Exhibit 4.2

DESCRIPTION OF CAPITAL STOCK 

The following description summarizes important terms of our capital stock. For a complete description, you should refer to our certificate of incorporation and bylaws, which are incorporated by reference as exhibits to the Annual Report on Form 10-K of which this exhibit is a part, as well as the relevant portions of the DGCL. 

General 

As of the date of this Annual Report on Form 10-K, the Company has authorized 500 million shares of common stock, par value $0.001 per share. As of December 31, 2020, there were 45,559,765 shares of common stock outstanding. 

Voting Rights 

Each holder of our common stock is entitled to one vote for each share on all matters submitted to a vote of the stockholders, including the election of directors. Under our certificate of incorporation and our bylaws, our stockholders do not have cumulative voting rights. Because of this, the holders of a majority of the shares of common stock entitled to vote in any election of directors are able to elect all of the directors standing for election, if they should so choose. 

Dividend Rights 

Subject to preferences that may be applicable to any then-outstanding preferred stock, holders of common stock are not entitled to receive ratably those dividends, if any, as may be declared from time to time by the Board out of legally available funds. 

Liquidation Rights 

In the event of our liquidation, dissolution or winding up, holders of common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities and the satisfaction of any liquidation preference granted to the holders of any then-outstanding shares of preferred stock. 

Other Rights and Preferences 

Holders of our common stock have no preemptive, conversion or subscription rights and there are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate in the future. 

Registration Rights 

Certain of our stockholders have the right to require us to register their shares under the Securities Act so that those shares may be publicly resold, as described below.

Registration on Form S-3 – Selling Stockholders

The holders of approximately 4.1 million shares of our common stock have the right to require us to register their shares under the Securities Act so that those shares may be publicly resold, and the Company is obligated to use commercially reasonable efforts to keep such registration statement continuously effective under the Securities Act. We will pay all expenses relating to such Form S-3 registration, subject to specified conditions and limitations. 

These registration rights will terminate, with respect to a particular holder, at the earlier of: (i) the time that such holder has sold of its registrable securities covered by the registration statement, and (ii) the date that all registrable securities covered by such registration statement may be sold by non-affiliates without volume or manner-of-sale restrictions pursuant to Rule 144, without the requirement for the Company to be in compliance with the current public information requirement under Rule 144 as determined in good faith by the Company.

Registration on Form S-3 – Lincoln Park

We are obligated to use our reasonable best efforts to keep a Form S-3 registration statement and related prospectus effective and current for all shares of common stock issuable by the Company to Lincoln Park Capital Fund, LLC (“Lincoln Park”) pursuant to the Purchase Agreement, dated March 27, 2020, between the Company and Lincoln Park. These registration rights will terminate on September 7, 2021.

Anti-Takeover Provisions 

The provisions of Delaware law, and our certificate of incorporation and our bylaws could have the effect of delaying, deferring or discouraging another person from acquiring control of our company. These provisions, which are summarized below, may have the effect of discouraging takeover bids. They are also designed, in part, to encourage persons seeking to acquire control of us to negotiate first with our Board. We believe that the benefits of increased protection of our potential ability to negotiate with an unfriendly or unsolicited acquirer outweigh the disadvantages of discouraging a proposal to acquire us because negotiation of these proposals could result in an improvement of their terms. 

 

Section 203 of the Delaware General Corporation Law 

We are subject to Section 203 of the DGCL, which prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, with the following exceptions:




		
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before such date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder; 




 

		
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upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding, but not the outstanding voting stock owned by the interested stockholder, those shares owned (i) by persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or 




 

		
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on or after such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of the stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock that is not owned by the interested stockholder. 




In general, Section 203 defines a “business combination” to include the following:




		
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any merger or consolidation involving the corporation and the interested stockholder; 




 

		
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any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder; 




 

		
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subject to specified exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder; 




 

		
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any transaction involving the corporation that has the effect of increasing the proportionate share of the stock or any class or series of the corporation beneficially owned by the interested stockholder; or 




 

		
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the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits by or through the corporation. 




In general, Section 203 defines an “interested stockholder” as an entity or person who, together with the person’s affiliates and associates, beneficially owns, or within three years prior to the time of determination of interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation. 

Our Certificate of Incorporation and Bylaws 

Our certificate of incorporation and bylaws include a number of provisions that could deter hostile takeovers or delay or prevent changes in control of our company, including the following:




		
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Classified Board. Our certificate of incorporation provides for our Board to be divided into three classes with staggered three-year terms. Only one class of directors is elected at each annual meeting of our stockholders, with the other classes continuing for the remainder of their respective three-year terms. Because our stockholders do not have cumulative voting rights, stockholders holding a majority of the shares of common stock outstanding is able to elect all of our directors. Our certificate of incorporation and our bylaws also provide that directors may be removed by the stockholders only for cause upon the vote of 66 2/3% or more of our outstanding common stock. Furthermore, the authorized number of directors may be changed only by resolution of the board of directors, and vacancies and newly created directorships on the board of directors may, except as otherwise required by law or determined by the board, only be filled by a majority vote of the directors then serving on the board, even though less than a quorum. 


