A reverse stock split would affect all stockholders uniformly and would not alter any stockholder's percentage interest in our equity, except to the extent that a reverse stock split would result in some of our stockholders owning a fractional share as described below.

        A reverse stock split would not, by itself, affect our assets or business prospects. The common stock resulting from the reverse stock split will remain fully paid and non-assessable. The reverse stock split will not affect the public registration of the common stock under the Securities Exchange Act of 1934, as amended. The reverse stock split will also not affect our shares of preferred stock.

        If approved and implemented, a reverse stock split may result in some stockholders owning "odd lots" of less than 100 shares of common stock. Odd lot shares may be more difficult to sell, and brokerage commissions and other costs of transactions in odd lots are generally somewhat higher than the costs of transactions in "round lots" of even multiples of 100 shares.

        Assuming reverse stock split ratios of 1-for-4, 1-for-6 and 1-for-8, which reflect the low end, middle and high end of the range that our stockholders are being asked to approve, the following table sets forth, (i) the number of shares of our common stock that would be issued and outstanding, (ii) the number of shares of common stock authorized (subject to Proposal No. 2), (iii) the aggregate number of shares of our common stock that would be reserved for issuance upon (a) conversion of our Series A convertible preferred stock, (b) exercise of outstanding warrants and (c) exercise of outstanding stock options and (iv) the number of shares of our common stock that would be reserved and available for future issuance under our equity incentive plans, each giving effect to the reverse stock split and based on securities outstanding as of November 1, 2017. Such amounts listed below are approximateMarch 31, 2021 (except as no fractional shares will be issued and share amounts shall be rounded down.

Treatment of Fractional Shares

        No fractional shares will be issued in connection with a reverse stock split. Stockholders who otherwise would be entitled to receive fractional shares because they hold a number of shares of common stock not evenly divisible by the number selected by the board for a reverse stock split ratio will be entitled, upon surrender of any certificate(s) representing such shares, to a cash payment

Table of Contents

(without interest) in lieu thereof equal to the fraction of one share of common stock that such holder would otherwise be entitled to receive multiplied by the closing price per share of our common stock on the first trading day that commences after the reverse stock split is effective on the NASDAQ Capital Market.

        Stockholders who receive a cash payment in lieu of such fractional shares will no longer have any rights as a stockholder with respect to such shares.

Accounting Matters

        The par value of our common stock will remain unchanged at $0.001 per share after a reverse stock split. The reverse stock split will not affect total assets, liabilities or shareholders' equity. However, the per share net income or loss and net book value of the common stock will be retroactively increased for each period because there will be fewer shares of common stock outstanding.

Procedure for Effecting a Reverse Stock Split and Exchange of Stock Certificates

        If stockholders approve the proposal to amend our Restated Certificate of Incorporation, as amended, and the board determines to implement the reverse stock split (with the ratio to be determined in the discretion of the board within the parameters described)indicated below), we will file with the Secretary of State of the State of Delaware a Certificate of Amendment of Restated Certificate of Incorporation, as amended, in the form attached hereto as Appendix A, or the Certificate of Amendment, reflecting such reverse stock split ratio determined by the board. The reverse stock split will become effective at the time and on the date of filing of, or at such later time as is specified in, the Certificate of Amendment, which we refer to as the "effective time" and the "effective date," respectively. The effective time of the Certificate of Amendment shall be determined in the discretion of our board of directors and in accordance with applicable law. Beginning at the effective time, each certificate representing shares of common stock will be deemed for all corporate purposes to evidence ownership of the number of whole shares into which the shares previously represented by the certificate were combined pursuant to the reverse stock split.

        Our board has approved the amendment to our Restated Certificate of Incorporation, as amended. The ratio of the reverse stock split, within the parameters described, and the implementation and timing of such reverse stock split shall be determined in the discretion of our board of directors.

        Following any reverse stock split, stockholders holding physical certificates would need to exchange those certificates. As we are now fully participating in the direct registration system, you will not receive a replacement physical certificate. Instead you will receive uncertificated shares and a written confirmation from our transfer agent, Computershare Trust Company, N.A., indicating the whole number of uncertificated shares you own after the effect of the reverse stock split and a cash payment in lieu of any fractional shares. Our common stock will also receive a new CUSIP number.

        If a reverse stock split is implemented, our transfer agent will advise registered stockholders of the procedures to be followed to exchange certificates in a letter of transmittal to be sent to stockholders. No written confirmations will be issued to a stockholder until the stockholder has surrendered the stockholder's outstanding certificate(s), together with the properly completed and executed letter of transmittal, to our transfer agent. Any old shares submitted for transfer, whether pursuant to a sale, other disposition or otherwise, will automatically be exchanged for new shares.Stockholders should not destroy any stock certificate(s) and should not submit any certificate(s) until requested to do so.

