Verona Pharma (VRNA) 10-K 29 Feb 24 2023 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 23, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38067
Entity Registrant Name	Verona Pharma plc
Entity Incorporation, State or Country Code	X0
Entity Tax Identification Number	98-1489389
Entity Address, Address Line One	3 More London Riverside
Entity Address, City or Town	London
Entity Address, Postal Zip Code	SE1 2RE
Entity Address, Country	GB
Country Region	44
City Area Code	203
Local Phone Number	283 4200
Title of 12(b) Security	Ordinary shares, nominal value £0.05 per share*
Trading Symbol	VRNA
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 1,500
Entity Common Stock, Shares Outstanding		646,524,958
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement that the registrant intends to file with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the registrant’s 2024 Annual Meeting of Shareholders are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Central Index Key	0001657312

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Audit Information [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	876
Auditor Location	Reading, United Kingdom

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 271,772	$ 227,827
Prepaid expenses	3,617	2,499
Tax incentive receivables	10,954	9,282
Other current assets	3,365	3,388
Total current assets	289,708	242,996
Non-current assets:
Furniture and equipment, net	24	73
Goodwill	545	545
Equity interest	15,000	15,000
Right-of-use assets	2,847	854
Total non-current assets:	18,416	16,472
Total assets	308,124	259,468
Current liabilities:
Accounts payable	3,492	2,910
Accrued expenses	3,585	13,752
Current operating lease liabilities	1,180	675
Taxes payable	0	283
Other current liabilities	435	1,409
Total current liabilities	8,692	19,029
Non-current liabilities:
Term loan	48,374	9,768
Non-current operating lease liabilities	1,775	205
Total non-current liabilities	50,149	9,973
Total liabilities	58,841	29,002
Commitments and contingencies
Shareholders' equity
Ordinary £0.05 par value shares: 667,659,630 and 631,338,246 issued, and 643,536,094 and 606,301,054 outstanding, at December 31, 2023 and 2022, respectively	42,771	40,526
Additional paid-in capital	601,063	529,187
Ordinary shares held in treasury	(1,517)	(1,549)
Accumulated other comprehensive loss	(4,601)	(4,601)
Accumulated deficit	(388,433)	(333,097)
Total shareholders' equity	249,283	230,466
Total liabilities and shareholders' equity	$ 308,124	$ 259,468

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical)	Dec. 31, 2023 £ / shares shares	Dec. 31, 2022 £ / shares shares
Statement of Financial Position [Abstract]
Common stock, par value (in pounds sterling per share) | (per share)	£ 0.05	£ 0.05
Common stock, issued (in shares)	667,659,630	631,338,246
Common stock, outstanding (in shares)	643,536,094	606,301,054

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenues	$ 0	$ 458
Cost of sales	0	(346)
Gross profit	0	112
Operating expenses:
Research and development (Note 11)	17,216	49,283
Selling, general and administrative	50,353	26,579
Total operating expenses	67,569	75,862
Operating loss	(67,569)	(75,750)
Other income/(expense):
Research and development tax credit	1,104	9,634
Loss on extinguishment of debt	0	(815)
Interest income	12,761	2,821
Interest expense	(2,057)	(521)
Foreign exchange gain/(loss)	1,866	(3,817)
Total other income, net	13,674	7,302
Loss before income taxes	(53,895)	(68,448)
Income tax expense	(474)	(253)
Net loss	$ (54,369)	$ (68,701)
Loss per ordinary share, basic (in dollars per share)	$ (0.09)	$ (0.13)
Loss per ordinary share, diluted (in dollars per share)	$ (0.09)	$ (0.13)
Weighted-average shares outstanding - basic (in shares)	634,142,660	529,071,526
Weighted-average shares outstanding - diluted (in shares)	634,142,660	529,071,526

Consolidated Statements of Shar

Consolidated Statements of Shareholders’ Equity - USD ($) $ in Thousands	Total	Public Stock Offering	At-The-Market Sales Agreement	Ordinary shares	Ordinary shares Public Stock Offering	Ordinary shares At-The-Market Sales Agreement	Additional paid-in capital	Additional paid-in capital Public Stock Offering	Additional paid-in capital At-The-Market Sales Agreement	Treasury Stock, Common	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2021				489,177,550
Beginning balance at Dec. 31, 2021	$ 148,005			$ 31,855			$ 385,070			$ (603)	$ (4,601)	$ (263,716)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(68,701)											(68,701)
Issuance of ordinary shares, net of issuance costs (in shares)					114,080,000	80,696
Issuance of ordinary shares, net of issuance costs		$ 140,197	$ 67		$ 6,918	$ 5		$ 133,279	$ 62
Issuance of ordinary shares to treasury (in shares)				28,000,000
Issuance of ordinary shares to treasury	0			$ 1,748						(1,748)
Restricted share units vested										680		(680)
Share options exercised	1,372						1,250			122
Share-based compensation	14,121						14,121
Common shares withheld for taxes on vested stock awards	(4,723)						(4,723)
Equity settled share-based compensation reclassified as cash-settled	$ 128						128
Ending balance (in shares) at Dec. 31, 2022	606,301,054			631,338,246
Ending balance at Dec. 31, 2022	$ 230,466			$ 40,526			529,187			(1,549)	(4,601)	(333,097)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(54,369)											(54,369)
Issuance of ordinary shares, net of issuance costs (in shares)						20,321,384
Issuance of ordinary shares, net of issuance costs			$ 56,909			$ 1,227			$ 55,682
Issuance of ordinary shares to treasury (in shares)				16,000,000
Issuance of ordinary shares to treasury	0			$ 1,018						(1,018)
Restricted share units vested										967		(967)
Share options exercised	1,949						1,866			83
Share-based compensation	19,012						19,012
Common shares withheld for taxes on vested stock awards	(4,389)						(4,389)
Equity settled share-based compensation reclassified as cash-settled	$ (295)						(295)
Ending balance (in shares) at Dec. 31, 2023	643,536,094			667,659,630
Ending balance at Dec. 31, 2023	$ 249,283			$ 42,771			$ 601,063			$ (1,517)	$ (4,601)	$ (388,433)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net loss	$ (54,369)	$ (68,701)
Adjustments to reconcile net income to net cash used in operating activities:
Foreign exchange (gain)/loss	(1,866)	3,817
Amortization of debt issuance costs	116	80
Accretion of redemption premium on debt	106	108
Share-based compensation	19,012	14,121
Depreciation and amortization	677	636
Changes in operating assets and liabilities:
Prepaid expenses	(1,118)	1,538
Tax incentive receivables	(1,104)	3,964
Other current assets	777	(1,325)
Accounts payable	486	(7,146)
Accrued expenses	(10,351)	(8,504)
Operating lease liabilities	(591)	(597)
Income taxes	(1,037)	136
Other current liabilities	(960)	1,196
Net cash used in operating activities	(50,222)	(59,862)
Cash flows from investing activities:
Purchases of furniture and equipment	0	(29)
Net cash used in investing activities	0	(29)
Cash flows from financing activities:
Proceeds from issuance of ordinary shares	56,909	149,797
Payment of offering costs in connection with the issuance of ordinary shares	0	(9,533)
Proceeds from Oxford Term Loan	9,996	10,000
Payment of debt issuance costs	(12)	(245)
Repayment of SVB Term Loan	0	(5,000)
SVB Term Loan repayment costs	0	(850)
Payments of withholding taxes from share-based awards	(4,685)	(4,723)
Proceeds from exercise of share options	1,949	1,372
Net cash provided by financing activities	92,869	140,818
Effect of exchange rate changes on cash and cash equivalents	1,298	(1,480)
Net change in cash and cash equivalents	43,945	79,447
Cash and cash equivalents at beginning of the year	227,827	148,380
Cash and cash equivalents at end of the year	271,772	227,827
Supplemental disclosure of cash flow information:
Income taxes paid	1,245	120
Interest paid	2,006	348
Loss on extinguishment of debt	0	815
Proceeds from (Repayments of) Other Long-Term Debt	$ 28,712	$ 0

