| Common Stock Warrants and Common Stock Warrant Liability | Note
9 - Common Stock Warrants and Common Stock Warrant Liability The
table summarizes the common stock warrant activity as of June 30, 2022 by warrant type:
Balance Balance Balance
Issue Date Warrant Type Term Exercise December 31, Issued Exercised Expired December 31, Issued Exercised Expired June 30,
November 21, 2017 Common Stock Offering Warrants November 21, 2022 $ 1.3659 (1) 143,501 - (21,787 ) - 121,714 - - - 121,714
June 20,
2018 Warrant Reissue December 20, 2023 $ 36.40 56,696 - - - 56,696 - - - 56,696
August
13, 2018 Rights Offering Warrants July 25, 2023 $ 23.00 202,943 - (499 ) - 202,444 - - - 202,444
August
13, 2018 Dealer Manager Warrants August 13, 2023 $ 34.50 13,393 - - - 13,393 - - - 13,393
July 16,
2019 Dealer Manager Warrants July 11, 2024 $ 33.75 8,334 - - - 8,334 - - - 8,334
January
28, 2020 Registered Direct Offering July 28, 2025 $ 9.00 177,500 - - - 177,500 - - - 177,500
January
28, 2020 Dealer Manager Warrants July 28, 2025 $ 10.00 13,315 - - - 13,315 - - - 13,315
March 6,
2020 Dealer Manager Warrants March 4, 2025 $ 3.76 13,228 - - - 13,228 - - - 13,228
April 21,
2020 Dealer Manager Warrants April 21, 2025 $ 3.97 118,073 - - - 118,073 - - - 118,073
April 24,
2020 Registered Direct Offering April 24, 2025 $ 3.05 50,000 - - - 50,000 - - - 50,000
October
26, 2020 Private Warrant Inducement April 27, 2026 $ 1.73 1,700,680 (700,680 ) 1,000,000 - - - 1,000,000
October
26, 2020 Dealer Manager Warrants April 27, 2026 $ 2.16 85,034 - 85,034 - - - 85,034
February
2, 2021 Private Placement Agreement August 2, 2026 $ 2.216 - 2,194,427 - - 2,194,427 - - - 2,194,427
February
2, 2021 Dealer Manager Warrants August 2, 2026 $ 2.848 - 329,164 - - 329,164 - - - 329,164
March
23, 2021 Dealer Manager Warrants March 23, 2026 $ 2.50 - 148,125 - - 148,125 - - - 148,125
2,582,697 4,531,447 4,531,447 (1) The initial exercise price of these warrants was $30.00 per share. Pursuant to antidilution price adjustment protection contained within these warrants, the initial exercise price of these warrants was adjusted downward to $29.40 on July 24, 2018, the record date of the 2018 Rights Offering (defined herein) and downward to $19.00 per share on August 13, 2018. These warrants were further adjusted downward from $19.00 to $7.13 and to $2.1122 on January 28, 2020 and March 4, 2020, respectively, in connection with separate Registered Direct Offerings. These warrants were further adjusted downward from $2.1122 to $1.3659 on October 26, 2020 in connection with a Registered Direct Offering. These warrants are subject to further adjustment pursuant to antidilution price adjustment protection. Outstanding Warrants As of June 30, 2022, we had 4,531,447 shares of
common stock issuable upon exercise of outstanding common stock warrants, at a weighted-average exercise price of $4.00 per share. On November 21, 2017, we issued a total of 232,875
detachable common stock warrants issued with the second public offering of 293,000 shares of our common stock at $20.00 per share. The
common stock warrant is exercisable until five years from the date of grant. Our common stock and detachable warrants exist independently
as separate securities. As such, we estimated the fair value of the common stock warrants, exercisable at $30.00 per share, to be $661
using a lattice model based on the following significant inputs: common stock price of $20.00; comparable company volatility of 73.8%;
remaining term five years; dividend yield of 0% and risk-free interest rate of 1.87%. The initial exercise price of these warrants was
$30.00 per share, which adjusted downward to $29.40 on July 24, 2018, the record date of the 2018 Rights Offering, and downward to $19.00
per share on August 13, 2018, the date of the 2018 Rights Offering, pursuant to antidilution price adjustment protection contained within
these warrants. The exercise price of the warrants was adjusted downward to $7.13 on January 28, 2020 in connection with a private placement
of common stock. Per guidance of ASC 260 – Earnings Per Share (“ASC260”), we recorded a deemed dividend of $285 on the
143,501 unexercised warrants that contained this antidilution price adjustment protection provision and was calculated as the difference
between the fair value of the warrants immediately prior to downward exercise price adjustment and immediately after the adjustment using
a Black Scholes model based on the following significant inputs: On January 28, 2020, common stock price of $7.90; comparable company
volatility of 73.8%; remaining term 2.82 years; dividend yield of 0% and risk-free interest rate of 1.45%. The exercise price of the warrants was adjusted
downward to $2.1122 on March 4, 2020 in connection with a private placement of common stock. Per guidance of ASC 260, we recorded a deemed
dividend of $129 on the 143,501 unexercised warrants that contained this antidilution price adjustment protection provision and was calculated
as the difference between the fair value of the warrants immediately prior to downward exercise price adjustment and immediately after