        Certain of our registered stockholders hold some or all of their shares electronically in book-entry form with our transfer agent. These stockholders do not hold physical certificates evidencing their ownership of our common stock. However, they are provided with a statement reflecting the number of shares of our common stock registered in their accounts. If a stockholder holds shares of common

Table of Contents

stock in book-entry form with our transfer agent, no action needs to be taken to receive post-reverse stock split shares or payment in lieu of fractional shares, if applicable. If a stockholder is entitled to post-reverse stock split shares, a transaction statement will automatically be sent to the stockholder's address of record indicating the number of shares of our common stock held following the reverse stock split.

        Upon a reverse stock split, we intend to treat stockholders holding our common stock in "street name," through a broker, bank or other nominee, in the same manner as registered stockholders whose shares are registered in their names. Brokers, banks or other nominees will be instructed to effect a reverse stock split for their beneficial holders holding our common stock in "street name." However, these brokers, banks or other nominees may have different procedures than registered stockholders for processing a reverse stock split. If you hold your shares with a broker, bank or other nominee and if you have any questions in this regard, we encourage you to contact your nominee.

No Appraisal Rights

        Stockholders do not have appraisal rights under the Delaware General Corporation Law or under our Restated Certificate of Incorporation, as amended, in connection with the reverse stock split.

Reservation of Right to Abandon the Amendment to our Restated Certificate of Incorporation, as amended

        Our board reserves the right to abandon the amendment to our Restated Certificate of Incorporation, as amended, described in this Proposal No. 1 without further action by our stockholders at any time before the effective time, even if stockholders approve such amendment at the special meeting of stockholders. By voting in favor of the amendment to our Restated Certificate of Incorporation, as amended, stockholders are also expressly authorizing the board to determine not to proceed with, and abandon, a reverse stock split if it should so decide.

Material U.S. Federal Income Tax Consequences of the Reverse Stock Split

        The following discussion is a summary of the material U.S. federal income tax consequences of the proposed reverse stock split to U.S. Holders (as defined below) of our common stock. This discussion is based on the Internal Revenue Code of 1986, as amended, which we refer to as the Code, U.S. Treasury Regulations promulgated thereunder, judicial decisions, and published rulings and administrative pronouncements of the U.S. Internal Revenue Service, which we refer to as the IRS, in each case in effect as of the date of this proxy statement. These authorities may change or be subject to differing interpretations. Any such change or differing interpretation may be applied retroactively in a manner that could adversely affect a U.S. Holder. We have not sought and will not seek any rulings from the IRS regarding the matters discussed below and there can be no assurance the IRS or a court will not take a contrary position to that discussed below regarding the tax consequences of the proposed reverse stock split.

        For purposes of this discussion, a "U.S. Holder" is a beneficial owner of our common stock that, for U.S. federal income tax purposes, is or is treated as (i) an individual who is a citizen or resident of the United States; (ii) a corporation (or any other entity or arrangement treated as a corporation) created or organized under the laws of the United States, any state thereof, or the District of Columbia; (iii) an estate, the income of which is subject to U.S. federal income tax regardless of its source; or (iv) a trust if (1) its administration is subject to the primary supervision of a court within the United States and all of its substantial decisions are subject to the control of one or more "United States persons" (within the meaning of Section 7701(a)(30) of the Code), or (2) it has a valid election in effect under applicable U.S. Treasury regulations to be treated as a United States person.

Table of Contents

        This discussion is limited to U.S. Holders who hold our common stock as a "capital asset" within the meaning of Section 1221 of the Code (generally, property held for investment). This discussion does not address all U.S. federal income tax consequences relevant to the particular circumstances of a U.S. Holder, including the impact of the Medicare contribution tax on net investment income. In addition, it does not address consequences relevant to U.S. Holders that are subject to special rules, including, without limitation, financial institutions, insurance companies, real estate investment trusts, regulated investment companies, grantor trusts, tax-exempt organizations, dealers or traders in securities or currencies, stockholders who hold our common stock as part of a position in a straddle or as part of a hedging, conversion or integrated transaction for U.S. federal income tax purposes, U.S. Holders that have a functional currency other than the U.S. dollar, or U.S. Holders who actually or constructively own 10% or more of our voting stock.

        If a partnership (or other entity treated as a partnership for U.S. federal income tax purposes) is the beneficial owner of our common stock, the U.S. federal income tax treatment of a partner in the partnership will generally depend on the status of the partner and the activities of the partnership. Accordingly, partnerships (and other entities treated as partnerships for U.S. federal income tax purposes) holding our common stock and the partners in such entities should consult their own tax advisors regarding the U.S. federal income tax consequences of the proposed reverse stock split to them.

