Subsequent Events	3 Months Ended
Mar. 31, 2026
Subsequent Events [Abstract]
Subsequent Events	12. Subsequent events On April 7, 2026, the Company converted 76,479.175 shares of its Series B into 76,479,164 shares of its common stock, par value $0.001 per share, pursuant to and in accordance with the Certificate of Designation of Preferences, Rights and Limitations of the Series B, as amended (the Certificate of Designation). No fractional shares of common stock were issued in connection with the partial mandatory conversion; in lieu of any fractional shares, the Company will pay each holder an amount in cash equal to the trading value of such fractional shares as of the close of business on the date of the conversion in accordance with the Certificate of Designation. Following the conversion, 42,839.11 shares of Series B remain issued and outstanding. On April 8, 2026, certain affiliates of Ikarian exercised a portion of their pre-funded warrants to purchase an aggregate of 8,488,229 shares of common stock at an exercise price of $0.001 per share, and the related aggregate exercise price of approximately $8,488.23 was paid to the Company. Following the exercise, pre-funded warrants to purchase an additional 14,552,811 shares of common stock remain outstanding. On April 14, 2026, the Company entered into the Merger Agreement with Obsidian and three newly formed companies – Parent, a subsidiary of Galera, and Onyx MergerSub, Inc. and Gazelle Merger Subsidiary, Inc., wholly-owned subsidiaries of Parent – which were incorporated in Delaware on April 10, 2026. Pursuant to the Merger Agreement, and upon the terms and subject to the satisfaction or waiver of the conditions described therein, Galera will be merged with and into Gazelle Merger Subsidiary, with Galera surviving as a wholly-owned subsidiary of Parent, and Obsidian will be merged with and into Obsidian Merger-Sub, with Obsidian surviving as a wholly-owned subsidiary of Parent. These mergers are intended to qualify as a tax-free reorganization for U.S. federal income tax purposes. Assuming that the Obsidian Merger is closed, the pre-merger equityholders of Obsidian will own approximately 53.2% and the pre-merger equityholders of Galera will own approximately 1.8% of the combined company. A PIPE financing will be closed concurrently with the Obsidian Merger for approximately $350.0 million, and the PIPE investors will own approximately 45.0% of the combined company. The percentage owned by Galera equityholders is based on a valuation of $13.8 million, including an assumption of net cash at closing of $1.8 million; for every $200,000 decrease in the Company’s net cash at closing the percentage owned by Galera equityholders will decrease approximately 2.5 basis points. Net cash as defined in the Merger Agreement can be a negative number and the amount of the adjustment is not capped. Furthermore, each holder of Galera common stock of record as of immediately prior to the consummation of the PIPE will be entitled to (i) one CVR for each share of Galera common stock held by such holder, representing the right to receive a pro rata portion of 80% of any potential future net proceeds received by Parent or its affiliates from the development, commercialization, licensing, sale or other disposition of Galera’s product candidate, tilarginine, or related intellectual property during the five years following the closing of the Obsidian Merger and (ii) one CVR for each share of Galera common stock held by such holder, representing the right to receive a pro rata portion of 95% of any potential future net proceeds received by Parent or its affiliates from the divestiture effected by the Asset Purchase and Sale Agreement with Biossil during the ten years following the closing of the Obsidian Merger. To effect the Obsidian Merger, the Company filed a registration statement on Form S-4 with the Securities and Exchange Commission (SEC) on April 22, 2026, which is subject to SEC review and comments before becoming effective. The Obsidian Merger will close after approval by the shareholders of Galera and Obsidian, the S-4 becomes effective, and certain other conditions, as specified in the Merger Agreement, are satisfied. At the Company’s Combined 2025 and 2026 Annual Meeting of Stockholders held on May 8, 2026, holders of a majority of the shares of the Company’s common stock approved an increase in the number of shares of authorized common stock from 200 million to 400 million. An amendment to the Company’s Restated Certificate of Incorporation reflecting the increase in authorized common stock was filed on May 11, 2026.

