75000 - Document - Document and Entity Information link:presentationLink link:calculationLink link:definitionLink 75010 - Statement - Condensed Consolidated Balance Sheets (Unaudited) link:presentationLink link:calculationLink link:definitionLink 75020 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 75030 - Statement - Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) link:presentationLink link:calculationLink link:definitionLink 75040 - Statement - Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 75050 - Statement - Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) link:presentationLink link:calculationLink link:definitionLink 75060 - Statement - Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 75070 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited) link:presentationLink link:calculationLink link:definitionLink 75080 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 995455 - Disclosure - Nature of the Business link:presentationLink link:calculationLink link:definitionLink 995465 - Disclosure - Summary of Significant Accounting Policies link:presentationLink link:calculationLink link:definitionLink 995475 - Disclosure - Merger with AlloVir link:presentationLink link:calculationLink link:definitionLink 995485 - Disclosure - Marketable Securities link:presentationLink link:calculationLink link:definitionLink 995495 - Disclosure - Fair Value Measurements link:presentationLink link:calculationLink link:definitionLink 995505 - Disclosure - Balance Sheet Components link:presentationLink link:calculationLink link:definitionLink 995515 - Disclosure - Significant Agreements link:presentationLink link:calculationLink link:definitionLink 995525 - Disclosure - Convertible Promissory Notes link:presentationLink link:calculationLink link:definitionLink 995535 - Disclosure - Leases link:presentationLink link:calculationLink link:definitionLink 995545 - Disclosure - Commitments and Contingencies link:presentationLink link:calculationLink link:definitionLink 995555 - Disclosure - Redeemable Convertible Preferred Stock link:presentationLink link:calculationLink link:definitionLink 995565 - Disclosure - Stockholders' Equity (Deficit) link:presentationLink link:calculationLink link:definitionLink 995575 - Disclosure - Stock-Based Compensation link:presentationLink link:calculationLink link:definitionLink 995585 - Disclosure - Net Loss Per Share Attributable to Common Stockholders link:presentationLink link:calculationLink link:definitionLink 995595 - Disclosure - Related Parties link:presentationLink link:calculationLink link:definitionLink 995605 - Disclosure - Defined Contribution Plan link:presentationLink link:calculationLink link:definitionLink 995615 - Disclosure - Segment Reporting link:presentationLink link:calculationLink link:definitionLink 995625 - Disclosure - Subsequent Events link:presentationLink link:calculationLink link:definitionLink 995635 - Disclosure - Summary of Significant Accounting Policies (Policies) link:presentationLink link:calculationLink link:definitionLink 995645 - Disclosure - Merger with AlloVir (Tables) link:presentationLink link:calculationLink link:definitionLink 995655 - Disclosure - Marketable Securities (Tables) link:presentationLink link:calculationLink link:definitionLink 995665 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 995675 - Disclosure - Balance Sheet Components (Tables) link:presentationLink link:calculationLink link:definitionLink 995685 - Disclosure - Leases (Tables) link:presentationLink link:calculationLink link:definitionLink 995695 - Disclosure - Stockholders' Equity (Deficit) (Tables) link:presentationLink link:calculationLink link:definitionLink 995705 - Disclosure - Stock-Based Compensation (Tables) link:presentationLink link:calculationLink link:definitionLink 995715 - Disclosure - Net Loss Per Share Attributable to Common Stockholders (Tables) link:presentationLink link:calculationLink link:definitionLink 995725 - Disclosure - Segment Reporting (Tables) link:presentationLink link:calculationLink link:definitionLink 995735 - Disclosure - Nature of the Business - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995745 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995755 - Disclosure - Merger with AlloVir - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995765 - Disclosure - Merger with AlloVir - Schedule of Number of Shares Common Stock Issued and Outstanding (Details) link:presentationLink link:calculationLink link:definitionLink 995775 - Disclosure - Marketable Securities - Summary of Amortized Cost and Estimated Fair Value of Marketable Securities (Details) link:presentationLink link:calculationLink link:definitionLink 995785 - Disclosure - Marketable Securities - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995795 - Disclosure - Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis (Details) link:presentationLink link:calculationLink link:definitionLink 995805 - Disclosure - Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis (Parenthetical) (Details) link:presentationLink link:calculationLink link:definitionLink 995815 - Disclosure - Fair Value Measurements - Summary of Estimated Fair Value of Derivative Liabilities Related to Redemption Features (Details) link:presentationLink link:calculationLink link:definitionLink 995825 - Disclosure - Fair Value Measurements - Summary of Estimated Fair Value Assumptions (Details) link:presentationLink link:calculationLink link:definitionLink 995835 - Disclosure - Fair Value Measurements - Summary of Aggregate Fair Values of Outstanding Level 3 Financial Instruments (Details) link:presentationLink link:calculationLink link:definitionLink 995845 - Disclosure - Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) link:presentationLink link:calculationLink link:definitionLink 995855 - Disclosure - Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 995865 - Disclosure - Significant Agreements - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995875 - Disclosure - Convertible Promissory Notes - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995885 - Disclosure - Leases - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995895 - Disclosure - Leases - Schedule of Operating Lease on Its Consolidated Balance Sheet (Details) link:presentationLink link:calculationLink link:definitionLink 995905 - Disclosure - Leases - Schedule of Components of Lease Cost (Details) link:presentationLink link:calculationLink link:definitionLink 995915 - Disclosure - Leases - Schedule of Future Minimum Annual Lease Commitments under Non-cancellable Operating Leases (Details) link:presentationLink link:calculationLink link:definitionLink 995925 - Disclosure - Leases - Schedule of Future Minimum Annual Lease Commitments under Non-cancellable Operating Leases (Details) 2 link:presentationLink link:calculationLink link:definitionLink 995935 - Disclosure - Commitments and Contingencies - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995945 - Disclosure - Redeemable Convertible Preferred Stock - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995955 - Disclosure - Stockholders' Equity (Deficit) - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995965 - Disclosure - Stockholders' Equity (Deficit) - Schedule of Common Stock Reserved