Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Statistical Measurement [Domain] Statistical Measurement [Domain] Investments in Marketable Securities Investment, Policy [Policy Text Block] Schedule of Debt Securities, Fair Value of U.S. Treasury Securities and Money Market Fund Debt Securities, Available-for-Sale [Table Text Block] Award Timing Predetermined Award Timing Predetermined [Flag] Unrealized gain on available for sale securities, tax OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax Entity File Number Entity File Number Additional paid-in capital Additional Paid-in Capital [Member] Research tax incentives Research And Development Expense, Tax Incentives Research And Development Expense, Tax Incentives Vesting of ordinary shares Share-based Compensation Arrangement by Share-based Payment Award, Options and Restricted Stock Units, Aggregate Intrinsic Value, Vested Share-based Compensation Arrangement by Share-based Payment Award, Options and Restricted Stock Units, Aggregate Intrinsic Value, Vested Iqbal Hussain [Member] Iqbal Hussain Tabular List, Table Tabular List [Table Text Block] Accounts payable Increase (Decrease) in Accounts Payable License License [Member] Shares withheld to pay employee withholding tax on share-based compensation Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Gross unrealized losses Gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Net loss per ordinary share - basic (in USD per share) Earnings Per Share, Basic Adjustment to Compensation: Adjustment to Compensation [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Commercial Paper Commercial paper, included in: Commercial Paper [Member] Genmab License Agreement Revenue from Contract with Customer [Text Block] Mario Alberto Accardi [Member] Mario Alberto Accardi Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary or Equity Method Investee, Sale of Stock, Type [Table] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Stock issued during period (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash Schedule of Cash and Cash Equivalents [Table Text Block] Adjustment to Compensation, Amount Adjustment to Compensation Amount Unamortized debt issuance costs and unamortized end of term charge Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Share-based compensation expense Share-Based Payment Arrangement, Noncash Expense U.S. Treasury and government agency securities US Government Corporations and Agencies Securities [Member] Stock options Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Cash and cash equivalents Cash and Cash Equivalents [Member] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Total shareholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Debt Securities, Available-for-Sale [Table] Debt Securities, Available-for-Sale [Table] Insider Trading Policies and Procedures [Line Items] Compensation expense recognized Share-based compensation Share-Based Payment Arrangement, Expense Schedule of Property and Equipment, Net Property, Plant and Equipment [Table Text Block] Ordinary shares, shares authorized (in shares) Common Stock, Shares Authorized Segment Reporting, Asset Reconciling Item [Line Items] Segment Reporting, Asset Reconciling Item [Line Items] Maximum number of undisclosed targets to research products Contract With Customer, Maximum Number Of Undisclosed Targets To Research Products Contract With Customer, Maximum Number Of Undisclosed Targets To Research Products Issuance of ordinary shares under ATM program, net of issuance costs (in shares) Stock Issued During Period, Shares, New Issues Current assets: Assets, Current [Abstract] Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period Total liabilities and shareholders' equity Liabilities and Equity Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward] Liabilities and shareholders’ equity Liabilities and Equity [Abstract] Cover [Abstract] Reclassification adjustment for realized net (loss) gain on available for sale marketable securities included in net loss, net of tax of $0.1 million in 2026 and $0.8 million in 2025 Reclassification adjustment for realized net (loss) gain on available for sale marketable securities included in net loss, net of tax Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Maximum Maximum [Member] Exercisable at end of period (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price General and administrative General and Administrative Expense [Member] Accounting Policies [Abstract] Remaining shares reserved for issuance (in shares) Share Repurchase Program, Remaining Authorized, Number of Shares Restricted stock awards Restricted Stock [Member] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Foreign currency translation adjustment Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Total principal payments, including End of Term Charge Long-Term Debt, Gross And End Of Term Charge Long-Term Debt, Gross And End Of Term Charge Other liabilities Other Liabilities, Noncurrent Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Shareholders’ equity: Statement of Stockholders' Equity [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Total comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Long-term investments Debt Securities, Available-for-Sale, Excluding Accrued Interest, Noncurrent Name Measure Name Schedule