Organization and description of

Organization and description of business operations	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and description of business operations	Organization and description of business operations Verona Pharma plc is incorporated and domiciled in the United Kingdom. Verona Pharma plc has one wholly-owned subsidiary, Verona Pharma, Inc., a Delaware corporation (together with Verona Pharma plc the “Company”). The address of the registered office is 1 Central Square, Cardiff, CF10 1FS, United Kingdom. The Company is a clinical-stage biopharmaceutical group focused on developing and commercializing innovative therapeutics for the treatment of respiratory diseases with significant unmet medical needs. The Company’s American Depositary Shares (“ADSs”) are listed on the Nasdaq Global Market (“Nasdaq”) and trade under the symbol “VRNA”. In August 2023, the U.S. Food and Drug Administration (“FDA”) accepted for review the Company’s New Drug Application (“NDA”) seeking approval of ensifentrine for the maintenance treatment of chronic obstructive pulmonary disease (“COPD”) and assigned a Prescription Drug User Fee Act (“PDUFA”) target action date of June 26, 2024. The FDA stated it is not currently planning to hold an advisory committee meeting to discuss the application. The Company is preparing for a potential commercial launch in 2024, subject to approval of the NDA. In conjunction with the submission of the NDA in June 2023, the Company paid a $3.2 million PDUFA application fee to the FDA. The Company requested a small business waiver of this application fee which was approved by the FDA and refunded in the three months ended December 31, 2023. Liquidity The Company has incurred recurring losses and negative cashflows from operations since inception, and has an accumulated deficit of $388.4 million as of December 31, 2023. The Company expects to incur additional losses and negative cash flows from operations until its products potentially gain regulatory approval and reach commercial profitability, if at all. The Company expects that its cash and cash equivalents as of December 31, 2023, will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next 12 months from the date of issuance. In August 2022, the Company completed an upsized public offering of 14,260,000 ADSs, each representing eight ordinary shares of the Company, nominal value £0.05 per share, at a price to the public of $10.50 per ADS, which includes the exercise in full by the underwriters of their option to purchase an additional 1,860,000 ADSs. The aggregate net proceeds from the offering were $140.2 million after deducting underwriting discounts and commissions and estimated offering expenses payable. During the year ended December 31, 2022, the Company sold 80,696 ordinary shares (equivalent to 10,087 ADSs) under its at the market offering program entered into in March 2021 (the “2021 ATM Program”), at an average price of approximately $0.86 per share (equivalent to $6.86 per ADS), raising aggregate net proceeds of $0.1 million after deducting issuance costs. As of December 31, 2022, there remained $99.2 million of ordinary shares, in the form of ADSs, available for sale under the 2021 ATM Program. During the year ended December 31, 2023, the Company sold 20,321,384 ordinary shares (equivalent to 2,540,173 ADSs) under the 2021 ATM Program, at an average price of approximately $2.88 per share (equivalent to $23.08 per ADS), raising aggregate net proceeds of $56.9 million after deducting issuance costs. In March 2023, through a registration statement on Form S-3, the Company replaced the 2021 ATM Program, with an open market sale agreement with Jefferies LLC (“Jefferies”) to sell its ordinary shares, in the form of ADSs, with aggregate gross proceeds of up to $200.0 million, from time-to-time, through an “at the market” equity offering program under which Jefferies will act as sales agent (the “2023 ATM Program”). Jefferies is entitled to a commission at a rate of up to 3.0% of the gross proceeds. In December 2023, the Company entered into a term loan facility (the “2023 Term Loan”) of up to $400.0 million with Oxford Finance LLC (“Oxford”), as collateral agent, and certain funds managed by Oxford and Hercules Capital, Inc. At closing $50.0 million was funded with up to four additional advances of an aggregate $350.0 million available subject to the Company meeting certain regulatory and commercial milestones. The 2023 Term Loan replaced the Company’s existing $150.0 million facility with Oxford Finance Luxembourg S.A R.L. Refer to Note 5 - Debt for additional details. The Company’s commercial revenue, if any, will be derived from sales of products that are not expected to be commercially available until the second half of 2024, if ever. Additionally, the Company may enter into out-licensing transactions from time to time but there can be no assurance that the Company can secure such transactions in the future. Accordingly, the Company may need to obtain substantial additional funds to achieve its business objectives including to further advance clinical and regulatory activities, to fund launch related costs and to create an effective sales and marketing organization to commercialize ensifentrine, if approved. Any such funding will need to be obtained through public or private financings, debt financing, collaboration or licensing arrangements or other arrangements. However, there is no guarantee the Company will be successful in securing additional capital on acceptable terms, or at all.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting policies	Basis of Presentation and Summary of Significant Accounting Policies Basis of presentation and consolidation The Consolidated Financial Statements include the accounts of Verona Pharma plc and its wholly-owned subsidiary Verona Pharma, Inc. All inter-company balances and transactions have been eliminated. The Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") and the following accounting policies have been consistently applied. Use of estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual and prepayment of research and development expenses and the fair value of share-based compensation. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from the Company’s estimates. Business combinations The Company applies the acquisition method to account for business combinations. The consideration transferred for the acquisition of a subsidiary is the fair value of the assets transferred, the liabilities incurred to the former owners of the acquiree and the equity interests issued by the Company. The consideration transferred includes the fair value of any asset or liability resulting from a contingent consideration arrangement. The excess of the cost of acquisition over the fair value of the Company's share of the identifiable net assets acquired is recorded as goodwill. Identifiable assets acquired and liabilities and contingent liabilities assumed in a business combination are measured initially at their fair values at the acquisition date. Acquisition-related costs are expensed as incurred and included in administrative expenses. Cash and cash equivalents The Company considers all highly liquid investments purchased with original maturities of ninety days or less at acquisition to be cash equivalents. Cash and cash equivalents includes deposits held at call with banks, and in money market funds investing in U.S. and U.K. government debt and liquid securities from highly rated institutions. Equity interest As part of the Nuance Agreement, the Company received an equity interest in Nuance Biotech, the parent company of Nuance Pharma (see Note 6 - Significant Agreements). As Nuance Biotech’s securities are not publicly traded, the equity interest’s fair value is not readily determinable. The Company therefore follows guidance from ASC 321-10-35-2 and uses the fair value measurement alternative and measures the securities at cost, which is deemed to be the value indicated by the last observable transaction in Nuance Biotech's stock, subject to impairment. The valuation will be adjusted for any observable price changes in orderly transactions for an identical or similar investment in Nuance Biotech, or if there is an indicator of impairment. Furniture and equipment, net Furniture and equipment comprise office furniture, computer equipment and leasehold improvements and are stated at cost less accumulated depreciation. Depreciation on furniture and equipment is calculated on a straight-line basis over the expected useful economic lives, generally two Goodwill Goodwill consists of goodwill related to the acquisition of Rhinopharma. Goodwill is not amortized but periodically tested for impairment. Impairment of long-lived assets The Company reviews long-lived assets for impairment annually or whenever events or changes in circumstances indicate that the carrying amount of assets may not be fully recoverable. Debt and debt issuance costs Upon issuance of a new debt instrument, the Company recognizes a liability equal to the proceeds received, less any allocation of proceeds to other instruments issued with the debt, other elements of the transaction, or features within the debt instrument itself. The proceeds generally approximate the present value of interest and principal payments of the debt. In situations where, for economic or legal reasons related to the Company’s financial difficulties, the borrower grants a concession to the Company that it would not otherwise consider, the related loan is classified as a troubled debt restructuring. If a restructuring does not constitute a troubled debt restructuring, it will be evaluated to consider if it should be accounted for as an extinguishment or as a modification. Debt may be considered extinguished when it has been modified and the terms of the new debt instruments and old debt instruments are “substantially different” (as defined in the debt modification guidance in ASC 470-50 “Debt-Modifications and Extinguishments”). Debt issuance costs relating to the Company’s debt instruments are recorded in Term loan on the Consolidated Balance Sheets as a direct reduction of the carrying amount of the related debt; these costs are deferred and amortized to interest expense using the effective interest method, over the respective terms of the related debt. Revenue recognition The Company’s revenue consists of revenue from the Company’s strategic agreements for the development and commercialization of ensifentrine. The terms of the agreements may include non-refundable upfront fees, payments based upon achievement of milestones and eventually revenue from the commercialized product. These agreements usually have both fixed and variable consideration. Non-refundable upfront fees are considered fixed, while milestone payments and revenue from the commercialized product are identified as variable consideration. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under agreements within the scope of ASC Topic 606, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. The Company’s performance obligations may include intellectual property rights, (which include the license, patents and developmental and regulatory data) and manufacturing and supply. Management are required to judge when performance obligations are satisfied and consequently when revenue is recognized. The Company allocates the total transaction price to each performance obligation based on the estimated relative standalone selling prices of the promised goods or service underlying each performance obligation. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied. If the right to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the right when the right is transferred to the customer, and the customer can use and benefit from the right. At the inception of the arrangement, the Company evaluates whether the development milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company, such as approvals from regulators, are not considered probable of being achieved until those approvals are received. Research and development costs Research and development (“R&D”) costs are expensed as incurred. Research and development expenses include salaries, share-based compensation and benefits of employees, and other costs related to the Company’s R&D activities, including pre-approval manufacturing costs, contracts with clinical research organizations and contract manufacturers. The Company is required to estimate its expenses resulting from its obligations under contracts with vendors and consultants and clinical site agreements in connection with its R&D efforts. The financial terms of these contracts are subject to negotiations which vary contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company’s objective is to reflect the appropriate clinical trial expenses in its Consolidated Financial Statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the trials and other development activities. Judgment is applied in determining assumptions related to patient progression and the timing of various aspects of the trial used to measure progress. The Company determines prepaid and accrual estimates through discussions with applicable personnel and outside service providers as to the progress of clinical trials, or other services completed. During the course of a clinical trial, the Company adjusts its rate of clinical trial expense recognition if actual results differ from its estimates. The Company makes estimates of its prepaid and accrued expenses as of each balance sheet date in its Consolidated Financial Statements based on facts and circumstances known at that time. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in the Company reporting amounts that are too high or too low for any particular period. The Company’s clinical trial prepaid and accrual expense is dependent upon the timely and accurate reporting of study recruitment from contract research organizations and activities carried out by other third-party vendors as well as the timely processing of any change orders from the contract research organizations. Share-based compensation The Company has a share-based compensation plan under which various types of equity-based awards may be granted, including stock options, restricted stock units (“RSUs”) and performance restricted stock units (“PRSUs”). The fair value of share options and RSUs, which are subject to milestone or service conditions with graded vesting, are recognized as compensation expense on a straight-line basis using the graded-vesting method; forfeitures are recognized as they occur. The fair value of PRSUs, which are subject to certain performance and service conditions, will be recognized over the remaining service period using the graded-vesting method once the performance conditions are determined to be probable of occurring. The Company uses the fair-value based method to determine compensation for all arrangements under which employees receive shares. The fair value of stock options is estimated on the date of grant using the Black-Scholes valuation model that uses assumptions for expected volatility, expected dividends, expected term, and the risk-free interest rate. Expected volatility is based on the historical volatility of the Company’s ordinary shares over the expected term of the options. The expected term of options granted is derived using the simplified method, which computes the expected term as the average of the sum of the vesting term plus the contract term. Historically the risk-free rate has been based on the appropriate U.K. government debt yield. After delisting its Ordinary shares from AIM on October 30, 2020, the Company used U.S. government debt yields. The fair-value of RSUs and PRSUs is calculated using the closing price of the Company’s ordinary shares on the date of grant. Details of the assumptions used are set out in Note 7 - Share-based compensation to the Consolidated Financial Statements. Other income - United Kingdom R&D tax credits Research and development tax credit relates to R&D tax credits receivable in the U.K. As a company that carries out extensive research and development activities, the Company is subject to the U.K. R&D Small and Medium Enterprise (“SME”) Program. Qualifying expenditures largely comprise employment costs for research staff, consumables, a proportion of relevant, permitted sub-contract costs and certain internal overhead costs incurred as part of research projects for which it does not receive income. Tax credits related to the SME Program are received as cash and are recorded as other income, as they are akin to grant income, in the Consolidated Statements of Operations and Comprehensive Loss. Income taxes The Company accounts for income taxes in accordance with ASC 740, “Income Taxes” (“ASC 740”). ASC 740 prescribes the use of the liability method, whereby deferred tax assets and liability account balances are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance, if necessary, to reduce deferred tax assets to their estimated realizable value. ASC 740 establishes a single model to address accounting for uncertain tax positions. ASC 740 clarified the accounting for income taxes by prescribing the minimum recognition threshold a tax position is required to meet before being recognized in the financial statements. The Company has no uncertain tax positions. Comprehensive loss The Company accounts for comprehensive loss in accordance with ASC 220, “Income Statement - Reporting Comprehensive Income”. Comprehensive loss represents all changes in shareholders’ equity during the period except those resulting from investments by, or distributions to, shareholders. Segment Reporting Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company has one operating and reportable segment, pharmaceutical development. Reporting and functional currencies The Consolidated Financial Statements are reported in U.S. dollars, which is also the functional currency of the Company’s subsidiary. Transactions in foreign currencies are remeasured into the Company’s functional currency at the rate of exchange prevailing at the date of the transaction. Any monetary assets and liabilities arising from these transactions are remeasured into our functional currency at exchange rates prevailing at the balance sheet date or on settlement. Resulting gains and losses are recorded in foreign exchange gain/(loss) in our Consolidated Statements of Operations. Treasury shares In the year ended December 31, 2020, the Company incorporated a trust to facilitate the acquisition of shares, by or for the benefit of employees and former employees. In the years ended December 31, 2023 and December 31, 2022 the Company issued 16.0 million ordinary shares (equivalent to 2.0 million ADSs) and 28.0 million (equivalent to 3.5 million ADSs), respectively, to the trust to cover expected shares issued upon the vesting of share awards to employees. The Company has the indirect ability to control the trust as trustees are required to act in accordance with the trust deed and because the Company controls the issuance of shares to cover awards. As a consequence, the trust is consolidated into the Company’s Consolidated Financial Statements. The shares that were issued to the trust that have not been issued to employees to satisfy vesting of share awards are included in the Consolidated Balance Sheets as Ordinary shares held in treasury. Fair value of financial instruments US GAAP defines fair value and requires companies to establish a framework for measuring fair value and disclosure about fair value measurements using a three-tier approach. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Our financial instruments include cash equivalents, equity interest, other assets, accounts payable and accrued expenses and other liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgement and therefore cannot be determined with precision. The carrying amounts of the other instruments are considered to be representative of their fair values because of their short-term nature. Concentration of credit risk Financial instruments that potentially subject the Company to concentration of credit risk consist of principally cash and cash equivalents, bank deposits and certain receivables. The Company holds cash and cash equivalents with highly rated financial institutions and in highly rated money market funds. Our deposits at these institutions may exceed insured limits, however the Company has not experienced any significant credit losses in these accounts and does not believe the Company is exposed to any significant credit risk on these instruments. Lease accounting The Company determines if an arrangement is a lease at inception. ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the term of the lease. For this purpose, the Company considers only payments that are fixed and determinable at the time of commencement. As the Company's leases do not provide an implicit rate, the Company determines the incremental borrowing rate in calculating the present value of lease payments. The ROU assets also include any lease payments made prior to commencement and are recorded net of any lease incentives received. The Company’s lease terms may include options to extend or terminate the lease. When it is reasonably certain the Company will exercise such options the lease will be recognized as a liability and a corresponding ROU asset also recognized. Operating leases are included in Right-of-use assets and in Current and Non-current operating lease liabilities on the Company's Consolidated Balance Sheets. Recently adopted accounting standards In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326)-Measurement of Credit Losses on Financial Instruments. This guidance replaces the current incurred loss impairment methodology. Under this model, on initial recognition and at each reporting period, an entity is required to recognize an allowance that reflects its current estimate of credit losses expected to be incurred over the life of the financial instrument based on historical experience, current conditions and reasonable and supportable forecasts. The guidance requires a modified retrospective transition approach through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. This update became effective for the Company on January 1, 2023 and the adoption of this update did not have a material impact on the Company’s financial statements and related disclosures. Recently issued accounting standards not yet adopted In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid. The standard is intended to benefit investors by providing more detailed income tax disclosures that would be useful in making capital allocation decisions. The amendments in this ASU are effective for annual periods beginning on January 1, 2025, and should be applied on a prospective basis with the option to apply the standard retrospectively. Early adoption is permitted. This ASU will have no impact on the Company's Consolidated Balance Sheets or Consolidated Statements of Operations and Comprehensive Loss. The Company is currently evaluating the impact to its income tax disclosures. In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures, which improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. In addition, the amendments enhance interim disclosure requirements, clarify circumstances in which an entity can disclose multiple segment measures of profit or loss, provide new segment disclosure requirements for entities with a single reportable segment, and contain other disclosure requirements. The purpose of the amendments is to enable investors to better understand an entity's overall performance and assess potential future cash flows. The amendments in this ASU are effective for annual periods beginning on January 1, 2024 and interim periods beginning on January 1, 2025, and should be applied on a retrospective basis for all periods presented. This ASU will have no impact on the Company's Consolidated Balance Sheets or Consolidated Statements of Operations and Comprehensive Loss. The Company is currently evaluating the impact to its segment disclosures.

