional number of shares of our common stock under the ESPP on the first day of each fiscal year of the Company beginning in fiscal year 2015, equal to the least of:

As of April 1, 2016, 1,184,272 shares of our common stock remained available for issuance under the ESPP. We currently expect that approximately 590,000 shares will be purchased in our May 2016 purchase, leaving approximately 594,272 shares remaining available for issuance under the ESPP. As of April 1, 2016, the per share closing price of our common stock as quoted on the New York Stock Exchange was $6.13. If our stockholders approve the Amendment, then the maximum number of shares of our common stock that will remain available for sale under the ESPP will be approximately 4,594,272 shares.

Administration.Our board of directors or a committee appointed by our board of directors (currently the Compensation Committee is the Administrator) administers the ESPP (referred to as the “Administrator”). The Administrator may interpret the terms of the ESPP, designate separate offerings under the ESPP, designate subsidiaries and affiliates as participating in the 423 component or the non-423 component of the ESPP, determine eligibility, adjudicate all disputed claims filed under the ESPP, and establish such procedures that it deems necessary for the administration of the ESPP.

Eligibility.Generally, all employees are eligible to participate if they are employed by us, or any participating subsidiary or affiliate of ours, for customarily at least 20 hours per week and more than five months in any calendar year. However, an employee may not be granted rights to purchase stock under the ESPP if such employee:

As of April 1, 2016, approximately 780 of our employees and our subsidiaries (including four executive officers) were eligible to participate in the ESPP.

Offering Periods.Our ESPP provides for consecutive, overlapping 24-month offering periods that are scheduled to start on the first trading day on or after May 21 and November 21 of each year and terminating on the last trading day on or before May 20 and November 20, approximately 24 months later. Each purchase period within an offering period will be approximately six months and will begin after one exercise date and will end with the next exercise date approximately six months later (except that the first purchase period in the offering period will begin on the first trading day of the offering period and end with the next exercise date). The Administrator may modify the terms of future offering periods, provided that no offering period may last more than 27 months. If the fair market value of our common stock on the exercise date is less than the fair market value on the first trading day of an offering period, all participants will be withdrawn from the offering period in which such exercise date occurred, as of immediately following their purchase of shares on the exercise date, and automatically will be enrolled in the immediately following offering period. Any eligible employee may participate in an offering period under the ESPP by timely submitting a properly completed subscription agreement on or before a date determined by the Administrator prior to the first day of the offering period or by following such other procedure the Administrator determines.

Contributions. Our ESPP permits participants to purchase shares of our common stock through payroll deductions (or any additional forms of payment that we may permit) of up to 15% of their eligible compensation, which includes base straight time gross earnings, but exclusive of payments for incentive compensation, bonuses, payments for overtime and shift premium, equity compensation income and other similar compensation. During a purchase period, a participant may not increase the rate of his or her contributions, but may decrease his or her rate of contributions one time to a rate of 0%.

Exercise of Purchase Right.Participants’ contributions to the ESPP are used to purchase shares on each exercise date (the last trading day of each six-month purchase period) during the offering period. The purchase price of the shares will be 85% of the lower of the fair market value of a share of our common stock on the first trading day of the applicable offering period or on the applicable exercise date. The Administrator may determine a different purchase price for future offering periods subject to applicable laws. A participant may purchase a maximum of 1,500 shares of our common stock during each purchase period. The Administrator may change the maximum number of shares of our common stock that a participant may purchase in any future offering periods.

Withdrawal. A participant may end his or her participation in the ESPP at any time and participation automatically will end upon termination of a participant’s employment with us. If a participant withdraws or is deemed to have withdrawn from the ESPP, all accrued contributions, if any, that have not yet been used to purchase shares will be returned to the participant.

Non-Transferability.A participant may not transfer contributions to the ESPP or purchase rights granted under the ESPP other than by will, the laws of descent and distribution, or, if the Administrator permits, by designation of a beneficiary.

Adjustments.In the event of certain changes in our capitalization, to prevent dilution or enlargement of the benefits or potential benefits intended to be made available under the ESPP, the Administrator will adjust the number and class of common stock that may be delivered under the ESPP, the purchase price per share and the number of shares covered by each unexercised purchase right under the ESPP, and the numerical share limits under the ESPP. In the event of our proposed dissolution or liquidation, any offering period then in progress will be shortened by setting a new exercise date and will terminate immediately before the completion of such

proposed dissolution or liquidation unless determined otherwise by the Administrator. Prior to the new exercise date, the Administrator will provide notice to participants that the exercise date has been changed to the new exercise date and that the participant’s purchase right will be exercised automatically on the new exercise date unless the participant already has withdrawn from the offering period.