for Future Issuance (Details) link:presentationLink link:calculationLink link:definitionLink 995975 - Disclosure - Stock-Based Compensation - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 995985 - Disclosure - Stock-Based Compensation - Summary of Stock Option Activity (Details) link:presentationLink link:calculationLink link:definitionLink 995995 - Disclosure - Stock-Based Compensation - Summary of RSAs Activity (Details) link:presentationLink link:calculationLink link:definitionLink 996005 - Disclosure - Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) link:presentationLink link:calculationLink link:definitionLink 996015 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Computation Of Basic And Diluted Net Loss Per Share Attributable To Common Stockholders (Details) link:presentationLink link:calculationLink link:definitionLink 996025 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 996035 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Potential Dilutive Securities Excluded From Computation Of Diluted Net Loss Per Share Attributable To Common Stockholders (Details) link:presentationLink link:calculationLink link:definitionLink 996045 - Disclosure - Net Loss Per Share Attributable to Common Stockholders - Potential Dilutive Securities Excluded From Computation Of Diluted Net Loss Per Share Attributable To Common Stockholders (Parenthetical) (Details) link:presentationLink link:calculationLink link:definitionLink 996055 - Disclosure - Related Parties - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 996065 - Disclosure - Segment Reporting - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 996075 - Disclosure - Segment Reporting - Summary of Segment Loss (Details) link:presentationLink link:calculationLink link:definitionLink Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Vested Other Research and Development Expense Other research and development costs Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Liabilities Accounts Payable and Accrued Expenses Business combination recognized identifiable assets acquired and liabilities assumed current liabilities accounts payable and accrued expenses. Accounts payable and accrued expenses 2022 Notes Twenty Twenty Two Bridge Notes [Member] Twenty twenty two bridge notes Entity Incorporation, State or Country Code Entity Incorporation State Country Code Premium On Issuance Of Convertible Promissory Notes Premium on issuance of convertible promissory notes Premium on issuance of convertible promissory notes (including $0 and $169 for a related party) Preferred stock issued Preferred Stock, Shares Issued Statement of Financial Position Location, Balance [Domain] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Balance, Beginning Balance, Ending Accounts payable Increase (Decrease) in Accounts Payable Plan Name [Axis] Plan Name Kalaris therapeutics, inc. Kalaris Therapeutics, Inc. [Member] Kalaris Therapeutics, Inc. Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Available-for-sale securities in continuous unrealized loss position for greater than 12 months Equity [Abstract] Payments for Tenant Improvements Tenant improvement allowance Entity Current Reporting Status Entity Current Reporting Status CDMO, CRO and Other Third-party Preclinical Studies, Clinical Trials and Consulting Costs CDMO, CRO and Other Third-party Preclinical Studies, Clinical Trials and Consulting Costs Fair Value, Inputs, Level 2 [Member] Level 2 Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Change In Fair Value Of Derivative Liability Change in fair value of derivative liability. Change in fair value of derivative liability Change in fair value of derivative liabilities (including $0 and $1,165 for a related party) Change in fair value of derivative liabilities (including $0 and $1,165 for a related party) Common Stock, Shares Authorized Common stock, shares authorized Prepaid Research and Development Expenses Prepaid research and development expenses. Prepaid research and development expenses Temporary Equity, Par or Stated Value Per Share Price per share Redeemable convertible preferred stock, par or stated value per share Fair Value by Liability Class [Domain] Document Fiscal Period Focus Document Fiscal Period Focus Twenty Twenty Three Bridge Notes [Member] Twenty twenty three bridge notes 2023 Notes Difference between the fair value at the issuance date and the principal amount of the note Debt Instrument Premium Discount Amount Debt instrument premium discount amount. Debt Instrument, Interest Rate, Stated Percentage Interest rate Entity Shell Company Entity Shell Company Temporary Equity, Shares Outstanding Temporary Equity Balance, Shares Temporary Equity Balance, Shares Redeemable Convertible Preferred Stock, Shares Outstanding Redeemable convertible preferred stock, shares outstanding Business Combination, Consideration Transferred, Equity Interest [Table] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances Initial fair value at issuance Segment Reporting, Policy [Policy Text Block] Segment information Cash and Cash Equivalent Cash and cash equivalents Gain (Loss) On Issuance Of Convertible Promissory Notes Gain (loss) on issuance of convertible promissory notes. Loss on issuance of convertible promissory notes Loss on issuance of convertible promissory notes (including $0, $1,341, $169 and $2,134 for a related party respectively) Percentage of Maximum Payroll Deductions of Base Salary or Wages Percentage of maximum payroll deductions of base salary or wages. Percentage of payroll deductions of base salary or wages Share Based Compensation Arrangement by Share Based Payment Award, Options, Exercised in Period, Weighted Average Fair Value Share based compensation arrangement by share based payment award, options, exercised in period, weighted average fair value. Weighted-average fair value of options exercised per share Subsidiary, Sale of Stock [Line Items] Common Stock, Shares, Issued Common stock, shares issued Common Stock, Shares, Issued, Total Common stock, shares issued Short-Term Debt [Table] Asset Class [Domain] Royalty Expiration Period Royalty expiration period. Royalty expiration period Statement [Table] Statement [Table] Proceeds from Issuance of Redeemable Convertible Preferred Stock Gross cash proceeds Proceeds from the issuance of redeemable convertible preferred stock, net of issuance costs Restricted Cash, Noncurrent Restricted cash Royalty Obligation - Related Party Royalty Obligation Related Party [Policy Text Block] Royalty obligation related party. Conversion of convertible promissory notes into common stock in connection with the Merger Shares Issued During Period Value Conversion of Convertible Promissory Notes into Common Stock at Acquisition Shares issued during period value conversion of convertible promissory notes into common stock at acquisition. Operating Income (Loss) [Abstract] Operating expenses: First And Second Tranches [Member] First And Second Tranches First and Second Tranches Share-Based Compensation Arrangement by Share-Based Payment Award, Purchase Price of Common Stock, Percent Estimated fair market value of underlying common stock Statement [Line Items] Statement [Line Items] Business Combination [Domain] Entity Filer Category Entity Filer Category Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Number of Shares Liabilities and Equity Total liabilities and stockholders' equity Payables and Accruals [Abstract] Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted Average Exercise Price Per Share, Options Exercisable, March 31, 2026 Business Combination, Voting Equity Interest Acquired, Percentage Equity own percentage Lessee, Operating Lease, Option to Terminate Operating lease, option to terminate description Cash and Cash Equivalents, Fair Value Disclosure Cash equivalents Shares Issued, Price Per Share Offering price per share Debt Securities, Available for Sale, Accumulated Gross Unrealized Loss, before Tax Current Debt securities, available-for-sale, accumulated gross unrealized loss, before tax current. Unrealized Losses Short-term Third Tranches [Member] Third Tranches Third Tranches Lessee Operating Lease Termination Penalty Lessee operating lease termination penalty. Termination penalty Stock Options Summary of significant accounting policies. Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Derivative Liability, Measurement Input Derivative liabilities Debt Securities, Available-for-Sale, Noncurrent Estimated Fair Value Long-term Long-term marketable securities Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash LeaseTerminate Month and Year Lease Termination Month And Year Lease termination month and year. Interest rate Debt Instrument, Interest Rate During Period Related Party [Member] Related Party Defined Contribution Plan [Text Block] Defined Contribution Plan Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies Compensation Payable Percentage Percentage of aggregate compensation payable. Aggregate compensation payable percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Number of options, granted Number of Shares, Options granted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Computation Of Basic And Diluted Net Loss Per Share Attributable To Common Stockholders Sale of Securities Consideration Received on Transaction Sale of securities consideration received on transaction. Sale of securities, offering price Net Proceeds From Issuance Of Private Placement Net proceeds from issuance of private placement. Net proceeds from issuance of private placement Net loss per share - basic Net loss per share - basic Earnings Per Share, Basic, Total Net loss per share attributable to common stockholders - basic Class Of Warrant Or Right, Exercised Warrants Or Rights Class of warrant or right, exercised warrants or rights. Pre-Funded Warrants exercised Significant Agreements [Table] Significant agreements. Change In Fair Value Of Tranche Liability Change in fair value of tranche liability. Change in fair value of tranche liability Change in fair value of tranche liability (including $0 and $331 for a related party) Change in fair value of tranche liability (including $0 and $331 for a related party) Liabilities, Current Total current liabilities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Adjustments to reconcile net loss to net cash used in operations: Salary and Wage, Excluding Cost of Good and Service Sold Salary and Wage, Excluding Cost of Good and Service Sold, Total Base salary or wages Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Summary of Aggregate Fair Values of Outstanding Level 3 Financial Instruments Loss On Extinguishment And On Issuance Of Convertible Promissory Notes Loss on extinguishment and on issuance of convertible promissory notes. Loss on extinguishment and on issuance of convertible promissory notes Loss on extinguishment and on issuance of convertible promissory notes (including $0 and $169 for a related party) Conversion of redeemable convertible preferred stock into common stock in connection with the Merger, Shares Shares Issued During Period Shares Conversion of Redeemable Convertible Preferred Stock into Common Stock at Acquisition Shares issued during period shares conversion of redeemable convertible preferred stock into common stock at acquisition. Accounting Standards Update [Axis] Equity, Attributable to Parent [Abstract] Stockholders' equity: Entity Small Business Entity Small Business Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Accumulated deficit Retained Earnings (Accumulated Deficit), Total Accumulated deficit Nature of Operations [Text Block] Nature of the Business Preferred Stock [Member] Preferred Stock Subsidiary or Equity Method Investee, Sale of Stock, Type [Table] Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period Number of options, Options cancelled Number of Shares, Options cancelled Sale of Stock, Price Per Share Share issued, average price per share Common stock price per share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value Aggregate Intrinsic Value, Options exercised Share-Based Payment Arrangement [Text Block] Stock-Based Compensation Organization, Consolidation and Presentation of Financial Statements [Abstract] Leases [Abstract] Options Grants under Equity Plans Options Grants under Equity Plans [Member] Options grants under equity plans. Maximum lease tenant improvement allowance Maximum Lease Tenant Improvement Allowance Maximum lease tenant improvement allowance. Amendment Flag Amendment Flag Loss Contingencies [Line Items] Twenty Twenty Four And Twenty Twenty Five Bridge Notes [Member] Twenty Twenty Four And Twenty Twenty Five Bridge Notes 2024 Bridge Notes and 2025 Bridge Notes Warrants exercised date Class of Warrant or Right, Date from which Warrants or Rights Exercisable Class of Warrant or Right, Number of Securities Called by Warrants or Rights Warrants to purchase aggregate share of common stock Warrants to purchase common stock Earnings Per Share, Policy [Policy Text Block] Net Loss Per Share Attributable to Common Stockholders Liabilities and Equity [Abstract] Liabilities and stockholders’ equity Entity Address, Postal Zip Code Entity Address Postal Zip Code Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Net cash used in operating activities Cash flows from operating activities Cash flows from operating activities Increase (Decrease) in Operating Lease Liability Operating lease liabilities Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description Common Stock [Member] Common Stock Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted Average Exercise Price Per Share, Options granted Lessee, Operating Lease, Liability, to be Paid, Year Three 2029 Amortization of Debt Discount (Premium) Amortization of debt discount Debt Securities, Available-for-Sale [Line Items] Entity Address, Address Line One Entity Address Address Line1 Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV Securities Purchase Agreement [Member] Securities Purchase Agreement [Member] Securities Purchase Agreement Earnings Per Share [Abstract] Income Tax, Policy [Policy Text Block] Income Taxes Temporary Equity, Carrying Amount, Attributable to Parent Temporary Equity Balance Temporary Equity Balance Redeemable Convertible Preferred Stock, Net Carrying Value Redeemable convertible preferred stock, $0.00001 par value, no shares authorized, issued and outstanding as of September 30, 2025; 75,151,340 shares authorized as of December 31, 2024; 43,151,340 shares issued and outstanding as of December 31, 