the adjustment using a Black Scholes model based on the following significant inputs: On March 4, 2020, common stock price of $2.88; comparable
company volatility of 74.5%; remaining term 2.71 years; dividend yield of 0% and risk-free interest rate of 0.68%. The exercise price of the warrants was adjusted
downward to $1.3659 on October 26, 2020 in connection with an inducement offering of common stock. Per guidance of ASC 260, we recorded
a deemed dividend of $22 on the 143,501 unexercised warrants that contained this antidilution price adjustment protection provision and
was calculated as the difference between the fair value of the warrants immediately prior to downward exercise price adjustment and immediately
after the adjustment using a Black Scholes model based on the following significant inputs: On October 26, 2020, common stock price of
$1.47; comparable company volatility of 96.5%; remaining term 2.08 years; dividend yield of 0% and risk-free interest rate of 0.18%. On June 20, 2018, we entered into an agreement
with a holder of 56,696 of the November 2017 warrants to exercise its original warrant representing 56,696 shares of common stock for
cash at the $30.00 exercise price for gross proceeds of $1.7 million, and we issued to holder a new warrant to purchase 56,696 shares
of common stock at an exercise price of $36.40 per share. The new warrant did not contain the antidilution price adjustment protection
that was contained within the exercised warrants. In June 2018, we recorded stock compensation expense of $1,700 representing the fair
value of the of 56,696 inducement warrants issued. We estimated the fair value of the common stock warrants, exercisable at $36.40 per
share, to be $1,700 using a Black Scholes model based on the following significant inputs: common stock price of $42.20; comparable company
volatility of 72.6%; remaining term five years; dividend yield of 0% and risk-free interest rate of 2.8%. Also, in June 2018, an additional
17,088 of the November 8, 2017 warrants that were in the money at the time of exercise, were exercised for gross proceeds of $513. On August 13, 2018, in connection with a rights
offering of 267,853 shares of our common stock (the “2018 Rights Offering”), we issued 267,853 warrants to purchase shares
of our common stock at an exercise price of $23.00 per share. We estimated the fair value of the common stock warrants, exercisable at
$23.00 per share, to be $3,600 using a Monte Carlo model based on the following significant inputs: common stock price of $18.80; comparable
company volatility of 159.0%; remaining term five years; dividend yield of 0% and risk-free interest rate of 2.77%. In connection with the closing of the 2018 Rights
Offering, we issued a warrant to purchase 13,393 shares of common stock to Maxim Partners LLC, an affiliate of the dealer-manager of the
2018 Rights Offering. We estimated the fair value of the common stock warrants, exercisable at $34.50 per share, to be $169 using a using
a Monte Carlo model based on the following significant inputs: common stock price of $18.80; comparable company volatility of 159.0%;
remaining term 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 8,334 shares of common stock at an exercise price of $33.75 per share as consideration
for providing services in connection with a common stock offering in July 2019. The warrant was fully vested and exercisable on the date
of issuance. The common stock warrant is exercisable until five years from the date of grant. We estimated the fair value of the common
stock warrants, exercisable at $33.75 per share, to be $127 using a lattice model based on the following significant inputs: common stock
price of $26.80; comparable company volatility of 133.3%; remaining term five years; dividend yield of 0% and risk-free interest rate
of 2.07%. Common Stock Warrants Issued in January
and March 2020 Private Placements In January and March 2020, in separate private
placements concurrent with registered direct offerings (collectively, the “2020 Registered Direct Offerings”) of shares of
our common stock, we also issued warrants to purchase an aggregate of up to 353,872 shares of common stock to certain institutional and
accredited investors that participated in the 2020 Registered Direct Offerings (the “2020 Warrants”). The warrants were issued
in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended (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 SEC on January 28, 2020
and our Current Report on Form 8-K filed with the SEC on March 6, 2020. The warrants issued in January 2020 to purchase
177,500 shares of common stock have an exercise price of $9.00 per share, are exercisable after July 28, 2020 and will expire July
28, 2025. We estimated the fair value of the common stock warrants, exercisable at $9.00 per share, to be $813 using a Black Scholes model
based on the following significant inputs: common stock price of $7.90; comparable company volatility of 73.8%; remaining term five years;
dividend yield of 0% and risk-free interest rate of 1.53%. The warrants issued in March 2020 to purchase
176,372 shares of common stock have an exercise price of $2.88 per share, are immediately exercisable and will expire September 8, 2025.