Merger or Change in Control.In the event of our merger or change in control, as defined under the ESPP, a successor corporation (or its parent or subsidiary) may assume or substitute each outstanding purchase right. If any outstanding purchase rights are not assumed or substituted, the offering period to which such purchase rights relate will be shortened by setting a new exercise date on which the offering period will end. The new exercise date will occur before the date of the proposed merger or change in control. The Administrator will notify each participant that the exercise date has been changed and that the participant’s purchase right will be exercised automatically on the new exercise date unless before such date the participant has withdrawn from the offering period.

Amendment; Termination.Our ESPP will terminate automatically in 2034, unless we terminate it sooner. The Administrator has the authority to amend, suspend, or terminate our ESPP at any time and for any reason, subject to the terms of the ESPP.

Number of Shares Purchased by Certain Individuals and Groups

Participation in the ESPP is voluntary and dependent on each eligible employee’s election to participate and his or her determination as to the level of contributions to be made. In addition, the number of shares that may be purchased under the ESPP generally is determined, in part, by the price of a share of our common stock on the first trading day of each offering period and the last trading day of the applicable purchase period. Accordingly, the actual number of shares of our common stock that may be purchased by any individual is not determinable in advance. The following table sets forth (i) the number of shares of our common stock that were purchased during fiscal year 2015 under the ESPP, and (ii) the weighted average per share purchase price paid for such shares, for each of our named executive officers, all current executive officers as a group, all non- employee directors as a group, and all other employees who participated in the ESPP as a group:

PROPOSAL NO. 3

RATIFICATION OF APPOINTMENT OF

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

OurFollowing a competitive request-for-proposal process, the audit committee has appointed Deloitte & ToucheArmanino LLP (“Deloitte”Armanino”), an independent registered public accounting firm, to audit our consolidated financial statements for our fiscal year ending December 31, 2016. During our fiscal year ended December 31, 2015, Deloitte2019. Armanino has served as our independent registered public accounting firm.

Notwithstanding the appointment of Deloitte and even if our stockholders ratify the appointment, our audit committee, in its discretion, may appoint another independent registered public accounting firm at any time during our fiscal year if our audit committee believes that such a change would be in the best interests of A10 Networks, Inc. and its stockholders. At the Annual Meeting, our stockholders are being asked to ratify the appointment of Deloitte as our independent registered public accounting firm for our fiscal year ending December 31, 2016. Our audit committee is submitting the appointment of Deloitte to our stockholders because we value our stockholders’ views on our independent registered public accounting firm and as a matter of good corporate governance.since September 2019. Representatives of DeloitteArmanino will be present at the Annual Meeting, and they will have an opportunity to make a statement and will be available to respond to appropriate questions from our stockholders.

At the Annual Meeting, our stockholders are being asked to ratify the appointment of Armanino as our independent registered public accounting firm for our fiscal year ending December 31, 2019. The audit committee is submitting the appointment of Armanino to our stockholders because we value our stockholders’ views on our independent registered public accounting firm and as a matter of good corporate governance. If our stockholders do not ratify the appointment of Deloitte,Armanino, our board of directors may reconsider the appointment.

Notwithstanding the appointment of Armanino and even if our stockholders ratify the appointment, the audit committee, in its discretion, may appoint another independent registered public accounting firm at any time during our fiscal year if the audit committee believes that such a change would be in the best interests of the Company and its stockholders.

During our fiscal years ended December 31, 2018 and 2017, Deloitte & Touche LLP (“Deloitte”) served as our independent registered public accounting firm. Representatives of Deloitte are not expected to be present at the Annual Meeting.

Change in Independent Registered Public Accounting Firm

As described in the Company’s Current Report on Form 8-K filed with the SEC on September 18, 2019 (the “8-K”), the audit committee approved the dismissal of Deloitte as our independent registered public accounting firm and engaged Armanino to serve in this role on September 16, 2019.

The audit reports of Deloitte on the consolidated financial statements of the Company for each of our two most recent fiscal years ended December 31, 2018 and 2017 did not contain an adverse opinion or a disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles, except that Deloitte’s audit report for the fiscal year ended December 31, 2018, which contained an unqualified opinion, included an emphasis-of-matter paragraph stating that the Company had changed its method of accounting for revenue from contracts with customers in 2018, due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606), using the modified retrospective approach.