2024; liquidation preference of $0 as of September 30, 2025 Supplemental Cash Flow Information [Abstract] Supplemental disclosure of cash flow information: Foreign Currency Transactions and Translations Policy [Policy Text Block] Foreign Currency Transactions Capitalized Software Implementation Costs, Policy [Policy Text Block] Capitalized software implementation costs policy. Capitalized Software Implementation Costs Stockholders' Equity Note, Redeemable Preferred Stock, Issue, Policy [Policy Text Block] Redeemable Convertible Preferred Stock Agreement of settlement resolving the claims in the Securities Class Action subject to Court approval Loss Contingency Settlement Agreement Amount Loss contingency settlement agreement amount. Statement of Financial Position Location, Balance [Axis] Management Fee Expense Consulting fees Operating Lease, Right-of-Use Asset Operating lease right-of-use assets Purchases of marketable securities Payments to Acquire Debt Securities, Available-for-Sale Class of Warrant or Right [Axis] Document Type Document Type Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Short-Term Investments [Abstract] Short-term marketable securities: Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Entity Central Index Key Entity Central Index Key Debt Securities, Available-for-Sale [Table Text Block] Summary of Amortized Cost and Estimated Fair Value of Marketable Securities In-kind services In kind Services In kind services Investments, Debt and Equity Securities [Abstract] Business Acquisition Equity Interests Number Of Shares Issued and Outstanding Business acquisition equity interests number of shares issued and outstanding. Total Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Net (decrease) increase in cash and cash equivalents and restricted cash Subsequent Event Type [Domain] Business Acquisition Equity Interests Outstanding Business acquisition equity interests outstanding. AlloVir's common stock outstanding Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive securities excluded from computation of earnings per share Balance Sheet Related Disclosures [Abstract] Business Combination, Consideration Transferred, Equity Interest, Type [Domain] Common Stock, Par or Stated Value Per Share Common stock, par value Accounting Standards Update [Domain] Royalities Due Royalities due. Royalities due Liabilities [Abstract] Liabilities: Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted Average Remaining Contractual Term (in years), Options outstanding Debt Securities, Available-for-Sale, Amortized Cost Amortized Cost, Total Amortized Cost Workers' Compensation Liability, Current Accrued compensation expense Stock Available For Grant Stock available for grant. Stock Available For Grant [Member] Debt Securities, Available-for-Sale Estimated Fair Value Estimated Fair Value Marketable securities Samsara [Member] Samsara. Samsara Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Number of Shares, Options exercised Proceeds from exercise of stock options, Shares Number of Shares, Options exercised General and Administrative Personnel Expenses General and administrative personnel expenses. General and administrative personnel expenses Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested, Number of Shares Number of Shares, Options outstanding, Beginning Balance Number of Shares, Options outstanding, Ending Balance Debt Disclosure [Abstract] Potential milestone payment upon achievement of development and regulatory milestones Potential Milestone Payment Upon Achievement Of Development And Regulatory Milestones Potential milestone payment upon achievement of development and regulatory milestones. Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Current Fiscal Year End Date Current Fiscal Year End Date Document Quarterly Report Document Quarterly Report Offering period, description Offering Period, Description Offering Period, description. Excess Stock, Shares Authorized Maximum aggregate number of shares of stock issued Entity Address, State or Province Entity Address State Or Province Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Restricted Stock Awards, Unvested as of March 31, 2026 Restricted Stock Awards, Unvested as of December 31, 2025 Total premium on debt Total Premium on Debt Total premium on debt. Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock outstanding Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive loss Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Unrealized Gains Research and Development Expense, Policy [Policy Text Block] Research and Development Expenses Common Stock, Capital Shares Reserved for Future Issuance Reserved shares of common stock for issuance Total shares reserved for future issuance Class of Warrant or Right [Domain] Business Combination, Transaction Cost, Excluding Separately Recognized Transaction Transaction costs Remaining contractual maturities of available-for-sale securities Debt Securities, Available for Sale Remaining Contractual Maturity Period Debt securities, available for sale remaining contractual maturity period. Other general and administrative expenses Other General and Administrative Expense Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Schedule of Stock-based Compensation Expense Short-term investments maturity period. Short Term Investments Maturity Period Short-term investments maturity period Stock Issued During Period, Value, Stock Options Exercised Issuance of common stock upon stock option exercises Proceeds from exercise of stock options Comprehensive Income, Policy [Policy Text Block] Comprehensive Loss Collaborative Arrangement Disclosure [Text Block] Significant Agreements Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive income (loss): Percentage of Discount Rate Percentage of discount rate. Percentage of discount rate Subsequent Event Subsequent Event [Member] Marketable Securities, Policy [Policy Text Block] Marketable Securities Other Assets, Noncurrent Other Assets, Noncurrent, Total Other non-current assets Measurement Input, Expected Term [Member] Expected Term (in years) Debt Securities, Available-for-Sale, Current Estimated Fair Value Short-term Short-term marketable securities Antidilutive Securities [Axis] Antidilutive Securities Business Combination, Recognized Asset Acquired, Prepaid Expense and Other Asset, Current Prepaid expenses and other current assets Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent Amortized Cost Long-term Amortized Cost Long-term Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Award vesting percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Aggregate Intrinsic Value, Vested and expected to vest, March 31, 2026 Interest Expense, Debt, Total Interest Expense, Debt Interest expense Former President [Member] Former president Former President AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) Cash and Cash Equivalents [Domain] Cash and Cash Equivalents Lessee, Operating Lease, Option to Extend Lease extend term description Minimum [Member] Minimum Financial Instrument [Axis] Financial Instrument Second Tranches [Member] Second Tranches Second Tranches Assets, Current [Abstract] Current assets: Merger agreement date. Merger Agreement Date Merger agreement date Accrued Professional and Legal Costs