Subsequent Event	12 Months Ended
Dec. 31, 2025
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events Transaction Agreement On March 31, 2026, we entered into a Transaction Agreement with Lilly and Purchaser. Under the terms of the Transaction Agreement, Purchaser (and/or at Parent’s election, its nominee(s)) will acquire the entire issued and to be issued share capital of the Company (the “Acquisition”) by means of the Scheme of Arrangement. Upon the Scheme of Arrangement becoming effective, the Company will become a wholly owned subsidiary of Purchaser. At the effective time of the Scheme of Arrangement (the “Effective Time”), holders of the Company Shares (including Company Shares represented by our ADSs), will be entitled to receive (i) $38.00 in cash per Company Share, without interest (the “Cash Consideration”), plus (ii) one non-transferable contingent value right entitling the holders to receive contingent cash payments of up to an aggregate of $9.00 per Company Share, contingent upon the achievement of specified milestones set forth in the CVR Agreement. The Acquisition and the Scheme of Arrangement have been recommended by the board of directors of the Company (the “Company Board”) and the boards of directors of Parent and Purchaser. Treatment of Company Equity Awards Pursuant to the Transaction Agreement, at the Effective Time: (i) each outstanding option with an exercise price below the cash consideration (each such option, a “Company Cash-Out Option”), whether vested or unvested, will be canceled and converted into the right to receive (A) a cash payment equal to the excess of the cash consideration over the exercise price, multiplied by the number of shares underlying such Company Cash-Out Option (less applicable withholding), and (B) one CVR per underlying Company Cash-Out Option; (ii) each outstanding option with an exercise price equal to or above the cash consideration (each such option, a “Company Underwater Option”) will fully vest prior to the Effective Time and will be exercisable prior to the Effective Time, with any portion remaining unexercised as of the Effective Time canceled for no consideration; and (iii) each outstanding restricted stock unit otherwise (each such restricted stock unit, a “Company RSU”) will fully vest and, at the Effective Time, will be canceled and converted into the right to receive (A) a cash payment equal to the cash consideration multiplied by the number of shares underlying such Company RSU (less applicable withholding) and (B) one CVR per underlying Company RSU. Conditions to Completion of the Acquisition The Acquisition is subject to customary closing conditions, including, among other things: (a) the approval of the Scheme of Arrangement by a majority in number representing not less than three-fourths (75%) in value of the members or class of members (as the case may be) present and voting (either in person or by proxy) at the Scheme Meeting (as defined in the Transaction Agreement) (including any separate class meeting which may be required by the High Court of Justice of England and Wales (the “Court”)) and the passing of the Company Shareholder Resolution (as defined in the Transaction Agreement) by members representing not less than three-fourths (75%) of the total voting rights of eligible members present and voting (either in person or by proxy) at the Company GM (as defined in the Transaction Agreement), (b) the sanctioning of the Scheme of Arrangement by the Court, (c) the expiration or termination of the applicable waiting period (and any extension thereof) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”), (d) the absence of any order, decree or ruling that remains in effect and enjoins, prevents, prohibits, or makes illegal the consummation of the Contemplated Transactions, (e) that each party’s respective representations and warranties, subject to certain customary materiality standards set forth in the Transaction Agreement, shall be true and correct as of the Effective Time, (f) the performance or compliance in all material respects with the other party’s obligations under the Transaction Agreement, and (g) no Company Material Adverse Effect (as defined in the Transaction Agreement) having occurred that is continuing at the Effective Time. Representations and Warranties; Covenants The Transaction Agreement includes customary representations, warranties and covenants of the Company, Parent and Purchaser. The Company has agreed, among other things, to use commercially reasonable efforts to operate its business in the ordinary course until the earlier of the Effective Time or the date the Transaction Agreement is terminated, and not to engage in specified types of transactions during such period. The Company has also agreed to customary non-solicitation restrictions, including not to initiate, solicit, knowingly encourage or knowingly facilitate discussions with third parties regarding other proposals for alternative business combination transactions involving the Company or change the recommendation of the Company Board to the Company’s shareholders regarding the Scheme of Arrangement, in each case, except as otherwise permitted by the Transaction Agreement, including to enter into an alternative transaction that constitutes a Superior Proposal (as defined in the Transaction Agreement) in compliance with the Company Board’s fiduciary duties under applicable law and subject to payment of a termination fee. Parent, Purchaser and the Company have agreed to use reasonable best efforts to take actions that may be required in order to obtain antitrust approval of the proposed transaction, subject to certain limitations. Termination and Termination Fee The Transaction Agreement also includes customary termination provisions for both the Company and Parent, including, among others, the right of both parties to terminate for failure to consummate the transactions contemplated by the Transaction Agreement and the Scheme of Arrangement (together, the “Contemplated Transactions”) on or before September 30, 2026, which date shall be extended to March 31, 2027 if the closing condition regarding the expiration of the waiting period (and any extension thereof) under the HSR Act remains unsatisfied. If the Transaction Agreement is terminated under certain circumstances specified in the Transaction Agreement, the Company will be required to pay Parent a termination fee of approximately $63 million (including under specified circumstances in connection with the Company’s entry into an agreement with respect to a Superior Proposal or the Company Board’s change of recommendation in favor of the Acquisition). The parties to the Transaction Agreement are also entitled to specifically enforce the terms and provisions of the Transaction Agreement. Voting and Support Agreements On March 31, 2026, in connection with the execution and delivery of the Transaction Agreement, entities affiliated with Medicxi Ventures, Index Ventures and affiliates of General Atlantic (collectively, the “Supporting Shareholders”), solely in their respective capacities as shareholders of the Company, each entered into a voting and support agreement (collectively, the “Voting Agreements”) with Parent and the Company, pursuant to which each Supporting Shareholder agreed, among other things, (i) to vote (or cause to vote) in favor of the Scheme of Arrangement and the Company Shareholder Resolution, (ii) to vote against other proposals to acquire the Company and (iii) to certain other restrictions on its ability to take actions with respect to the Company and its Company Shares. The Voting Agreements have been included to provide information regarding their terms. They are not intended to modify or supplement any factual disclosures about the applicable Supporting Shareholder or the Company in any public reports filed with the SEC by the Company. The foregoing description of the Voting Agreements is qualified in all respects by reference to the full copy of the form of Voting Agreement. Contingent Value Rights Agreement At or prior to the Effective Time, Parent, Purchaser and Computershare Inc., a Delaware Corporation, and its affiliate, Computershare Trust Company, N.A., a federally chartered trust company, will enter into the CVR Agreement. Pursuant to the Transaction Agreement, each holder of Company Shares (including Company Shares represented by the ADS) and each holder of Company Covered Award (as defined in the CVR Agreement) will be entitled to receive one CVR for each Company Share or Company Covered Award, as applicable, which represents the right to receive contingent cash payments of up to an aggregate of $9.00 per Company Share, without interest and less any applicable tax withholding upon the achievement of specified regulatory milestones for cleminorexton (formerly ORX750) or ORX142 (the “Milestones”). The Milestones include receipt of U.S. regulatory approval for ORX750 or ORX142 for the treatment of idiopathic hypersomnia, any indication and narcolepsy type 2, respectively, in each case prior to the applicable milestone deadline. The CVR will be subject to the terms and conditions set forth in the CVR Agreement. Each CVR represents a contractual right only. The CVRs will not be transferable, except in the limited circumstances specified in the CVR Agreement, will not be evidenced by certificate or other instrument and will not be registered or listed for trading. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Purchaser or the Company. Any potential payout of the CVR is subject to various risks and uncertainties related to the development of cleminorexton or ORX142 and U.S. Food and Drug Administration clearances. There can be no assurance that the Milestones will be achieved prior to their expiration or termination of the CVR Agreement, or that payment will be required of Parent with respect to the Milestones. The foregoing description of the CVR Agreement does not purport to be complete and is subject to, and is qualified in its entirety by, the full text of the form of the CVR Agreement.

