COMMON STOCK WARRANTS

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

COMMON STOCK WARRANTS

STOCKHOLDERS’ EQUITY

Preferred Stock

We are authorized to issue 10 million shares of preferred stock with a par value of $0.001. Rights and any series designation would be established at time of issuance of preferred stock. As of December 31, 2022 and 2021 there was no preferred stock outstanding.

Common Stock

We are authorized to issue 100 million shares of common stock with a par value of $0.001 per share. Stockholders of common stock have unlimited voting rights and are entitled to receive the net assets of the Company upon dissolution, subject to the rights of the preferred stockholders, if any.

We had the following common stock offerings in 2022 and 2021:

November 2022. We consummated a private placement with certain institutional and accredited investors and issued an aggregate of 67,572 shares of our common stock at a purchase price of $3.50 per share, pre-funded warrants to purchase up to an aggregate of 1,361,000 shares of common stock at a purchase price of $3.50 per pre-funded warrant (“Pre-Funded Warrants”) and associated warrants to purchase up to an aggregate of 2,857,144 share of common stock at $3.165 per share, for gross proceeds of approximately $5.0 million, prior to deducting placement agent fees and offering expenses. In connection with this offering, we issued the placement agent warrants to purchase up to 107,143 shares of common stock with an exercise price of $4.375 per share.

Of the Pre-Funded Warrants, 131,000 were exercised in December 2022, with the remaining 1,230,000 exercised in early 2023.

The common stock, Pre-Funded Warrants and warrants sold in this November 2022 public offering were offered and sold pursuant to a registration statement on Form S-1 (File No. 333-267991) initially filed with the SEC on October 24, 2022, as amended, which was declared effective by the SEC on November 16, 2022.

March 2021. We consummated a registered direct offering with certain institutional investors and issued an aggregate of 98,750 shares of our common stock at a purchase price of $40.00 per share for gross proceeds of approximately $3.95 million, pursuant to a prospectus, dated August 24, 2018, and a prospectus supplement, dated March 22, 2021, in connection with a takedown from our shelf registration statement on Form S-3 (File No. 333-225712). In connection with the offering, we issued the placement agent warrants to purchase up to 7,408 shares of common stock at an exercise price per share of $50.00 per share.

February 2021. We consummated a private placement with certain institutional and accredited investors and issued an aggregate of 198,443 shares of our common stock at a purchase price of $45.57 per share, pre-funded warrants to purchase up to an aggregate of 21,000 shares of common stock at a purchase price of $2.2775 per pre-funded warrant and associated warrants to purchase up to an aggregate of 109,730 shares of common stock, for gross proceeds of approximately $10.0 million, prior to deducting placement agent fees and offering expenses. During 2021, all 420,000 pre-funded shares had been distributed. In connection with the offering, we issued the placement agent warrants to purchase up to 329,164 shares of common stock with an exercise price of $2.8481 per share.

COMMON STOCK WARRANTS

The following is the activity for common stock warrants:

Issue Date	Warrant Type	Term Date	Exercise Price		Balance December 31, 2020	Issued	Exercised	Expired	Balance December 31, 2021	Issued	Exercised	Expired	Balance December 31, 2022
November 2017	Common Stock Offering	November 2022	$	27.32	7,175	—	(1,089)	—	6,086	—	—	(6,086)	—
June 2018	Reissue	December 2023	$	728.00	2,835	—	—	—	2,835	—	—	—	2,835
August 2018	Rights Offering	July 2023	$	460.00	10,149	—	(25)	—	10,124	—	—	—	10,124
August 2018	Dealer Manager	August 2023	$	690.00	670	—	—	—	670	—	—	—	670
July 2019	Dealer Manager	July 2024	$	675.00	419	—	—	—	419	—	—	—	419
January 2020	Registered Direct Offering	July 2025	$	180.00	8,761	—	—	—	8,761	—	—	—	8,761
January 2020	Dealer Manager	July 2025	$	200.00	667	—	—	—	667	—	—	—	667
March 2020	Dealer Manager	March 2025	$	75.13	664	—	—	—	664	—	—	—	664
April 2020	Dealer Manager	April 2025	$	79.40	5,906	—	—	—	5,906	—	—	—	5,906
April 2020	Registered Direct Offering	April 2025	$	61.00	2,500	—	—	—	2,500	—	—	—	2,500
October 2020	Private Inducement	April 2026	$	34.500	35,034	—	(35,034)	—	—	—	—	—	—
October 2020	Private Inducement	November 2027	$	3.165	50,000	—	—	—	50,000	—	—	—	50,000
October 2020	Dealer Manager	April 2026	$	43.12	4,254	—	—	—	4,254	—	—	—	4,254
February 2021	Private Placement Agreement	August 2026	$	44.32	—	82,300	—	—	82,300	—	—	—	82,300
February 2021	Private Placement Agreement	November 2027	$	3.165	—	27,430	—	—	27,430	—	—	—	27,430
February 2021	Dealer Manager	August 2026	$	56.96	—	16,460	—	—	16,460	—	—	—	16,460
March 2021	Dealer Manager	March 2026	$	50.00	—	7,408	—	—	7,408	—	—	—	7,408
November 2022	Pre-Funded Warrants	February 2023	$	3.50	—	—	—	—	—	1,361,000	(131,000)	—	1,230,000
November 2022	Series A	November 2027	$	3.165	—	—	—	—	—	1,428,572	—	—	1,428,572
November 2022	Series B	December 2023	$	3.165	—	—	—	—	—	1,428,572	—	—	1,428,572
November 2022	Dealer Manager	November 2027	$	4.375	—	—	—	—	—	107,143	—	—	107,143
					129,034	133,598	(35,059)	—	226,484	4,325,287	(131,000)	—	4,414,685

