6.    Convertible Preferred Stock and Stockholders’ Equity (Deficit)

Series A 8% Senior Convertible Preferred Stock

On April 18, 2019, we entered into a Securities Purchase Agreement, dated as of April 18, 2019, with Lisa Walsh (the “Preferred SPA”), pursuant to which we issued 250,000 shares of our Series A 8% Senior Convertible Preferred Stock, par value $0.0001 per share (the “Series A Preferred Stock”), which shares have a stated value of $4.00, grant holders the same voting rights as holders of our shares of common stock, and are convertible into shares of our common stock at price of $80.00 per share, subject to a floor price of $30.00 and to adjustment under our Certificate of Designations of the Preferences, Rights and Limitations of the Series A Preferred Stock, in consideration for $1,000,000 (the “Initial Tranche”). The Series A Preferred Stock may be issued in tranches of at least $500,000 and in an aggregate of up to $5 million. In connection with the Initial Tranche, the Company also issued to Ms. Walsh a warrant to purchase 12,756 shares of our common stock.

The Series A Preferred Stock contains an embedded conversion feature that the Company has determined is a derivative requiring bifurcation.  The fair value of the derivative liability at the issuance of the Series A Preferred Stock was $216,000, which was recorded as a derivative liability with the offset recorded as a discount to the Series A Preferred Stock. (See Note 5 – Fair Value Measurements for the fair value computation.)

The authorized, issued and outstanding shares of Series A Preferred Stock and liquidation preferences as of March 31, 2021, were as follows:

 

 

The Series A Preferred Stock rights, privileges and preferences are as follows:

Dividends — The holders of the Series A Preferred Stock are entitled to receive cumulative dividends at the rate per share of 8% per annum, payable on conversion.  The form of the dividend payment on the Series A Preferred Stock will be determined based on the legal availability of funds for the payment and the satisfaction of the Equity Conditions (as defined in the Certificate of Designations) for the 5 consecutive trading days immediately prior to the payment date.  The form of the payment, depending on the priority, may be made in cash or shares of common stock at the Company’s option. If funds are not available and the Equity Conditions have not been met, the dividends will accrue to the next payment date or accrete to the Stated Value. The Company accrued dividends of $20,000 for each of the three months ended March 31, 2021 and 2020.

Liquidation Rights — In the event of any liquidation, dissolution, or winding-up of the Company, each holder of Series A Preferred Stock is entitled to receive an amount equal to the Stated Value, plus accrued and unpaid dividends and any other fees or liquidated damages before any distribution will be made to holders of junior securities. If assets are insufficient for such payment, then the entire assets will be distributed only to the holders of the Series A Preferred Stock. A fundamental or change of control transaction is not deemed a liquidation.

Conversion — Each share of Series A Preferred Stock is convertible at the option of the holder into the number of shares of common stock (subject to adjustment for certain events, including dilutive issuances, stock splits, and reclassifications) determined by multiplying such number by the ratio of the Stated Value by a conversion price, which price is originally equal to $80.00 (the “Fixed Conversion Price”). However, if the closing price of the common stock is less than the Fixed Conversion Price, then the Fixed Conversion Price may be reduced to equal 95% of the lowest volume weighted average price of the common stock for the previous 10 trading days, which price shall not be less than $30. Notwithstanding the foregoing, unless the Company obtains stockholder approval pursuant to the rules and regulations of The Nasdaq Capital Market, the Company cannot issue shares of common stock upon conversion of the Series A Preferred Stock in the event that such issuance exceeds 19.99% of the issued and outstanding shares of the Company’s common stock as of April 18, 2019 or if such conversion is considered a “change of control” under Nasdaq rules and regulations.

Voting Rights — Each holder has the right to one vote for each share of common stock into which such preferred stock could be converted. So long as any shares of Series A Preferred Stock are outstanding, the Company shall not, without first obtaining the approval of more than 67% of the holders of Series A Preferred Stock then outstanding, voting together as a separate class (a) alter or amend the Certificate of Designations or alter or change adversely the powers, rights or preferences of the Series A Preferred Stock, including amending the Company’s certificate of incorporation or other charter documents in any manner adversely affecting the holders of the Series A Preferred Stock; (b) authorize or create any class of stock ranking as to dividends, redemption or distribution of assets upon a liquidation senior to, or otherwise pari passu with, the Series A Preferred Stock; (c) increase the total number of authorized shares of Series A Preferred Stock; or (d) enter into any agreement with respect to any of the foregoing.