of Share-based Compensation Expense Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Amortization of discount of marketable securities Investment Income, Net, Amortization of Discount and Premium Secured Debt Secured Debt [Member] Operating lease Operating Lease, Liability, Current Additional cash payment (in USD per share) Common Stock, Additional Cash Payment Common Stock, Additional Cash Payment Document Fiscal Period Focus Document Fiscal Period Focus Award Timing Method Award Timing Method [Text Block] Office furniture Furniture and Fixtures [Member] U.S. Treasury securities, amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss Award Type [Axis] Award Type [Axis] Loan and Security Agreement (carried at amortized cost) Long-Term Debt Total assets Assets Trading Symbol Trading Symbol Vested (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Entity Address, City or Town Entity Address, City or Town Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Other segment items Segment Reporting, Other Segment Item, Amount Effect of exchange rate on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Restricted stock units Restricted Stock Units Restricted Stock Units (RSUs) [Member] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Assets Assets, Fair Value Disclosure [Abstract] Gregory Weinhoff [Member] Gregory Weinhoff Entity Emerging Growth Company Entity Emerging Growth Company Research and development Research and Development Expense (Excluding Acquired in Process Cost) Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Debt Securities, Available-for-Sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Beginning balance (in shares) Ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Significant other observable inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Ordinary shares, shares outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Plan Name [Axis] Plan Name [Axis] Document Information [Table] Document Information [Table] PEO PEO [Member] Interest and investment income Interest income Investment Income, Interest American Depositary Shares American Depositary Shares [Member] American Depositary Shares Tia Bush [Member] Tia Bush Other R&D expenses: Other R&D Expenses [Abstract] Other R&D Expenses Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Stock option exercises Stock Issued During Period, Value, Stock Options Exercised Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Investments above with unrealized loss, gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, Before Tax, Without Accumulated Unrealized Loss Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, Before Tax, Without Accumulated Unrealized Loss Expected stock price volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Number of shares issued per ordinary share (in shares) Sale Of Stock, Number Of Shares Issued Per Ordinary Share Sale Of Stock, Number Of Shares Issued Per Ordinary Share Accumulated Deficit Retained Earnings [Member] Prepaid expenses and other current assets Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Schedule of Accrued Expenses and Other Current Liabilities Schedule of Accrued Liabilities [Table Text Block] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Share-Based Payment Arrangement [Abstract] Cash, cash equivalents, and restricted cash at beginning of period Cash, cash equivalents, and restricted cash at end of period Total Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income tax expense Income tax expense Income Tax Expense (Benefit) Research and development costs Prepaid Research and Development Costs Prepaid Research and Development Costs Purchases of investments in marketable securities Payments to Acquire Marketable Securities Sale of Stock [Domain] Sale of Stock [Domain] Document Information [Line Items] Document Information [Line Items] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Product and Service [Domain] Product and Service [Domain] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Property and equipment, at cost Property, Plant and Equipment, Gross Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Eli Lilly Agreement Restructuring and Related Activities Disclosure [Text Block] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Proceeds from option exercises Proceeds from Stock Options Exercised City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Options vested and expected to vest at end of period, weighted-average remaining contractual term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Accrued expenses and other current liabilities Accrued expenses and other current liabilities Accrued Liabilities, Current Research and development costs Accrued Research And Development Expense, Current Accrued Research And Development Expense, Current Unvested beginning balance (in shares) Unvested ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Commitments and Contingencies Disclosure [Abstract] Termination fee Termination Fee Termination Fee Maximum additional potential option exercise fee Revenue, Remaining Performance Obligation, Variable Consideration Amount Revenue, Remaining Performance Obligation, Variable Consideration Amount Cash flows from investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] General and administrative General and administrative expenses General