During our two most recent fiscal years and subsequent interim period from January 1, 2019 to September 16, 2019, (i) there were no disagreements with Deloitte on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures that, if not resolved to Deloitte’s satisfaction, would have caused Deloitte to make reference to the subject matter of such disagreements in their reports on the Company’s consolidated financial statements for such years, and (ii) there were no “reportable events” as defined in Item 304(a)(1)(v) of Regulation S-K, except as described below.

As previously disclosed in Item 9A of the Company’s Annual Reports on Form 10-K for each of the fiscal years ended December 31, 2018 and 2017, the Company concluded that its internal control over financial reporting was not effective as of December 31, 2018 and 2017 due to material weaknesses related to the Company’s control environment and monitoring activities and revenue recognition. The audit committee has discussed these matters with Deloitte, and the Company has authorized Deloitte to respond fully to any inquiries by Armanino concerning these matters.

The Company provided Deloitte with a copy of the disclosures it made in the 8-K and requested that Deloitte furnish the Company with a letter addressed to the SEC stating whether or not Deloitte agrees with the statements made therein. A copy of Deloitte’s letter was filed as Exhibit 16.1 to the 8-K.

During our two most recent fiscal years ended December 31, 2018 and 2017 and subsequent interim period from January 1, 2019 to September 16, 2019, neither the Company nor anyone on its behalf consulted Armanino regarding (i) the application of accounting principles to a specified transaction, either completed or proposed, except as described below, or the type of audit opinion that might be rendered on the Company’s consolidated financial

statements, and neither a written report nor oral advice was provided to the Company that Armanino concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing or financial reporting issue, or (ii) any matter that was either the subject of a “disagreement,” as that term is defined in Item 304(a)(1)(iv) of Regulation S-K, or a “reportable event,” as that term is defined in Item 304(a)(1)(v) of Regulation S-K.

During our fiscal year ended December 31, 2017, Armanino provided tax services to the Company consisting of a review of the Company’s quarterly and annual tax provision calculations. In approving the selection of Armanino as our independent registered public accounting firm, the audit committee considered these services previously provided by Armanino and concluded that such services would not adversely affect the independence of Armanino.

Fees Paid to the Independent Registered Public Accounting Firm

The following table presents fees for professional audit services and other services rendered to our companythe Company by Deloitte for our fiscal years ended December 31, 20142018 and 2015.2017.

REPORT OF THE AUDIT COMMITTEE

The audit committee is a committee of the board of directors comprised solely of independent directors as required by the listing standards of the New York Stock Exchange and rules and regulations of the SEC. The audit committee operates under a written charter approved by the board of directors, which is available on our web sitewebsite at http://investors.a10networks.com. The composition of the audit committee, the attributes of its members and the responsibilities of the audit committee, as reflected in its charter, are intended to be in accordance with applicable requirements for corporate audit committees. The audit committee reviews and assesses the adequacy of its charter and the audit committee’s performance on an annual basis.

With respect to the company’sour financial reporting process, theour management of the company is responsible for (1) establishing and maintaining internal controls and (2) preparing the company’sour consolidated financial statements. Our independent registered public accounting firm Deloitte & Touche LLP (“Deloitte”), is responsible for auditing these financial statements. It is the responsibility of the audit committee to oversee these activities. It is not the responsibility of the audit committee to prepare our financial statements. These are the fundamental responsibilities of management. In the performance of its oversight function, the audit committee has:

Based on the audit committee’s review and discussions with management and Deloitte, the audit committee recommended to the board of directors that the audited financial statements be included in theour Annual Report on Form 10-K for the fiscal year ended December 31, 20152018 for filing with the Securities and Exchange Commission.

Respectfully submitted by the members of the audit committee of the board of directors:

Alan S. Henricks (Chair)

Peter Y. Chung

Tor R. Braham
Phillip J. Salsbury

This report of the audit committee is required by the SEC and, in accordance with the SEC’s rules, will not be deemed to be part of or incorporated by reference by any general statement incorporating by reference this proxy statement into any filing under the Securities Act of 1933, as amended (“Securities Act”), or under the Exchange Act, except to the extent that we specifically incorporate this information by reference, and will not otherwise be deemed “soliciting material” or “filed” under either the Securities Act or the Exchange Act.

EXECUTIVE OFFICERS

The following table identifies certain information about our executive officers as of April 7, 2016.September 30, 2019. Officers are elected by our board of directors to hold office until their successors are elected and qualified. There are no family relationships among any of our directors or executive officers.