Redemption — The Series A Preferred Stock is not mandatorily redeemable as it does not have a set redemption date or a date after which the shares may be redeemed by the holders. However, if a Triggering Event (as defined in the Certificate of Designations) occurs, then each holder will receive 120% of the aggregate Stated Value, plus all accrued and unpaid dividends and any other fees or liquidated damages.  Additionally, upon such an event, the divided rate of the Series A Preferred Stock increases to 18% per annum. A Triggering Event is defined as any (1) default on credit obligations; (2) default on payment of certain Series A Preferred Stock payments or a default under the Certificate of Designations and any related transaction document entered into in connection with the issuance of the Series A Preferred Stock; (3) bankruptcy of the Company; (4) ineligibility for listing of the Company’s common stock on a trading market; (5) change of control or fundamental transaction entered into by the Company, or other transaction entered into by the Company where more than 51% of the Company’s assets are sold; (6) failure of the Company to perform certain regulatory reporting; (7) failure to timely deliver certificates representing shares of common stock upon conversion of the shares of Series A Preferred Stock; (8) failure of the Company to maintain a sufficient number of reserved shares pursuant to the Preferred SPA; and (9) judgment is entered or filed against the Company or its subsidiaries in excess of an aggregate of $100,000 or the Company or any of its subsidiaries experiences a loss of property in excess of an aggregate of $100,000.  The Company has elected not to adjust the carrying values of the Series A Preferred Stock to the liquidation preferences of such shares because it is uncertain whether or when an event would occur that would obligate the Company to pay the liquidation preferences to holders of shares and at the balance sheet date, these circumstances were not probable. Subsequent adjustments to the carrying values of the liquidation preferences will be made only when it becomes probable that such a liquidation event will occur. 

Rights Upon a Subsequent Financing - So long as holders of shares of Series A Preferred Stock hold such shares with an aggregate Stated Value equal to or exceeding $250,000, upon any issuance of shares of our common stock, Common Stock Equivalents (as defined in the Preferred SPA), conventional debt or a combination of such securities and/or debt (a “Subsequent Financing”), unless the proposed terms of a Subsequent Financing shall have first been delivered to such holders in reasonable detail and such holders have first been granted the option to purchase such securities pursuant to such terms, such holders have the right to purchase all, and no less than all, of the securities offered to investors in a Subsequent Financing on the same terms, conditions and price provided for in the Subsequent Financing. In addition, so long as holders of shares of Series A Preferred Stock hold such shares with an aggregate Stated Value equal to or exceeding $500,000, if we effect a Subsequent Financing, such holders have a right to tender shares of Series A Preferred Stock for the securities offered pursuant to a Subsequent Financing.

Subsequent Equity Sales - In the event that we or any of our subsidiaries issue additional shares of common stock and/or common stock equivalents in connection with a financing pursuant to which the effective price per share for such securities is less than the then conversion price of the Series A Preferred Stock, then subject to certain exceptions set forth in the Certificate of Designations, such conversion price will be reduced to such the effective price of such issued securities.

Common Stock

On January 30, 2018, the Company’s board of directors approved the establishment of the Company’s 2018 Long-Term Stock Incentive Plan (the “LTIP”) and termination of its Carve-Out Plan (the “Plan”). Under the LTIP, the aggregate maximum number of shares of common stock (including shares underlying options) that may be issued under the LTIP pursuant to awards of Restricted Shares or Options will be limited to 15% of the outstanding shares of common stock , which calculation shall be made on the first trading day of each new fiscal year; provided that, in any year no more than 8% of the common stock or derivative securitization with common stock underlying 8% of the common stock may be issued in any fiscal year. Thereafter, the 15% evergreen provision governs the LTIP. For fiscal year 2021, up to 672,180 shares of common stock are available for participants under the LTIP.

For the three months ended March 31, 2021 and 2020, 352 and 353 shares of restricted stock, respectively, were released with an intrinsic value of approximately $1,000 and $2,000, respectively.

A summary of activity related to restricted stock awards (excluding the deferred shares) for the three months ended March 31, 2021 is presented below:

 

As of March 31, 2021, the unamortized compensation costs related to the unvested restricted stock awards was approximately $2,383,000 which is to be amortized on a straight-line basis over a weighted-average period of approximately 2.9 years.