Accrued professional and legal costs. Accrued professional and legal costs Conversion of convertible promissory notes into common stock in connection with the Merger, Shares Shares Issued During Period Shares Conversion of Convertible Promissory Notes into Common Stock at Acquisition Shares issued during period shares conversion of convertible promissory notes into common stock at acquisition. Fair Value, Inputs, Level 3 [Member] Level 3 Deferred Transaction And Financing Issuance Costs Included In Accounts Payable And Accrued Expenses And Other Current Liabilities Deferred transaction and financing issuance costs included in accounts payable and accrued expenses and other current liabilities. Deferred transaction and financing issuance costs included in accounts payable and accrued expenses and other current liabilities Conversion Price Discount Rate Conversion Price Discount Rate Per share price paid by investors Segment Reporting [Abstract] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Business Combination [Policy Text Block] Acquisitions Liabilities, Current [Abstract] Current liabilities: Related Party Transactions [Abstract] Business Combination, Consideration Transferred, Equity Interest, Type [Axis] Business services agreement term Related Party Transaction, Business Services Agreement Term Related party transaction, business services agreement term. Shares, Outstanding Balance, Shares Balance, Shares Derivative liabilities [Member] Derivative liabilities. Derivative Liabilities Lessee, operating lease, renewal term Lessee, Operating Lease, Renewal Term One-time cash milestone payment upon event of liquidity One Time Cash Milestone Payment Upon Event Of Liquidity One-time cash milestone payment upon event of liquidity. Lessee, Leases [Policy Text Block] Leases AlloVir Note [Member] AlloVir Note AlloVir Note Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Unvested as of March 31, 2026 Weighted Average Grant Date Fair Value, Unvested as of December 31, 2025 General and Administrative Expense [Member] General and Administrative Total lease liabilities Operating Lease, Liability Present value of operating lease liabilities Capitalized software implementation costs Capitalized Computer Software, Net Pre-Funded Warrants [Member] Pre-Funded Warrants. Pre-Funded Warrants Marketable Securities, Noncurrent Long-term marketable securities 2019 Stock Option and Grant Plan Two Thousand Nineteen Stock Option And Grant Plan [Member] 2019 Stock Option And Grant Plan. Liabilities, Noncurrent [Abstract] Noncurrent Liabilities: Accrued Research And Development Expenses, Current Accrued research and development expenses current. Accrued research and development expenses Business Acquisition Equity Interest Restricted Stock Units Accelerated and Settled Business acquisition equity interest restricted stock units accelerated and settled. AlloVir's restricted stock units accelerated and settled in common stock Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net loss Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent Cash and cash equivalents Loss Contingencies [Table] Weighted-average common shares outstanding - basic Weighted-average shares outstanding - basic Weighted-average common shares outstanding Series B two Redeemable Convertible Preferred Stock [Member] Series B two redeemable convertible preferred stock. Series B-2 Series B-2 Redeemable Convertible Preferred Stock Stock-Based Compensation Expense Share-Based Payment Arrangement, Director [Policy Text Block] Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value Aggregate Intrinsic Value, Exercisable, March 31, 2026 Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Subsequent Events Subsequent Events [Text Block] Related Party Transactions Disclosure [Text Block] Related Parties APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition, Total Stock-based compensation expense Equity, Attributable to Parent Balance Balance Total stockholders' equity Preferred Stock, Par or Stated Value Per Share Preferred stock, par or stated value per share Preferred stock, par value Basis of Accounting, Policy [Policy Text Block] Basis of Presentation Consultant [Member] Consultant. Consultant Statement of Stockholders' Equity [Abstract] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] AlloVir [Member] AlloVir. AlloVir Percentage of common stock issued Percentage Of Common Stock Issued Percentage of common stock issued. Use of Estimates, Policy [Policy Text Block] Use of Estimates Debt Instruments, Maturity Date Debt Instruments, Maturity Date Maturity date Entity Address, Address Line Two Entity Address, Address Line Two Fair Value Disclosures [Text Block] Fair Value Measurements Agreement Termination Written Notice Period Agreement termination written notice period. Agreement termination written notice period Potential gross proceeds from sale of equity securities Potential Gross Proceeds From Sale Of Equity Securities Potential gross proceeds from sale of equity securities. Debt Instrument, Name [Domain] Measurement Input, Discount Rate [Member] Discount Rate Sublicense Fee Percentage After First Dose Sublicense fee percentage after first dose. Sublicense fee percentage after first dose Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration] Other segment items Segment Reporting, Other Segment Item, Amount Plan Name [Domain] Plan Name University Of California San Diego [Member] University Of California San Diego. University of California, San Diego Interest Expense, Operating and Nonoperating Interest Expense, Operating and Nonoperating, Total Interest expense (including $1,384 and $78 for a related party) Interest expense Interest expense (including $1,384 and $78 for a related party) 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] Patent costs. Patent Costs Patent Costs [Policy Text Block] Deferred Charges, Policy [Policy Text Block] Deferred transaction costs Other Non-current Assets Other Noncurrent Assets [Member] Significant agreements. Significant Agreements [Abstract] Related and Nonrelated Parties [Axis] Related Party Property, Plant and Equipment, Policy [Policy Text Block] Property and Equipment, Net Preferred Stock, Convertible, Conversion Ratio Conversion ratios Weighted Average Number of Shares, Common Stock Subject to Repurchase or Cancellation Less: Weighted-average common shares subject to repurchase Entity Address, City or Town Entity Address City Or Town Number of Reportable Segments Number of reportable segments Security Exchange Name Security Exchange Name At The Market Offering [Member] At the market offering. At-the-Market Offering Counterparty Name [Axis] Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Number of Shares, Vested and expected to vest, March 31, 2026 Reimbursement Of Patent Costs Incurred Reimbursement of patent costs incurred. Reimbursement of patent costs incurred Measurement Input Type [Domain] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name Stockholders' Equity Note [Abstract] Debt Instrument, Increase, Accrued Interest Accrued interest Related Party Transaction, Business Services Agreement Terminated Period Related party transaction, business services agreement terminated period. Business services agreement terminated