Lee Chenhas served as our President, Chief Executive Officer and as a member of our board of directors since July 2004, and as the Chairmanchairman of our board of directors since March 2014. From 1996 to August 2004, Mr. Chen served in a variety of positions, including as Vice President of Software Engineering and Quality Assurance at Foundry Networks, Inc., a company that designed, manufactured and sold high-end enterprise and service provider switches and routers, as well as wireless, security, and traffic management solutions. Mr. Chen has previously held management and senior technical positions at OTS, Apple Computer, Convergent Technologies, Inc. and InSync Group, and was a co-founder of Centillion Networks, Inc. Mr. Chen has an M.S.E.E. from San Jose State University and a B.S. in Electrophysics from National Chiao-Tung University in Taiwan. Mr. Chen is a technology pioneer, especially in the area of Internet Protocol Multicast and System & System Security, and holds numerous patents.

Rajkumar Jalanhas served as our Chief Technology Officer since November 2008. From 2005 to 2008, he served as a consultant to the Company.our company. From 1996 to 2002, Mr. Jalan served in various capacities, including as a Director of IP Routing, for Foundry Networks, Inc., a company that designed, manufactured and sold high- end enterprise and service provider switches and routers, as well as wireless, security, and traffic management solutions. Prior to Foundry, he worked on a wide range of networking technologies from Ethernet, Token-Ring, ATM and Digital Switching Systems. Mr. Jalan’s prior employers included Bay Networks, Inc. and Network Equipment Technologies Inc. Mr. Jalan holds a number of patents related to Layer 2/Layer 3 as well as Layer 4/ Layer 7 switching. He has a B.Tech from the Indian Institute of Technology, Bombay.

Greg StraughnRobert Cochranhas served as our Executive Vice President, Legal and Corporate Collaboration since November 2016, our Chief FinancialRisk Compliance Officer since July 2011October 2016 and brings to us more than 30 years of executive leadership and financial expertise. From September 1998 to June 2010, Mr. Straughn served as the Chief Financial Officer for Kabira Technologies, Inc., a provider of high-performance software products to the telecommunications and financial services market. During his tenure at Kabira, Mr. Straughn was instrumental in helping grow the company from startup through its eventual acquisition by Tibco Software, Inc. Previously, he served as the Chief Financial Officer of AT&T, Inc./Pacific Bell Internet Services, Inc., an Internet company, Principal and General Manager for Meridian Business Systems, and the Chief Financial Officer of PacTel Finance. Mr. Straughn has a B.S. in Finance from the University of California at Berkeley and is the author of two books on financial and general management of small businesses.

Robert CochranhasSecretary since August 2004. He previously served as our Vice President, Legal and Corporate Collaboration sincefrom January 2012 to November 2016 and as a member of our board of directors sincefrom April 2012.2012 to November 2018. Mr. Cochran has servedcurrently serves as our Secretary since August 2004,a director of Techpoint, Inc., a fabless semiconductor company that designs, markets, and previously served on our board of directors from August 2004 to October 2004.sells mixed-signal integrated circuits for HD video applications in the security surveillance and automotive markets. From January 1993 to January 2012, Mr. Cochran was an attorney in private practice in Woodside, California, where he had served as our outside legal counsel since our incorporation.incorporation until he joined us in 2012. From 2004 to 2010, Mr. Cochran served as a director of Techwell, Inc., a fabless semiconductor public company that was acquired by Intersil Corporation. Mr. Cochran also serves as a director of two privately held companies.designed, marketed, and sold mixed-signal integrated circuits. Mr. Cochran has a J.D. from Harvard Law School and an A.B. in Economics from Harvard University.

Ray SmetsTom Constantinohas served as our Executive Vice President, Chief Financial Officer since June 2017. From November 2015 to December 2016, Mr. Constantino served as the Vice President of Finance and Head of Accounting & Finance Operations at Western Digital Corporation, a company that provides data storage solutions. While at Western Digital, from March 2012 to November 2015, Mr. Constantino served as Chief Financial Officer of its HGST subsidiary. His experience also includes the role of vice president, corporate finance at Hitachi Global Storage Technologies and approximately 16 years in various financial and operational roles at Hewlett-Packard. Also, from January 2017 to May 2017, Mr. Constantino was an independent consultant providing Chief Financial Officer and Senior Finance Executive consulting services. Mr. Constantino began his career in public accounting at PricewaterhouseCoopers and holds a Bachelor’s of Science in Business Administration from San Jose State University.