2020 Stock Incentive Plan

On July 27, 2020, the board of directors adopted the Company’s 2020 Stock Incentive Plan (the “2020 Stock Plan”) and the reservation of an aggregate of 650,000 shares of the Company’s common stock authorized for issuance under the 2020 Stock Plan, subject to stockholder approval. The 2020 Stock Plan authorizes the grant of equity-based compensation to the Company’s senior managers, employees, directors, consultants, professionals and service providers in the form of stock options, restricted stock and restricted stock units. On July 27, 2020, the Company also granted, subject to stockholder approval, an aggregate of 614,824 restricted stock units to senior managers, employees, directors, consultants. Each of the awards are scheduled to vest on the first, second, and third anniversaries of August 15, 2020, so long as such award recipient remains in service of the Company on each such anniversary. Each restricted stock unit represents the right to receive one share of the Company’s common stock under the 2020 Stock Plan. On October 20, 2020, the Company held the 2020 Annual Meeting of Stockholders and approved the adoption of the 2020 Stock Plan and the reservation of an aggregate of 650,000 shares of the Company’s common stock. In connection with the approval, the Company issued 614,824 restricted stock units to employees, directors and consultants.

A summary of activity related to restricted stock units under the Company’s 2020 Stock Plan for the three months ended March 31, 2021 is presented below:

 

As of March 31, 2021, the unamortized compensation costs related to the unvested restricted stock units was approximately $1,281,000 which is to be amortized on a straight-line basis over a weighted-average period of approximately 2.4 years.

February 2020 Private Placement

On February 28, 2020, the Company completed a private placement (the “February 2020 Private Placement”) of 91,062 units (the “Units”), each unit consisting of (i) one (1) share of common stock and (ii) a warrant to purchase 0.50 of a share of common stock (the “February 2020 Warrants”), at a price per Unit of $9.17. The Units were issued pursuant to a Unit Purchase Agreement, dated February 4, 2020, and a subscription agreement, dated February 28, 2020 by and among the Company and the purchasers signatory thereto. In connection with the February 2020 Private Placement, we paid Alexander Capital, L.P. (“Alexander”) cash fees of $83,000 and issued to Alexander a warrant to purchase 4,553 shares of common stock (the “February 2020 Alexander Warrant”). Such warrant is exercisable at a per share price of $8.80 and is exercisable at any time during the five-year period commencing on the date of issuance. The February 2020 Private Placement, which was priced above market, resulted in gross proceeds of $835,000 before fees and other expenses associated with the transaction.

The February 2020 Warrants are exercisable to purchase up to an aggregate of 45,534 shares of common stock commencing on the date of issuance at an exercise price of $9.80 per share, subject to adjustment upon stock splits, reverse stock splits, and similar capital changes. The February 2020 Warrants are exercisable immediately and will expire on the close of business on February 28, 2025. The exercise of the February 2020 Warrants are subject to beneficial ownership limitations such that each holder of such February 2020 Warrant may exercise it to the extent that such exercise would result in such holder being the beneficial owner in excess of 4.99% (or, upon election of such holder, 9.99%), which beneficial ownership limitation may be increased or decreased up to 9.99% upon notice to the Company, provided that any increase in such limitation will not be effective until 61 days following notice to the Company.

The grant date fair value of February 2020 Warrants was $103,000, which was recorded within stockholders’ equity as a cost of issuance and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet. The fair value of such warrants was determined using the Black-Scholes Model based on the following weighted average assumptions: common stock price on date of grant of $6.00; expected dividend yield of 0.0%; expected volatility of 59.0%; risk-free interest rate of 0.89% and expected life of 5 years.

The fair value of the February 2020 Alexander Warrant at issuance was $11,000. The fair value of such warrant was estimated using the Black-Scholes Model based on the following weighted average assumptions: common share price on date of grant $6.00, expected dividend yield 0%, expected volatility 59%, risk-free interest rate 0.89% and expected life of 5 years. The fair value was recorded within stockholders’ equity as a cost of issuance and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet.