On March 31, 2026, we entered into a Transaction Agreement with Lilly and Purchaser. Under the terms of the Transaction Agreement, Purchaser (and/or at Parent’s election, its nominee(s)) will acquire the entire issued and to be issued share capital of the Company (the “Acquisition”) by means of the Scheme of Arrangement. Upon the Scheme of Arrangement becoming effective, the Company will become a wholly owned subsidiary of Purchaser.

At the effective time of the Scheme of Arrangement (the “Effective Time”), holders of the Company Shares (including Company Shares represented by our ADSs), will be entitled to receive (i) $38.00 in cash per Company Share, without interest (the “Cash Consideration”), plus (ii) one non-transferable contingent value right entitling the holders to receive contingent cash payments of up to an aggregate of $9.00 per Company Share, contingent upon the achievement of specified milestones set forth in the CVR Agreement. The Acquisition and the Scheme of Arrangement have been recommended by the board of directors of the Company (the “Company Board”) and the boards of directors of Parent and Purchaser.

canceled and converted into the right to receive (A) a cash payment equal to the excess of the cash consideration over the exercise price, multiplied by the number of shares underlying such Company Cash-Out Option (less applicable withholding), and (B) one CVR per underlying Company Cash-Out Option; (ii) each outstanding option with an exercise price equal to or above the cash consideration (each such option, a “Company Underwater Option”) will fully vest prior to the Effective Time and will be exercisable prior to the Effective Time, with any portion remaining unexercised as of the Effective Time canceled for no consideration; and (iii) each outstanding restricted stock unit otherwise (each such restricted stock unit, a “Company RSU”) will fully vest and, at the Effective Time, will be canceled and converted into the right to receive (A) a cash payment equal to the cash consideration multiplied by the number of shares underlying such Company RSU (less applicable withholding) and (B) one CVR per underlying Company RSU.