        In addition, the following discussion does not address the U.S. federal estate and gift tax, alternative minimum tax, or state, local and non-U.S. tax law consequences of the proposed reverse stock split. Furthermore, the following discussion does not address any tax consequences of transactions effectuated before, after or at the same time as the proposed reverse stock split, whether or not they are in connection with the proposed reverse stock split.

Each stockholder should consult his, her or its own tax advisors concerning the particular U.S. federal tax consequences of the reverse stock split, as well as the consequences arising under the laws of any other taxing jurisdiction, including any state, local or foreign income tax consequences.

        The proposed reverse stock split is intended to be treated as a "recapitalization" for U.S. federal income tax purposes pursuant to Section 368(a)(1)(E) of the Code. As a result, a U.S. Holder generally should not recognize gain or loss upon the proposed reverse stock split for U.S. federal income tax purposes, except with respect to cash received in lieu of a fractional share of our common stock, as discussed below. A U.S. Holder's aggregate adjusted tax basis in the shares of our common stock received pursuant to the proposed reverse stock split should equal the aggregate adjusted tax basis of the shares of our common stock exchanged therefor (reduced by the amount of such basis that is allocated to any fractional share of our common stock). The U.S. Holder's holding period in the shares of our common stock received pursuant to the proposed reverse stock split should include the holding period in the shares of our common stock exchanged therefor. U.S. Treasury Regulations provide detailed rules for allocating the tax basis and holding period of shares of common stock surrendered in a recapitalization to shares received in the recapitalization. U.S. Holders of shares of our common stock acquired on different dates and at different prices should consult their tax advisors regarding the allocation of the tax basis and holding period of such shares.

        A U.S. Holder that, pursuant to the proposed reverse stock split, receives cash in lieu of a fractional share of our common stock should recognize capital gain or loss in an amount equal to the difference, if any, between the amount of cash received and the portion of the U.S. Holder's aggregate adjusted tax basis in the shares of our common stock surrendered that is allocated to such fractional share. Such capital gain or loss will be short term if the pre-reverse stock split shares were held for one year or less at the effective time of the reverse stock split and long term if held for more than one year. No gain or loss will be recognized by us as a result of the proposed reverse stock split.

Table of Contents

        A U.S. Holder of our common stock may be subject to information reporting and backup withholding on cash paid in lieu of a fractional share in connection with the proposed reverse stock split. A U.S. Holder of our common stock will be subject to backup withholding if such U.S. Holder is not otherwise exempt and such U.S. Holder does not provide its taxpayer identification number in the manner required or otherwise fails to comply with applicable backup withholding tax rules. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be refunded or allowed as a credit against a U.S. Holder's federal income tax liability, if any, provided the required information is timely furnished to the IRS. U.S. Holders of our common stock should consult their own tax advisors regarding their qualification for an exemption from backup withholding and the procedures for obtaining such an exemption.

        The U.S. federal income tax discussion set forth above does not discuss all aspects of U.S. federal income taxation that may be relevant to a particular stockholder in light of such stockholder's circumstances and income tax situation.Accordingly, we urge you to consult with your own tax advisor with respect to all of the potential U.S. federal, state, local and foreign tax consequences to you of the reverse stock split.

Recommendation of the Board of Directors

Our board of directors unanimously recommends that the stockholders vote FOR the proposal to amend our Restated Certificate of Incorporation, as amended, to effect a reverse stock split of our issued and outstanding common stock by a whole number ratio of not less than 1-for-4 and not more than 1-for-8, such ratio and the implementation and timing of such reverse stock split to be determined in the discretion of our board of directors at any time prior to our 2018 annual meeting of stockholders, and, in connection therewith, to decrease the number of authorized shares of our common stock on a basis proportional to the reverse stock split ratio.

Table of Contents

PROPOSAL TWO

APPROVE AN AMENDMENT TO OUR RESTATED CERTIFICATE OF INCORPORATION, AS AMENDED, TO SET THE NUMBER OF AUTHORIZED SHARES OF OUR COMMON STOCK AT A NUMBER DETERMINED BY CALCULATING THE PRODUCT OF 280,000,000 MULTIPLIED BY TWO TIMES (2X) THE REVERSE STOCK SPLIT RATIO.

General

        In October 2017, our board approved, subject to stockholder approval and the implementation of the reverse stock split described in Proposal No. 1, an additional amendment to our Restated Certificate of Incorporation, as amended, to set the number of authorized number of shares of our common stock at a number determined by calculating the product of 280,000,000 multiplied by two times (2x) the reverse stock split ratio. If Proposal No. 1 and Proposal No. 2 are approved and the reverse stock split is implemented then, effectively, upon such split, the number of our authorized shares of common stock will be decreased proportionally to the reverse stock split ratio, and then such decreased amount will be increased by 200%.