April 2020 Public Offering

On April 23, 2020, the Company closed an underwritten public offering of 1,525,000 shares of its common stock, pre-funded common stock purchase warrants to purchase up to an aggregate of 475,000 shares of common stock, and common stock purchase warrants to purchase up to an aggregate of 2,000,000 shares of the Company’s common stock (the “April 2020 Public Offering”). Each share of common stock or pre-funded common stock purchase warrant was sold together with one common stock purchase warrant to purchase one share of common stock at a combined price to the public of $3.25 per share and common stock purchase warrant (or $3.24 per pre-funded common stock purchase warrant and common stock purchase warrant). Gross proceeds before deducting underwriting discounts, commissions and other offering expenses were approximately $6.5 million. In addition, the Company granted to Maxim a 45-day option to purchase up to an additional 300,000 shares of common stock and/or common stock purchase warrants to purchase up to an aggregate of 300,000 shares of common stock, at the public offering price, less discounts and commissions, of which Maxim partially exercised its option to purchase additional common stock purchase warrants to purchase up to an aggregate of 229,100 shares of common stock. Each common stock purchase warrant is immediately exercisable for one share of common stock at an exercise price of $3.25 per share and will expire five years from issuance.  The Company also issued a warrant to Maxim to purchase up to 100,000 shares of common stock in connection with the April 2020 Public Offering (the “April 2020 Maxim Warrant”). Such warrant has an exercise price of $3.90 per share and is fully vested.

May 2020 Shelf Registration

On May 18, 2020, we registered for resale, pursuant to a prospectus supplement to our shelf registration statement, an aggregate of 60,250 shares of common stock, 50,000 of which shares were the Alexander Settlement Shares, and the remaining 10,250 of such shares which were issued to one of the Company’s vendors pursuant to the Settlement Letter, dated May 12, 2020, by and between us and such vendor.

Purchase Agreements

On June 4, 2020, we entered into a securities purchase agreement (the “June 4, 2020 Purchase Agreement”) with several accredited investors providing for the issuance of (i) 2,275,000 shares of the Company’s common stock and (ii) warrants, with a term of 5.5 years, to purchase an aggregate of up to 2,275,000 shares of common stock at an exercise price of $2.55 per share, subject to customary adjustments thereunder, which warrants were immediately exercisable upon issuance and on a cashless basis if such warrants have not been registered on or before six months after the date of issuance. Pursuant to the June 4, 2020 Purchase Agreement, the investors purchased all of the securities sold thereby for an aggregate purchase price of $5,801,000. Pursuant to the June 4, 2020 Purchase Agreement, an aggregate of 2,275,000 shares of common stock were issued to the investors in a registered direct offering pursuant to a prospectus supplement to the Company’s currently effective registration statement on Form S-3, which was declared effective on September 6, 2019. The Company filed the prospectus supplement on June 5, 2020. Maxim acted as the placement agent. The warrants were issued to the investors in a concurrent private placement transaction pursuant to an exemption from the registration requirements of the Securities Act provided in Section 4(a)(2) of the Securities Act and/or Regulation D promulgated thereunder. The Company paid Maxim a fee of approximately $464,000, which was equal to 8% of the aggregate purchase price paid by investors placed by Maxim and certain expenses. The June 4, 2020 Purchase Agreement contains customary representations, warranties and agreements of the Company and the investors and customary indemnification rights and obligations of the parties thereto. The offering of the securities pursuant to the June 4, 2020 Purchase Agreement was closed on June 8, 2020.

On June 9, 2020, we entered into a securities purchase agreement (the “June 9, 2020 Purchase Agreement”) with several accredited investors providing for the issuance of (i) 2,040,000 shares of the Company’s common stock and (ii) warrants, with a term of 5.5 years, to purchase an aggregate of up to 2,040,000 shares of common stock at an exercise price of $2.61 per share, subject to customary adjustments thereunder, which warrants were immediately exercisable upon issuance and on a cashless basis if the Warrants have not been registered on or before six months after the date of issuance. Pursuant to the June 9, 2020 Purchase Agreement, the investors purchased all of the securities sold thereby for an aggregate purchase price of $5,324,000. Pursuant to the June 9, 2020 Purchase Agreement, an aggregate of 2,040,000 shares of common stock were issued to the investors in a registered direct offering, pursuant to a prospectus supplement to the Company’s currently effective registration statement on Form S-3, which was declared effective on September 6, 2019. The Company filed the prospectus supplement on June 10, 2020. Maxim acted as the placement agent. The warrants were issued to the investors in a concurrent private placement transaction pursuant to an exemption from the registration requirements of the Securities Act provided in Section 4(a)(2) of the Securities Act and/or Regulation D promulgated thereunder. The Company paid Maxim a fee of approximately $426,000, which was equal to 8% of the aggregate purchase price paid by investors placed by Maxim and certain expenses. The June 9, 2020 Purchase Agreement contains customary representations, warranties and agreements of the Company and the investors and customary indemnification rights and obligations of the parties thereto. The offering of the securities pursuant to the June 9, 2020 Purchase Agreement was closed on June 11, 2020.

