Exhibit 4.10

    

    

    DESCRIPTION OF THE REGISTRANT’S SECURITIES

    REGISTERED PURSUANT TO SECTION 12 OF THE

    SECURITIES EXCHANGE ACT OF 1934

     

    The following description sets forth certain material terms and provisions of our securities that are registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). This description
      also summarizes relevant provisions of the General Corporation Law of Delaware (the “DGCL”). The following description is a summary and does not purport to be complete. It is subject to, and qualified in its entirety by reference to, the applicable
      provisions of the DGCL and our eighth amended and restated certificate of incorporation, as amended (our “Certificate of Incorporation”), and our second amended and restated bylaws (our “Bylaws”), each of which is incorporated by reference as an
      exhibit to the Annual Report on Form 10-K of which this Exhibit 4.10 is a part. We encourage you to read our Certificate of Incorporation, our Bylaws, and the applicable provisions of the DGCL for additional information.

     

    DESCRIPTION OF COMMON STOCK

     

    Our Certificate of Incorporation provides the authority to issue 75,000,000 shares of common stock, par value $0.00033 per share. As December 31, 2019, there were 5,281,237 shares of common stock outstanding. Each share
      of our common stock has the same relative rights and is identical in all respects to each other share of our common stock. The rights, preferences and privileges of holders of our common stock are subject to the rights, preferences and privileges of
      the holders of shares of any series of preferred stock that we have issued or may issue in the future.

     

     Voting Rights

     

    The holders of our common stock are entitled to one vote per share on any matter to be voted upon by our stockholders. Our Certificate of Incorporation does not permit cumulative voting in connection with the election of
      directors.

     

    Dividends

     

    The holders of our common stock are entitled to dividends, if any, as our board of directors may declare from time to time from funds legally available for that purpose, subject to the holders of other classes of stock,
      if any, at the time outstanding having prior rights as to dividends, if any.

     

    Liquidation Rights

     

    Upon any voluntary or involuntary liquidation, dissolution, or winding up of our affairs, the holders of our common stock are entitled to share ratably in all assets remaining after the payment of creditors, subject to
      any prior liquidation distribution rights of holders of other classes of stock, if any, at the time outstanding.

     

    Miscellaneous

     

    Holders of our common stock have no preemptive, conversion, redemption or sinking fund rights. The outstanding shares of our common stock are, and the shares of common stock to be offered hereby when issued will be,
      validly issued, fully paid and non-assessable.

     

    Nasdaq Listing

     

    Our common stock is listed on the Nasdaq Capital Market under the symbol “PDSB.”

     

    Transfer Agent and Registrar

     

    The transfer agent and registrar for our common stock is Computershare Trust Company, N.A..

    

    

    
      
        


    

    

    DESCRIPTION OF PREFERRED STOCK

     

    Our Certificate of Incorporation provides the authority to issue 5,000,000 shares of preferred stock, par value $0.00033 per share. Our board of directors has the authority, subject to limitations
      prescribed by the DGCL, to issue preferred stock in one or more series, to establish from time to time the number of shares to be included in each series and to fix the designation, powers, preferences and rights of the shares of each series and any
      of its qualifications, limitations and restrictions. Our board of directors also can increase or decrease the number of shares of any series, but not below the number of shares of that series then outstanding.

    We have no current plans to issue any shares of preferred stock and no shares of our authorized preferred stock have been designated or issued.

     

    Voting Rights

     

    The DGCL provides that the holders of preferred stock will have the right to vote separately as a class on any proposal involving fundamental changes in the rights of holders of that preferred stock. This right is in
      addition to any voting rights that may be provided for in the applicable certificate of designation.

     

    Transfer Agent and Registrar

     

    The transfer agent and registrar for any series of preferred stock will be set forth in the applicable prospectus supplement.

     

    Other

     

    Our issuance of preferred stock could decrease the amount of earnings and assets available for distribution to the holders of common stock or could adversely affect the rights and powers, including voting rights, of the
      holders of common stock. The issuance of preferred stock could have the effect of decreasing the market price of our common stock.

     

    Delaware Anti-Takeover Law and Provisions of Certificate of Incorporation and Bylaws

    

    

    Delaware Anti-Takeover Law. We are subject to Section 203 of the Delaware General Corporation Law. Section 203 generally prohibits a Delaware corporation from engaging in any
      business combination with an “interested stockholder” for a period of three years after the date that such stockholder became an interested stockholder, unless:

    

    

    	
             

          	
            •

          	
            prior to the date of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

          
	
             

          	
            •

          	
            upon consummation 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
              commenced, 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

          
	
             

          	
            •

          	
            at or subsequent to the date of the transaction, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least
              66 2∕3% of the outstanding voting stock which is not owned by the interested stockholder.

          


     

    

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

    

    

    	
             

          	
            •

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

          
	
             

          	
            •

          	
            any sale, lease, exchange, mortgage, pledge, transfer or other disposition of 10% or more of the assets of the corporation to or with the interested stockholder;

          
	
             

          	
            •

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

          
	
             

          	
            •

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

          
	
             

          	
            •

          	
            the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided 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 before the time of determination of
      interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation.

     

    

    Under specific circumstances, Section 203 makes it more difficult for an “interested stockholder” to effect various business combinations with a corporation for a three-year period, although the stockholders may, by
      adopting an amendment to the corporation’s certificate of incorporation or bylaws, elect not to be governed by this section, effective 12 months after adoption.

    

    

    Our Certificate of Incorporation and Bylaws do not exclude us from the restrictions of Section 203. We anticipate that the provisions of Section 203 might encourage companies interested in acquiring us to negotiate in
      advance with our board of directors since the stockholder approval requirement would be avoided if a majority of the directors then in office approve either the business combination or the transaction that resulted in the stockholder becoming an
      interested stockholder.

