Capitalization and Equity Structure | Capitalization and Equity Structure Summary The Company’s authorized capital stock at March 31, 2022 and December 31, 2021 consisted of 141,429 shares of common stock and 10,000 shares of preferred stock. As of March 31, 2022 and December 31, 2021, there were 12,844 and 12,693, respectively, shares of common stock issued and outstanding and no shares of preferred stock issued and outstanding. Common Stock February 2021 Offering In February 2021, the Company entered into an amended and restated underwriting agreement (the "Underwriting Agreement") with H.C. Wainwright & Co., LLC ("Wainwright"), to sell 3,902 shares of the Company's common stock for a public price of $10.25 per share, for gross proceeds of $40,000 (the "February 2021 Offering"). The Company received net proceeds of $36,504 from the February 2021 Offering after deducting underwriting discounts, commissions and estimated offering expenses. Pursuant to the Underwriting Agreement, the Company issued, to certain designees of Wainwright, five year warrants (the “2021 Warrants”) to purchase shares of Common Stock in an amount equal to 7.0% of the aggregate number of shares sold in the February 2021 Offering, or 273 shares, at an exercise price of $12.81 per share. At the Market Offering In October 2020, the Company entered into an At The Market Offering Agreement (the "ATM Agreement") with H.C. Wainwright & Co., LLC (the "Agent"), under which the Company may issue and sell shares of its common stock, from time to time, to or through the Agent. The Company may offer and sell shares having an aggregate offering price of up to $7,500 under the registration statement and prospectus supplement filed with the SEC related to such offering. Under the ATM Agreement, shares of the Company's common stock may not be sold for a price lower than $6.75 per share. The Company did not sell any shares under the ATM agreement during the three months ended March 31, 2022 . As of March 31, 2022, the Company has $6,668 available for future offerings under the prospectus filed with respect to the ATM Agreement. Warrants Warrants outstanding as of March 31, 2022 and December 31, 2021 were as follows: Source Exercise Term December 31, 2021 Issued Exercised March 31, 2022 2021 Warrants $ 12.81 5 273 — — 273 June 2020 Investor Warrants $ 5.18 5.5 127 — — 127 June 2020 Placement Agent Warrants $ 5.64 5 39 — — 39 December 2019 Warrants $ 8.10 5 556 — — 556 December 2019 Placement Agent Warrants $ 8.44 5 52 — — 52 May 2019 Warrants $ 3.52 5 193 — — 193 1,240 — — 1,240 During the three months ended March 31, 2021, the Company received net proceeds of $1,417 from the exercise of 358 warrants and issued 300 shares of common stock, respectively, as a result of those exercises. No warrants were exercised during the three months ended March 31, 2022. 2021 Warrants In February 2021, the Company issued the 2021 Warrants, exercisable for up to 273 shares of the Company’s common stock at an exercise price of $12.81 per share. The 2021 Warrants were exercisable immediately, and will expire five years from the date of issuance, or on February 11, 2026. In addition, the 2021 Warrants contain a cashless exercise provision, whereby, if, at the time a holder exercises its 2021 Warrants, a registration statement registering the issuance or the resale of the shares of common stock underlying the 2021 Warrants under the Securities Act is not then effective or available for the issuance of such shares, then in lieu of making the cash payment otherwise contemplated to be made to the Company upon such exercise in payment of the aggregate exercise price, the holder may elect to instead receive, upon such exercise (either in whole or in part), the net number of shares of the Company’s common stock determined according to a formula set forth in the 2021 Warrants. The 2021 Warrants will be automatically exercised on a cashless basis on their expiration date. The 2021 Warrants could also require payment of liquidated damages by the Company in the form of cash payments in the event of a failure by the Company to timely deliver shares of common stock upon exercise of such warrants. The 2021 Warrants also contain a put option, under which, if the Company enters into a Fundamental Transaction, as defined in the 2021 Warrants, the Company or any successor entity will, at the option of a holder of a 2021 Warrant, exercisable concurrently with or at any time within 30 days after the consummation of such Fundamental Transaction, purchase such holder’s 2021 Warrant by paying to such holder an amount of cash equal to the Black-Scholes value of the remaining unexercised portion of such holder’s 2021 Warrant within five The warrant liability related to the 2021 Warrants is measured at fair value upon issuance and at each reporting date using certain estimated inputs, which are classified within Level 3 of the fair value hierarchy. The following assumptions were used in the Black-Scholes Model to measure the fair value of the 2021 Warrants: March 31, 2022 December 31, 2021 Current share price $ 2.89 $ 2.65 Conversion price $ 12.81 $ 12.81 Risk-free interest rate 2.44 % 1.13 % Expected term (years) 3.86 4.11 Volatility of stock 95.67 % 98.3 % June 2020 Investor Warrants In June 2020, the Company issued warrants (the "June 2020 Investor Warrants"), exercisable for up to 874 shares of the Company’s common stock at an exercise price of $5.18 per share. The June 2020 Investor Warrants were immediately exercisable, and will expire five and one-half years from the date of issuance, or on December 10, 2025. In addition, the June 2020 Investor Warrants contain a cashless exercise provision, whereby, if, at the time a holder exercises its June 2020 Investor Warrants, a registration statement registering the issuance or the resale of the shares of common stock underlying the June 2020 Investor Warrants under the Securities Act is not then effective or available for the issuance of such shares, then in lieu of making the cash payment otherwise contemplated to be made to the Company upon such exercise in payment of the aggregate exercise price, the holder may elect to instead receive, upon such exercise (either in whole or in part), the net number of shares of the Company’s common stock determined according to a formula set forth in the June 2020 Investor Warrant. The June 2020 Investor Warrants will be automatically exercised on a cashless basis on their expiration date. The June 2020 Investor Warrants could also require payment of liquidated damages by the Company in the form of cash payments in the event of a failure by the Company to timely deliver shares of common stock upon exercise of such warrants. During the three months ended March 31, 2022 and 2021, no shares and 270 shares of the June 2020 Investor Warrants were exercised, respectively. The June 2020 Investor Warrants also contain a put option, under which, if the Company enters into a Fundamental Transaction, as defined in the June 2020 Investor Warrants, the holders of the June 2020 Investor Warrants will be entitled to receive upon exercise of the June 2020 Investor Warrants the kind and amount of securities, cash or other property that the holders would have received had they exercised the June 2020 Investor Warrants immediately prior to such fundamental transaction. Alternatively, the Company or any successor entity will, at the option of a holder of a June 2020 Investor Warrant, exercisable concurrently with or at any time within 30 days after the consummation of such Fundamental Transaction, purchase such holder’s June 2020 Investor Warrant by paying to such holder an amount of cash equal to the Black-Scholes value of the remaining unexercised portion of such holder’s June 2020 Investor Warrant. Because of this put-option provision, the June 2020 Investor Warrants are classified as a liability and are marked to market at each reporting date. The warrant liability related to the June 2020 Investor Warrants is measured at fair value at each reporting and exercise date using certain estimated inputs, which are classified within Level 3 of the fair value hierarchy. The following assumptions were used in the Black-Scholes Model to measure the fair value of the June 2020 Investor Warrants: March 31, 2022 December 31, 2021 Current share price $ 2.89 $ 2.65 Conversion price $ 5.18 $ 5.18 Risk-free interest rate 2.44 % 1.11 % Expected term (years) 3.69 3.94 Volatility of stock 97.1 % 103.9 % June 2020 Placement Agent Warrants In June 2020, the Company issued warrants (the "June 2020 Placement Agent Warrants"), exercisable for up to 122 shares of the Company’s common stock, to the placement agent for such offering. The June 2020 Placement Agent Warrants have substantially the same form as the June 2020 Investor Warrants, including the put option described above, except that they have an exercise price per share equal to $5.64, subject to adjustment in certain circumstances, and will expire on June 7, 2025. During the three months ended March 31, 2022 and 2021, no shares and 83 shares of the June 2020 Placement Agent Warrants were exercised, respectively. Because of the put-option provision in the June 2020 Placement Agent Warrants, these warrants are classified as a liability and are marked to market at each reporting date. The warrant liability related to the June 2020 Placement Agent Warrants is measured at fair value at each reporting and exercise date using certain estimated inputs, which are classified within Level 3 of the fair value hierarchy. The following assumptions were used in the Black-Scholes Model to measure the fair value of the June 2020 Placement Agent Warrants: March 31, 2022 December 31, 2021 Current share price $ 2.89 $ 2.65 Conversion price $ 5.64 $ 5.64 Risk-free interest rate 2.45 % 1.03 % Expected term (years) 3.19 3.44 Volatility of stock 99.8 % 100.0 % December 2019 Warrants In December 2019, pursuant to a securities purchase agreement (the "December 2019 Offering"), the Company issued warrants (the "December 2019 Warrants") to purchase 556 shares of common stock. The December 2019 Warrants are currently exercisable, have an exercise price of $8.10 per share, and will expire five years from the date they initially became exercisable, or on June 21, 2025. The December 2019 Warrants also contain a cashless exercise provision and could require cash payments in the event of a failure to timely deliver securities or in the event of insufficient authorized shares. The December 2019 Warrants will be automatically exercised on a cashless basis on their expiration date. The December 2019 Warrants also contain a put option, under which, if the Company enters into a Fundamental Transaction, as defined in the December 2019 Warrants, the Company or any successor entity will, at the option of a holder of a December 2019 Warrant, exercisable concurrently with or at any time within 30 days after the consummation of such Fundamental Transaction, purchase such holder’s December 2019 Warrant by paying to such holder an amount of cash equal to the Black-Scholes value of the remaining unexercised portion of such holder’s December 2019 Warrant within five The warrant liability related to the December 2019 Warrants is measured at fair value at each reporting date using certain estimated inputs, which are classified within Level 3 of the fair value hierarchy. The following assumptions were used in the Black-Scholes Model to measure the fair value of the December 2019 Warrants: March 31, 2022 December 31, 2021 Current share price $ 2.89 $ 2.65 Conversion price $ 8.10 $ 8.10 Risk-free interest rate 2.45 % 1.04 % Expected term (years) 3.22 3.47 Volatility of stock 99.5 % 99.7 % December 2019 Placement Agent Warrants In December 2019, in connection with the December 2019 Offering, the Company issued warrants to purchase 52 shares of the Company’s common stock to the placement agent for such offering (the "December 2019 Placement Agent Warrants"). The December 2019 Placement Agent Warrants have substantially the same form as the December 2019 Warrants, except that they have an exercise price per share equal to $8.44, subject to adjustment in certain circumstances, and will expire on December 18, 2025. The warrant liability related to the December 2019 Placement Agent Warrants is measured at fair value at each reporting date using certain estimated inputs, which are classified within Level 3 of the fair value hierarchy. The following assumptions were used in the Black-Scholes Model to measure the fair value of the December 2019 Placement Agent Warrants: March 31, 2022 December 31, 2021 Current share price $ 2.89 $ 2.65 Conversion price $ 8.44 $ 8.44 Risk-free interest rate 2.4 % 0.96 % Expected term (years) 2.72 2.97 Volatility of stock 103.5 % 102.9 % Management has assessed that the likelihood of a Change of Control (as defined in the December 2019 Placement Agent Warrants), occurring during the term of the December 2019 Placement Agent Warrants is low, and that if such an event were to occur, the difference between the cashless exercise value and the warrants fair value is nominal. May 2019 Warrants In May 2019, pursuant to an underwriting agreement, (the "May 2019 Offering"), the Company issued the warrants (the "May 2019 Warrants") to purchase 444 shares of common stock. The May 2019 Warrants are currently exercisable, have a current exercise price of $3.52 per share, and will expire five years from the date of their issuance, or on May 24, 2024. The May 2019 Warrants contain a price protection feature, pursuant to which, subject to certain exceptions, if shares of common stock are sold or issued in the future, or securities convertible or exercisable for shares of the Company’s common stock are sold or issued in the future, for consideration, or with an exercise price or conversion price, as applicable, per share less than the exercise price per share then in effect for the May 2019 Warrants, the exercise price of the May 2019 Warrants is reduced to the consideration paid for, or the exercise price or conversion price of, as the case may be, the securities issued in such offering. Pursuant to this provision, in connection with the June 2020 Offering, the exercise price of the May 2019 Warrants was reduced to $3.52 per share, being the amount that is equal to the lower of (x) the consideration paid for the securities issued in the June 2020 Offering, or $4.51 per share, (y) the lowest exercise price of the June 2020 Investor Warrants, or $5.18, and (z) the lowest one-day volume-weighted average price of the Company’s Common Stock on the Nasdaq Capital Market as measured each day during the five trading day period starting on June 8, 2020, rounded to the nearest share, or $3.52. During the three months ended March 31, 2022 and 2021, no shares and 5 shares of the May 2019 warrants were exercised respectively. In addition, if the Company effects or enters into any issuance of common stock or options or convertible securities exercisable for or convertible into common stock at a price which varies or may vary with the market price of the shares of the Company's common stock, subject to certain exceptions, a May 2019 Warrant holder may, at the time of exercise of the holder’s warrant, elect to exercise the warrant at such variable price. The May 2019 Warrants include a put option, whereby while the May 2019 Warrants are outstanding, if the Company enters into a Change of Control, as defined in the May 2019 Warrants, the Company or any successor entity will, at the option of a 2019 Warrant holder exercise within 90 days after the public disclosure of the Change of Control transaction, purchase such holder’s May 2019 Warrants by paying to such holder an amount of cash equal to the Black-Scholes value of the remaining unexercised portion of such warrants on the later date of consummation of the Change of Control transaction or two trading days after the notice of such request. Because of this put option provision, the May 2019 Warrants are classified as a liability and are marked to market at each reporting date. The warrant liability related to the May 2019 Warrants is measured at fair value at each reporting and exercise date using certain estimated inputs, which are classified within Level 3 of the fair value hierarchy. The following assumptions were used in a combination of the Black-Scholes Model and the Lattice Model to measure the fair value of the May 2019 Warrants: March 31, 2022 December 31, 2021 Current share price $ 2.89 $ 2.65 Conversion price $ 3.52 $ 3.52 Risk-free interest rate 2.31 % 0.83 % Expected term (years) 2.2 2.4 Volatility of stock 108.6 % 109.1 % |