Prepaid expenses

Prepaid expenses	12 Months Ended
	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	Prepaid expenses Prepaid expenses consisted of the following (in thousands): December 31, 2023 2022 Clinical trial and other development costs $ 59 $ 38 Insurance 3,558 2,027 Other — 434 Total prepaid expenses $ 3,617 $ 2,499

Property leases

Property leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Property leases	Property leases The Company’s Right-of-use assets (“ROU”) relate to rented office space in London, Georgia and two in North Carolina with leases ending in 2025, 2025, 2024 and 2027, respectively. In the year ended December 31, 2023, the Company entered into a lease arrangement in North Carolina for office space and extended its existing London lease. As a result of these two agreements, the Company recognized a lease liability and a corresponding ROU asset of $2.7 million. Additionally, the supplemental noncash ROU asset obtained in exchange for operating lease liabilities is $2.7 million. In the year ended December 31, 2022, the Company entered into a lease arrangement in Georgia for office space and extended its existing London lease recognizing a lease liability and a corresponding ROU asset of $0.7 million. To calculate lease liabilities the Company used a weighted average discount rate of 11% and 4% for the years ended December 31, 2023 and December 31, 2022, respectively. The weighted average remaining lease term as of December 31, 2023 and December 31, 2022 wa s 3.3 years a nd 1.5 years, respectively. Minimum annual payments over the remaining lease periods as of December 31, 2023 are as follows (in thousands): 2024 $ 1,175 2025 842 2026 788 2027 784 Total minimum future lease payments $ 3,589 Less: imputed interest (634) Total operating lease liabilities $ 2,955 The total operating lease expense included in selling, general and administrative costs was $0.7 million for the year ended December 31, 2023.

Accrued expenses

Accrued expenses	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued expenses	Accrued expenses Accrued expenses consisted of the following (in thousands): December 31, 2023 2022 Clinical trial and other development costs $ 752 $ 12,314 Professional fees, listing and general corporate costs 2,039 1,364 People related costs 794 74 Total accrued expenses $ 3,585 $ 13,752

Warrants

Warrants	12 Months Ended
	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Warrants	Warrants On May 2, 2022 all remaining warrants expired. No warrants were exercised or forfeited in the years ended December 31, 2023 and 2022. In 2016, the Company issued 31,115,926 units to new and existing investors at the placing price of £1.4365 per unit. Each unit comprised one ordinary share and one warrant. The warrant holders could subscribe for 0.4 of an ordinary share at a per share exercise price of £1.7238 until May 2, 2022. The warrant holders could opt for a cashless exercise of their warrants, whereby the warrant holders could choose to exchange the warrants held for a reduced number of warrants exercisable at nil consideration. The reduced number of warrants was calculated based on a formula considering the share price and the exercise price of the warrants. If, after a transaction, should the warrants be exercisable for unlisted securities, the warrant holders were able to demand a cash payment instead of the delivery of the underlying securities. Accordingly, the warrants were accounted for as a liability under ASC 480 “Distinguishing Liabilities from Equity”. The warrants were measured at fair value, classified as Level 3 in the fair value hierarchy, with movements recorded in other income/(expense) in the Consolidated Statements of Operations and Comprehensive Loss. At December 31, 2021, 31,003,155 warrants remained outstanding and entitled the investors to subscribe for, in aggregate, a maximum of 12,401,262 ordinary shares. The warrants had no intrinsic value as at December 31, 2021. There have been no changes in valuation techniques or transfers between fair value measurement levels during the years ended December 31, 2023 and 2022. There has been no change in fair value between December 31, 2021, and May 2, 2022 (expiration). The warrants were valued using the Black-Scholes model and the table below presents the assumptions used: December 31, 2022 Exercise price in pounds sterling £ 1.7238 Risk-free interest rate 0.07 % Expected term to exercise 0.33 Annualized volatility 51.6 % Dividend rate — % Calculated value of the warrants, in thousands of U.S. dollars $ — The following table shows the movement of the value of the warrants (in thousands): December 31, 2022 At January 1 $ 2,246 Fair value adjustment (2,246) At December 31 $ —

Term loan

Term loan	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Term loan	Debt In November 2020, the Company entered into a term loan facility of up to $30.0 million (the “SVB Term Loan”), consisting of advances of $5.0 million funded at closing and $10.0 million and $15.0 million contingent upon achievement of certain clinical development milestones and other specified conditions. On October 14, 2022 (the “2022 Effective Date”), the Company entered into a loan and security agreement with Oxford Finance Luxembourg S.À R.L. for an aggregate amount of up to $150.0 million (the “Oxford Term Loan”). The Oxford Term Loan provided for an initial term loan advance in an aggregate amount of $10.0 million funded on the 2022 Effective Date (the “Oxford Term A Loan”), and up to four additional term loan advances in an aggregate amount of $140.0 million, contingent upon the achievement of certain clinical and regulatory development milestones as well as other specified conditions. The proceeds from the Oxford Term Loan were used for general corporate and working capital purposes, and a portion of the proceeds of the Oxford Term A Loan were used to repay in full the existing outstanding indebtedness owed under the SVB Term Loan. On March 24, 2023, the Company received $10.0 million under the second term loan advance (the “Oxford Term B Loan”). On December 27, 2023 (the “2023 Effective Date”), the Company entered into a term loan facility of up to $400.0 million (the “2023 Term Loan” or “Loan Agreement”), consisting of a term loan advance in an aggregate amount of $50.0 million funded on the 2023 Effective Date (the “Term A Loan”) and four additional term loan advances subject to certain terms and conditions, as discussed below, in the amounts of $100.0 million (the “Term B Loan”), $75.0 million (the “Term C Loan”), $75.0 million (the “Term D Loan”) and $100.0 million (the “Term E Loan”). The 2023 Term Loan was entered into with Oxford Finance LLC, a Delaware limited liability company (“Oxford”), as collateral agent, and certain funds managed by Oxford and Hercules Capital, Inc. party thereto (collectively, the “Lenders”). The net proceeds of the 2023 Term Loan will be used for general corporate and working capital purposes. The Company received net proceeds from the Term A Loan of $28.4 million which primarily consisted of the Term A Loan proceeds of $50.0 million partially offset by the repayment, in full, of the existing outstanding indebtedness owed by the Company under the Oxford Term Loan of $20.0 million, lender and third-party fees related to the Loan Agreement of $1.4 million and interest amounts of $0.2 million. Based upon the Company’s accounting evaluation of the Loan Agreement, as well as the Oxford entities involved and terms of both the 2023 Term Loan and the Oxford Term Loan, the Company has applied modification accounting to the portion of the Term A Loan associated with Oxford. As such, no gain or loss is recorded upon the modification with the unamortized debt issuance costs at the 2023 Effective Date from the Oxford Term Loans included as amounts the outstanding amount under the 2023 Term Loan. Additionally, certain fees included in the net proceeds were expensed based on the applicable guidance und er ASC 470. The portion of the Term A Loan associated with Hercules Capital, Inc. has been accounted for as the issuance of new debt with the applicable accounting applied under ASC 470. The Term B Loan will be available, subject to customary terms and conditions, during the period commencing on the date the Company receives approval from the United States Food and Drug Administration for its New Drug Application for ensifentrine through and including the earliest of (i) the date that is 30 days immediately following the date the Company receives such approval and (ii) September 15, 2024. The Term C Loan will be available, subject to customary terms and conditions (including the prior borrowing of the Term B Loan), during the period commencing on the later of (i) September 15, 2025 and (ii) prior to September 30, 2025, the achievement by the Company of a specified net sales milestone. The Term D Loan will be available, subject to customary terms and conditions (including the prior borrowing of the Term C Loan), during the period commencing on the later of (i) February 15, 2026 and (ii) prior to March 31, 2026, the achievement by the Company of a specified net sales milestone. The Term E Loan will be available, subject to customary terms and conditions (including the prior borrowing of the Term D Loan) prior to June 1, 2028 at the Lenders sole discretion and upon the Company’s request. The 2023 Term Loan will mature on December 1, 2028. Each advance under the Loan Agreement accrues interest at a floating per annum rate (the “Basic Rate”) equal to (a) the greater of (i) the 1-Month CME Term SOFR (as defined in the Loan Agreement) reference rate on the last business day of the month that immediately precedes the month in which the interest will accrue and (ii) 5.34%, plus (b) 5.85%. Notwithstanding the foregoing, (i) in no event shall the Basic Rate (x) for the Term A Loan be less than 11.19% and (y) for each other 2023 Term Loan be less than the Basic Rate on the business day immediately prior to the funding date of such 2023 Term Loan, (ii) the Basic Rate for the Term A Loan for the period from the Effective Date through and including December 31, 2023 was 11.19% and (iii) the Basic Rate for each 2023 Term Loan shall not increase by more than 2.00% above the applicable Basic Rate as of the funding date of each such 2023 Term Loan. The 2023 Term Loan provides for interest-only payments on a monthly basis until the payment date immediately preceding June 1, 2028. Thereafter, amortization payments will be payable monthly in equal installments of principal plus monthly payments of accrued interest. Upon repayment (whether at maturity, upon acceleration or by prepayment or otherwise), the Borrower shall make a final payment to the Lenders in the amount of 2.50% to 3.50% of the aggregate 2023 Term Loan advanced, depending on when a 2023 Term Loan is repaid (the “Final Payment”). The Borrower may prepay the 2023 Term Loan in full or in part provided that the Borrower (i) provides ten (10) days’ prior written notice to Oxford and the Lenders, (ii) pays on the date of such prepayment (A) all outstanding principal plus accrued and unpaid interest, (B) a prepayment fee of 2.00% of the 2023 Term Loan advanced if paid on or before December 27, 2025; 1.50% of the 2023 Term Loan advanced if paid after December 27, 2025 and before December 27, 2026; 1.00% of the 2023 Term Loan advanced if paid after December 27, 2026, (C) the Final Payment and (D) all other sums, if any, that shall become due and payable under the Loan Agreement, including interest at the default rate with respect to any past due amounts. Amounts outstanding during an event of default are payable upon the Required Lenders’ (as defined in the Loan Agreement) demand and shall accrue interest at an additional rate of 5.00% per annum and (iii) any partial prepayment of the 2023 Term Loans shall be in a denomination that is a whole number multiple of $5.0 million. The 2023 Term Loan is secured by a lien on substantially all of the assets of the Company, other than intellectual property, provided that a lien on intellectual property will be granted on the earlier of (i) the funding date of any 2023 Term Loan that would cause the aggregate principal amount of outstanding 2023 Term Loan drawn pursuant to the Loan Agreement to exceed $50.0 million and (ii) prior to the Borrower or the Company entering into a Permitted Royalty Financing (as defined in the Loan Agreement). The Company has also granted Oxford and the Lenders a negative pledge with respect to its intellectual property. The Loan Agreement contains customary representations and warranties, covenants and events of default, including two financial covenants: (i) commencing on July 1, 2025, the Borrower is required to maintain certain levels of cash in the United States subject to control agreements in favor of Oxford; provided that such liquidity covenant shall not apply at any given time if the market capitalization of the Company at such time is at least $3.0 billion and (ii) commencing on September 30, 2025, the Borrower and the Company are required to maintain quarterly trailing six-month net product revenue from the sale of ensifentrine; provided that such revenue covenant will be waived at any time (x) the Borrower and the Company’s unrestricted cash balance on the last calendar day of each month during such quarter is equal to or greater than the product of 1.25 multiplied by the aggregate principal amount of outstanding 2023 Term Loan on such date, (y)(1) the Borrower and the Company’s unrestricted cash balance on the last calendar day of each month during such quarter is equal to or greater than the product of 0.5 multiplied by the aggregate principal amount of outstanding 2023 Term Loan on such date and (2) the average of the daily VWAP of the Company’s American Depositary Shares for each of the five trading days preceding the last trading day of each month during such quarter multiplied by the total number of issued and outstanding American Depositary Shares of the Company is at least $1.5 billion, or (z) the average of the daily VWAP of the Company’s American Depositary Shares for each of the five trading days preceding the last trading day of each month during such quarter multiplied by the total number of issued and outstanding American Depositary Shares of the Company is at least $3.0 billion. The Loan Agreement also contains other customary provisions, such as expense reimbursement, as well as indemnification rights for the benefit of Oxford and the Lenders. As of December 31, 2023 the interest rate was approximately 11% per annum and there was no material difference between the carrying value and the estimated fair value of the 2023 Term Loan. Future principal payments, which exclude the end of term charge, in connection with the 2023 Term Loan as of December 31, 2023 are as follows (in thousands): 2024 $ — 2025 — 2026 — 2027 — 2028 50,000 Total $ 50,000