period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Total cash, cash equivalents and restricted cash, at end of the period Pre-Funded Warrant Notice Period Pre-funded warrant notice period. Pre-funded warrant notice period Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Statistical Measurement [Domain] Measurement Input, Probability of achievement [Member] Measurement Input, Probability of achievement. Probability of Achievement Exercise price per share Exercise Price per Share Purchase price Assets, Current Total current assets Total stock-based compensation expense Stock-based compensation expense Stock-based compensation expense Business Acquisition Director's and Officer's Insurance Recognized Business acquisition director's and officer's insurance recognized. Director's and officer's insurance recognized Document Period End Date Document Period End Date Title and Position [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV Related party Tranche liability fair value disclosure Related party tranche liability fair value disclosure. Tranche liability for a related party Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number Number of Shares, Exercisable, March 31, 2026 Convertible Promissory Note [Member] Convertible promissory note. 2024 Convertible Promissory Note Statement of Financial Position [Abstract] Restricted Stock Units (RSUs) [Member] Restricted Stock Units Redeemable Convertible Preferred Stock Redeemable Convertible Preferred Stock [Member] Other Accrued Expenses and Other Current Liabilities Other accrued expenses and other current liabilities. Other accrued expenses and other current liabilities Other prepaid expenses and other current assets Other Prepaid Expenses and Other Current Assets Other prepaid expenses and other current assets. Antidilutive Security, Excluded EPS Calculation [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract] Reconciliation of cash, cash equivalents and restricted cash: Class of Stock [Axis] Tranches [Member] Tranches Tranche Liabilities Total liabilities Financial Instruments [Domain] Financial Instruments Initial Cash Consideration Initial Cash Consideration Initial cash consideration Lessee, Operating Lease, Liability, to be Paid, Year Two 2028 Restricted Cash Restricted cash Restricted Stock [Member] Restricted Common Stock Restricted Stock Prepaid Expense and Other Assets, Current [Abstract] Weighted-average common shares outstanding - diluted Weighted-average common shares outstanding - diluted Weighted-average shares outstanding - diluted Securities Act File Number Entity File Number Royalty Obligation Due To Related Party, Noncurrent Royalty obligation due to related party, noncurrent. Royalty obligation - related party License Maintenance Payments First Four Anniversaries License maintenance payments first four anniversaries. License maintenance payments for first four anniversaries Short-term investments. Short Term Investments Policy [Text Block] Short-Term Investments OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Unrealized loss on marketable securities, net of tax Cover [Abstract] Measurement Input Type [Axis] Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Total prepaid expenses and other current assets Issuance of Series B-2 redeemable convertible preferred stock upon conversion of convertible promissory notes in connection with the Merger Temporary Equity Issuance of Redeemable Convertible Preferred Stock Value upon Conversion of Convertible Promissory Notes at Acquisition Temporary equity issuance of redeemable convertible preferred stock value upon conversion of convertible promissory notes at acquisition. Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Outstanding Stock Maximum Cumulative increase in number shares reserved for issuance, percentage Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Number of Operating Segments Number of operating segments Sale of Stock [Domain] Sale of Stock Restricted Stock Awards And Unvested Founders' Shares [Member] Restricted stock awards and unvested founders’ shares . Restricted Stock Awards and Unvested Founders' Shares Segment Reporting Disclosure [Text Block] Segment Reporting General and Administrative Expense, Total General and administrative personnel expenses General and administrative expenses General and administrative (including $73 and $151 for a related party) December Two Thousand Twenty Five Private Placement [Member] December Two Thousand Twenty Five Private Placement. December 2025 Private Placement Stock Issued During Period, Shares, Acquisitions Recognition of AlloVir common stock outstanding at the closing of the Merger, Shares Two Thousand and Nineteen Equity Incentive Plan [Member] Two thousand and nineteen equity incentive plan. 2019 Plan Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) Recognized gain for change in fair value of tranche liability Debt Instrument, Convertible, Conversion Price Conversion price per share Letter of credit in favor of lessor Letter of Credit in Favor of Lessor Letter of credit in favor of lessor. Payment of Deferred Transaction Costs and Issuance Costs Payment of deferred transaction costs and issuance costs. Payment of deferred transaction costs and issuance costs Loss on issuance of convertible promissory notes Gain (Loss) on Extinguishment of Debt Gain (Loss) on Extinguishment of Debt, Total Share-Based Compensation Arrangement by Share-Based Payment Award, Option, Nonvested, Weighted Average Exercise Price Share-Based Compensation Arrangement by Share-Based Payment Award, Option, Nonvested, Weighted Average Exercise Price, Ending Balance Share-Based Compensation Arrangement by Share-Based Payment Award, Option, Nonvested, Weighted Average Exercise Price, Beginning Balance Exercise price per share unvested and unexercised Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted Average Exercise Price Per Share, Options Vested and expected to vest, March 31, 2026 Accrued expenses and other current liabilities Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities. Total accrued expenses and other current liabilities Accrued expenses and other current liabilities (including $73 and $67 due to a related party) Debt Securities, Available For Sale, Accumulated Gross Unrealized Loss, Before Tax Non Current Debt securities, available-for-sale, accumulated gross unrealized loss, before tax non current. Unrealized Losses Long-term Property, Plant and Equipment, Useful Life Estimated useful life New Accounting Pronouncements, Policy [Policy Text Block] Recently Issued Accounting Pronouncements Not Yet Adopted Minimum percentage of voting stock Minimum Percentage of Voting Stock Minimum percentage of voting stock. Schedule of Future Minimum Annual Lease Commitments under Non-cancellable Operating Leases Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Sales agent commissions percentage Sales Agent Commissions Percentage Sales agent commissions percentage. Depreciation expense Depreciation Depreciation, Total Redeemable Convertible Preferred Stock Redeemable Convertible Preferred Stock [Text Block] Redeemable convertible preferred stock. Available for Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Current Available for sale debt securities accumulated gross unrealized gain before tax