and Administrative Expense Unrecognized compensation expense related to unvested stock option awards Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Net cash used in operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Debt securities, available-for-sale, fair value Debt Securities, Available-for-Sale, Excluding Accrued Interest Potential additional development and sales milestone Revenue From Contract With Customer, Potential Additional Development, Regulatory And Sales Milestone Payments Revenue From Contract With Customer, Potential Additional Development, Regulatory And Sales Milestone Payments Schedule of Assumptions Used to Estimate Fair Value of Stock Option Awards Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Estimate of payment Loss Contingency, Estimate of Possible Loss PEO Total Compensation Amount PEO Total Compensation Amount Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Vested and expected to vest at end of period (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Money Market fund Money Market Funds [Member] LockBody technology program expenses Research And Development Expense, Technology Platform Research And Development Expense, Technology Platform Equity Components [Axis] Equity Components [Axis] Entity Ex Transition Period Entity Ex Transition Period Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of reportable segments Number of Reportable Segments Supplemental disclosure: Supplemental Cash Flow Information [Abstract] Entity Address, Country Entity Address, Country Other Performance Measure, Amount Other Performance Measure, Amount Weighted-Average Exercise Price Per Share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Schedule of Restrictions on Cash and Cash Equivalents Restrictions on Cash and Cash Equivalents [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Total current liabilities Liabilities, Current Receivable per company share (in USD per share) Common Stock, Receivable Per Company Share Common Stock, Receivable Per Company Share Individual: Individual [Axis] Restricted cash (included within Other non-current assets) Restricted Cash Other Other Assets, Current Research and development Research and Development Expense [Member] Net cash (used in) provided by investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Genmab A/S Genmab A/S [Member] Genmab A/S Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation and Consolidation Basis of Accounting, Policy [Policy Text Block] Investments above with unrealized loss, gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax, Without Accumulated Unrealized Loss Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax, Without Accumulated Unrealized Loss Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Entity Interactive Data Current Entity Interactive Data Current Other Orexin program expenses Research And Development Expense, Other Program Expense Research And Development Expense, Other Program Expense Plan Name [Domain] Plan Name [Domain] Expected weighted average recognition period Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Stock option exercises (in shares) Exercised (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period License and other revenue Revenue from Contract with Customer [Policy Text Block] Aggregate intrinsic value of exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value Less: Segment Reconciliation [Abstract] Purchase obligation Purchase Obligation Segment Information Segment Reporting Disclosure [Text Block] Aggregate Intrinsic Value (in millions) Share-Based Compensation Arrangement By Share-Based Payment Award, Aggregate Intrinsic Value [Abstract] Share-Based Compensation Arrangement By Share-Based Payment Award, Aggregate Intrinsic Value Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Long-Lived Tangible Asset [Axis] Long-Lived Tangible Asset [Axis] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Deferred tax asset Deferred Income Tax Assets, Net Depreciation and amortization Depreciation, Depletion and Amortization Other non-current assets Other Assets, Noncurrent Interest payable Interest Payable, Current Entity Central Index Key Entity Central Index Key PEO Name PEO Name Schedule of Maturities of Long-Term Debt Schedule of Maturities of Long-Term Debt [Table Text Block] License and other revenue License and other revenue Revenues Aggregate net proceeds from shares sold Sale of Stock, Consideration Received on Transaction Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Arrangement Duration Trading Arrangement Duration Computer equipment Computer Equipment [Member] Segments [Axis] Segments [Axis] Investments above with no unrealized loss, amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, After Allowance For Credit Loss, With Accumulated Unrealized Loss Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, After Allowance For Credit Loss, With Accumulated Unrealized Loss Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Number of debt securities Number Of Debt Securities Number Of Debt Securities Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Maximum aggregate development and regulatory milestone payments Collaborative Arrangement, Rights and Obligations, Maximum Aggregate Development and Regulatory Milestone Payments Collaborative Arrangement, Rights and Obligations, Maximum