Significant agreements

Significant agreements	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Significant agreements	Significant agreements Ligand agreement In 2006 the Company acquired Rhinopharma and assumed contingent liabilities owed to Ligand UK Development Limited (“Ligand”) (formerly Vernalis Development Limited). The Company refers to the assignment and license agreement as the Ligand Agreement. Ligand assigned to the Company all of its rights to certain patents and patent applications relating to ensifentrine and related compounds (the "Ligand Patents") and an exclusive, worldwide, royalty-bearing license under certain Ligand know-how to develop, manufacture and commercialize products (the "Ligand Licensed Products") developed using Ligand Patents, Ligand know-how and the physical stock of certain compounds. The Company is obligated to pay a milestone payment of £5.0 million on obtaining the first approval of any regulatory authority for the commercialization of a Ligand Licensed Product, low single digit royalties based on the future sales performance of all Ligand Licensed Products and a portion equal to a mid-twenty percent of any consideration received from any sub-licensees for the Ligand Patents and for Ligand know-how. Royalties payable are based on the future sales performance so the amount payable is unlimited. At the time each contingency is resolved, the Company will record the contingent consideration payment (or payable) in connection with the Ligand Agreement as an expense. In March 2022, the Company entered into an Amendment Agreement (the “Amendment”) with Ligand whereby the Ligand Agreement was amended to clarify certain ambiguous terms in the Ligand Agreement. Pursuant to the Amendment: • the Company agreed to pay to Ligand (i) $2.0 million within five business days of the date of the Amendment and (ii) $15.0 million upon the first commercial sale of ensifentrine by the Company or a sub-licensee, which amount is payable in cash or, at the Company's discretion, by the issuance of Company equity of equivalent value, as determined based on the volume-weighted average price of the Company's American Depositary Shares on the Nasdaq Global Market over the ten (10) trading days including and prior to such milestone event; • the Ligand Agreement shall expire on March 24, 2042 unless terminated earlier by either party in accordance with its terms; • upon termination of the Ligand Agreement, any Sub-licensee (as defined in the Amendment) shall have the right to enter into a direct license agreement with Ligand for the portion of the Program IP (as defined in the Amendment) that was sub-licensed by such Sub-licensee; • the milestone payment may be paid in cash or, at the Company’s discretion, by issuing to Ligand shares in the Company of equivalent value; and • each party’s right to terminate the Ligand Agreement is conditioned upon such party obtaining a final judgment of the English High Court declaring that the other party is in material breach of its obligations under the Ligand Agreement. The Company accounted for the $2.0 million payment at execution of the Amendment as selling, general and administrative expense in the consolidated statements of operations and comprehensive loss as the payment is related to a contract modification. Nuance agreement The Company entered into a collaboration and license agreement (the “Nuance Agreement”) with Nuance Pharma Limited (“Nuance Pharma”) effective June 9, 2021 (the “Nuance Effective Date”), under which the Company granted Nuance Pharma the exclusive rights to develop and commercialize ensifentrine in Greater China (China, Taiwan, Hong Kong and Macau). In return, the Company received an unconditional right to consideration aggregating $40.0 million consisting of $25.0 million in cash and an equity interest, valued at $15.0 million as of the Nuance Effective Date, in Nuance Biotech, the parent company of Nuance Pharma. The Company is eligible to receive future milestone payments of up to $179.0 million triggered upon achievement of certain clinical, regulatory, and commercial milestones, as well as tiered double-digit royalties as a percentage of net sales of the products in Greater China. The Company will recognize these milestones when it is probable that a significant revenue reversal would not occur. As of December 31, 2023, the $15.0 million equity interest was recorded as Equity interest on the Consolidated Balance Sheet. The equity interest is recorded at cost as the Company has elected to use the measurement alternative for equity investments without readily determinable fair values. The Company evaluates this investment for indicators of impairment quarterly. The Company did not identify events or changes in circumstances that may have a significant effect on the fair value of the investment during the year ended December 31, 2023. Under the terms of the Nuance Agreement, at any time until three months prior to the expected submission of the first New Drug Application in Greater China, if (i) a third party is interested in partnering with the Company, either globally or in territory covering at least the United States or Europe, for the development and/or commercialization of ensifentrine or (ii) the Company undergoes a change of control, the Company will have an exclusive option right to buy back the license granted to Nuance Pharma and all related assets. The price is agreed to be equal to the aggregate of (i) all prior amounts paid by Nuance Pharma to the Company in cash under the agreement and (ii) all development and regulatory costs incurred and paid by Nuance Pharma in connection with the development and commercialization of ensifentrine under the Nuance Agreement multiplied by a single-digit factor range dependent upon achievement of certain milestones, subject to a specified maximum amount. The Nuance Agreement will continue on a jurisdiction-by-jurisdiction and product-by-product basis until the expiration of royalty payment obligations with respect to such product in such jurisdiction unless earlier terminated by the parties. Either party may terminate the Nuance Agreement for an uncured material breach or bankruptcy of the other party. Nuance Pharma may also terminate the Nuance Agreement at will upon 90 days' prior written notice. The Company reviewed the buy-back option and determined that because it is conditional on a third party the Company does not have the practical ability to exercise it and, accordingly, the contract is accounted for under ASC 606. On April 13, 2022, the Company formalized the Agreement for the Manufacture and Supply of ensifentrine (“Nuance Supply Agreement”) with Nuance Pharma. The Company determined that the manufacturing and supply of ensifentrine to Nuance represents a distinct and separate performance obligation, for which consideration to be received is variable based on the quantities to be ordered by Nuance. Revenue earned with the manufacture and supply of the licensed product is, and will be, recognized as the supply is delivered to Nuance. The Company has determined it is acting as principal in relation to the manufacture and supply under the Agreement. In its capacity as principal, the Company will recognize the associated revenue on a gross basis. In the year ended December 31, 2022, the Company recognized $0.5 million of revenue in relation to the clinical supply of ensifentrine to Nuance Pharma.

Benefit plans

Benefit plans	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Benefits plans	Benefit plans The Company maintains a 401(k) defined contribution retirement plan in the U.S. and a defined contribution plan in the U.K. for its employees and executive directors. The assets of the plans are held separately from those of the Company in independently administered funds.

Taxation

Taxation	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Taxation	Taxation Verona Pharma plc operates in the United Kingdom and Verona Pharma, Inc. in the United States and they are subject to income taxes in those countries. For the year ended December 31, 2023 the U.K. corporation tax is charged at 23.5% and the U.S. Federal Income tax rate is 21%. The components of (profit)/loss before income taxes are as follows (in thousands): December 31, 2023 2022 United States $ (7,429) $ (3,868) United Kingdom 61,324 72,316 Total $ 53,895 $ 68,448 The components of income tax expense are as follows (in thousands): December 31, 2023 2022 United States $ 474 $ 253 United Kingdom — — Total current tax expense $ 474 $ 253 United States $ — $ — United Kingdom — — Total deferred tax expense — — Total income tax expense $ 474 $ 253 A reconciliation of the U.K. statutory income tax rate to our effective income tax rate is as follows (in percentages): December 31, 2023 2022 U.K. tax rate 23.5 % 19.0 % Non-deductible expenses (8.0) % (1.8) % Research and development incentive (4.1) % (8.0) % Share options exercised 5.4 % 2.1 % Change in deferred tax valuation allowance (18.1) % (11.6) % Other differences 0.4 % (0.1) % Effective income tax rate (0.9) % (0.4) % Components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2023 2022 Deferred tax liabilities: Contingent liability (1) $ (53,851) $ (34,565) Total deferred tax liabilities (53,851) (34,565) Deferred tax assets: Net operating losses 54,012 38,893 IPR&D asset (1) 47,793 32,700 Future exercisable shares 7,548 11,964 Other 21 (516) Total deferred tax assets 109,374 83,041 Less: valuation allowance (55,523) (48,476) Deferred tax assets, net of valuation allowance $ — $ — Movements in the deferred tax valuation allowance Valuation allowance at January 1 $ 48,476 $ 30,252 Change in tax rates (851) — Increase in valuation allowance 7,898 18,224 Valuation allowance at December 31 $ 55,523 $ 48,476 (1) These relate to the difference in the tax base of the IP R&D asset and assumed contingent liability and the financial reporting base, which is nil under U.S. GAAP. Management has reviewed cumulative tax losses and projections of future taxable losses and determined that it is not more likely than not that they will be realized. Accordingly, valuation allowances have been provided over deferred tax assets. At December 31, 2023 and December 31, 2022, the Company had U.K. net operating losses (“NOLs”) of $216.0 million and $155.6 million, respectively. The NOLs can be carried forward indefinitely to be offset against future taxable profits, but this is restricted to an annual £5 million allowance after which there will be a 50% restriction in the profits that can be covered by losses brought forward. The Company files separate income tax returns in the U.K. and the U.S. All necessary income tax filings have been completed for all years up to and including December 31, 2022. The Company’s R&D Tax Incentive Claim for the year ended December 31, 2022 is currently under routine review by HMRC. No material adjustments are expected to be made to the claimed amount as a result of this review. No interest or penalties were recognized in the Consolidated Statements of Operations and Comprehensive Loss or Consolidated Balance Sheets. As of December 31, 2023, the Company has no uncertain tax positions.

Share based compensation

Share based compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Share based compensation	Share-based compensation The Company operates various share based incentive plans for its staff and issues ordinary shares or ADSs when share-based awards are exercised. The Company records share-based compensation expense related to share options and RSUs granted to employees and directors. The expense is included in Research and development and Selling, general and administrative costs, based on the nature of individual employees’ functions, and represents the relevant year's allocation of the expense. The costs of share-based compensation to employees are recognized in the Consolidated Statements of Operations and Comprehensive Loss, together with a corresponding increase in equity over the vesting period. Options are issued with an exercise price of the closing market price on the day before the grant and generally vest over a period of one The following table shows the allocation of share-based compensation between research and development and selling, general and administrative costs (in thousands): December 31, 2023 2022 Research and development $ 4,228 $ 5,420 Selling, general and administrative 14,784 8,701 Total share-based compensation $ 19,012 $ 14,121 EMI Option Plan and Pre-IPO Option Plan The EMI Option Plan and the Pre-IPO Option Plan were adopted by our board of directors on September 18, 2006, and July 24, 2012, respectively. The total number of shares that may be issued under these plans is the current number of outstanding options over 114,000 ordinary shares, or 14,250 ADSs, for the EMI Option Plan and 1,320,000 ordinary shares, or 165,000 ADSs, for the Pre-IPO Option Plan. No further awards have been granted under either plan since the 2017 Incentive Award Plan was adopted, and no further awards will be granted under them. 2017 Incentive Award Plan The 2017 Incentive Award Plan was adopted by our board of directors and became effective on April 26, 2017, in order to grant share based compensation to certain of the Company’s directors and employees. It provides for the grant of stock options, RSUs, and other share-based awards to Company’s directors, officers, employees and non-employee directors. Share option activity The number of options, the weighted average grant date fair value per stock option, and the weighted average exercise price are all shown below on a per ordinary shares basis. The Company’s ADSs that are listed on the Nasdaq Global Market each represent eight ordinary shares. The following table shows share option activity and includes the options outstanding from all three plans: Number of share options Weighted average exercise price (1) Weighted average remaining contractual term (years) Aggregate intrinsic value (thousands) Outstanding at January 1, 2022 12,695,200 $ 1.38 6.5 Granted 9,024,000 0.90 Forfeited (620,016) 1.04 Exercised (1,822,688) 0.75 Outstanding at December 31, 2022 19,276,496 $ 1.22 7.2 $ 39,412 Granted 7,376,000 2.46 Forfeited (464,680) 0.89 Expired (240,000) 3.07 Exercised (1,258,192) 1.55 Outstanding at December 31, 2023 24,689,624 $ 1.56 7.4 $ 24,022 Exercisable at December 31, 2023 12,904,640 $ 1.30 5.8 $ 15,574 (1) The exercise prices relate to the equivalent price for an ordinary share, calculated as one eighth of the ADS price. The following summarizes the aggregate intrinsic value and cash receipts related to stock option exercise activity for the years ended December 31: ($ in thousands) 2023 2022 Aggregate intrinsic value of stock options exercised $ 1,861 $ 2,413 Cash receipts from stock options exercised $ 1,949 $ 1,372 Determining the fair value of share options The total fair values of the options, estimated using the Black-Scholes option-pricing model for equity-settled compensation, amounted to $13.2 million for options granted in the year ended December 31, 2023 and $5.9 million for instruments granted in the year ended December 31, 2022. The cost is amortized over the vesting period of the options on a straight-line basis using the graded-vesting method. The following assumptions were used for the Black-Scholes valuation of share options granted in 2023 and 2022. Expected volatility Volatility is calculated using historical daily averages of the Company's share price over a period that is in line with the expected life of the options. Fair value of ordinary shares Prior to delisting from the AIM in October 2020, the fair value of ordinary shares was based on the closing share price of the Company’s shares on AIM on the evening before the date of grant. Subsequently, the fair value has been based on the closing price of ADSs traded on Nasdaq on the evening before the date of grant. Risk-free interest rate The risk-free interest rate has been based on U.K. Government debt yield for the relevant term at the time of grant up until October 20, 2020 when the company delisted from AIM. After this, appropriate U.S Treasury yield rates were used. Expected term As the Company does not have sufficient history to estimate its expected term, the Company applied the simplified method of estimating the expected term of the options, as described in the SEC’s Staff Accounting Bulletins 107 and 110. The expected term, calculated under the simplified method, is applied to all stock options which have similar contractual terms. Using this method, the expected term is determined using the average of the vesting period and the contractual life of the stock options granted. Expected dividend There are no expected dividends. A summary of the weighted-average assumptions applicable to the share options granted in the applicable years is as follows: December 31, 2023 2022 Risk-free interest rate 3.40% - 4.69% 2.09% - 4.20% Expected lives, years 5-7 5-7 Expected volatility 80.64% - 87.26% 82.50% - 84.27% Expected dividend yield — % — % Grant date fair value (per share) $1.69 - $3.27 $0.34 - $1.33 Restricted stock units activity The following table shows RSU activity: Number of RSUs Weighted average grant date fair value Weighted average remaining contractual term (years) Outstanding at January 1, 2022 38,347,352 $ 0.97 1.2 Granted 12,877,864 1.07 Forfeited (1,006,264) 1.03 Vested (15,676,608) 0.96 Outstanding at December 31, 2022 34,542,344 $ 1.01 1.2 Granted 3,596,872 1.66 Forfeited (303,648) 1.10 Vested (18,332,944) 0.99 Outstanding at December 31, 2023 19,502,624 $ 1.14 1.2 The intrinsic value of RSUs that vested in the years ended December 31, 2023 and 2022, was $41.5 million and $14.3 million, respectively. As of December 31, 2023, total compensation cost related to share options and RSUs granted but not yet recognized was $20.0 million. This cost will be amortized to expense over a weighted average remaining period of 1.9 years and will be adjusted for subsequent forfeitures. Performance Restricted Stock Units (“PRSUs”) The Company began issuing PRSUs during 2023. PRSUs will begin to vest upon achievement of certain performance goals and are subject to continued service. The fair value of PRSUs will be recognized over the remaining service period using the graded-vesting method once the performance conditions are determined to be probable of occurring. Due to the presence of the performance conditions, which are not yet considered probable under the applicable accounting framework, the Company recognized no compensation expense for the PRSUs in 2023. A summary of the Company’s PRSU activity for the year ended December 31, 2023 is as follows: Number of PRSUs Weighted average grant date fair value Aggregate Intrinsic Value (thousands) Outstanding at January 1, 2023 — $ — Granted 10,790,144 1.66 Forfeited (60,000) 1.66 Outstanding at December 31, 2023 10,730,144 $ 1.66 $ 26,665

Net loss per share

Net loss per share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net loss per share	Net loss per share Net loss per share is calculated on an ordinary share basis. The Company’s ADSs that are listed on the Nasdaq Global Market each represent eight ordinary shares. The following table shows the computation of basic and diluted earnings per share for 2023 and 2022 (in thousands, except share and per share amounts): December 31, 2023 2022 Numerator: Net loss $ (54,369) $ (68,701) Net loss available to ordinary shareholders - basic and diluted $ (54,369) $ (68,701) Denominator: Weighted-average shares outstanding - basic and diluted 634,142,660 529,071,526 Net loss per share - basic and diluted $ (0.09) $ (0.13) During the years ended December 31, 2023 and 2022, outstanding share options, RSUs and PRSUs of 54.9 million and 53.8 million, respectively, were not included in the computation of diluted earnings per ordinary share, because to do so would be antidilutive.

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies

Related party transactions and

Related party transactions and other shareholder matters	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related party transactions and other shareholder matters	Related party transactions and other shareholder matters In the years ended December 31, 2023 and 2022 there were no related party transactions.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of presentation and consolidation	Basis of presentation and consolidation The Consolidated Financial Statements include the accounts of Verona Pharma plc and its wholly-owned subsidiary Verona Pharma, Inc. All inter-company balances and transactions have been eliminated. The Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") and the following accounting policies have been consistently applied.
Use of estimates	Use of estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual and prepayment of research and development expenses and the fair value of share-based compensation. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from the Company’s estimates.
Business combinations	Business combinations The Company applies the acquisition method to account for business combinations. The consideration transferred for the acquisition of a subsidiary is the fair value of the assets transferred, the liabilities incurred to the former owners of the acquiree and the equity interests issued by the Company. The consideration transferred includes the fair value of any asset or liability resulting from a contingent consideration arrangement. The excess of the cost of acquisition over the fair value of the Company's share of the identifiable net assets acquired is recorded as goodwill. Identifiable assets acquired and liabilities and contingent liabilities assumed in a business combination are measured initially at their fair values at the acquisition date. Acquisition-related costs are expensed as incurred and included in administrative expenses.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investments purchased with original maturities of ninety days or less at acquisition to be cash equivalents. Cash and cash equivalents includes deposits held at call with banks, and in money market funds investing in U.S. and U.K. government debt and liquid securities from highly rated institutions.
Short term investments	Equity interest As part of the Nuance Agreement, the Company received an equity interest in Nuance Biotech, the parent company of Nuance Pharma (see Note 6 - Significant Agreements). As Nuance Biotech’s securities are not publicly traded, the equity interest’s fair value is not readily determinable. The Company therefore follows guidance from ASC 321-10-35-2 and uses the fair value measurement alternative and measures the securities at cost, which is deemed to be the value indicated by the last observable transaction in Nuance Biotech's stock, subject to impairment. The valuation will be adjusted for any observable price changes in orderly transactions for an identical or similar investment in Nuance Biotech, or if there is an indicator of impairment.
Furniture and equipment, net	Furniture and equipment, net Furniture and equipment comprise office furniture, computer equipment and leasehold improvements and are stated at cost less accumulated depreciation. Depreciation on furniture and equipment is calculated on a straight-line basis over the expected useful economic lives, generally two
Goodwill	Goodwill Goodwill consists of goodwill related to the acquisition of Rhinopharma. Goodwill is not amortized but periodically tested for impairment.
Impairment of long-lived assets	Impairment of long-lived assets
Debt and debt issuance costs	Debt and debt issuance costs Upon issuance of a new debt instrument, the Company recognizes a liability equal to the proceeds received, less any allocation of proceeds to other instruments issued with the debt, other elements of the transaction, or features within the debt instrument itself. The proceeds generally approximate the present value of interest and principal payments of the debt. In situations where, for economic or legal reasons related to the Company’s financial difficulties, the borrower grants a concession to the Company that it would not otherwise consider, the related loan is classified as a troubled debt restructuring. If a restructuring does not constitute a troubled debt restructuring, it will be evaluated to consider if it should be accounted for as an extinguishment or as a modification. Debt may be considered extinguished when it has been modified and the terms of the new debt instruments and old debt instruments are “substantially different” (as defined in the debt modification guidance in ASC 470-50 “Debt-Modifications and Extinguishments”). Debt issuance costs relating to the Company’s debt instruments are recorded in Term loan on the Consolidated Balance Sheets as a direct reduction of the carrying amount of the related debt; these costs are deferred and amortized to interest expense using the effective interest method, over the respective terms of the related debt.
Revenue recognition	Revenue recognition The Company’s revenue consists of revenue from the Company’s strategic agreements for the development and commercialization of ensifentrine. The terms of the agreements may include non-refundable upfront fees, payments based upon achievement of milestones and eventually revenue from the commercialized product. These agreements usually have both fixed and variable consideration. Non-refundable upfront fees are considered fixed, while milestone payments and revenue from the commercialized product are identified as variable consideration. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under agreements within the scope of ASC Topic 606, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. The Company’s performance obligations may include intellectual property rights, (which include the license, patents and developmental and regulatory data) and manufacturing and supply. Management are required to judge when performance obligations are satisfied and consequently when revenue is recognized. The Company allocates the total transaction price to each performance obligation based on the estimated relative standalone selling prices of the promised goods or service underlying each performance obligation. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied. If the right to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the right when the right is transferred to the customer, and the customer can use and benefit from the right. At the inception of the arrangement, the Company evaluates whether the development milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company, such as approvals from regulators, are not considered probable of being achieved until those approvals are received.
Research and development costs	Research and development costs Research and development (“R&D”) costs are expensed as incurred. Research and development expenses include salaries, share-based compensation and benefits of employees, and other costs related to the Company’s R&D activities, including pre-approval manufacturing costs, contracts with clinical research organizations and contract manufacturers. The Company is required to estimate its expenses resulting from its obligations under contracts with vendors and consultants and clinical site agreements in connection with its R&D efforts. The financial terms of these contracts are subject to negotiations which vary contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company’s objective is to reflect the appropriate clinical trial expenses in its Consolidated Financial Statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the trials and other development activities. Judgment is applied in determining assumptions related to patient progression and the timing of various aspects of the trial used to measure progress. The Company determines prepaid and accrual estimates through discussions with applicable personnel and outside service providers as to the progress of clinical trials, or other services completed. During the course of a clinical trial, the Company adjusts its rate of clinical trial expense recognition if actual results differ from its estimates. The Company makes estimates of its prepaid and accrued expenses as of each balance sheet date in its Consolidated Financial Statements based on facts and circumstances known at that time. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in the Company reporting amounts that are too high or too low for any particular period. The Company’s clinical trial prepaid and accrual expense is dependent upon the timely and accurate reporting of study recruitment from contract research organizations and activities carried out by other third-party vendors as well as the timely processing of any change orders from the contract research organizations.
Share-based compensation	Share-based compensation The Company has a share-based compensation plan under which various types of equity-based awards may be granted, including stock options, restricted stock units (“RSUs”) and performance restricted stock units (“PRSUs”). The fair value of share options and RSUs, which are subject to milestone or service conditions with graded vesting, are recognized as compensation expense on a straight-line basis using the graded-vesting method; forfeitures are recognized as they occur. The fair value of PRSUs, which are subject to certain performance and service conditions, will be recognized over the remaining service period using the graded-vesting method once the performance conditions are determined to be probable of occurring. The Company uses the fair-value based method to determine compensation for all arrangements under which employees receive shares. The fair value of stock options is estimated on the date of grant using the Black-Scholes valuation model that uses assumptions for expected volatility, expected dividends, expected term, and the risk-free interest rate. Expected volatility is based on the historical volatility of the Company’s ordinary shares over the expected term of the options. The expected term of options granted is derived using the simplified method, which computes the expected term as the average of the sum of the vesting term plus the contract term. Historically the risk-free rate has been based on the appropriate U.K. government debt yield. After delisting its Ordinary shares from AIM on October 30, 2020, the Company used U.S. government debt yields. The fair-value of RSUs and PRSUs is calculated using the closing price of the Company’s ordinary shares on the date of grant.
Other income - U.K. R&D tax credits	Other income - United Kingdom R&D tax credits Research and development tax credit relates to R&D tax credits receivable in the U.K. As a company that carries out extensive research and development activities, the Company is subject to the U.K. R&D Small and Medium Enterprise (“SME”) Program. Qualifying expenditures largely comprise employment costs for research staff, consumables, a proportion of relevant, permitted sub-contract costs and certain internal overhead costs incurred as part of research projects for which it does not receive income. Tax credits related to the SME Program are received as cash and are recorded as other income, as they are akin to grant income, in the Consolidated Statements of Operations and Comprehensive Loss.
Income taxes	Income taxes The Company accounts for income taxes in accordance with ASC 740, “Income Taxes” (“ASC 740”). ASC 740 prescribes the use of the liability method, whereby deferred tax assets and liability account balances are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance, if necessary, to reduce deferred tax assets to their estimated realizable value. ASC 740 establishes a single model to address accounting for uncertain tax positions. ASC 740 clarified the accounting for income taxes by prescribing the minimum recognition threshold a tax position is required to meet before being recognized in the financial statements. The Company has no uncertain tax positions.
Comprehensive loss	Comprehensive loss The Company accounts for comprehensive loss in accordance with ASC 220, “Income Statement - Reporting Comprehensive Income”. Comprehensive loss represents all changes in shareholders’ equity during the period except those resulting from investments by, or distributions to, shareholders.
Segment Reporting	Segment Reporting Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company has one operating and reportable segment, pharmaceutical development.
Foreign Currencies	Reporting and functional currencies The Consolidated Financial Statements are reported in U.S. dollars, which is also the functional currency of the Company’s subsidiary. Transactions in foreign currencies are remeasured into the Company’s functional currency at the rate of exchange prevailing at the date of the transaction. Any monetary assets and liabilities arising from these transactions are remeasured into our functional currency at exchange rates prevailing at the balance sheet date or on settlement. Resulting gains and losses are recorded in foreign exchange gain/(loss) in our Consolidated Statements of Operations.
Treasury shares	Treasury shares In the year ended December 31, 2020, the Company incorporated a trust to facilitate the acquisition of shares, by or for the benefit of employees and former employees. In the years ended December 31, 2023 and December 31, 2022 the Company issued 16.0 million ordinary shares (equivalent to 2.0 million ADSs) and 28.0 million (equivalent to 3.5 million ADSs), respectively, to the trust to cover expected shares issued upon the vesting of share awards to employees. The Company has the indirect ability to control the trust as trustees are required to act in accordance with the trust deed and because the Company controls the issuance of shares to cover awards. As a consequence, the trust is consolidated into the Company’s Consolidated Financial Statements. The shares that were issued to the trust that have not been issued to employees to satisfy vesting of share awards are included in the Consolidated Balance Sheets as Ordinary shares held in treasury.
Fair value of financial instruments	Fair value of financial instruments US GAAP defines fair value and requires companies to establish a framework for measuring fair value and disclosure about fair value measurements using a three-tier approach. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Our financial instruments include cash equivalents, equity interest, other assets, accounts payable and accrued expenses and other liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgement and therefore cannot be determined with precision. The carrying amounts of the other instruments are considered to be representative of their fair values because of their short-term nature.
Concentration of credit risk	Concentration of credit risk Financial instruments that potentially subject the Company to concentration of credit risk consist of principally cash and cash equivalents, bank deposits and certain receivables. The Company holds cash and cash equivalents with highly rated financial institutions and in highly rated money market funds. Our deposits at these institutions may exceed insured limits, however the Company has not experienced any significant credit losses in these accounts and does not believe the Company is exposed to any significant credit risk on these instruments.
Lease accounting	Lease accounting The Company determines if an arrangement is a lease at inception. ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the term of the lease. For this purpose, the Company considers only payments that are fixed and determinable at the time of commencement. As the Company's leases do not provide an implicit rate, the Company determines the incremental borrowing rate in calculating the present value of lease payments. The ROU assets also include any lease payments made prior to commencement and are recorded net of any lease incentives received. The Company’s lease terms may include options to extend or terminate the lease. When it is reasonably certain the Company will exercise such options the lease will be recognized as a liability and a corresponding ROU asset also recognized. Operating leases are included in Right-of-use assets and in Current and Non-current operating lease liabilities on the Company's Consolidated Balance Sheets.
Recently issued and adopted accounting standards	Recently adopted accounting standards In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326)-Measurement of Credit Losses on Financial Instruments. This guidance replaces the current incurred loss impairment methodology. Under this model, on initial recognition and at each reporting period, an entity is required to recognize an allowance that reflects its current estimate of credit losses expected to be incurred over the life of the financial instrument based on historical experience, current conditions and reasonable and supportable forecasts. The guidance requires a modified retrospective transition approach through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. This update became effective for the Company on January 1, 2023 and the adoption of this update did not have a material impact on the Company’s financial statements and related disclosures. Recently issued accounting standards not yet adopted In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid. The standard is intended to benefit investors by providing more detailed income tax disclosures that would be useful in making capital allocation decisions. The amendments in this ASU are effective for annual periods beginning on January 1, 2025, and should be applied on a prospective basis with the option to apply the standard retrospectively. Early adoption is permitted. This ASU will have no impact on the Company's Consolidated Balance Sheets or Consolidated Statements of Operations and Comprehensive Loss. The Company is currently evaluating the impact to its income tax disclosures. In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures, which improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. In addition, the amendments enhance interim disclosure requirements, clarify circumstances in which an entity can disclose multiple segment measures of profit or loss, provide new segment disclosure requirements for entities with a single reportable segment, and contain other disclosure requirements. The purpose of the amendments is to enable investors to better understand an entity's overall performance and assess potential future cash flows. The amendments in this ASU are effective for annual periods beginning on January 1, 2024 and interim periods beginning on January 1, 2025, and should be applied on a retrospective basis for all periods presented. This ASU will have no impact on the Company's Consolidated Balance Sheets or Consolidated Statements of Operations and Comprehensive Loss. The Company is currently evaluating the impact to its segment disclosures.

Prepaid expenses (Tables)

Prepaid expenses (Tables)	12 Months Ended
	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Prepaid Expenses	Prepaid expenses consisted of the following (in thousands): December 31, 2023 2022 Clinical trial and other development costs $ 59 $ 38 Insurance 3,558 2,027 Other — 434 Total prepaid expenses $ 3,617 $ 2,499

Property leases (Tables)

Property leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Minimum Annual Operating Lease Payments	Minimum annual payments over the remaining lease periods as of December 31, 2023 are as follows (in thousands): 2024 $ 1,175 2025 842 2026 788 2027 784 Total minimum future lease payments $ 3,589 Less: imputed interest (634) Total operating lease liabilities $ 2,955

Accrued expenses (Tables)

Accrued expenses (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): December 31, 2023 2022 Clinical trial and other development costs $ 752 $ 12,314 Professional fees, listing and general corporate costs 2,039 1,364 People related costs 794 74 Total accrued expenses $ 3,585 $ 13,752

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Fair Value Valuation Assumptions of Warrants	The warrants were valued using the Black-Scholes model and the table below presents the assumptions used: December 31, 2022 Exercise price in pounds sterling £ 1.7238 Risk-free interest rate 0.07 % Expected term to exercise 0.33 Annualized volatility 51.6 % Dividend rate — % Calculated value of the warrants, in thousands of U.S. dollars $ —
Schedule of Movement of the Value of the Warrants	The following table shows the movement of the value of the warrants (in thousands): December 31, 2022 At January 1 $ 2,246 Fair value adjustment (2,246) At December 31 $ —

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Future Principle Payments	Future principal payments, which exclude the end of term charge, in connection with the 2023 Term Loan as of December 31, 2023 are as follows (in thousands): 2024 $ — 2025 — 2026 — 2027 — 2028 50,000 Total $ 50,000

Taxation (Tables)

Taxation (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Components of loss before income taxes	The components of (profit)/loss before income taxes are as follows (in thousands): December 31, 2023 2022 United States $ (7,429) $ (3,868) United Kingdom 61,324 72,316 Total $ 53,895 $ 68,448
Components of income tax expense	The components of income tax expense are as follows (in thousands): December 31, 2023 2022 United States $ 474 $ 253 United Kingdom — — Total current tax expense $ 474 $ 253 United States $ — $ — United Kingdom — — Total deferred tax expense — — Total income tax expense $ 474 $ 253
Reconciliation of the U.K. statutory income tax rate	A reconciliation of the U.K. statutory income tax rate to our effective income tax rate is as follows (in percentages): December 31, 2023 2022 U.K. tax rate 23.5 % 19.0 % Non-deductible expenses (8.0) % (1.8) % Research and development incentive (4.1) % (8.0) % Share options exercised 5.4 % 2.1 % Change in deferred tax valuation allowance (18.1) % (11.6) % Other differences 0.4 % (0.1) % Effective income tax rate (0.9) % (0.4) %
Deferred tax assets and liabilities	Components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2023 2022 Deferred tax liabilities: Contingent liability (1) $ (53,851) $ (34,565) Total deferred tax liabilities (53,851) (34,565) Deferred tax assets: Net operating losses 54,012 38,893 IPR&D asset (1) 47,793 32,700 Future exercisable shares 7,548 11,964 Other 21 (516) Total deferred tax assets 109,374 83,041 Less: valuation allowance (55,523) (48,476) Deferred tax assets, net of valuation allowance $ — $ — Movements in the deferred tax valuation allowance Valuation allowance at January 1 $ 48,476 $ 30,252 Change in tax rates (851) — Increase in valuation allowance 7,898 18,224 Valuation allowance at December 31 $ 55,523 $ 48,476 (1) These relate to the difference in the tax base of the IP R&D asset and assumed contingent liability and the financial reporting base, which is nil under U.S. GAAP.