The Acquisition is subject to customary closing conditions, including, among other things: (a) the approval of the Scheme of Arrangement by a majority in number representing not less than three-fourths (75%) in value of the members or class of members (as the case may be) present and voting (either in person or by proxy) at the Scheme Meeting (as defined in the Transaction Agreement) (including any separate class meeting which may be required by the High Court of Justice of England and Wales (the “Court”)) and the passing of the Company Shareholder Resolution (as defined in the Transaction Agreement) by members representing not less than three-fourths (75%) of the total voting rights of eligible members present and voting (either in person or by proxy) at the Company GM (as defined in the Transaction Agreement), (b) the sanctioning of the Scheme of Arrangement by the Court, (c) the expiration or termination of the applicable waiting period (and any extension thereof) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”), (d) the absence of any order, decree or ruling that remains in effect and enjoins, prevents, prohibits, or makes illegal the consummation of the Contemplated Transactions, (e) that each party’s respective representations and warranties, subject to certain customary materiality standards set forth in the Transaction Agreement, shall be true and correct as of the Effective Time, (f) the performance or compliance in all material respects with the other party’s obligations under the Transaction Agreement, and (g) no Company Material Adverse Effect (as defined in the Transaction Agreement) having occurred that is continuing at the Effective Time.

The Transaction Agreement includes customary representations, warranties and covenants of the Company, Parent and Purchaser. The Company has agreed, among other things, to use commercially reasonable efforts to operate its business in the ordinary course until the earlier of the Effective Time or the date the Transaction Agreement is terminated, and not to engage in specified types of transactions during such period. The Company has also agreed to customary non-solicitation restrictions, including not to initiate, solicit, knowingly encourage or knowingly facilitate discussions with third parties regarding other proposals for alternative business combination transactions involving the Company or change the recommendation of the Company Board to the Company’s shareholders regarding the Scheme of Arrangement, in each case, except as otherwise permitted by the Transaction Agreement, including to enter into an alternative transaction that constitutes a Superior Proposal (as defined in the Transaction Agreement) in compliance with the Company Board’s fiduciary duties under applicable law and subject to payment of a termination fee. Parent, Purchaser and the Company have agreed to use reasonable best efforts to take actions that may be required in order to obtain antitrust approval of the proposed transaction, subject to certain limitations.

The Transaction Agreement also includes customary termination provisions for both the Company and Parent, including, among others, the right of both parties to terminate for failure to consummate the transactions contemplated by the Transaction Agreement and the Scheme of Arrangement (together, the “Contemplated Transactions”) on or before September 30, 2026, which date shall be extended to March 31, 2027 if the closing condition regarding the expiration of the waiting period (and any extension thereof) under the HSR Act remains unsatisfied. If the Transaction Agreement is terminated under certain circumstances specified in the Transaction Agreement, the Company will be required to pay Parent a termination fee of approximately $63 million (including under specified circumstances in connection with the Company’s entry into an agreement with respect to a Superior Proposal or the Company Board’s change of recommendation in favor of the Acquisition). The parties to the Transaction Agreement are also entitled to specifically enforce the terms and provisions of the Transaction Agreement.

Shareholders”), solely in their respective capacities as shareholders of the Company, each entered into a voting and support agreement (collectively, the “Voting Agreements”) with Parent and the Company, pursuant to which each Supporting Shareholder agreed, among other things, (i) to vote (or cause to vote) in favor of the Scheme of Arrangement and the Company Shareholder Resolution, (ii) to vote against other proposals to acquire the Company and (iii) to certain other restrictions on its ability to take actions with respect to the Company and its Company Shares.

At or prior to the Effective Time, Parent, Purchaser and Computershare Inc., a Delaware Corporation, and its affiliate, Computershare Trust Company, N.A., a federally chartered trust company, will enter into the CVR Agreement. Pursuant to the Transaction Agreement, each holder of Company Shares (including Company Shares represented by the ADS) and each holder of Company Covered Award (as defined in the CVR Agreement) will be entitled to receive one CVR for each Company Share or Company Covered Award, as applicable, which represents the right to receive contingent cash payments of up to an aggregate of $9.00 per Company Share, without interest and less any applicable tax withholding upon the achievement of specified regulatory milestones for cleminorexton (formerly ORX750) or ORX142 (the “Milestones”). The Milestones include receipt of U.S. regulatory approval for ORX750 or ORX142 for the treatment of idiopathic hypersomnia, any indication and narcolepsy type 2, respectively, in each case prior to the applicable milestone deadline. The CVR will be subject to the terms and conditions set forth in the CVR Agreement. Each CVR represents a contractual right only. The CVRs will not be transferable, except in the limited circumstances specified in the CVR Agreement, will not be evidenced by certificate or other instrument and will not be registered or listed for trading. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Purchaser or the Company.