        Our board believes that, if Proposal No. 2 is not approved, following the implementation of a reverse stock split of our issued and outstanding common stock and the proportionate decrease in our authorized common stock as described in Proposal No. 1, we would have limited flexibility to issue shares of common stock in connection with possible future financings, joint ventures, acquisitions, stock incentive plans and other general corporate purposes. As a result, our board believes that a 2x increase in our authorized common stock in such instance is in our and our stockholders' best interests because it will provide us with that flexibility. We do not currently have any plans, understandings, arrangements, commitments or agreements, written or oral, for the issuance of the additional shares of common stock that would be authorized if this proposal is approved. However, we desire to have the shares available to provide additional flexibility to use our common stock for business and financial purposes in the future as well to have sufficient shares available to provide appropriate equity incentives for our employees.

        Proposal No. 2 is subject to, and conditioned upon, approval of the amendment to our Restated Certificate of Incorporation, as amended, to effect the reverse stock split in Proposal No. 1. If the reverse stock split pursuant to Proposal No. 1 and the amendment pursuant to this Proposal No. 2 are approved by the requisite vote of our stockholders, and our board determines to implement such proposals, the change in the number of shares of our authorized common stock would become effective upon the date and time set by our board, as set forth in the amendment to our Restated Certificate of Incorporation, as amended, to be filed with the Secretary of State of the State of Delaware. In addition, our board reserves the right, notwithstanding stockholder approval and without further action by our stockholders, to abandon the amendment if, at any time prior to the effectiveness of the filing of the amendment with the Secretary of State, our board, in its sole discretion, determines that it is no longer in our best interest and the best interests of our stockholders to proceed. Our board does not anticipate receiving further authorization from stockholders for the issuance of any newly authorized shares, except as required by applicable laws, rules and regulations.

        The form of the proposed amendment to our Restated Certificate of Incorporation, as amended, to effect the reverse stock split and set the number of authorized shares of our common stock at a number determined by calculating the product of 280,000,000 multiplied by two times (2x) the reverse stock split ratio is attached as Appendix A to this proxy statement. Any amendment to our Restated Certificate of Incorporation, as amended, to set the number of authorized shares of our common stock at a certain number will be based on the reverse stock split ratio fixed by our board, within the range approved by our stockholders pursuant to Proposal No. 1.

Table of Contents

Effect of the Proposal

        We currently have 280,000,000 shares of common stock authorized for issuance under our Restated Certificate of Incorporation, as amended. Assuming (i) reverse stock split ratios of 1-for-4, 1-for-6 and 1-for-8, which reflect the low end, middle and high end of the range that our stockholders are being asked to approve, and (ii) that the number of our authorized shares of common stock is reduced proportionally to the reverse stock split ratios of 1-for-4, 1-for-6 and 1-for-8 and then subsequently increased by 2x as provided in Proposal No. 2, the following table sets forth (a) the number of shares of our common stock that would be authorized, (b) the number of shares of our common stock that would be issued and outstanding, (c) the aggregate number of shares of our common stock that would be reserved for issuance upon (1) conversion of our Series A convertible preferred stock, (2) exercise of outstanding warrants and (3) exercise of outstanding stock options and (d) the number of shares of our common stock that would be reserved and available for future issuance under our equity incentive plans, each giving effect to the reverse stock split and based on securities outstanding as of November 1, 2017. The following table also sets forth the number of shares of our common stock that would be authorized if this Proposal No. 2 is not approved. Such amounts listed below are approximate as no fractional shares will be issued and share amounts shall be rounded down.

        The additional shares of authorized common stock would have the same rights and privileges as the shares of common stock currently issued and outstanding. Holders of our common stock have no preemptive rights.

Reservation of Right to Abandon the Amendment to our Restated Certificate of Incorporation, as amended

        Our board reserves the right to abandon the amendment to our Restated Certificate of Incorporation, as amended, described in this Proposal No. 2 without further action by our stockholders

Table of Contents

at any time before the effective time, even if stockholders approve such amendment at the special meeting of stockholders.

Recommendation of the Board of Directors

Our board of directors recommends that stockholders vote FOR the proposal to amend our Restated Certificate of Incorporation, as amended, to set the number of authorized shares of our common stock at a number determined by calculating the product of 280,000,000 multiplied by two times (2x) the reverse stock split ratio.

Table of Contents

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL
OWNERS AND MANAGEMENT

        On November 1, 2017, we had 194,870,303 shares of common stock issued and outstanding. The following table sets forth information we know about the beneficial ownership of our common stock as of November 1, 2017, by: