The Company’s capital structure consists of ordinary shares and undesignated preferred shares. Under Irish law, the Company is prohibited from allotting shares without consideration. Accordingly, at least the nominal value of the shares issued underlying any warrant, pre-funded warrant, restricted share award, restricted share unit, performance share award, bonus share or any other share based grant must be paid pursuant to the Irish Companies Act 2014 (Irish Companies Act).

Ordinary Shares

At the Company’s annual general meeting of shareholders on May 3, 2023, the Company’s shareholders approved an increase of 60,000,000 ordinary shares of $0.01 par value each to the number of authorized ordinary shares and the Company’s Articles of Association were amended accordingly. The Company has authorized ordinary shares of 80,000,000 ordinary shares of $0.01 par value each as of December 31, 2023. The holders of ordinary shares are entitled to one vote for each share held. The holders of ordinary shares currently have preemptive rights over 60,000,000 ordinary shares and no preemptive or other subscription rights over 20,000,000 ordinary shares. There are no redemption or sinking fund provisions with respect to the authorized ordinary shares.

The Company filed a universal shelf registration statement on Form S-3 with the SEC, which was declared effective on October 17, 2022 (File No. 333-267795), and pursuant to which the Company registered for sale up to $100.0 million of any combination of debt securities, ordinary shares, preferred shares, subscription rights, purchase contracts, units and/or warrants from time to time and at prices and on terms that the Company may determine.

On October 7, 2022, the Company entered into a sales agreement with HC Wainwright, as agent, pursuant to which the Company may offer and sell ordinary shares, nominal value $0.01 per share, for aggregate gross sales proceeds of up to $16.0 million (subject to the availability of ordinary shares), from time to time through HC Wainwright by any method permitted that is deemed to be an "at the market offering" as defined in Rule 415 (a)(4) promulgated under the Securities Act of 1933, as amended. During the years ended December 31, 2023 and 2022, the Company sold 639,825 and 356,933 ordinary shares under the “at-the-market” agreement at an average price of $1.68 and $1.25 per share for net proceeds of $1.0 million and $0.4 million, respectively.

On February 3, 2021, the Company entered into an underwriting agreement (the Underwriting Agreement) pursuant to which it issued and sold 2,318,840 ordinary shares, $0.01 nominal value per share, at a public offering price per share of $17.25 (the February 2021 Underwritten Offering). The February 2021 Underwritten Offering closed on February 8, 2021. Pursuant to the Underwriting Agreement, the Company granted the underwriter an option for a period of 30 days to purchase up to an additional 347,826 ordinary shares on the same terms and conditions, which the underwriter exercised in full on February 10, 2021. This exercise increased the total number of ordinary shares sold by the Company in the offering to 2,666,666 shares, which resulted in aggregate gross proceeds of $46,000 and net proceeds of $42,119 after deducting underwriting discounts and commissions and other offering expenses.

On February 9, 2021, the Company completed a registered direct offering (the February 2021 Registered Direct Offering), pursuant to which the Company issued and sold an aggregate of 1,166,666 ordinary shares, $0.01 nominal value per share, at a purchase price per share of $30.00, for aggregate gross proceeds of $35,000 and net proceeds of $32,235 after deducting placement agent fees and other offering expenses. The closing date of the February 2021 Registered Direct Offering was February 12, 2021. The Company offered the ordinary shares in the June 3, 2020 Offering, June 30, 2020 Offering, February 2021 Underwritten Offering and February 2021 Registered Direct Offering pursuant to its universal shelf registration statement on Form S-3, which was declared effective on July 16, 2019 (File No. 333-232569).

Beginning on January 21, 2021 to December 31, 2023, certain noteholders of $40,691 aggregate principal amount of Exchangeable Notes have exchanged their notes for an aggregate of 3,760,155 of the Company’s ordinary shares, which included accrued and unpaid interest relating to such notes. The aggregate principal amount of Exchangeable Notes outstanding as of December 31, 2023 was $11,117.

Warrants to purchase Ordinary Shares

In connection with the initial drawdown under the Loan and Security Agreement, the Company issued SVB and LSF warrants to purchase an aggregate of 19,890 Series B convertible preferred shares (which converted into warrants to purchase 1,326 ordinary shares upon the Company’s IPO) at an exercise price of $282.75 per share. These warrants will expire on April 27, 2028. No warrants had been exercised as of December 31, 2023.