As of December 31, 2022, we had 4,414,685 shares of common stock issuable upon exercise of outstanding common stock warrants, at a weighted-average exercise price of $6.58 per share and expiring as follows:

	Weighted Average Exercise Price		Shares
Years Ending December 31:
2023	$	5.99	2,672,201
2024	675.00		419
2025	128.75		18,498
2026	46.54		110,422
2027	3.25		1,613,145
	6.58		4,414,685

Common Stock Warrant Inducement

In June 2018, in order to induce an existing warrant holder to exercise its original warrant representing 2,835 shares of common stock for cash at the $600.00 exercise price for gross proceeds of $1.7 million, we issued to the holder a new warrant to purchase 2,835 shares of common stock at an exercise price of $728.00 per share. In connection with the issuance of these inducement warrants, we recorded stock-based compensation expense of $1,700, representing the fair value of the inducement warrants issued using the Black Scholes model based on the following significant inputs: common stock price of $844.00 per share; comparable company volatility of 72.6%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 2.8%.

Common Stock Warrants Issued in August 2018 Rights Offering

In August 2018, in connection with a rights offering of 13,393 shares of our common stock, we issued warrants to purchase 13,393 shares of our common stock at an exercise price of $460.00 per share. We estimated the fair value of these warrants to be $3.6 million using a Monte Carlo model based on the following significant inputs: common stock price of $376.00 per share; comparable company volatility of 159.0%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 2.77%.

In connection with the closing of the August 2018 rights offering, we issued warrants to purchase 670 shares of our common stock at an exercise price of $690.00 per share to Maxim Partners LLC, an affiliate of the dealer-manager of the rights offering. We estimated the fair value of these warrants to be $169,000 using a using a Monte Carlo model based on the following significant inputs: common stock price of $376.00 per share; comparable company volatility of 159.0%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 2.77%.

Common Stock Warrant Issued to Underwriter of Common Stock Offering

In July 2019, we issued to H.C. Wainwright & Co., as placement agent, a warrant to purchase 419 shares of common stock at an exercise price of $675.00 per share as consideration for providing services in connection with a common stock offering in July 2019.

We estimated the fair value of this warrant to be $127,000 using a lattice model based on the following significant inputs: common stock price of $536.00 per share; comparable company volatility of 133.3%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 2.07%.

Common Stock Warrants Issued in January 2020 Private Placement

In January 2020, in a private placement concurrent with a registered direct offering of shares of our common stock, we also issued warrants to purchase an aggregate of up to 8,875 shares of common stock to certain institutional and accredited investors that participated in the 2020 Registered Direct Offerings (the “January 2020 Warrants”). These warrants were issued in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act and Rule 506(b) of Regulation D promulgated thereunder. Terms used but not otherwise defined herein will have the meanings given them in

the warrants, attached as Exhibit 4.1 to our Current Report on Form 8-K filed with the Securities and Exchange Commission (the “SEC”) on January 28, 2020.

We estimated the fair value of the January 2020 Warrants to be $813,000 using a Black Scholes model based on the following significant inputs: common stock price of $158.00 per share; comparable company volatility of 73.8%; remaining term of five years; dividend yield of 0% and risk-free interest rate of 1.53%.

For so long as the January 2020 Warrants remain outstanding, the exercise price and number of shares of common stock issuable upon exercise of these warrants are subject to adjustment as follows: (a) upon payment of a stock dividend or other distribution on a class or series of shares common stock, not including shares issued under this warrant; (b) upon subdivision (by stock spilled, stock dividend, recapitalization, or otherwise) or combination (by reverse stock split or otherwise) of shares of common stock; or (c) upon the issuance of any shares of capital stock by reclassification of shares of the common stock.