Chris White has served as our Executive Vice President of Worldwide Sales since July 2013.January 2018. From November 2016 to December 2011 to July 2013,2017, Mr. Smets was Senior Vice President of Field Operations, Sales and International Development for Metaswitch Networks, Inc., a telecommunications company. From December 2008 to November 2011, heWhite was Vice President and General Manager at Cisco Systems, Inc., a designer and manufacturer of computer networking devices.Sales, Strategic Accounts & Archive for

Proofpoint, an enterprise security company based in Sunnyvale, California. From September 2007June 2011 to August 2008,November 2016, Mr. SmetsWhite was Executive Vice President Sales, Americas Partners & Alliances for Hitachi Data Systems. Chris has over 24 years of Salesdirect and Marketing for Packeteer Inc., an application classificationindirect sales experience, focused on selling with and traffic prioritization systems provider.through channel and alliance partners. His prior employers include NetApp, Symantec Corporation, Veritas and ADP. Mr. SmetsWhite has also held executive positions at Netopia Inc., a providerBachelor of carrier-class broadband customer premise equipment, McAfee Security, Inc., a security software company, and Bellsouth Telecommunications/ AT&T, Inc., a telecommunications company. Mr. Smets has an M.B.A. from Nova-Southeastern University, and a B.S. in Computer EngineeringArt Degree, Social Sciences from the University of Florida, and is an alumnus of the Stanford University Executive Program.

California, Irvine.

Neil Wu BeckerGunter Reisshas served as our Vice President of Worldwide Marketing since October 2017 and Communications since April 2016. From May 2015 to March 2016, Mr. Becker was Head of Worldwide Public Relations for Micron Technology, a memory chip maker. From February 2014 to May 2015, Mr. Becker wasas our Vice President of Marketing Communications at Armor Defense, a secure managed cloud provider.Strategic Alliances from October 2014 to October 2017. From March 20062005 to February 2014, Mr. BeckerReiss served in various capacities for Ericsson, including Vice President, Strategy & Business Development PA IP & Broadband/ BU Networks of Ericsson Silicon Valley and Director, Partnership Business Development & Sourcing, Strategic Sourcing North America of Ericsson Inc. He also spent three years in England in senior leadership roles with Damovo and IPC. Gunter served on the board of privately held Skorpios Technologies and was a varietymember of positions, including asDirector of Public Relations at Cisco Systems, Inc., a designer and manufacturer of computer networking devices. Mr. Becker has an M.S. in Mass Communications from San Jose State University, and a B.A. in Englishthe Sun Microsystems customer advisory board. He received his electrical engineering degree from the UniversityHigher Technical School in Vienna, Austria. He is an alumnus of California, Davis.the UCLA Executive M&A program and the UC Berkeley Haas School of Business Venture Capitalist Executive Program.

EXECUTIVE COMPENSATION

Processes and Procedures for Compensation Decisions

Our compensation committee is responsible for the executive compensation programs for our executive officers and reports to our board of directors on its discussions, decisions and other actions. Typically, our Chief Executive Officer makes recommendations to our compensation committee regarding, and often attends committee meetings and is involved inrelating to the determination of, compensation for the respective executive officers that report to him, except that our Chief Executive Officer does not make recommendations as to his own compensation. Our Chief Executive Officer makes recommendations to our compensation committee regarding short- and long-term compensation for all executive officers (other than himself) based on our results, an individual executive officer’s contribution toward these results and performance toward individual goal achievement. Our compensation committee then reviews the recommendations and other data and makes decisions as to total compensation for each executive officer other than the Chief Executive Officer, as well as each individual compensation component. Our compensation committee makes recommendations to our board of directors regarding compensation for our Chief Executive Officer. The independent members of our board of directors make the final decisions regarding executive compensation for our Chief Executive Officer.

Our compensation committee is authorized to retain the services of one or more executive compensation advisors, as it sees fit, in connection with the establishment of our compensation programs and related policies. In 2015, Radford,Compensia, a national compensation consultant, washas been retained by our compensation committee to provide information, recommendations and other advice relating to executive compensation on an ongoing basis. Radfordcompensation. Compensia was engaged to assist our compensation committee in developing an appropriate group of peer companies to help us determine the appropriate level of overall compensation for our executive officers, as well as assess each separate element of compensation, with a goal of ensuring that the compensation we offer to our executive officers is competitive and fair.