In connection with the June 3, 2020 Offering completed on June 5, 2020, pursuant to the June 3, 2020 SPA, in a concurrent private placement, the Company issued and sold to institutional investors warrants to purchase up to 99,057 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $24.30 per ordinary share, subject to adjustment in certain circumstances, and will expire on December 5, 2025. Warrants to purchase 13,868 ordinary shares, amounting to 7% of the ordinary shares issued under the June 3, 2020 SPA, were issued to designees of the placement agent on the closing of the June 3, 2020 Offering. Upon closing, the warrants issued to such designees were exercisable immediately at an exercise price of $31.5465 per ordinary share and will expire on June 3, 2025. No warrants had been exercised as of December 31, 2023.

In connection with the June 30, 2020 Offering completed on July 2, 2020, pursuant to the June 30, 2020 SPA, in a concurrent private placement, the Company has also issued and sold to institutional investors warrants to purchase up to 112,422 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $21.30 per ordinary share, subject to adjustment in certain circumstances, and will expire on January 2, 2026. Warrants to purchase 15,739 ordinary shares, amounting to 7% of the ordinary shares issued under the June 30, 2020 SPA, were issued to designees of the placement agent on closing of the June 30, 2020 Offering. Upon closing, the warrants issued to such designees were exercisable immediately at an exercise price of $27.7965 per

ordinary share and will expire on June 30, 2025. As of December 31, 2023, warrants issued in connection with the June 30, 2020 Offering had been exercised for 84,317 ordinary shares, for net proceeds of $1,796.

In connection with the October 2020 Offering, the Company issued and sold warrants to purchase up to 1,346,153 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $9.75 per ordinary share, subject to adjustment in certain circumstances, and will expire on October 27, 2025. Warrants to purchase 125,641 ordinary shares, which represents a number of ordinary shares equal to 7.0% of the aggregate number of ordinary shares and pre-funded warrants sold in the October 2020 Offering, were issued to designees of the placement agent on closing of the October 2020 Offering. Upon closing, the warrants issued to such designees became exercisable immediately at an exercise price of $12.1875 per ordinary share and expire on October 22, 2025. As of December 31, 2023, warrants issued in connection with the October 2020 Offering had been exercised for 1,392,701 ordinary shares, for net proceeds of $13,885.

In connection with the February 2021 Underwritten Offering, the Company issued to the underwriter’s designees warrants to purchase 162,318 ordinary shares, amounting to 7.0% of the aggregate number of ordinary shares sold in the February 2021 Underwritten Offering which closed on February 8, 2021. The warrants issued to such designees have an exercise price of $21.5625 per ordinary share, were exercisable upon issuance and will expire on February 3, 2026. As of December 31, 2023, warrants issued in connection with the February 2021 Underwritten Offering had been exercised for 25,333 ordinary shares, for net proceeds of $546.

In connection with the February 2021 Underwritten Offering, the Company granted the underwriter an option for a period of 30 days to purchase an additional 347,826 ordinary shares. Upon the underwriter’s exercise of its option, on February 10, 2021, the Company issued warrants to purchase an additional 24,347 ordinary shares to the underwriter’s designees, amounting to 7.0% of the aggregate number of additional ordinary shares sold pursuant to the underwriter’s option. The warrants issued to such designees have an exercise price of $21.5625 per ordinary share, were exercisable upon issuance and will expire on February 3, 2026. No warrants had been exercised as of December 31, 2023.

In connection with the February 2021 Registered Direct Offering which closed on February 12, 2021, warrants to purchase 81,666 ordinary shares, amounting to 7.0% of the aggregate number of ordinary shares issued under the securities purchase agreement, were issued to designees of the placement agent upon closing. The warrants issued to such designees were exercisable upon issuance at an exercise price of $37.50 per ordinary share and will expire on February 9, 2026. No warrants had been exercised as of December 31, 2023.

Undesignated Preferred Shares

The Company has authorized 100,000,000 undesignated preferred shares of $0.01 par value each as of December 31, 2023. The Company's Board of Directors is authorized by the Company’s Articles of Association to determine the rights attaching to the undesignated preferred shares including rights of redemption, rights as to dividends, rights on winding up and conversion rights. There were no undesignated preferred shares in issue as of December 31, 2023 or December 31, 2022.