| Summary of changes in stockholders' equity |
The following tables present changes in shareholders’ equity for the three months ended March 31, 2025 and 2024 (in thousands, except share and per share amounts): | | | | | | | | | | | | | | | | | | | | | | | | | | | | Accumulated | | | | | | | | | | | | | Additional | | Other | | | | Total | | | Common Stock | | Paid-in | | Comprehensive | | Accumulated | | Shareholders' | | | Shares | | Amount | | Capital | | Income (Loss) | | Deficit | | Equity | Three Months Ended March 31, 2025: | | | | | | | | | | | | | | | | | | Balances, December 31, 2024 | | 60,534,695 | | $ | 61 | | $ | 460,016 | | $ | 64 | | $ | (360,552) | | $ | 99,589 | Issuance of common stock upon exercise of stock options | | 8,219 | | | — | | | 10 | | | — | | | — | | | 10 | Share-based compensation expense | | — | | | — | | | 1,905 | | | — | | | — | | | 1,905 | Net change in accumulated other comprehensive income (loss) | | — | | | — | | | — | | | (21) | | | — | | | (21) | Net loss | | — | | | — | | | — | | | — | | | (18,914) | | | (18,914) | Balances, March 31, 2025 | | 60,542,914 | | $ | 61 | | $ | 461,931 | | $ | 43 | | $ | (379,466) | | $ | 82,569 | | | | | | | | | | | | | | | | | | | Three Months Ended March 31, 2024: | | | | | | | | | | | | | | | | | | Balances, December 31, 2023 | | 39,625,271 | | $ | 40 | | $ | 381,154 | | $ | (48) | | $ | (289,418) | | $ | 91,728 | Issuance of common stock upon exercise of stock options | | 5,000 | | | — | | | 10 | | | — | | | — | | | 10 | Share-based compensation expense | | — | | | — | | | 1,903 | | | — | | | — | | | 1,903 | Cashless exercise of pre-funded warrants | | 3,502,376 | | | 3 | | | (3) | | | — | | | — | | | — | Acquisition and retirement of treasury shares pursuant to Exchange Agreement | | (3,000,000) | | | (3) | | | (5,697) | | | — | | | — | | | (5,700) | Net change in accumulated other comprehensive income (loss) | | — | | | — | | | — | | | (30) | | | — | | | (30) | Net loss | | — | | | — | | | — | | | — | | | (17,050) | | | (17,050) | Balances, March 31, 2024 | | 40,132,647 | | $ | 40 | | $ | 377,367 | | $ | (78) | | $ | (306,468) | | $ | 70,861 |
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| Schedule of warrant activity |
The following table summarizes PFW activity for the nine months ended March 31, 2025: | | | | | | | | | | | 2021 | | 2022 | | Exchange | | 2024 | | | | PFWs | | PFWs | | PFWs | | PFWs | | Total | Outstanding, June 30, 2024 | 123,000 | (1) | 8,147,371 | (2) | 3,000,000 | (3) | 3,750,000 | (4) | 15,020,371 | Cashless exercise of PFWs: | | | | | | | | | | Shares surrendered for exercise price | — | | (435) | (5) | (616) | (6) | — | | (1,051) | Shares of common stock issued | — | | (2,525,883) | (5) | (2,999,384) | (6) | — | | (5,525,267) | Outstanding, March 31, 2025 | 123,000 | | 5,621,053 | | — | | 3,750,000 | | 9,494,053 |
| (1) | In connection with an underwritten offering in October 2021, PFWs were issued to purchase 1,661,461 shares of common stock at an issuance price of $6.49 per share (the “2021 PFWs”). The exercise price of the 2021 PFWs is $0.01 per share. For the fiscal year ended June 30, 2024, the holders elected cashless exercises for a total of 1,538,461 of the 2021 PFWs resulting in 123,000 shares that remained outstanding as of June 30, 2024. |
| (2) | In connection with a registered direct offering in May 2022, the Company issued 1,973,684 Class A PFWs and 10,947,371 Class B PFWs to purchase an aggregate of 12,921,055 shares of common stock at an issuance price of $3.799 per warrant (the “2022 PFWs”). The exercise price of the 2022 PFWs is $0.001 per share. For the fiscal year ended June 30, 2024, the holders elected cashless exercises for a total of 4,773,684 of the 2022 PFWs resulting in 8,147,371 shares that remained outstanding as of June 30, 2024. |
| (3) | As discussed below under the caption Exchange Agreement, the Company issued 3,000,000 Exchange PFWs on March 8, 2024. The exercise price of the Exchange PFWs is $0.001 per share. The Exchange PFWs were initially classified as a derivative liability until May 13, 2024 when the terms were amended to permit reclassification within shareholders’ equity. |
| (4) | As discussed below under the caption 2024 Underwritten Offering, the Company issued 2024 PFWs for the purchase of 3,750,000 shares of common stock on June 17, 2024. The exercise price of the 2024 PFWs is $0.001 per share. |
| (5) | In November 2024, a holder of certain 2022 PFWs provided notice of cashless exercise of 2,526,318 Class B PFWs that resulted in the issuance of 2,525,883 shares of common stock. |
| (6) | In October 2024, all holders of Exchange PFWs provided notice of cashless exercises of 3,000,000 Exchange PFWs that resulted in the issuance of 2,999,384 shares of common stock in October 2024. |
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