In the event that we declare or make any dividend or other distribution of our assets to holders of our common stock, each January 2020 Warrants holder will be entitled to participate in such distribution to the same extent that such holder would have participated therein if the holder had held the number of shares of common stock acquirable upon exercise of the January 2020 Warrants.

In the event of a Fundamental Transaction, as described in the January 2020 Warrants and generally including the sale, transfer or other disposition of all or substantially all of our properties or assets; our consolidation or merger with or into another person or reorganization; a recapitalization, reorganization or reclassification in which our common stock is converted into other securities, cash or property; or any acquisition of our outstanding common stock that results in any person or group becoming the beneficial owner of 50% of the voting power represented by our outstanding common stock, then the holders of the 2020 Warrants will be entitled to receive upon exercise of such warrants the kind and amount of securities, cash, assets or other property that the holders would have received had they exercised the January 2020 Warrants immediately prior to such Fundamental Transaction. Subject to certain limitations, in the event of a Fundamental Transaction the January 2020 Warrants holder may at its option require us or any successor entity to purchase such warrant from the holder by paying to the holder an amount of cash equal to the Black Scholes Value of the remaining unexercised portion of the 2020 Warrant on the date of the consummation of the Fundamental Transaction.

Any time that we grant, issue, or sell any securities pro rata to all of the record holders of our common stock (the “2020 Purchase Right”), each holder of January 2020 Warrants will be entitled to acquire the aggregate amount of securities that the holder could have acquired if the holder had held the number of shares of common stock acquirable upon exercise of the applicable January 2020 Warrants. However, to the extent that an exercise of a 2020 Purchase Right would exceed the Beneficial Ownership Limitation (defined below), then to such extent the 2020 Purchase Right will be held in abeyance until such time, if ever, that complete exercise of the 2020 Purchase Right would not exceed the Beneficial Ownership Limitation.

After the Initial Exercisability Date, the January 2020 Warrants will be exercisable, at the option of each holder, in whole or in part, by delivering to us a duly executed exercise notice accompanied by payment in full for the number of shares of our common stock purchased upon such exercise. If, at the time a holder exercises the January 2020 Warrants (but not sooner than six months following the date of such warrant), a registration statement registering the issuance of the shares of common stock underlying the January 2020 Warrants under the Securities Act is not then effective or available, nor is any current prospectus thereto available, and an exemption from registration under the Securities Act is not available for the issuance of such shares, then in lieu of making the cash payment otherwise contemplated to be made to us upon such exercise in payment of the aggregate exercise price, the holder may elect instead to receive upon such exercise (either in whole or in part) the number of shares of common stock determined according to a formula set forth in the January 2020 Warrants.

Limitations on Exercise. A holder (together with its affiliates) may not exercise any portion of the January 2020 Warrants to the extent that the holder would own more than 4.99% of the outstanding common stock after exercise (the “Beneficial Ownership Limitation”), except that upon at least 61 days’ prior notice from the holder to us, the holder may increase the Beneficial Ownership Limitation up to 9.99% of the number of shares of our common stock outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the January 2020

Warrants. No fractional shares of common stock will be issued in connection with the exercise of a January 2020 Warrants. In lieu of fractional shares, we will either pay the holder an amount in cash equal to the fractional amount multiplied by the exercise price or round up to the next whole share.

Except as otherwise provided in the January 2020 Warrants or by virtue of such holder’s ownership of shares of our common stock, the holders of the January 2020 Warrants do not have the rights or privileges of holders of our common stock, including any voting rights, unless and until they exercise such warrants.

Common Stock Warrants Issued in April 2020 Public Offering

In April 2020, in connection with a previously announced public offering of our common stock, we issued warrants to purchase 78,715 shares of common stock at an exercise price of $61.00 to the participants in the public offering (the “April 2020 Warrants”). We estimated the fair value of these warrants to be $2.4 million using a Black Scholes model based on the following significant inputs: common stock price of $48.00 per share; comparable company volatility of 87.9%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 0.18%.

The common stock, pre-funded warrants and warrants sold in this April 2020 public offering were offered and sold pursuant to a registration statement on Form S-1 (File No. 333-236302) initially filed with the SEC on February 7, 2020, as amended (“Registration Statement”), which was declared effective by the SEC on February 14, 2020. The Post-Effective Amendment No. 2 to the Registration Statement was declared effective by the SEC on April 21, 2020.