Settlement Agreements

On May 14, 2020, we entered into a settlement agreement with Alexander (the “Alexander Settlement Agreement”), pursuant to which, in consideration for Alexander releasing us from all claims against us arising out of that certain engagement agreement, dated February 6, 2020, that we entered into with Alexander (the “Alexander Engagement Agreement”), other than indemnification for certain third-party claims, we agreed to (i) pay Alexander a one-time cash payment of $125,000 and (ii) issue to Alexander 50,000 shares of our common stock (the “Alexander Settlement Shares”) which had a value of approximately $111,000. We also released Alexander from the same type of claims against Alexander, other than indemnification for certain third-party claims. In connection with the Alexander Settlement Agreement, on May 14, 2020, we also entered into a leak-out agreement with Alexander (the “Alexander Leak-Out Agreement”), pursuant to which Alexander shall not dispose of more than 5,000 shares of common stock in any trading day, commencing on the date of such agreement and ending on the date on which Alexander no longer holds any Alexander Settlement Shares.

On November 9, 2020, in order to resolve a dispute between certain investors (the “February 2020 Holders”) and the Company regarding certain registration rights in connection with the February 2020 Private Placement, the Company entered into a settlement and release agreement with each of the February 2020 Holders (the “Settlement Agreement”), pursuant to which (i) the Company and the February 2020 Holders agreed to amend the original warrants issued in February 2020 (the “Original Warrants”) to provide for the purchase of one additional share of common stock for each share of common stock available under the Original Warrants, totaling 45,534 additional common stock purchase warrants, (ii) the Company and the February 2020 Holders agreed to amend the Original Warrants to reduce the exercise price to $2.55, and (iii) the Company agreed to issue an additional 236,375 shares of common stock and 236,369 common stock purchase warrants to purchase up to 236,369 shares of common stock. As consideration for the foregoing, the February 2020 Holders agreed to release any and all claims they may have against the Company, including, but not limited to, claims arising in connection with any securities held by the February 2020 Holders.

Warrants for Shares of Common Stock

The Company has issued warrants to purchase shares of common stock to employees and consultants as compensation for services rendered, as well as in conjunction with the purchase of shares of common stock in equity and debt transactions.

In connection with the March 2020 Note, the Company issued the March 2020 Note to the investor and the March 2020 Maxim Warrant to Maxim to purchase shares of common stock of 227,679 and 20,400, respectively (see Note 4 – Borrowings) at an exercise price of $6.40 per share. The grant date fair value of such warrants was $625,000, which was recorded as debt discount with the offset recorded to additional paid-in capital on the condensed consolidated balance sheets. The fair value of such warrants was determined using the Black-Scholes Model based on the following weighted average assumptions: common stock price on date of grant of $5.40; expected dividend yield of 0.0%; expected volatility of 61.0%; risk-free interest rate of 0.38% and expected life of 5 years.

Such warrant issued to the investor contained an adjustment provision such that if the Company issues or sells any shares of common stock or common stock equivalents (as defined in the March 2020 Note), subject to certain exceptions, at an effective price lower than the conversion price, then in effect, the conversion price shall be reduced to the price per share paid for such shares of common stock or common stock equivalents. The common stock and common stock equivalents issued by the Company in the April 2020 Public Offering were issued at price per share of $3.25, which was lower than the conversion price then in effect. Additionally, the Alexander Settlement Shares, issued to Alexander under the Alexander Settlement Agreement, on May 14, 2020, were issued at a price per share which was lower than the conversion price then in effect. The Company modified the exercise price of the March 2020 Warrant as a result of each of these transactions and calculated the incremental fair value related to these modifications. The resulting deemed dividend from these down round adjustments was $134,000, and this is included as an offset to additional paid-in capital in the accompanying condensed consolidated balance sheets.

Concurrent with the April 2020 Public Offering, the Company issued prefunded warrants for $475,000 at an exercise price of $0.01 per share. These warrants were exercised immediately upon the closing of the transactions for proceeds of $4,750 and the investors received 475,000 shares of common stock.