    

    

    Further, our Certificate of Incorporation provides that, unless we consent to the selection of an alternative forum, the Court of Chancery of the State of Delaware is the sole and exclusive forum, to the fullest extent
      permitted by law, for: (a) any derivative action or proceeding brought on our behalf; (b) any action asserting a claim of breach of a fiduciary duty owed by any of our directors, officers or other employees to us or our stockholders; (c) any action
      asserting a claim arising pursuant to the DGCL, our eighth amended and restated certificate of incorporation, as amended, or our second amended and restated bylaws; or (d) any action asserting a claim against us governed by the internal affairs
      doctrine. This choice of forum provision does not preclude or contract the scope of exclusive federal or concurrent jurisdiction for any actions brought under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended.
      Accordingly, our exclusive forum provision will not relieve us of our duties to comply with the federal securities laws and the rules and regulations thereunder, and our stockholders will not be deemed to have waived our compliance with these laws,
      rules and regulations. Any person or entity purchasing or otherwise acquiring any interest in any of our securities shall be deemed to have notice of and consented to these provisions. These exclusive-forum provisions may limit a stockholder’s
      ability to bring a claim in a judicial forum of its choosing for disputes with us or our directors, officers or other employees, which may discourage lawsuits against us and our directors, officers and other employees.

    

    

    
      
        


    

    Certificate of Incorporation and Bylaws. Provisions of our Certificate of Incorporation and Bylaws may delay or discourage transactions involving an actual or potential change of
      control or change in our management, including transactions in which stockholders might otherwise receive a premium for their shares, or transactions that our stockholders might otherwise deem to be in their best interests. Therefore, these
      provisions could adversely affect the price of our common stock. Among other things, our Certificate of Incorporation and Bylaws will:

    

    

    	
             

          	
            •

          	
            permit our board of directors to issue up to 5,000,000 shares of preferred stock, with any rights, preferences and privileges as they may designate;

          
	
             

          	
            •

          	
            provide that the authorized number of directors may be changed only by the board of directors;

          
	
             

          	
            •

          	
            provide that all vacancies on our board of directors, including as a result of newly created directorships, may, except as otherwise required by law, be filled by the affirmative vote of a majority of directors then in office, even if less
              than a quorum;

          
	
             

          	
            •

          	
            divide our board of directors into three classes;

          
	
             

          	
            •

          	
            require that any action to be taken by our stockholders must be effected at a duly called annual or special meeting of stockholders and not be taken by written consent;

          
	
             

          	
            •

          	
            provide that stockholders seeking to present proposals before a meeting of stockholders or to nominate candidates for election as directors at a meeting of stockholders must provide advance notice in writing, and also specify requirements
              as to the form and content of a stockholder's notice;

          


    	
             

          	
            •

          	
            not provide for cumulative voting rights, thereby allowing the holders of a majority of the shares of common stock entitled to vote in any election of directors to elect all of the directors standing for election;

          
	
             

          	
            •

          	
            provide that special meetings of our stockholders may be called only by the board of directors;

          
	
             

          	
            •

          	
            not preclude or contract the scope of exclusive federal or concurrent jurisdiction for any actions brought under the Securities Act or the Exchange Act; and

          
	
             

          	
            •

          	
            not relieve us of our duties to comply with the federal securities laws and the rules and regulations thereunder, and our stockholders will not be deemed to have waived our compliance with these laws, rules and regulations.

             

          


     

    

    Potential Effects of Authorized but Unissued Stock

    

    

    We have shares of common stock and preferred stock available for future issuance without stockholder approval. We may utilize these additional shares for a variety of corporate purposes, including future public offerings
      to raise additional capital, to facilitate corporate acquisitions or payment as a dividend on the capital stock.

    

    

    The existence of unissued and unreserved common stock and preferred stock may enable our board of directors to issue shares to persons friendly to current management or to issue preferred stock with terms that could
      render more difficult or discourage a third-party attempt to obtain control of us by means of a merger, tender offer, proxy contest or otherwise, thereby protecting the continuity of our management. In addition, the board of directors has the
      discretion to determine designations, rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences of each series of preferred stock, all to the
      fullest extent permissible under the Delaware General Corporation Law and subject to any limitations set forth in our Certificate of Incorporation. The purpose of authorizing the board of directors to issue preferred stock and to determine the rights
      and preferences applicable to such preferred stock is to eliminate delays associated with a stockholder vote on specific issuances. The issuance of preferred stock, while providing desirable flexibility in connection with possible financings,
      acquisitions and other corporate purposes, could have the effect of making it more difficult for a third-party to acquire, or could discourage a third-party from acquiring, a majority of our outstanding voting stock.

    

    

      Indemnification

     

    Our Certificate of Incorporation contains provisions permitted under the DGCL relating to the liability of directors. The provisions eliminate, to the extent legally permissible, a director’s liability for monetary
      damages for a breach of fiduciary duty, except in circumstances involving wrongful acts, such as the breach of a director’s duty of loyalty or acts or omissions that involve intentional misconduct or a knowing violation of law. The limitation of
      liability described above does not alter the liability of our directors and officers under federal securities laws. Furthermore, our certificate of incorporation contains provisions to indemnify our directors and officers to the fullest extent
      permitted by the DGCL. These provisions do not limit or eliminate our right or the right of any stockholder of ours to seek non-monetary relief, such as an injunction or rescission in the event of a breach by a director or an officer of his duty of
      care to us. We believe that these provisions assist us in attracting and retaining qualified individuals to serve as directors.