Common Stock Warrants Issued to Placement Agent in 2020 Private Placements

In connection with the separate private placements concurrent with registered direct offerings of shares of our common stock, we issued to H.C. Wainwright & Co., LLC, as placement agent, in January 2020, warrants to purchase 667 shares of common stock at an exercise price of $200.00 per share and in March 2020, warrant to purchase 664 shares of common stock at an exercise price of $75.13 per share. These warrants were issued in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act and Rule 506(b) of Regulation D promulgated thereunder and have substantially similar terms as the January 2020 Warrants described above, except for differing exercise prices.

We estimated the fair value of the January 2020 warrants issued in January to be $58,000 using a Black Scholes model based on the following significant inputs: common stock price of $158.00; comparable company volatility of 73.8%; remaining term of five years; dividend yield of 0% and risk-free interest rate of 1.53%.

We estimated the fair value of the March 2020 warrants to be $17,000 using a Black Scholes model based on the following significant inputs: common stock price of $47.00 per share; comparable company volatility of 74.8%; remaining term of six years; dividend yield of 0%; and risk-free interest rate of 0.39%.

Common Stock Warrants Issued to Placement Agent in 2020 Registered Direct Offering

In connection with the public offering of (preferred or common) stock in April 2020, we issued to H.C. Wainwright & Co., LLC, as placement agent, warrants to purchase 5,906 shares of common stock at an exercise price of $79.40 per share. These warrants were issued in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act and Rule 506(b) of Regulation D promulgated thereunder, and have substantially similar terms as the April 2020 Warrants described above, except for differing exercise prices.

We estimated the fair value of these warrants to be $167,000 using a Black Scholes model based on the following significant inputs: common stock price of $48.00 per share; comparable company volatility of 87.9%; remaining term of six years; dividend yield of 0%; and risk-free interest rate of 0.18%.

Common Stock Warrants Issued in October 2020 Private Warrant Inducement

In October 2020, in connection with an inducement agreement with an existing accredited investor to exercise 85,034 outstanding warrants to purchase an equal number of shares of our common stock, we issued new unregistered warrants to purchase up to an aggregate of 85,034 shares of common stock at an exercise price of $34.50 per share. The original

warrants were issued in March and April, 2020, whereby the per share exercise price of the original warrants were reduced from $57.60 per share and $61.00 per share, respectively, to $34.50 per share.

We estimated the fair value of these warrants to be $1.8 million using a Black Scholes model based on the following significant inputs: common stock price of $29.40 per share; comparable company volatility of 96.5%; remaining term of six years; dividend yield of 0%; and risk-free interest rate of 0.18%.

In connection with the November 2022 registered direct offering with certain institutional and accredited investors, we modified the terms of the then outstanding warrants related to 50,000 shares to an exercise price of $3.165 per share and extended the expiration date to November 2027. We estimated the fair value of these warrants to be $110,000 using a Black Scholes model based on the following significant inputs: common stock price of $3.03 per share; comparable company volatility of 93.9%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 3.83%.

Common Stock Warrants Issued to Placement Agent in October 2020 Inducement Offering

In connection with the private warrant inducement in October 2020 of 85,034 shares of our common warrants, we issued to H.C. Wainwright & Co., LLC, as placement agent, warrants to purchase 4,254 shares of common stock at an exercise price of $43.12 per share. These warrants have substantially similar terms as the January 2020 Warrants described above, except for differing exercise prices.

We estimated the fair value of these warrants to be $86,000 using a Black Scholes model based on the following significant inputs: common stock price of $29.40 per share; comparable company volatility of 96.5%; remaining term of six years; dividend yield of 0%; and risk-free interest rate of 0.18%.

Common Stock Warrants Issued in February 2021 Private Placement Agreement

In February 2021, in connection with a private placement agreement with certain institutional and accredited investors, we issued common stock warrants to purchase up to an aggregate of 109,730 shares of common stock at an exercise price of $44.32 per share. The warrants were exercisable immediately and have an exercise period of five and one-half years from the date of issuance. The warrant holder may not exercise any portion of such holder’s warrants to the extent that the holder, together with its affiliates, would beneficially own more than 4.99% (or, at the election of the holder, 9.99%) of our outstanding shares of common stock immediately after exercise, except that upon at least 61 days’ prior notice from the holder to us, the holder may increase the beneficial ownership limitation to up to 9.99% of the number of shares of common stock outstanding immediately after giving effect to the exercise.

We estimated the fair value of these warrants to be $3.1 million using a Black Scholes model based on the following significant inputs: common stock price of $38.60 per share; comparable company volatility of 95.6%; remaining term of six years; dividend yield of 0% and risk-free interest rate of 0.18%.

