DESCRIPTION OF COMMON STOCK

        The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders. Our stockholders do not have cumulative voting rights in the election of directors. Accordingly, holders of a majority of the shares voting are able to elect all of our directors. Subject to preferences that may apply to any then outstanding shares of preferred stock, the holders of outstanding shares of our common stock are entitled to receive dividends out of assets legally available for distribution at the times and in the amounts, if any, that our board of directors may determine from time to time. In the event of our liquidation, dissolution or winding up, subject to the rights of each series of our preferred stock, which may, from time to time come into existence, holders of our common stock are entitled to share ratably in all of our assets remaining after we pay our liabilities. Holders of our common stock have no preemptive or other subscription or conversion rights. Our common stock is not redeemable and there are no sinking fund provisions applicable to our common stock. Please refer to "Description of Capital Stock" in the accompanying prospectus for additional information relating to the common stock offered hereby.

DESCRIPTION OF CAPITAL STOCK

        Our Restated Certificate of Incorporation provides that we are authorized to issue 100,000,000 shares of capital stock. Our authorized capital stock is comprised of 90,000,000 shares of common stock, $0.001 par value per share, and 10,000,000 shares of preferred stock, par value $0.001 per share.

        The following description is a summary of the material terms of our capital stock and certain provisions of our Restated Certificate of Incorporation and Amended and Restated Bylaws. This description does not purport to be complete. For information on how you can obtain our Restated Certificate of Incorporation and Amended and Restated Bylaws, see "Where You Can Find More Information."

Common Stock

        We are authorized to issue up to 90,000,000 shares of our common stock, par value $0.001 per share.

        The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders. Our stockholders do not have cumulative voting rights in the election of directors. Accordingly, holders of a majority of the shares voting are able to elect all of our directors. Subject to preferences that may apply to any then outstanding shares of preferred stock, the holders of outstanding shares of our common stock are entitled to receive dividends out of assets legally available for distribution at the times and in the amounts, if any, that our board of directors may determine from time to time. In the event of our liquidation, dissolution or winding up, subject to the rights of each series of our preferred stock, which may, from time to time come into existence, holders of our common stock are entitled to share ratably in all of our assets remaining after we pay our liabilities. Holders of our common stock have no preemptive or other subscription or conversion rights. Our common stock is not redeemable and there are no sinking fund provisions applicable to our common stock.

Preferred Stock

        Our board of directors is authorized, subject to limitations imposed by Delaware law, to issue up to 10,000,000 shares of preferred stock, par value $0.001 per share, in one or more series, without

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stockholder approval. Our Board of Directors is authorized to fix the number of shares of preferred stock and to determine or (so long as no shares of such series are then outstanding) alter for each such series, such voting powers, full or limited, or no voting powers, and such designations, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in the resolution or resolutions adopted by the Board of Directors providing for the issuance of such shares and as may be permitted by Delaware General Corporation Law. The rights, privileges, preferences and restrictions of any such additional series may be subordinated to, pari passu with, or senior to any of those of any present or future class or series of our capital stock. Our Board of Directors is also authorized to decrease the number of shares of any series, prior or subsequent to the issue of that series, but not below the number of shares of such series then outstanding. In case the number of shares of any series shall be so decreased, the shares constituting any decrease shall resume the status which they had prior to the adoption of the resolution originally fixing the number of shares of such series.

        This section describes the general terms and provisions of our preferred stock. The applicable prospectus supplement will describe the specific terms of any shares of preferred stock offered through that prospectus supplement, as well as any general terms described in this section that will not apply to those shares of preferred stock. We will file a copy of the certificate of designation that contains the terms of each new series of preferred stock with the SEC each time we issue a new series of preferred stock. Each certificate of designation will establish the number of shares included in a designated series and fix the designation, powers, privileges, preferences and rights of the shares of each series as well as any applicable qualifications, limitations or restrictions. You should refer to the applicable certificate of designation as well as our Restated Certificate of Incorporation before deciding to buy shares of our preferred stock as described in the applicable prospectus supplement.

Anti-Takeover Provisions of Delaware Law and Charter Provisions

Interested Stockholder Transactions

        We are subject to Section 203 of the General Corporation Law of the State of Delaware, 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 holder;



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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 began, excluding, for purposes of determining the number of shares outstanding, those shares owned by persons who are directors and also officers and by 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.