Share based compensation (Table

Share based compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Allocation of Share Based Compensation Expense	The following table shows the allocation of share-based compensation between research and development and selling, general and administrative costs (in thousands): December 31, 2023 2022 Research and development $ 4,228 $ 5,420 Selling, general and administrative 14,784 8,701 Total share-based compensation $ 19,012 $ 14,121
Share Option Activity	The following table shows share option activity and includes the options outstanding from all three plans: Number of share options Weighted average exercise price (1) Weighted average remaining contractual term (years) Aggregate intrinsic value (thousands) Outstanding at January 1, 2022 12,695,200 $ 1.38 6.5 Granted 9,024,000 0.90 Forfeited (620,016) 1.04 Exercised (1,822,688) 0.75 Outstanding at December 31, 2022 19,276,496 $ 1.22 7.2 $ 39,412 Granted 7,376,000 2.46 Forfeited (464,680) 0.89 Expired (240,000) 3.07 Exercised (1,258,192) 1.55 Outstanding at December 31, 2023 24,689,624 $ 1.56 7.4 $ 24,022 Exercisable at December 31, 2023 12,904,640 $ 1.30 5.8 $ 15,574 (1) The exercise prices relate to the equivalent price for an ordinary share, calculated as one eighth of the ADS price. The following summarizes the aggregate intrinsic value and cash receipts related to stock option exercise activity for the years ended December 31: ($ in thousands) 2023 2022 Aggregate intrinsic value of stock options exercised $ 1,861 $ 2,413 Cash receipts from stock options exercised $ 1,949 $ 1,372
Schedule of Weighted-Average Assumptions	A summary of the weighted-average assumptions applicable to the share options granted in the applicable years is as follows: December 31, 2023 2022 Risk-free interest rate 3.40% - 4.69% 2.09% - 4.20% Expected lives, years 5-7 5-7 Expected volatility 80.64% - 87.26% 82.50% - 84.27% Expected dividend yield — % — % Grant date fair value (per share) $1.69 - $3.27 $0.34 - $1.33
Restricted Stock Unit Activity	The following table shows RSU activity: Number of RSUs Weighted average grant date fair value Weighted average remaining contractual term (years) Outstanding at January 1, 2022 38,347,352 $ 0.97 1.2 Granted 12,877,864 1.07 Forfeited (1,006,264) 1.03 Vested (15,676,608) 0.96 Outstanding at December 31, 2022 34,542,344 $ 1.01 1.2 Granted 3,596,872 1.66 Forfeited (303,648) 1.10 Vested (18,332,944) 0.99 Outstanding at December 31, 2023 19,502,624 $ 1.14 1.2
Summary of the Company’s PRSU Activity	A summary of the Company’s PRSU activity for the year ended December 31, 2023 is as follows: Number of PRSUs Weighted average grant date fair value Aggregate Intrinsic Value (thousands) Outstanding at January 1, 2023 — $ — Granted 10,790,144 1.66 Forfeited (60,000) 1.66 Outstanding at December 31, 2023 10,730,144 $ 1.66 $ 26,665

Net loss per share (Tables)

Net loss per share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earning Per Share	The following table shows the computation of basic and diluted earnings per share for 2023 and 2022 (in thousands, except share and per share amounts): December 31, 2023 2022 Numerator: Net loss $ (54,369) $ (68,701) Net loss available to ordinary shareholders - basic and diluted $ (54,369) $ (68,701) Denominator: Weighted-average shares outstanding - basic and diluted 634,142,660 529,071,526 Net loss per share - basic and diluted $ (0.09) $ (0.13)

Organization and description _2

Organization and description of business operations (Details) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Aug. 15, 2022 USD ($) $ / shares shares	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) subsidiary shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2023 £ / shares	Dec. 31, 2023 USD ($) $ / shares Rate	Dec. 27, 2023 USD ($) loanAdvance	Dec. 31, 2022 £ / shares	Dec. 31, 2022 USD ($) $ / shares	Oct. 14, 2022 USD ($) loanAdvance	Nov. 30, 2020 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of wholly owned subsidiaries | subsidiary			1
Class of Stock [Line Items]
Payments for application fees		$ 3,200
Accumulated deficit						$ 388,433			$ 333,097
Number of shares issued in sale (in shares) | shares				80,696
Number of ordinary shares per ADS	8					800%
Common stock, par value (in pounds sterling per share) | (per share)	$ 0.05				£ 0.05			£ 0.05
Sale of stock price per share (in dollars per share) | $ / shares									$ 0.86
Term Loan Facility | Secured Debt
Class of Stock [Line Items]
Debt instrument, face amount											$ 30,000
2023 Term Loan | Secured Debt
Class of Stock [Line Items]
Debt instrument, face amount							$ 400,000
Line of Credit | Oxford Term Loan
Class of Stock [Line Items]
Maximum borrowing capacity										$ 150,000
Number of loan advances | loanAdvance										4
Line of Credit | 2023 Term Loan
Class of Stock [Line Items]
Maximum borrowing capacity							$ 400,000
Number of loan advances | loanAdvance							4
Line of Credit | 2023 Term A Loan
Class of Stock [Line Items]
Maximum borrowing capacity							$ 50,000
Line of Credit | 2023 Term B, C, D, E Loan
Class of Stock [Line Items]
Maximum borrowing capacity							$ 350,000
Public Stock Offering
Class of Stock [Line Items]
Consideration received from sale of stock	$ 140,200
ATM Program
Class of Stock [Line Items]
Number of shares issued in sale (in shares) | shares			20,321,384
Sale of stock price per share (in dollars per share) | $ / shares						$ 2.88
Consideration received from sale of stock			$ 56,900
American Depository Shares
Class of Stock [Line Items]
Number of shares issued in sale (in shares) | shares				10,087
Sale of stock price per share (in dollars per share) | $ / shares									$ 6.86
Consideration received from sale of stock				$ 100
Maximum aggregate offering price						$ 200,000
Commission fee percentage						3%
Remaining ordinary shares available for sale									$ 99,200
American Depository Shares | Public Stock Offering
Class of Stock [Line Items]
Number of shares issued in sale (in shares) | shares	14,260,000
Sale of stock price per share (in dollars per share) | $ / shares	$ 10.50
American Depository Shares | Over-Allotment Option
Class of Stock [Line Items]
Number of shares issued in sale (in shares) | shares	1,860,000
American Depository Shares | ATM Program
Class of Stock [Line Items]
Number of shares issued in sale (in shares) | shares			2,540,173
Sale of stock price per share (in dollars per share) | $ / shares						$ 23.08

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting policies (Details)	12 Months Ended
	Dec. 31, 2023 segment shares	Dec. 31, 2022 shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of operating segments | segment	1
Number of reportable segments | segment	1
Ordinary shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Issuance of ordinary shares to treasury (in shares) | shares	16,000,000	28,000,000
Issuance of ordinary shares to treasury as ADS equivalent (in shares) | shares	2,000,000	3,500,000
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Furniture and equipment, useful life	2 years
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Furniture and equipment, useful life	5 years

Prepaid expenses (Details)

Prepaid expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Clinical trial and other development costs	$ 59
Insurance	3,558
Other	0
Total prepaid expenses	$ 3,617	$ 2,499

Property leases - Narrative (De

Property leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Discount rate (in percent)	11%	4%
Weighted average remaining lease term	3 years 3 months 18 days	1 year 6 months
Operating lease expense	$ 0.7
Building
Lessee, Lease, Description [Line Items]
Right-of-use assets recognized with associated liability		$ 0.7
London | Building
Lessee, Lease, Description [Line Items]
Right-of-use assets recognized with associated liability	$ 2.7

Property leases - Maturity (Det

Property leases - Maturity (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 1,175
2025	842
2026	788
2027	784
Total minimum future lease payments	3,589
Less: imputed interest	(634)
Total operating lease liabilities	$ 2,955

Accrued expenses (Details)

Accrued expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Clinical trial and other development costs	$ 752	$ 12,314
Professional fees, listing and general corporate costs	2,039	1,364
People related costs	794	74
Total accrued expenses	$ 3,585	$ 13,752

Warrants - Narrative (Details)

Warrants - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 shares	Dec. 31, 2022 £ / shares shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2017 £ / shares shares
Other Liabilities Disclosure [Abstract]
Number of warrants exercised and forfeited	0	0
Stock warrants (in shares)			12,401,262	31,115,926
Issue price of warrants (in pounds sterling per share) | £ / shares				£ 1.4365
Number of shares called by each warrant				0.4
Exercise price of stock warrant (in pound sterling per share) | £ / shares		£ 1.7238		£ 1.7238
Number of outstanding warrants			31,003,155
Intrinsic value | $			$ 0

Warrants - Fair Value Assumptio

Warrants - Fair Value Assumptions (Details) $ in Thousands	Dec. 31, 2022 £ / shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2017 £ / shares shares
Class of Warrant or Right [Line Items]
Stock warrants (in shares) | shares		12,401,262	31,115,926
Exercise price of stock warrant (in pound sterling per share) | £ / shares	£ 1.7238		£ 1.7238
Expected term to exercise		3 months 29 days
Calculated value of the warrants, in thousands of U.S. dollars | $		$ 0
Risk-free interest rate
Class of Warrant or Right [Line Items]
Measurement Input		0.0007
Annualized volatility
Class of Warrant or Right [Line Items]
Measurement Input		0.516
Dividend rate
Class of Warrant or Right [Line Items]
Measurement Input		0

Warrants - Movement in Value (D

Warrants - Movement in Value (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Warrant Activity
At January 1	$ 2,246
Fair value adjustment	(2,246)
At December 31	$ 0

Term loan (Details)

Term loan (Details) $ in Thousands			1 Months Ended	12 Months Ended
	Dec. 27, 2023 USD ($) loanAdvance	Mar. 24, 2023 USD ($)	Nov. 30, 2020 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Oct. 14, 2022 USD ($) loanAdvance
Debt Instrument [Line Items]
Proceeds from Oxford Term Loan				$ 9,996	$ 10,000
Repayment of Oxford term loan				0	5,000
Payments of lenders and third party fees				$ 12	$ 245
Term Loan Facility | Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount			$ 30,000
Proceeds from Oxford Term Loan			5,000
Term B Loan | Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount			10,000
Term C Loan | Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount			$ 15,000
Oxford Term Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 150,000
Number of loan advances | loanAdvance						4
Oxford Term Loan | Secured Debt
Debt Instrument [Line Items]
Repayment of Oxford term loan	$ 20,000
Oxford Term A Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 10,000
Oxford Term B, C, D, E Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 140,000
Oxford Term B Loan | Line of Credit
Debt Instrument [Line Items]
Proceeds from lines of credit		$ 10,000
2023 Term B | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	100,000
2023 Term C | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	75,000
2023 Term D | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	75,000
2023 Term E Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	100,000
2023 Term A Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 50,000
2023 Term A Loan | Line of Credit | Base Rate
Debt Instrument [Line Items]
Term loan increase	11.19%
2023 Term A Loan | Line of Credit | Debt Instrument Interest Rate, Period One | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	5.85%
2023 Term A Loan | Line of Credit | Debt Instrument Interest Rate, Period One | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	5.34%
2023 Term A Loan | Secured Debt
Debt Instrument [Line Items]
Proceeds from Oxford Term Loan	$ 50,000
Net proceeds	28,400
2023 Term Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 400,000
Number of loan advances | loanAdvance	4
Effective interest				11%
2023 Term Loan | Line of Credit | Base Rate
Debt Instrument [Line Items]
Term loan increase	2%
2023 Term Loan | Line of Credit | Minimum
Debt Instrument [Line Items]
Term loan threshold	$ 50,000
Market capitalization, company value	3,000,000
Average daily VWAP multiplied by total number of issued and outstanding	1,500,000
2023 Term Loan | Line of Credit | Maximum
Debt Instrument [Line Items]
Average daily VWAP multiplied by total number of issued and outstanding	3,000,000
2023 Term Loan | Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount	400,000
Payments of lenders and third party fees	1,400
Interest expense	$ 200
Interest rate in the event of default	5%
Denomination multiple	$ 5,000
2023 Term Loan | Secured Debt | First Anniversary
Debt Instrument [Line Items]
Prepayment fee (in percent)	2%
2023 Term Loan | Secured Debt | Second Anniversary
Debt Instrument [Line Items]
Prepayment fee (in percent)	1.50%
2023 Term Loan | Secured Debt | After Second Anniversary and Prior to Maturity
Debt Instrument [Line Items]
Prepayment fee (in percent)	1%
2023 Term Loan | Secured Debt | Minimum
Debt Instrument [Line Items]
Final payment (in percent)	2.50%
2023 Term Loan | Secured Debt | Maximum
Debt Instrument [Line Items]
Final payment (in percent)	3.50%

Term loan - Future Principle Pa

Term loan - Future Principle Payments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Disclosure [Abstract]
2024	$ 0
2025	0
2026	0
2027	0
2028	50,000
Total	$ 50,000

Significant agreements (Details

Significant agreements (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2022 USD ($) tradingDay	Dec. 31, 2023 USD ($)	Jun. 09, 2021 USD ($)
Ligand UK Development Limited
Capitalized Contract Cost [Line Items]
Sublicense Payment	$ 2,000
Sublicense Payment, Equity Issuance, Threshold Trading Days | tradingDay	10
Ligand UK Development Limited | Selling, General and Administrative Expenses
Capitalized Contract Cost [Line Items]
Sublicense Payment	$ 2,000
Ligand UK Development Limited | First Commercial Sale
Capitalized Contract Cost [Line Items]
Sublicense Payment	$ 15,000
Nuance (Shanghai) Pharma Co Ltd
Capitalized Contract Cost [Line Items]
Transaction price			$ 40,000
Accounts receivable			25,000
Equity interest receivable		$ 15,000	15,000
Future eligible milestone payments			$ 179,000
Contract with Customer, Liability, Revenue Recognized		$ 500

Benefit plans (Details)

Benefit plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Contribution cost	$ 600	$ 300

Taxation - Loss Before Tax (Det

Taxation - Loss Before Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
United States	$ (7,429)	$ (3,868)
United Kingdom	61,324	72,316
Loss before income taxes	$ 53,895	$ 68,448

Taxation - Tax Expense (Benefit

Taxation - Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
United States	$ 474	$ 253
United Kingdom	0	0
Total current tax expense	474	253
United States	0	0
United Kingdom	0	0
Total deferred tax expense	0	0
Total income tax expense	$ 474	$ 253

Taxation - Reconciliation of St

Taxation - Reconciliation of Statutory Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U.K. tax rate	23.50%	19%
Non-deductible expenses	(8.00%)	(1.80%)
Research and development incentive	(4.10%)	(8.00%)
Share options exercised	5.40%	2.10%
Change in deferred tax valuation allowance	(18.10%)	(11.60%)
Other differences	0.40%	(0.10%)
Effective income tax rate	(0.90%)	(0.40%)

Taxation - Deferred Tax Assets

Taxation - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred tax liabilities:
Contingent liability	$ (53,851)	$ (34,565)
Total deferred tax liabilities	(53,851)	(34,565)
Deferred tax assets:
Net operating losses	54,012	38,893
IPR&D asset	47,793	32,700
Future exercisable shares	7,548	11,964
Other	21	(516)
Total deferred tax assets	109,374	83,041
Less: valuation allowance	(55,523)	(48,476)
Deferred tax assets, net of valuation allowance	0	0
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset
Valuation Allowance [Roll Forward]
Valuation allowance at January 1	48,476	30,252
Change in tax rates	(851)	0
Increase in valuation allowance	7,898	18,224
Valuation allowance at December 31	$ 55,523	$ 48,476

Taxation - Narrative (Details)

Taxation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Net operating loss	$ 216,000,000	$ 155,600,000
Interest and penalties recognized	0	0
Interest accrued	0	0
Penalties accrued	$ 0	$ 0

Share based compensation - Shar

Share based compensation - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	$ 19,012	$ 14,121
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	4,228	5,420
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	$ 14,784	$ 8,701

Share based compensation - Narr

Share based compensation - Narrative (Details) $ in Thousands	12 Months Ended		69 Months Ended
	Dec. 31, 2023 USD ($) Rate shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2022 shares	Aug. 15, 2022	Jul. 24, 2012 shares	Sep. 18, 2006 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number granted (in shares)	7,376,000	9,024,000
Number of ordinary shares per ADS	800%			8
Fair value for instruments granted during period | $	$ 13,200	$ 5,900
EMI Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number granted (in shares)			0
Pre-IPO Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number granted (in shares)			0
Share Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contract life	10 years
Share Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Share Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Share Options | EMI Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized						114,000
Number of American Depository Shares authorized						14,250
Further awards to be granted (in shares)	0
Share Options | Pre-IPO Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized					1,320,000
Number of American Depository Shares authorized					165,000
Further awards to be granted (in shares)	0
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic and fair value, vested | $	$ 41,500	$ 14,300
Cost related to share options and RSUs granted but not yet recognized | $	$ 20,000
Expected period for recognition	1 year 10 months 24 days
Performance Restricted Stock Unit (PRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic and fair value, vested | $	$ 26,665
Cost related to share options and RSUs granted but not yet recognized | $	$ 17,800
Expected period for recognition	1 year

Share based compensation - Sh_2

Share based compensation - Share Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares Rate shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 $ / shares shares	Aug. 15, 2022
Share-Based Payment Arrangement [Abstract]
Number of ordinary shares per ADS	800%			8
Number of share options
Beginning balance outstanding | shares	19,276,496	12,695,200
Granted | shares	7,376,000	9,024,000
Forfeited | shares	(464,680)	(620,016)
Expired | shares	240,000
Exercised | shares	(1,258,192)	(1,822,688)
Ending balance outstanding | shares	24,689,624	19,276,496	12,695,200
Exercisable | shares	12,904,640
Weighted average exercise price
Outstanding, Beginning Balance, Weighted average exercise price (in dollars per share) | $ / shares	$ 1.22	$ 1.38
Granted, Weight average exercise price (in dollars per share) | $ / shares	2.46	0.90
Forfeited, Weight average exercise price (in dollars per share) | $ / shares	0.89	1.04
Expired, Weight average exercise price (in dollars per share) | $ / shares	3.07
Exercised, Weight average exercise price (in dollars per share) | $ / shares	1.55	0.75
Exercisable, Weight average exercise price (in dollars per share) | $ / shares	1.30
Outstanding, Ending Balance, Weighted average exercise price (in dollars per share) | $ / shares	$ 1.56	$ 1.22	$ 1.38
Stock option activity, additional disclosures
Outstanding, Weighted average remaining contractual term (years)	7 years 4 months 24 days	7 years 2 months 12 days	6 years 6 months
Exercisable, Weighted average remaining contractual term (years)	5 years 9 months 18 days
Outstanding, Aggregate intrinsic value (in dollars) | $	$ 24,022	$ 39,412
Exercisable, Aggregate intrinsic value (in dollars) | $	15,574
Aggregate intrinsic value of stock options exercised | $	1,861	2,413
Proceeds from exercise of share options | $	$ 1,949	$ 1,372

Share based compensation - Weig

Share based compensation - Weighted-Average Assumptions (Details) - Share Options - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	3.40%	2.09%
Risk-free interest rate, maximum	4.69%	4.20%
Expected volatility, minimum	80.64%	82.50%
Expected volatility, maximum	87.26%	84.27%
Expected dividend yield	0%	0%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected lives, years	5 years	5 years
Grant date fair value (in dollars per share)	$ 1.69	$ 0.34
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected lives, years	7 years	7 years
Grant date fair value (in dollars per share)	$ 3.27	$ 1.33

Share based compensation - RSU

Share based compensation - RSU and PRSU Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
RSU Activity
Outstanding, beginning balance	34,542,344	38,347,352
Outstanding, ending balance	19,502,624	34,542,344	38,347,352
Weighted average grant date fair value
Beginning balance (in dollars per share)	$ 1.01	$ 0.97
Granted (in dollars per share)	1.66	1.07
Forfeited (in dollars per share)	1.10	1.03
Vested (in dollars per share)	0.99	0.96
Ending balance (in dollars per share)	$ 1.14	$ 1.01	$ 0.97
Restricted Stock Units
RSU Activity
Granted	3,596,872	12,877,864
Forfeited	(303,648)	(1,006,264)
Vested	(18,332,944)	(15,676,608)
Weighted average grant date fair value
Outstanding, Weighted average remaining contractual term	1 year 2 months 12 days	1 year 2 months 12 days	1 year 2 months 12 days
Intrinsic and fair value, vested	$ 41,500	$ 14,300
Performance Restricted Stock Unit (PRSUs)
RSU Activity
Outstanding, beginning balance	0
Granted	10,790,144
Forfeited	(60,000)
Outstanding, ending balance	10,730,144	0
Weighted average grant date fair value
Beginning balance (in dollars per share)	$ 0
Granted (in dollars per share)	1.66
Forfeited (in dollars per share)	1.66
Ending balance (in dollars per share)	$ 1.66	$ 0
Intrinsic and fair value, vested	$ 26,665

Net loss per share - Computatio

Net loss per share - Computation (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares Rate shares	Dec. 31, 2022 USD ($) $ / shares shares	Aug. 15, 2022
Earnings Per Share [Abstract]
Number of ordinary shares per ADS	800%		8
Numerator:
Net loss | $	$ (54,369)	$ (68,701)
Denominator:
Weighted-average shares outstanding - basic (in shares)	634,142,660	529,071,526
Weighted-average shares outstanding - diluted (in shares)	634,142,660	529,071,526
Loss per ordinary share, diluted (in dollars per share) | $ / shares	$ (0.09)	$ (0.13)
Loss per ordinary share, basic (in dollars per share) | $ / shares	$ (0.09)	$ (0.13)
Antidilutive securities excluded from computation of loss per share (in shares)	54,900,000	53,800,000

Commitments and contingencies (

Commitments and contingencies (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2023	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Maximum exposure				$ 6,900
Accounts payable				$ 1,500
Loss in period	$ 2,100
Reversal of research and development costs		$ 6,300	$ 1,500