Aggregate Development and Regulatory Milestone Payments Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Unrecognized compensation expense excluding options Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Share price (in USD per share) Share Price Other, net Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Share-based Compensation Share-Based Payment Arrangement [Text Block] Cash and cash equivalents and short-term investments Cash And Cash Equivalents And Short Term Investments Cash And Cash Equivalents And Short Term Investments Assets Assets [Abstract] Long term debt Long-Term Debt, Excluding Current Maturities Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Statement of Financial Position Location, Balance [Axis] Statement of Financial Position Location, Balance [Axis] Entity Address, Address Line Three Entity Address, Address Line Three Forfeited (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Fair Value Measurement Fair Value Disclosures [Text Block] Credit Facility [Domain] Credit Facility [Domain] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Entity Address, Address Line One Entity Address, Address Line One 2021 Plan 2021 Plan [Member] 2021 Plan Entity Address, Address Line Two Entity Address, Address Line Two Accumulated Other Comprehensive Income AOCI Attributable to Parent [Member] Shares withheld to pay employee withholding tax on share-based compensation (in shares) Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Operating lease liabilities Operating Lease, Liability, Noncurrent Eli Lilly Eli Lilly [Member] Eli Lilly Fair Value as of Grant Date Award Grant Date Fair Value Entity Registrant Name Entity Registrant Name Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Municipal bonds Municipal bonds, included in: Municipal Bonds [Member] Investments above with unrealized loss, amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, After Allowance For Credit Loss, Without Accumulated Unrealized Loss Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, After Allowance For Credit Loss, Without Accumulated Unrealized Loss Personnel expenses Labor and Related Expense Options and RSU Share-Based Payment Arrangement, Options And Restricted Stock Unit [Member] Share-Based Payment Arrangement, Options And Restricted Stock Unit Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Document Quarterly Report Document Quarterly Report Total Assets, Fair Value Disclosure The fair value of LSA, classified as Level 2 under ASC Topic 820, Fair Value Measurement Long-Term Debt, Fair Value Number of debt securities, loss position Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Interest receivable Interest Receivable, Current Counterparty Name [Domain] Counterparty Name [Domain] Number of operating segments Number of Operating Segments Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Options outstanding, weighted-average remaining contractual term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Schedule of Debt Schedule of Debt [Table Text Block] Granted (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Reportable Segment Reportable Segment [Member] Reportable Segment Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Restatement Determination Date: Restatement Determination Date [Axis] Non-PEO NEO Non-PEO NEO [Member] Aggregate intrinsic value of options Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Schedule of Prepaid Expenses and Other Current Assets Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Other, net Proceeds from (Payment for) Other Financing Activity Sale of Stock [Axis] Sale of Stock [Axis] Gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Name Trading Arrangement, Individual Name Award Type [Domain] Award Type [Domain] Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Purchase obligation, to be paid, within one year Purchase Obligation, to be Paid, Remainder of Fiscal Year Schedule of Restricted Stock and Restricted Stock Unit, Activity Share-Based Payment Arrangement, Activity [Table Text Block] Expected dividend yield Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Sale of stock, consideration receivable (up to) Sale Of Stock, Maximum Consideration Receivable Sale Of Stock, Maximum Consideration Receivable MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Name Awards Close in Time to MNPI Disclosures, Individual Name Unvested beginning balance (in USD per share) Unvested ending balance (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Share-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Country Region Country Region 2027 Long-Term Debt, Maturity, Year One Aggregate intrinsic value of vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Financial Instruments [Domain] Financial Instruments [Domain] Segments [Domain] Segments [Domain] Income Statement Location [Axis] Statement of Income Location, Balance [Axis] Cash and Cash Equivalent [Table] Cash and Cash Equivalent [Table] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Statement of Financial Position Location, Balance [Domain] Statement of Financial Position Location, Balance [Domain] Amortization of debt issuance costs and exit fee of long-term debt Amortization of Debt Issuance Costs and Discounts Less: Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Company Selected Measure Name Company