We estimated the fair value of the common stock warrants, exercisable at $2.88 per share, to be $242 using a Black Scholes model based
on the following significant inputs: common stock price of $2.35; comparable company volatility of 74.8%; remaining term five and one-half
years; dividend yield of 0% and risk-free interest rate of 0.39%. For so long as the 2020 Warrants remain outstanding,
the exercise price and number of shares of common stock issuable upon exercise of the warrants are subject to adjustment as follows: (a) upon
payment of a stock dividend or other distribution on a class or series of shares of common stock, not including shares issued under this
warrant; (b) upon subdivision (by stock spilt, 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 2020 Warrant 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 2020 Warrant. In the event of a Fundamental Transaction, as
described in the 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 2020 Warrants immediately prior to such Fundamental Transaction.
Subject to certain limitations, in the event of a Fundamental Transaction the 2020 Warrant 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 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 2020 Warrant. 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 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 2020
Warrant (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 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 2020 Warrant. Limitations on Exercise Except as otherwise provided in the 2020 Warrants
or by virtue of such holder’s ownership of shares of our common stock, the holders of the 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 On April 24, 2020, in connection with a previously
announced public offering of 145,586 Class A Units and 1,428,722 Class B Units, we issued warrants to purchase 1,574,308 shares of common
stock to the participants in the public offering and have an exercise price of $3.05 per share (the “April 2020 Warrants”).
These warrants are immediately exercisable and will expire April 24, 2025. The Common Stock, Pre-Funded Warrants and Warrants
sold in this 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. We estimated the fair value of the common stock
warrants, exercisable at $3.05 per share, to be $2,402 using a Black Scholes model based on the following significant inputs: common stock
price of $2.40; comparable company volatility of 87.9%; remaining term five years; dividend yield of 0% and risk-free interest rate of
0.18%. Common Stock Warrants Issued to Placement
Agent in 2020 Registered Direct Offerings and Private Placement In connection with the separate private placements
concurrent with registered direct offerings of shares of our common stock in January and March 2020, we issued to H.C. Wainwright &
Co., LLC, as placement agent, a warrant to purchase 13,228 shares of common stock and a warrant to purchase 13,313 shares of common stock.