Subsequent Events

3 Months Ended

Mar. 31, 2026

12.

Subsequent events

On April 7, 2026, the Company converted 76,479.175 shares of its Series B into 76,479,164 shares of its common stock, par value $0.001 per share, pursuant to and in accordance with the Certificate of Designation of Preferences, Rights and Limitations of the Series B, as amended (the Certificate of Designation). No fractional shares of common stock were issued in connection with the partial mandatory conversion; in lieu of any fractional shares, the Company will pay each holder an amount in cash equal to the trading value of such fractional shares as of the close of business on the date of the conversion in accordance with the Certificate of Designation. Following the conversion, 42,839.11 shares of Series B remain issued and outstanding.

On April 8, 2026, certain affiliates of Ikarian exercised a portion of their pre-funded warrants to purchase an aggregate of 8,488,229 shares of common stock at an exercise price of $0.001 per share, and the related aggregate exercise price of approximately $8,488.23 was paid to the Company. Following the exercise, pre-funded warrants to purchase an additional 14,552,811 shares of common stock remain outstanding.

On April 14, 2026, the Company entered into the Merger Agreement with Obsidian and three newly formed companies – Parent, a subsidiary of Galera, and Onyx MergerSub, Inc. and Gazelle Merger Subsidiary, Inc., wholly-owned subsidiaries of Parent – which were incorporated in Delaware on April 10, 2026. Pursuant to the Merger Agreement, and upon the terms and subject to the satisfaction or waiver of the conditions described therein, Galera will be merged with and into Gazelle Merger Subsidiary, with Galera surviving as a wholly-owned subsidiary of Parent, and Obsidian will be merged with and into Obsidian Merger-Sub, with Obsidian surviving as a wholly-owned subsidiary of Parent. These mergers are intended to qualify as a tax-free reorganization for U.S. federal income tax purposes.

Assuming that the Obsidian Merger is closed, the pre-merger equityholders of Obsidian will own approximately 53.2% and the pre-merger equityholders of Galera will own approximately 1.8% of the combined company. A PIPE financing will be closed concurrently with the Obsidian Merger for approximately $350.0 million, and the PIPE investors will own approximately 45.0% of the combined company. The percentage owned by Galera equityholders is based on a valuation of $13.8 million, including an assumption of net cash at closing of $1.8 million; for every $200,000 decrease in the Company’s net cash at closing the percentage owned by Galera equityholders will decrease approximately 2.5 basis points. Net cash as defined in the Merger Agreement can be a negative number and the amount of the adjustment is not capped.

Furthermore, each holder of Galera common stock of record as of immediately prior to the consummation of the PIPE will be entitled to (i) one CVR for each share of Galera common stock held by such holder, representing the right to receive a pro rata portion of 80% of any potential future net proceeds received by Parent or its affiliates from the development, commercialization, licensing, sale or other disposition of Galera’s product candidate, tilarginine, or related intellectual property during the five years following the closing of the Obsidian Merger and (ii) one CVR for each share of Galera common stock held by such holder, representing the right to receive a pro rata portion of 95% of any potential future net proceeds received by Parent or its affiliates from the divestiture effected by the Asset Purchase and Sale Agreement with Biossil during the ten years following the closing of the Obsidian Merger.

To effect the Obsidian Merger, the Company filed a registration statement on Form S-4 with the Securities and Exchange Commission (SEC) on April 22, 2026, which is subject to SEC review and comments before becoming effective. The Obsidian Merger will close after approval by the shareholders of Galera and Obsidian, the S-4 becomes effective, and certain other conditions, as specified in the Merger Agreement, are satisfied.

At the Company’s Combined 2025 and 2026 Annual Meeting of Stockholders held on May 8, 2026, holders of a majority of the shares of the Company’s common stock approved an increase in the number of shares of authorized common stock from 200 million to 400 million. An amendment to the Company’s Restated Certificate of Incorporation reflecting the increase in authorized common stock was filed on May 11, 2026.