		
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Classified Board. Our certificate of incorporation provides for our Board to be divided into three classes with staggered three-year terms. Only one class of directors is elected at each annual meeting of our stockholders, with the other classes continuing for the remainder of their respective three-year terms. Because our stockholders do not have cumulative voting rights, stockholders holding a majority of the shares of common stock outstanding is able to elect all of our directors. Our certificate of incorporation and our bylaws also provide that directors may be removed by the stockholders only for cause upon the vote of 66 2/3% or more of our outstanding common stock. Furthermore, the authorized number of directors may be changed only by resolution of the board of directors, and vacancies and newly created directorships on the board of directors may, except as otherwise required by law or determined by the board, only be filled by a majority vote of the directors then serving on the board, even though less than a quorum. 




 

		
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Special Meetings of Stockholders and Stockholder Action by Written Consent. Our certificate of incorporation and bylaws provide that all stockholder actions must be effected at a duly called meeting of stockholders and eliminate the right of stockholders to act by written consent without a meeting. Our bylaws also provide that only our chairman of the board, Chief Executive Officer (or if there is no Chief Executive Officer, the President) or the board of directors pursuant to a resolution adopted by a majority of the total number of authorized directors may call a special meeting of stockholders. 




 

		
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Advance Notice Requirements for Stockholder Proposals. Our bylaws provide that stockholders seeking to present proposals before a meeting of stockholders, including the nomination of director candidates, must provide timely advance notice in writing, and specifies requirements as to the form and content of a stockholder’s notice. 




 

		
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Amendment to Certificate of Incorporation and Bylaws. Our certificate of incorporation and bylaws provide that the stockholders cannot amend the provisions described above except by a vote of 66 2/3% or more of our outstanding common stock. 




The combination of these provisions makes it more difficult for our existing stockholders to replace our Board as well as for another party to obtain control of us by replacing our Board. Since our Board has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our Board to issue preferred stock with voting or other rights or preferences that could impede any attempt to effect a change of control of our company. 

These provisions are intended to enhance the likelihood of continued stability in the composition of our Board and its policies and to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to reduce our vulnerability to hostile takeovers and to discourage tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and may have the effect of delaying changes in our control or management. As a consequence, these provisions may also inhibit fluctuations in the market price of our stock that could result from actual or rumored takeover attempts. We believe that the benefits of these provisions, including increased protection of our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure our company, outweigh the disadvantages of discouraging takeover proposals, because negotiation of takeover proposals could result in an improvement of their terms. 

Choice of Forum 

Our certificate of incorporation provides that the Court of Chancery of the state of Delaware (the “Chancery Court”) is the exclusive forum for: (i) any derivative action or proceeding brought on our behalf; (ii) any action asserting a breach of fiduciary duty; (iii) any action asserting a claim against us arising pursuant to the DGCL, our certificate of incorporation or our bylaws; (iv) or any action asserting a claim against us that is governed by the internal affairs doctrine, in each case provided that the Chancery Court has subject matter jurisdiction. If the Chancery Court does not have subject matter jurisdiction, then such actions may be brought in any state court located in the state of Delaware (the “State Courts”) or, if and only if the State Courts lack subject matter jurisdiction, in the federal district court for the District of Delaware. 

This exclusive forum provision does not apply to suits brought to enforce any liability or duty created by the Exchange Act or any other claim for which the federal courts have exclusive jurisdiction. To the extent that any such claims may be based upon federal law claims, Section 27 of the Exchange Act creates exclusive federal jurisdiction over all suits brought to enforce any duty or liability created by the Exchange Act or the rules and regulations thereunder. 

Our certificate of incorporation further provides that the federal district courts of the United States will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act, although stockholders cannot waive compliance with the federal securities laws and the rules and regulations thereunder. The enforceability of similar choice of forum provisions in some other companies’ certificates of incorporation has been challenged in legal proceedings, and it is possible that, in connection with any action, a court could find the choice of forum provisions contained in our certificate of incorporation to be inapplicable or unenforceable. 

In March 2020, the Delaware Supreme Court issued a decision in Salzburg et al. v. Sciabacucchi, which found that an exclusive forum provision similar to the one in our certificate of incorporation providing for claims under the Securities Act to be brought in federal court is facially valid under Delaware law. We intend to enforce the federal forum selection provision in our certificate of incorporation, but we do not know whether courts in other jurisdictions will agree with the Sciabacucchi decision or enforce it.

Limitation of Liability and Indemnification 

Our certificate of incorporation provides that no director will be personally liable for monetary damages for breach of any fiduciary duty as a director, except with respect to liability:




		
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for any breach of the director’s duty of loyalty to us or our stockholders; 




 

		
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for acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law; 




 

		
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under Section 174 of the DGCL (governing distributions to stockholders); or 




 

		
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for any transaction from which the director derived any improper personal benefit. 




If the DGCL is amended to authorize corporate action further eliminating or limiting the personal liability of directors, then the liability of our directors will be eliminated or limited to the fullest extent permitted by the DGCL, as so amended. The modification or repeal of this provision of our certificate of incorporation will not adversely affect any right or protection of a director existing at the time of such modification or repeal. 

Our bylaws also provide that we will, to the fullest extent permitted by law, indemnify our directors and officers against all liabilities and expenses in any suit or proceeding or arising out of their status as an officer or director or their activities in these capacities. We will also indemnify any person who, at our request, is or was serving as a director, officer, employee, agent or trustee of another corporation or of a partnership, limited liability company, joint venture, trust or other enterprise. We may, by action of our Board, provide indemnification to our employees and agents within the same scope and effect as the foregoing indemnification of directors and officers. 

 

Transfer Agent and Registrar 

The transfer agent and registrar for our common stock is Broadridge Corporate Issuer Solutions, Inc. 1717 Arch Street, Suite 1300, Philadelphia, Pennsylvania 19103.