Fiscal 20152018 Summary Compensation Table

The following table provides information regarding the total compensation for services rendered in all capacities that was earned by each individual who served as our principal executive officer at any time in 2015,2018, and our two other most highly compensated executive officers who were serving as executive officers as of December 31, 2015.2018. These individuals were our named executive officers (each, an “NEO” and together, the “NEOs”) for 2015.2018.

Non-Equity Incentive Plan Compensation

For our 20152018 fiscal year, Mr. Kapoor wasMessrs. Constantino and White were eligible to receive a non-equity incentiveannual cash bonuses based 80% on corporate performance goals and 20% on individual performance goals, under our 2018 Executive Cash Incentive Plan, as approved by the compensation committee. The 2018 Executive Cash Incentive Plan was established under and subject to the terms of our Executive Incentive Compensation Plan, as described in further detail below. Mr. Constantino’s target bonus opportunity for our 2018 fiscal year was equal to approximately 65% of his 2018 base salary and Mr. White’s target bonus opportunity for our 2018 fiscal year was equal to approximately 67% of his 2018 base salary. The corporate performance goals under such plan bonusrelated to our revenue and non-GAAP operating income for 2018. Generally, the portion of the plan based on corporate performance goals would result in funding of bonuses upon the achievement of threshold levels of both revenue and non-GAAP operating income as specified in a performance goal matrix approved by the Compensation Committee.compensation committee. The bonus opportunity for Mr. Kapoormaximum amount that could be earned on the individual performance goals was based100% and the maximum amount that could be earned on the corporate performance goals related to our 2015 revenue. was 150%.

In early 2016,2019, our Chief Executive Officer evaluated, and presented to the compensation committee, the progress made towards achieving the corporate and individual performance goals in accordance with the terms of the Executive Cash Incentive Plan and made a recommendation to our Compensation Committeecompensation committee regarding histhe bonus amount for each of Messrs. Constantino and White based on this evaluation. The bonusbonuses for Messrs. Constantino and White, as recommended wasdetermined pursuant to the terms of the Executive Cash Incentive Plan and our Chief Executive Officer’s recommendation, were approved in early 2016.on March 4, 2019. For the 20152018 fiscal year, Mr. KapoorConstantino earned a cash bonus of $65,442.$44,053 for achievement of his individual performance goals and Mr. White earned a cash bonus of $47,613 for achievement of his individual performance goals. The amount earned on corporate performance goals was $0 because the corporate performance goals were not met.

Mr. Chen is not eligible to receive an annual cash bonus.

Emerging Growth Company Status

We are an “emerging growth company,” as defined in the JOBS Act. As an emerging growth company, we are exempt from certain requirements related to executive compensation, including the requirements to hold nonbinding advisory votes on executive compensation and to provide information relating to the ratio of total compensation of our Chief Executive Officer to the median of the annual total compensation of all of our employees, each as required by the Investor Protection and Securities Reform Act of 2010, which is part of the Dodd-Frank Act.

Executive Officer Employment Agreements

Offer Letters

We have entered into offer letters with each of our NEOs.

Lee Chen Offer Letter

Under Mr. Chen’s offer letter dated July 30, 2004, we hired Mr. Chen as our CEO. The letter provided for no base salary for Mr. Chen and an initial equity award grant to be determined. Mr. Chen’s current annual base salary is $0.

Sanjay KapoorTom Constantino Offer Letter

Under Mr. Kapoor’sConstantino’s offer letter dated March 15, 2015,May 14, 2017, we hired Mr. KapoorConstantino as our Vice President of Global Marketing.EVP, Chief Financial Officer. The letter provided for Mr. Kapoor’sConstantino’s initial base salary, and bonus opportunity plus(on a prorated basis), and sign-on bonus. In addition, the letter provided for an initial restricted stock unit grantaward and an initial option award covering 95,000175,000 and 135,000 shares, respectively, which wasare scheduled to vest over four4 years, subject to his continued service with us through each applicable vesting date. His award was eligible for accelerated vesting under his Change in Control and Severance Agreement, described below. Under the terms of his offer, his base salary was $260,000.

Ray Smets Offer Letter

Under Mr. Smets’ offer letter dated July 18, 2013, we hired Mr. Smets as our Vice President, Global Sales. The letter provided for Mr. Smets’ initial base salary and bonus opportunity, plus an initial option grant covering 200,000 shares which vest over four years subject to his continued service with us through each applicable vesting date. His award isawards are eligible for accelerated vesting under his Change in Control and Severance Agreement, described below. Mr. Smets’Constantino’s current annual base salary is $305,000$350,075.

