operation and expansion of our business. Any determination to pay cash dividends in the future will depend upon, among other things, our results of operations, plans for expansion, tax considerations, available net profits and reserves, limitations under law, financial condition, capital requirements and other factors that our board of directors considers to be relevant.
Preferred Stock
Under the terms of our amended and restated certificate of incorporation, our board of directors is authorized to direct us to issue shares of preferred stock in one or more series without stockholder approval. Our board of directors has the discretion to determine the rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, of each series of preferred stock.
The purpose of authorizing our board of directors to issue preferred stock and determine its rights and preferences is to eliminate delays associated with a stockholder vote on specific issuances. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions, future financings 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 seeking to acquire, a majority of our outstanding voting stock. Upon the closing of this offering, there will be no shares of preferred stock outstanding, and we have no present plans to issue any shares of preferred stock.
Options
As of March 31, 2021, options to purchase an aggregate of 189,069 shares of our common stock were outstanding under our 2005 Equity Incentive Plan, or our 2005 Plan (all of which were vested and exercisable as of such date), options to purchase 576,806 shares of common stock were outstanding under our 2016 Equity Incentive Plan, or our 2016 Plan (of which 353,774 shares were vested and exercisable as of such date) and options to purchase 996,730 shares of common stock were outstanding under our 2020 Incentive Award Plan, or our 2020 Plan (of which 123,093 shares were vested and exercisable as of such date).
Registration Rights
Certain holders shares of our common stock are entitled to certain rights with respect to the registration of such shares for public resale under the Securities Act, pursuant to our eighth amended and restated investors’ rights agreement, as amended, or the investor rights agreement, until the rights otherwise terminate pursuant to the terms of the investor rights agreement. The registration of shares of common stock as a result of the following rights being exercised would enable holders to trade these shares without restriction under the Securities Act when the applicable registration statement is declared effective.
Form S-1 Registration Rights
If at any time the holders of at least 30% of the registrable securities then outstanding request in writing that we effect a registration with respect to all or part of such registrable securities then outstanding having an anticipated aggregate offering price that would exceed $5,000,000, we may be required to register their shares. We are obligated to effect at most two registrations in response to these demand registration rights. If the holders requesting registration intend to distribute their shares by means of an underwriting, the managing underwriter of such offering will have the right to limit the numbers of shares to be underwritten for reasons related to the marketing of the shares.
Piggyback Registration Rights
If at any time we propose to register any shares of our common stock under the Securities Act, subject to certain exceptions, the holders of registrable securities then outstanding will be entitled to notice of the
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