        Section 203 defines "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, lease, exchange, mortgage, pledge, transfer or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;



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subject to certain 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 "interested stockholder" as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation or any entity or person affiliated with or controlling or controlled by such entity or person.

Certificate of Incorporation and Bylaws

        Provisions in our Restated Certificate of Incorporation and Amended and Restated Bylaws may have the effect of discouraging certain transactions that may result in a change in control of our company. Some of these provisions provide that stockholders cannot act by written consent and impose advance notice requirements and procedures with respect to stockholder proposals and the nomination of candidates for election as directors. Our Restated Certificate of Incorporation allows us to issue shares of preferred stock (see "Blank Check Preferred Stock") or common stock without any action by stockholders. Our directors and our officers are indemnified by us to the fullest extent permitted by applicable law pursuant to our Restated Certificate of Incorporation. Our Board of Directors is expressly authorized to make, alter or repeal our Amended and Restated Bylaws. These provisions may make it more difficult for stockholders to take specific corporate actions and may make it more difficult or discourage an attempt to obtain control of the Company by means of a proxy contest, tender offer, merger or otherwise.

Blank Check Preferred Stock

        Our Restated Certificate of Incorporation authorizes our Board of Directors to approve the issuance of up to 10,000,000 shares of preferred stock, without further approval of the stockholders, and to determine the rights and preferences of any series of preferred stock. The Board could issue one or more series of preferred stock with voting, conversion, dividend, liquidation or other rights that would adversely affect the voting power and ownership interest of holders of our common stock. This authority may have the effect of deterring hostile takeovers, delaying or preventing a change in control and discouraging bids for our common stock at a premium over the market price.

DESCRIPTION OF WARRANTS

        We may issue warrants to purchase common stock, preferred stock or other securities described in this prospectus. We may issue warrants independently or as part of a unit with other securities. Warrants sold with other securities as a unit may be attached to or separate from the other securities. The prospectus supplement relating to any warrants we are offering will describe specific terms relating to the offering, including a description of any other securities sold together with the warrants. These terms will include some or all of the following:

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the title of the warrants;



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the aggregate number of warrants offered;



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the price or prices at which the warrants will be issued;

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the designation, number and terms of any common stock, preferred stock or other securities purchasable upon exercise of the warrants and procedures by which those numbers may be adjusted;



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the exercise price of the warrants, including any provisions for changes or adjustments to the exercise price, and terms relating to the currency in which such price is payable;



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the dates or periods during which the warrants are exercisable;



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the designation and terms of any securities with which the warrants are issued as a unit;



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if the warrants are issued as a unit with another security, the date on or after which the warrants and the other security will be separately transferable;



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any minimum or maximum amount of warrants that may be exercised at any one time;



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any terms relating to the modification of the warrants;



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a discussion of material federal income tax considerations, if applicable; and



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any other terms of the warrants and any other securities sold together with the warrants, including, but not limited to, the terms, procedures and limitations relating to the transferability, exchange, exercise or redemption of the warrants.

        The applicable prospectus supplement will describe the specific terms of any warrant units.

        The descriptions of the warrants in this prospectus and in any prospectus supplement are summaries of the material provisions of the applicable warrant agreements. These descriptions do not restate those agreements in their entirety and do not contain all of the information that you may find useful. We urge you to read the applicable agreements because they, and not the summaries, define many of your rights as holders of the warrants or any warrant units. For more information, please review the form of the relevant agreements, which will be filed with the SEC promptly after the offering of warrants or warrant units and will be available as described under the heading "Where You Can Find More Information."

DESCRIPTION OF DEPOSITARY SHARES

        The following briefly summarizes the general provisions of depositary shares representing interests in shares of our preferred stock. Each issuance of shares will be issued under a depositary agreement to be entered into between us and a bank or trust company as depositary. The shares will be evidenced by depositary receipts. You should read the more detailed provisions of the deposit agreement and the form of depositary receipt for provisions that may be important to you. The particular terms of any depositary shares that we offer will be set forth in the applicable prospectus supplement. The prospectus supplement will also state whether any of the generalized provisions summarized below do not apply to the depositary shares being offered. We urge you to review the applicable agreements because they, and not the summaries, define many of your rights as a holder of the depositary shares. For more information, please review the form of deposit agreement and form of depositary receipts relating to each series of the preferred stock, which will be filed with the SEC promptly after the offering of that series of preferred stock and will be available as described under the heading "Where You Can Find More Information."

General

        We may elect to have shares of our preferred stock represented by depositary shares. The shares of any series of our preferred stock underlying the depositary shares will be deposited under a separate deposit agreement between us and a bank or trust company that we select. The prospectus supplement relating to a series of depositary shares will set forth the name and address of this depositary. Subject

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to the terms of the deposit agreement, each owner of a depositary share will be entitled, proportionately, to all the rights, preferences and privileges of the preferred stock represented by such depositary share, including dividend, voting, redemption, conversion, exchange and liquidation rights, if any, and all the limitations of the series of preferred stock.

        The depositary shares will be evidenced by depositary receipts issued pursuant to the deposit agreement, each of which will represent the applicable interest in a number of shares of a particular series of our preferred stock described in the applicable prospectus supplement.

        A holder of depositary shares will be entitled to receive the shares of preferred stock, but only in whole shares of preferred stock, underlying those depositary shares. If the depositary receipts delivered by the holder evidence a number of depositary shares in excess of the whole number of shares of preferred stock to be withdrawn, the depositary will deliver to that holder at the same time a new depositary receipt for the excess number of depositary shares.

Dividends and Other Distributions

        The depositary will distribute all cash dividends or other cash distributions it receives in respect of the series of preferred stock represented by the depositary shares to the record holders of depositary receipts represented by the depositary shares in proportion, to the extent possible, to the number of depositary shares owned by those holders. The depositary, however, will distribute only the amount that can be distributed without attributing to any depositary share a fraction of one cent, and any undistributed balance will be added to and treated as part of the next sum received by the depositary for distribution to record holders of depositary receipts then outstanding.

        If there is a dividend or distribution other than in cash in respect of the series of preferred stock represented by the depositary shares, the depositary will distribute property received by it to the record holders of depositary receipts in proportion, insofar as possible, to the number of depositary shares owned by those holders, unless the depositary determines that it is not feasible to make such a distribution. In that case, the depositary may, with our approval, adopt any method that it deems equitable and practicable to effect the distribution, including a public or private sale of the property and distribution of the net proceeds from the sale to the holders.

        The amount distributed in any of the above cases will be reduced by any amount we or the depositary are required to withhold on account of taxes.

Conversion and Exchange

        If any series of preferred stock underlying the depositary shares is subject to provisions relating to its conversion or exchange as set forth in an applicable prospectus supplement, each record holder of depositary receipts will have the right or obligation to convert or exchange the depositary shares evidenced by the depositary receipts pursuant to those provisions.

Redemption of Depositary Shares

        If any series of preferred stock underlying the depositary shares is subject to redemption and we redeem the preferred stock represented by the depositary shares, the depositary shares will be redeemed from the proceeds received by the preferred stock depositary resulting from the redemption, in whole or in part, of the preferred stock held by the depositary. Whenever we redeem a share of preferred stock held by the depositary, the depositary will redeem as of the same redemption date a proportionate number of depositary shares representing the shares of preferred stock that were redeemed. The redemption price per depositary share will be equal to the aggregate redemption price payable with respect to the number of shares of preferred stock underlying the depositary shares. If fewer than all the depositary shares are to be redeemed with respect to a specific series of preferred

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stock, the depositary shares to be redeemed will be selected by lot or proportionately as we may determine.

        After the date fixed for redemption, the depositary shares called for redemption will no longer be deemed to be outstanding and all rights of the holders of the depositary shares will cease, except the right to receive the redemption price. In order to redeem their depositary shares, holders must surrender their depositary receipts to the depositary. Any redemption price that we deposit with the depositary relating to depositary shares which are not redeemed by the holders of the depositary shares will be returned to us after a period of two years from the date the funds are deposited by us.

Voting

        Upon receipt of notice of any meeting at which the holders of any shares of preferred stock underlying the depositary shares are entitled to vote, the depositary will mail the information contained in the notice to the record holders of the depositary receipts. Each record holder of the depositary receipts on the record date, which will be the same date as the record date for the preferred stock, may then instruct the depositary as to the exercise of the voting rights pertaining to the number of shares of preferred stock underlying that holder's depositary shares. The depositary will try to vote, to the extent practicable, the number of shares of preferred stock underlying the depositary shares in accordance with the instructions, and we will agree to take all reasonable action which the depositary deems necessary to enable the depositary to do so. The depositary will abstain from voting the preferred stock to the extent that it does not receive specific written instructions from holders of depositary receipts representing the preferred stock.

Record Date

        Subject to the provisions of the deposit agreement, whenever:

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any cash dividend or other cash distribution becomes payable;



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any distribution other than cash is made;



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any rights, preferences or privileges are offered with respect to the preferred stock;



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the depositary receives notice of any meeting at which holders of preferred stock are entitled to vote or of which holders of preferred stock are entitled to notice; or



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the depositary receives notice of the mandatory conversion of or any election by us to call for the redemption of any preferred stock,

the depositary will in each instance fix a record date, which will be the same as the record date for the preferred stock, for the determination of the holders of depositary receipts:

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who will be entitled to receive dividend, distribution, rights, preferences or privileges or the net proceeds of any sale, or

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who will be entitled to give instructions for the exercise of voting rights at any such meeting or to receive notice of the meeting or the redemption or conversion.

Withdrawal of Preferred Stock

        Upon surrender of depositary receipts at the principal office of the depositary, upon payment of any unpaid amount due the depositary, and subject to the terms of the deposit agreement, the owner of the depositary shares evidenced by the depositary receipts is entitled to delivery of the number of whole shares of preferred stock and all money and other property, if any, represented by the depositary shares. Partial shares of preferred stock will not be issued. If the depositary receipts delivered by the holder evidence a number of depositary shares in excess of the number of depositary shares

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representing the number of whole shares of preferred stock to be withdrawn, the depositary will deliver to the holder at the same time a new depositary receipt evidencing the excess number of depositary shares. Holders of preferred stock that are withdrawn will not be entitled to deposit the preferred stock that have been withdrawn under the deposit agreement or to receive depositary receipts.

Amendment and Termination of the Deposit Agreement

        We and the depositary may at any time agree to amend the form of depositary receipt and any provision of the deposit agreement. However, any amendment that materially and adversely alters the rights of holders of depositary shares will not be effective unless the amendment has been approved by the holders of at least a majority of the depositary shares then outstanding. The deposit agreement may be terminated by us or by the depositary only if all outstanding shares have been redeemed or if a final distribution in respect of the underlying preferred stock has been made to the holders of the depositary shares in connection with our liquidation, dissolution or winding up.

Charges of Depositary

        We will pay all charges of the depositary including charges in connection with the initial deposit of the preferred stock, the initial issuance of the depositary receipts, the distribution of information to the holders of depositary receipts with respect to matters on which preference stock is entitled to vote, withdrawals of the preferred stock by the holders of depositary receipts or redemption or conversion of the preferred stock, except for taxes (including transfer taxes, if any) and other governmental charges and any other charges expressly provided in the deposit agreement to be at the expense of holders of depositary receipts or persons depositing preferred stock.

DESCRIPTION OF UNITS

        As specified in the applicable prospectus supplement, we may issue units comprised of one or more of the other securities described in this prospectus in any combination. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The prospectus supplement will describe:

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the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances the securities comprising the units may be held or transferred separately;



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a description of the terms of any unit agreement governing the units;



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a description of the provisions for the payment, settlement, transfer or exchange of the units;



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a discussion of material federal income tax considerations, if applicable; and



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whether the units will be issued in fully registered or global form.

        The descriptions of the units and any applicable underlying security or pledge or depository arrangements in this prospectus and in any prospectus supplement are summaries of the material provisions of the applicable agreements. These descriptions do not restate those agreements in their entirety and may not contain all the information that you may find useful. We urge you to read the applicable agreements because they, and not the summaries, define many of your rights as holders of the units. For more information, please review the form of the relevant agreements, which will be filed with the SEC promptly after the offering of units and will be available as described under the heading "Where You Can Find More Information."

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