In connection with the November 2022 registered direct offering with certain institutional and accredited investors, we modified the terms related to 27,430 shares of these warrants to an exercise price of $3.165 per share and extended the expiration date to November 2027. We estimated the fair value of these warrants to be $60,000 using a Black Scholes model based on the following significant inputs: common stock price of $3.03 per share; comparable company volatility of 93.9%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 3.83%.

Common Stock Warrants Issued to Placement Agent in February 2021 Private Placement Agreement

In connection with the private placement in February 2021, we issued to H.C. Wainwright & Co., LLC, as placement agent, warrants to purchase up to 16,460 shares of common stock with an exercise price of $56.96 per share.

We estimated the fair value of these warrants to be $435,000 using a Black Scholes model based on the following significant inputs: common stock price of $38.60 per share; comparable company volatility of 95.6%; remaining term six years; dividend yield of 0%; and risk-free interest rate of 0.18%.

Common Stock Warrants Issued to Placement Agent in March 2021 Registered Direct Offering

In March 2021, we consummated a registered direct offering with certain institutional investors and issued an aggregate of 98,750 shares of our common stock at a purchase price of $40.00 per share for gross proceeds to us of approximately $3.95 million, before deducting fees payable to the placement agent and other estimated offering expenses payable by us. These shares were offered and sold pursuant to a prospectus, dated August 24, 2018, and a prospectus supplement, dated March 22, 2021, in connection with a takedown from our shelf registration statement on Form S-3 (File No. 333-225712).

In connection with the registered direct offering in March 2021, we issued to H.C. Wainwright & Co., LLC, as the placement agent, warrants to purchase up to 7,408 shares of common stock at an exercise price of $50.00 per share . The placement agent warrants, and the shares of common stock issuable upon exercise thereof, will be issued in reliance on the exemption from registration provided in Section 4(a)(2) under the Securities Act of 1933, as amended, and Regulation D promulgated thereunder.

We estimated the fair value of these warrants to be $181,000 using a Black Scholes model based on the following significant inputs: common stock price of $35.20 per share; comparable company volatility of 100.8%; remaining term of five years; dividend yield of 0%; and risk-free interest rate of 0.31%.

Common Stock Warrants Issued in November 2022 Common Stock Offering

In November 2022, in connection with a registered direct offering with certain institutional and accredited investors, we issued common stock warrants as follows:

•Pre-Funded Warrants to purchase up to an aggregate of 1,361,000 shares of common stock at an exercise price of $3.50 per share, which are exercisable immediately and terminate until exercised in full. A portion of the Pre-Funded Warrants were exercised in December 2022, with the last traunch of these warrants being exercised in February 2023. We estimated the fair value of the Pre-Funded Warrants to be $153,000 using a Black Scholes model based on the following significant inputs: common stock price of $3.03 per share; comparable company volatility of 93.9%; remaining term of three months; dividend yield of 0% and risk-free interest rate of 3.83%.

•Series A warrants to purchase up to an aggregate of 1,428,572 shares at an exercise price of $3.165 per share, which are exercisable immediately and expire five years from date of issuance.We estimated the fair value of the Series A warrants to be $3.1 million using a Black Scholes model based on the following significant inputs: common stock price of $3.03 per share; comparable company volatility of 93.9%; remaining term of five years; dividend yield of 0% and risk-free interest rate of 3.83%.

•Series B warrants to purchase up to an aggregate of 1,428,572 shares at an exercise price of $3.165 per share, which are exercisable immediately and expire 13 months from date of issuance. We estimated the fair value of the Series B warrants to be $1.6 million using a Black Scholes model based on the following significant inputs: common stock price of $3.03 per share; comparable company volatility of 93.9%; remaining term of five years; dividend yield of 0% and risk-free interest rate of 3.83%.

Common Stock Warrants Issued to Placement Agent in November 2022 Common Stock Offering

In connection with the registered direct offering in November 2022, we issued to H.C. Wainwright & Co., LLC, as the placement agent, warrants to purchase up to 107,143 shares of common stock. The placement agent warrants will be exercisable commencing six months following the date of issuance, expire five years following the date of sale and have an exercise price per share of $4.375 per share. The placement agent warrants, and the shares of common stock issuable upon exercise thereof, will be issued in reliance on the exemption from registration provided in Section 4(a)(2) under the Securities Act of 1933, as amended, and Regulation D promulgated thereunder.

We estimated the fair value of these warrants to be $240,000 using a Black Scholes model based on the following significant inputs: common stock price of $3.25; comparable company volatility of 93.9%; remaining term five years; dividend yield of 0%; and risk-free interest rate of 3.83%.