The 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. These warrants have substantially similar terms as the 2020 Warrants described above, except that
the placement agent warrant issued in January 2020 has an exercise price of $10.00 per share, and the placement agent warrant issued in
March 2020 has an exercise price of $3.7563 per share. We estimated the fair value of the common stock
warrants issued in January, with an exercise price of $10.00 per share, to be $58 using a Black Scholes model based on the following significant
inputs: common stock price of $7.90; comparable company volatility of 73.8%; remaining term five years; dividend yield of 0% and risk-free
interest rate of 1.53%. We estimated the fair value of the common stock
warrants issued in March, with an exercise price of $3.7563 per share, to be $17 using a Black Scholes model based on the following significant
inputs: common stock price of $2.35; comparable company volatility of 74.8%; remaining term five and one-half years; dividend yield of
0% and risk-free interest rate of 0.39%. In connection with the public offering of 145,586
Class A Units and 1,428,722 Class B Units on April 24, 2020, we issued to H.C. Wainwright & Co., LLC, as placement agent, warrants
to purchase 118,073 shares of common stock. The 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. These warrants have substantially similar terms
as the April 2020 Warrants described above, except that the placement agent warrant issued has an exercise price of $3.97 per share. We estimated the fair value of the common stock
warrants issued in April, with an exercise price of $3.97 per share, to be $167 using a Black Scholes model based on the following significant
inputs: common stock price of $2.40; comparable company volatility of 87.9%; remaining term five and one-half 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 1,700,680 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 1,700,680 shares of common stock at an exercise price
of $1.725 per share. The warrants issued were immediately exercisable with an exercise period of five and one-half years from the date
of issuance. The Original Warrants were issued on March 6, 2020 and on April 24, 2020. Pursuant to the Letter Agreement, the per share
exercise price of the Original Warrants were reduced from $2.88 and $3.05, respectively, to $1.725. We estimated the fair value of the
common stock warrants, exercisable at $1.725 per share, to be $1,806 using a Black Scholes model based on the following significant inputs:
common stock price of $1.47; comparable company volatility of 96.5%; remaining term five and one-half years; dividend yield of 0% and
risk-free interest rate of 0.18%. Common Stock Warrants Issued to Placement
Agent in October 2020 Inducement Offering In connection with the private warrant inducement
in October 2020 of 1,700,680 shares of our common warrants, we issued to H.C. Wainwright & Co., LLC, as placement agent, warrants
to purchase 85,034 shares of common stock. These warrants have substantially similar terms as the 2020 Warrants described above, except
that the placement agent warrant issued in October 2020 has an exercise price of $2.156 per share. We estimated the fair value of these common stock
warrants, with an exercise price of $2.156 per share, to be $86 using a Black Scholes model based on the following significant inputs:
common stock price of $1.47; comparable company volatility of 96.5%; remaining term 5.5 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 2,194,427 shares of common stock at an exercise price of $2.216 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 the common stock warrants, exercisable at $2.216 per share,
to be $3,052 using a Black Scholes model based on the following significant inputs: common stock price of $1.93; comparable company volatility
of 95.6%; remaining term five and one-half years; dividend yield of 0% and risk-free interest rate of 0.18%. 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 329,164 shares of common stock with
an exercise price of $2.8481 per share. The warrants are exercisable immediately and have an exercise period of five and one-half years
from the date of issuance. We estimated the fair value of these common stock warrants, with an exercise price of $2.8481 per share, to
be $435 using a Black Scholes model based on the following significant inputs: common stock price of $1.93; comparable company volatility
of 95.6%; remaining term five and one-half 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 On March 23, 2021, we consummated a registered
direct offering with certain institutional investors and issued an aggregate of 1,975,000 shares of our common stock, par value $0.001
per share at a purchase price of $2.00 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. The 1,975,000 shares of common stock sold in the offering
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 148,125 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 $2.50 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 common stock warrants, with an
exercise price of $2.50 per share, to be $181 using a Black Scholes model based on the following significant inputs: common stock price
of $1.76; comparable company volatility of 100.8%; remaining term five years; dividend yield of 0% and risk-free interest rate of 0.31%. Deemed Dividend Adjustment-Warrant Modified
Terms Revaluation On March 3, 2020, we issued an aggregate of 51,414
common shares in a cashless exercise of 56,625 warrants issued in December 2016 and November 2017. Consideration for the exercise of these
warrants was the full settlement of an outstanding litigation reserve of $238. On October 26, 2020, in connection with the private
warrant inducement with an existing accredited investor to exercise 1,700,680 outstanding warrants (“Original Warrants”),
we agreed to modify the terms of the original warrants that were originally issued on March 6, 2020 and on April 24, 2020. Pursuant to
the agreement, the per share exercise price of the original warrants were reduced from $2.88 and $3.05, respectively, to $1.725. Per recent proposed guidance of ASC 260, we determined
that this was an exchange of the existing 1,700,680 warrants that were affected and the difference between the fair value of the warrants
immediately prior to modification of terms and immediately after the adjustment was a cost of raising capital and was recorded as a reduction
of equity. The difference between the fair value of the warrants immediately prior to modification of terms and immediately after the
adjustment was calculated as $237, using a Black Scholes model based on the following significant inputs: On October 26, 2020: common
stock price of $1.47; comparable company volatility of 96.5%; remaining term 4.5-4.8 years; dividend yield of 0% and risk-free interest
rate of 0.18. |