Selected Measure Name Debt Debt Disclosure [Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Accounts payable Accounts Payable, Current Operating lease payments reducing operating lease liabilities Operating Lease, Payments Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] All Executive Categories All Executive Categories [Member] Ordinary shares: £0.002 nominal value: 222,480,776 shares authorized, 154,728,966 issued and outstanding at March 31, 2026: 222,480,776 shares authorized, 149,228,068 issued and outstanding at December 31, 2025 Common Stock, Value, Issued Short-term investments Short-Term Investments Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Tax incentive receivable Increase (Decrease) In Tax Incentive Receivables Increase (Decrease) In Tax Incentive Receivables Weighted average ordinary shares outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Commitments and contingencies (Note 8) Commitments and Contingencies Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Entity Small Business Entity Small Business End of term charge Long-Term Debt, Gross, End Of Term Charge Long-Term Debt, Gross, End Of Term Charge Entity Transition Report Document Transition Report Short-term investments Short-Term Investments [Member] Underlying Securities Award Underlying Securities Amount Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Purchase obligation, to be paid, year one through five Purchase Obligation, to be Paid, Year One through Five Purchase Obligation, to be Paid, Year One through Five Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Revenue from Contract with Customer [Abstract] Investments above with no unrealized loss, gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, Before Tax, With Accumulated Unrealized Loss Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, Before Tax, With Accumulated Unrealized Loss Options exercisable, weighted-average remaining contractual term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Operating leases, net Increase (Decrease) in Operating Lease Liability Document Type Document Type Significant unobservable inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Name Outstanding Recovery, Individual Name Additional paid-in capital Additional Paid in Capital Office equipment Office Equipment [Member] Product and Service [Axis] Product and Service [Axis] Proceeds from issuance of shares under ATM program, net of issuance costs Proceeds from Issuance of Common Stock Collaborative Arrangement, Transaction with Party to Collaborative Arrangement Collaborative Arrangement, Transaction with Party to Collaborative Arrangement [Member] All Individuals All Individuals [Member] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Tax incentive receivable Tax Incentive Receivable, Current Tax Incentive Receivable, Current Fair Value Disclosures [Abstract] Vested and expected to vest at end of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Name Forgone Recovery, Individual Name Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Underwriter Offering Underwriter Offering [Member] Underwriter Offering Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Karen Anderson [Member] Karen Anderson Payment of employee withholding taxes related to withheld shares for stock based compensation plans Payment, Tax Withholding, Share-Based Payment Arrangement Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Other comprehensive (loss) income: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Alternative [Abstract] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Current liabilities: Liabilities, Current [Abstract] Weighted-Average Remaining Contractual Term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Vesting of ordinary shares (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options and Restricted Stock Units, Vested in Period Share-based Compensation 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Date Current Fiscal Year End Date Class of Stock [Axis] Class of Stock [Axis] Expected term Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Weighted-Average Grant Date Fair Value Per Share Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Shares available for grant (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Statement [Table] Statement [Table] Other non-operating income (expense), net Other Nonoperating Income (Expense) Change in deferred taxes Deferred Income Tax Expense (Benefit) Adjustments to reconcile net loss to net cash used in operating 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Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Antidilutive securities excluded from computation of diluted weighted-average ordinary shares outstanding (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount All Adjustments to Compensation All Adjustments to Compensation [Member] Amendment Flag Amendment Flag 2028 Long-Term Debt, Maturity, Year Two Termination Date Trading Arrangement Termination Date Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] Transferable contingent value Common Stock, Transferable Contingent Value Common Stock, Transferable Contingent Value Value added tax receivable Value Added Tax Receivable Schedule of Stock Option Activity Share-Based Payment Arrangement, Option, Activity [Table 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