Additionally, as a result of the April 2020 Public Offering, the Company issued warrants to purchase shares of common stock to the common stock investors, prefunded warrants investors, and Maxim of 1,525,000,  475,000 and 291,000, respectively. The warrants have an exercise price of $3.25 per share and are fully vested. The grant date fair value of those warrants was $2,606,000, which was recorded within stockholders’ equity as a cost of issuance and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet. The fair value of the warrants was determined using the Black-Scholes Model based on the following weighted average assumptions: common stock price on date of grant of $2.50; expected dividend yield of 0.0%; expected volatility of 64.0%; risk-free interest rate of 0.37% and expected life of 5 years.

The Company also issued the April 2020 Maxim Warrant to purchase up to 100,000 shares of common stock to Maxim in connection with the April 2020 Public Offering. Such warrant has an exercise price of $3.90 per share and is fully vested. The fair value of such warrant at issuance was $106,000. The fair value of the warrant was estimated using the Black-Scholes Model based on the following weighted average assumptions: common share price on date of grant $2.50, expected dividend yield 0%, expected volatility 64%, risk-free interest rate 0.37% and expected life of 5 years. The fair value was recorded within stockholders’ equity as a cost of issuance and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet.

In connection with the offering pursuant to the June 4, 2020 Purchase Agreement, the Company issued warrants to the investors to purchase up to an aggregate of 2,275,000 shares of common stock. Such warrants have an exercise price of $2.55 per share and are fully vested. The grant date fair value of those warrants was $3,153,000, which was recorded within stockholders’ equity as a cost of issuance and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet. The fair value of such warrants was determined using the Black-Scholes Model based on the following weighted average assumptions: common stock price on date of grant of $2.52; expected dividend yield of 0.0%; expected volatility of 64.0%; risk-free interest rate of 0.45% and expected life of 5.5 years.

In connection with the offering pursuant to the June 9, 2020 Purchase Agreement, the Company issued warrants to the investors to purchase up to an aggregate of 2,040,000 shares of common stock. Such warrants have an exercise price of $2.61 per share and are fully vested. The grant date fair value of those warrants was $2,375,000, which was recorded within stockholders’ equity as a cost of issuance and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet. The fair value of such warrants was determined using the Black-Scholes Model based on the following weighted average assumptions: common stock price on date of grant of $2.25; expected dividend yield of 0.0%; expected volatility of 64.0%; risk-free interest rate of 0.32% and expected life of 5.5 years.

In January 2021, pursuant to the Company’s solicitation of certain warrant holders, such warrant holders agreed to exercise warrants to purchase an aggregate of 1,221,675 shares of common stock for net proceeds of approximately $2.9 million. In consideration for their exercise of these warrants, for cash, the exercising holders are being issued new warrants to purchase up to an aggregate of 305,419 shares of common stock, at an exercise price of $4.20 per share, which are exercisable for a period of five years. The grant date fair value of those warrants was $567,000, which was recorded as warrant inducement expense and an increase to additional paid-in capital on the accompanying condensed consolidated balance sheet. The fair value of such warrants was determined using the Black-Scholes Model based on the following weighted average assumptions: common stock price on date of grant of $3.85; expected dividend yield of 0.0%; expected volatility of 60.1%; risk-free interest rate of 0.45% and expected life of 5.0 years.

The Company had additional exercises in the quarter ended March 31, 2021 totaling 864,576 shares for proceeds of $2,342,000.

Information regarding warrants for common stock outstanding and exercisable as of March 31, 2021 is as follows:

 

* Weighted average

Warrants exercisable as of March 31, 2021 excludes warrants to purchase 15,000 shares of common stock issued to a marketing firm, which vest upon the achievement of certain milestones. Additionally, warrants to purchase 20,722 shares of common stock which are shown above with a price of $15.80 are pre-funded warrants under which the holder must only pay $0.20 per share to complete the exercise.

Information regarding warrants for common stock outstanding and exercisable as of December 31, 2020 is as follows:

 

* Weighted average

Warrants exercisable as of December 31, 2020 exclude a warrant to purchase 15,000 shares of common stock issued to a marketing consulting firm. Such warrant will vest in three tranches upon the achievement of certain milestones. Additionally, warrants to purchase 20,722 shares of common stock which are shown above with a price of $15.80 are pre-funded warrants under which the holder must only pay $0.20 per share to complete the exercise.