Chris White Offer Letter

Under Mr. White’s offer letter dated December 15, 2017, we hired Mr. White as our Executive Vice President of Worldwide Sales. The letter provided for an initial base salary of $378,000, a 2018 performance bonus of up to $252,000 and he earned a commissionsign on bonus of $294,408 for 2015.$75,000. In addition, the letter specified that Mr. White would receive an initial RSU

grant and an initial stock option award, each covering a number of shares equivalent to a value of $700,000. The letter also detailed the method of calculation of such awards and the vesting schedule that would apply to each. Mr. White’s current annual base salary is $378,000.

Change in Control and Severance Agreements

We entered into a Change in Control and Severance Agreement (each, an “Agreement” and together, the “Agreements”) with each of our NEOs.

Each NEO’s Agreement provides that if, after the executive completes at least one year of employment with us or if promoted to an executive position, completes at least one year in an executive role and (a) we terminate the executive’s employment with us for any reason other than for cause and not due to the executive’s death or disability, or (b) the executive resigns for Good Reason (as defined in the Agreement), and in each case the termination does not occur during the Change in Control Period (as defined in the Agreement), the executive will receive the following severance benefits: (i) continuing payments of salary severance for a period of 12 months (in the case of Mr. Chen) or nine months (in the case of the other NEOs), and (ii) continuing payments to reimburse the executive for COBRA continuation coverage for a period of up to 12 months (in the case of Mr. Chen) or nine months (in the case of the other NEOs).

Each Agreement further provides that if we terminate the executive’s employment with us for any reason other than cause and not due to the executive’s death or disability, or the executive resigns for Good Reason, and in each case the termination occurs during the Change in Control Period, the executive will receive the following severance benefits: (i) a lump sum cash payment equal to 150% (in the case of Mr. Chen) or 100% (in the case of the other NEOs) of the greater of the executive’s salary in effect as of immediately prior to his employment termination or the Change in Control, (ii) a lump sum cash payment equal to 150% (in the case of Mr. Chen) or 100% (in the case of the other NEOs) of the greater of the executive’s target bonus in effect for the year in which the executive’s employment terminates or the Change in Control occurs, (iii) continuing payments to reimburse the executive for COBRA continuation coverage for a period of up to 18 months (in the case of Mr. Chen) or 12 months (in the case of the other NEOs), and (iv) 100% accelerated vesting of the executive’s outstanding equity awards, with any applicable performance goals considered achieved at the target levels.

In order to receive the severance benefits under the Agreement, the executive must sign and not revoke a release of claims in our favor and comply with confidentiality obligations.

As defined in the Agreements, “Cause” generally means the executive’s (i) repeated failure to perform his duties and responsibilities to the Company or abide in all material respects with the Company’s policies after receiving written notice, (ii) engagement in illegal conduct injurious to the Company in any material respect, (iii) material violation or material breach of his confidential information and invention agreement with the Company that is not cured within 20 days of written notice or is incapable of cure, or (iv) conviction or plea of no contest to a felony (other than motor vehicle offenses that do not materially impair the executive’s performance of his employment duties) or any crime involving fraud, embezzlement or other offense involving moral turpitude, and/or committing any act of embezzlement, dishonesty or fraud against or the misappropriation of material property belonging to the Company.

As defined in the Agreements, “Change in Control Period” generally means, subject to the occurrence of a Change in Control, the period beginning on the date that an agreement to enter into such Change in Control is signed and executed, and ending on the date 12 months following such Change in Control. As will be defined in the Agreements, “Change in Control” generally means the occurrence of any of the following events: (i) a change in our ownership that occurs on the date that any one person or persons acting as a group (“Person”), acquires ownership of our stock that, together with the stock already held by such Person, constitutes more than 50% of the total voting power of our stock; or (ii) a change in our effective control that occurs on the date that a majority of members of our board of directors is replaced during any 12-month period by directors whose appointment or election is not endorsed by a majority of the members of our board of directors prior to the date of the appointment or election; or (iii) a change in the ownership of a substantial portion of our assets that occurs on the date that any Person acquires (or has acquired during a 12-month period) assets from us with a total gross fair market value equal to or more than 50% of the total gross fair market value of all of our assets immediately prior to such acquisition(s), excluding any transfer to an entity that is controlled by our stockholders immediately after the transfer and any transfer of assets by us to an entity, 50% or more of the total value or voting power

of which is owned, directly or indirectly, by us. For purposes of this definition, gross fair market value means the value of our assets, or the value of our assets being disposed of, determined without regard to any liabilities associated with such assets.

As defined in the Agreements, “Good Reason” generally means the executive’s voluntary termination of employment with us within 90 days following the expiration of our cure period following one or more of the following occurring without the executive’s prior consent: (i) a material reduction in the executive’s gross base salary other than in connection with a similar reduction for all similarly-situatedsimilarly situated employees; (ii) a material reduction in the executive’s authority, duties, or responsibilities; or (iii) a relocation of the executive’s principal place of work to a location that is more than 50 miles from his current principal work site for us. The executive may not resign for Good Reason without first providing us with notice within 60 days of the initial existence of the condition that he believes constitutes Good Reason identifying the grounds for Good Reason and a reasonable cure period of at least 30 days following the date of such notice, during which such grounds must not have been cured.

Executive Incentive Compensation Plan

In March 2014, our board of directors adopted an Executive Incentive Compensation Plan, referred to as our Bonus Plan. Our Bonus Plan allows our compensation committee to provide cash incentive awards to selected employees, including our NEOs, based upon performance goals established by our compensation committee.

Under the Bonus Plan, our compensation committee determines the performance goals applicable to awards, which goals may include, without limitation: attainment of research and development milestones, sales bookings, business divestitures and acquisitions, cash flow, cash position, earnings (which may include any calculation of earnings, including but not limited to earnings before interest and taxes, earnings before taxes, earnings before interest, taxes, depreciation and amortization and net earnings), earnings per share, net income, net profit, net sales, operating cash flow, operating expenses, operating income, operating margin, overhead or other expense reduction, product defect measures, product release timelines, productivity, profit, return on assets, return on capital, return on equity, return on investment, return on sales, revenue, revenue growth, sales results, sales growth, stock price, time to market, total stockholder return, working capital, and individual objectives such as peer reviews or other subjective or objective criteria. Performance goals that include the Company’s financial results may be determined in accordance with U.S. generally accepted accounting principles, or GAAP, or such financial results may consist of non-GAAP financial measures and any actual results may be adjusted by our compensation committee for one-time items or unbudgeted or unexpected items when determining whether the performance goals have been met. The goals may be on the basis of any factors our compensation committee determines relevant, and may be adjusted on an individual, divisional, business unit or company-wide basis. Any criteria used may be measured on such basis as our compensation committee determines. The performance goals may differ from participant to participant and from award to award.

Our compensation committee may, in its sole discretion and at any time, increase, reduce or eliminate a participant’s actual award, and/or increase, reduce or eliminate the amount allocated to the bonus pool for a particular performance period. The actual award may be below, at or above a participant’s target award, in our compensation committee’s discretion. Our compensation committee may determine the amount of any reduction on the basis of such factors as it deems relevant, and it is not required to establish any allocation or weighting with respect to the factors it considers.

Actual awards are paid in cash (or its equivalent) in a single lump sum only after they are earned and approved by our compensation committee. Unless otherwise determined by our compensation committee, to earn an actual award, a participant must be employed by the Company (or an affiliate of the Company) through the date the bonus is paid. Payment of bonuses occurs as soon as administratively practicable after they are earned, but no later than the dates set forth in the Bonus Plan.

Our board of directors has the authority to amend, alter, suspend or terminate the Bonus Plan provided such action does not alter or impair the existing rights of any participant with respect to any earned bonus.

Retirement Plan

We maintain a tax-qualified 401(k) retirement plan for all employees who satisfy certain eligibility requirements under the plan. The plan provides eligible employees with an opportunity to save for retirement on a tax-advantaged basis. Participants of our 401(k) plan are able to defer a percentage of their eligible compensation, subject to applicable annual Internal Revenue Code and plan limits. All participants’ interests in their deferrals are 100% vested when contributed. Beginning in January 2015, weWe also provide matching contributions under our 401(k) plan that generally vest over a 4-year period based on the participant’s employment. The Company matches 50% of the first 6% of eligible compensation contributed, for up to $2,500 per year. Pre-tax contributions are allocated to the participant’s individual account and

are then invested in selected investment alternatives according to the participant’s directions. The 401(k) plan is intended to qualify under Internal Revenue Code Section 401(a) with the plan’s related trust intended to be tax exempt under Internal Revenue Code Section 501(a). As a tax-qualified retirement plan, the 401(k) plan allows contributions, and earnings on those contributions, not to be taxable to the employees until distributed from the 401(k) plan.