current. Unrealized Gains Short-term Twenty Twenty Four Bridge Notes [Member] Twenty Twenty Four Bridge Notes 2024 Bridge Notes 2024 Notes Aggregate Advance Aggregate advance. Aggregate advance Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common stock, shares outstanding Operating Lease, Liability, Current Operating lease liability, current Operating lease liabilities, current Document Transition Report Document Transition Report Short-Term Investments Short-Term Investments, Total Short-term investments Short-term marketable securities Operating Expenses Total operating expenses Research and Development Expense Research and development expenses Research and development (including $15 and $13 for a related party) Temporary equity, issuance costs Temporary Equity Stock Issued Issuance Costs Temporary equity stock issued issuance costs. Lessee, Operating Leases [Text Block] Leases Conversion of Stock, Amount Issued Conversion of redeemable convertible preferred stock shares into common stock in connection with the Merger Debt Securities, Available-for-Sale, Amortized Cost, Current Amortized Cost Short-term Amortized Cost Short-term Statement of Cash Flows [Abstract] Prepaid Insurance and Other Current Assets Prepaid Insurance and other current assets. Prepaid insurance and other current assets Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted Average Grant Date Fair Value Stock Issued During Period, Value, New Issues Issuance of common stock in public offering, net of underwriting discounts, commissions and offering costs Issuance of shares Share-Based Payment Arrangement, Option, Activity [Table Text Block] Summary of Stock Option Activity Unvested restricted stock. Unvested Restricted Stock [Member] Unvested Restricted Stock Equity [Text Block] Stockholders' Equity (Deficit) Earnings Per Share [Text Block] Net Loss Per Share Attributable to Common Stockholders Temporary Equity [Line Items] Net loss Net loss Total fair value at issuance of derivative instrument Total Fair Value At Issuance Of Derivative Instrument Total fair value at issuance of derivative instrument. Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Aggregate Intrinsic Value, Options outstanding at January 1, 2024 Aggregate Intrinsic Value, Options outstanding, Beginning Balance Aggregate Intrinsic Value, Options outstanding, Ending Balance First Tranches First Tranches First Tranches [Member] Operating Lease, Cost Operating lease cost Operating Lease, Payments Cash payments for measurement of lease liabilities Assets [Abstract] Assets Assets: Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expense and other current assets Prepaid Professional and Legal Costs Prepaid professional and legal costs. Prepaid professional and legal costs Document Fiscal Year Focus Document Fiscal Year Focus Debt Instrument, Measurement Input Tranche liability Common shares issued for conversion of debt Debt Conversion, Converted Instrument, Shares Issued Sublicense Fee Percentage within One Year Sublicense fee percentage within one year. Sublicense fee percentage within one year Change in fair value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease), Total Convertible Promissory Notes Derivative Liabilities [Policy Text Block] Convertible promissory notes derivative liabilities. Convertible Promissory Notes Derivative Liabilities Shares Issued During Period Value Conversion of Redeemable Convertible Preferred Stock into Common Stock at Acquisition Shares issued during period value conversion of redeemable convertible preferred stock into common stock at acquisition. Conversion of redeemable convertible preferred stock into common stock in connection with the Merger Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Cash flows from investing activities: Retirement Benefits [Abstract] Accounts Payable, Current Accounts payable Accounts Payable, Current, Total Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested in Period, Fair Value Total fair value of options vested Interest Expense, Nonoperating Interest Expense, Nonoperating, Total Interest expense (including $0 and $1,384 for a related party) Research and Development Expense [Member] Research and Development Research and Development Expenses Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Marketable Securities Accrued Royalties Noncurrent Accrued royalties noncurrent. Accrued royalties noncurrent Other non-current assets Increase (Decrease) in Other Noncurrent Assets Issuance of redeemable convertible preferred stock upon conversion of convertible promissory notes Debt Conversion, Converted Instrument, Amount Issuance of conversion of convertible promissory notes Fair Value Measurement, Policy [Policy Text Block] Fair Value Measurement Tranche Liability [Policy Text Block] Tranche Liability. Tranche Liability Temporary Equity Disclosure [Abstract] Proceeds from Stock Options Exercised Proceeds from the exercise of stock options Fair Value Disclosures [Abstract] Commitments and Contingencies Disclosure [Abstract] Stock Issued During Period, Value, Acquisitions Recognition of AlloVir common stock outstanding at the closing of the Merger Lessee, Operating Lease, Liability, to be Paid, Year One 2027 Sale of Stock, Consideration Received on Transaction Sale of stock, offering price Common stock capital shares reserved for future issuance. Common Stock Capital Shares Reserved For Future Issuance Table [Text Block] Schedule of Common Stock Reserved for Future Issuance Stock Issued Issuance Costs Stock issued issuance costs. Issuance costs Debt Instrument [Axis] Share-Based Payment Arrangement [Abstract] U.S. government treasury securities. U S Government Treasury Securities [Member] U.S. Government Treasury Securities Sale of Stock [Axis] Sale of Stock Two thousand twenty stock option and grant plan. Two Thousand Twenty Stock Option And Grant Plan [Member] 2020 Stock Option and Grant Plan Business Combination, Consideration Transferred, Equity Interest [Table Text Block] Schedule of Number of Shares Common Stock Issued and Outstanding Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Summary of RSAs Activity Estimated fair value Debt Instrument, Fair Value Disclosure, Total Debt Instrument, Fair Value Disclosure Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Net cash used in investing activities Private Placement [Member] Private Placement Title of 12(b) Security Security12b Title Thereafter Lessee Operating Lease Liability Payments Due After Year Four Lessee operating lease liability payments due after year four. License Maintenance Payments Fifth and Subsequent Anniversary License maintenance payments fifth and subsequent anniversary. License maintenance payments for fifth and subsequent anniversary Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Exercise price per share, cancelled Weighted Average Exercise Price Per Share, Options cancelled Money Market Funds [Member] Money Market Funds Related and Nonrelated Parties [Domain] Related Party Unaudited condensed financial statements. Unaudited Condensed Financial Statements [Policy Text Block] Unaudited Condensed Financial Statements Shares issued Redeemable convertible preferred stock, shares issued Redeemable Convertible Preferred Stock, Shares Issued Stock Redeemed or Called During Period, Shares Redemption of common stock issued Summary of significant accounting policies. Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Scientific Advisor - Board [Member] Scientific Advisor - Board [Member] Scientific Advisor-Board Member Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year 2026 (remaining 9 months) Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Changes in assets and liabilities: Corporate and agency bonds. Corporate and Agency Bonds [Member] Corporate and agency bonds Corporate and Agency Bonds Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted Average Exercise Price Per Share, Options outstanding, Ending Balance Weighted Average Exercise Price Per Share, Options outstanding, Beginning Balance Fair Value, Recurring and Nonrecurring [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Merger with AlloVir Business Combination [Text Block] Additional Paid-in Capital [Member] Additional Paid-In Capital Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Accrued expenses and other current liabilities Accrued expenses and other current liabilities Statement of Income Location, Balance [Axis] Income Statement Location Change in Accounting Principle, Accounting Standards Update, Adoption Date Trading Symbol Trading Symbol Related Party Transaction [Table] Schedule Of Related Party Transactions By Related Party [Table] Conversion of redeemable convertible preferred stock into common stock in connection with the Merger Temporary Equity Conversion of Redeemable Convertible Preferred Stock Value into Common Stock at Acquisition Temporary equity conversion of redeemable convertible preferred stock value into common stock at acquisition. Proceeds from Notes Payable Proceeds from issuance of convertible promissory notes Proceeds from the issuance of convertible promissory notes (including $0 and $3,402 from a related party), net of issuance costs Subsequent Event Type [Axis] Issuance of Common Stock and Equity Elimination in Connection With the Merger Issuance of common stock and equity elimination in connection with the merger. Issuance of common stock and equity elimination in connection with the Merger Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Cash flows from financing activities: Prepaid Professional Services Prepaid professional services. Prepaid professional services Entity Ex Transition Period Entity Ex Transition Period Lessee, Operating Lease, Liability, to be Paid Total lease payments Internal Research and Development Personnel Expenses Internal research and development personnel expenses Internal research and development personnel costs Business Combination, Consideration Transferred, Equity Interest [Line Items] Accounting Standards Update 2016-13 [Member] ASU 2016-13 Undiscounted payments Lessee, Operating Lease, Liability, Undiscounted Excess Amount Less: interest Common Stock Exchange Ratio Common stock exchange ratio. Common stock exchange ratio Equity Components [Axis] Equity Components Schedule Of Operating Lease On Its Consolidated Balance Sheet [Table Text Block] Schedule of operating lease on its consolidated balance sheet. Schedule of Operating Lease on Its Consolidated Balance Sheet Nonoperating Income (Expense) Total other income, net Equity Component [Domain] Equity Component Asset Class [Axis] 2025 Bridge Notes Twenty Twenty Five Bridge Notes [Member] Twenty Twenty Five Bridge Notes 2020 employee stock purchase plan. Two Thousand And Twenty Employee Stock Purchase Plan [Member] 2020 Employee Stock Purchase Plan Business Combination [Axis] Temporary Equity Conversion of Redeemable Convertible Preferred Stock Shares into Common Stock at Acquisition Temporary equity conversion of redeemable convertible preferred stock shares into common stock at acquisition. Conversion of redeemable convertible preferred stock into common stock in connection with the Merger, Shares Prepaid insurance Prepaid Insurance License Agreement Payment License agreement payment. License agreement payment Stock Issued During Period, Shares, Employee Stock Purchase Plans Purchase of common stock under the 2020 employee stock purchase plan, Shares Stock issued under employee stock purchase plan Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period Term of contract Weighted Average Number Of Shares Outstanding Before Repurchase Weighted average number of shares outstanding before repurchase. Weighted average common shares outstanding Maximum [Member] Maximum Debt instrument, converted ratio Debt Instrument, Convertible, Conversion Ratio Statistical Measurement [Axis] Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted Average Exercise Price Per Share, Options exercised Common Stock, Value, Issued Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common Stock, Value, Issued, Total Common stock, $0.0001 and $0.0001 par value as of March 31, 2026 and December 31, 2025, respectively; 300,000,000 shares authorized as of March 31, 2026 and December 31, 2025; 22,992,291 and 22,902,418 shares issued and outstanding as of March 31, 2026 and December 31, 2025, respectively Issuance of Series B-2 redeemable convertible preferred stock upon conversion of convertible promissory notes in connection with the Merger, Shares Temporary Equity Issuance of Redeemable Convertible Preferred Stock Shares upon Conversion of Convertible Promissory Notes at Acquisition Temporary equity issuance of redeemable convertible preferred stock shares upon conversion of convertible promissory notes at acquisition. January Twenty Twenty Five AlloVir Convertible Promissory Note [Member] January Twenty Twenty Five AlloVir Convertible Promissory Note January 2025 AlloVir Convertible Promissory Note Cash and Cash Equivalents [Abstract] Cash equivalents: Tranche Liability Tranche liability [Member] Tranche liability. License Agreement [Member] License Agreement. License Agreement Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive loss: Deferred Costs, Current Deferred Costs, Current, Total Deferred transaction costs Accrued Expenses and Other Current Liabilities [Table Text Block] Accrued expenses and other current liabilities. Schedule of Accrued Expenses and Other Current Liabilities Merger transaction costs recognized in additional paid-in capital Merger Transaction Costs Recognized In Additional Paid In Capital Merger transaction costs recognized in additional paid-in capital. Preferred Stock, Shares Authorized Preferred stock, shares authorized Future royalty payment liability Future Royalty Payment Liability Future royalty payment liability. Royalty Expense Interest expense for royalty liability Change in the fair value of derivative liability Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments Premium On Issuance Of Debt Premium on issuance of debt. Premium on issuance of convertible promissory notes Premium on issuance of convertible promissory notes (including $169 and $2,134 for a related party) Related Party Transaction [Line Items] Related Party Transaction [Line Items] Derivative Liabilities Derivative Financial Instruments, Liabilities [Member] Business Combination [Table] Entity Registrant Name Entity Registrant Name Debt Disclosure [Text Block] Convertible Promissory Notes Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Unrealized Losses Unrealized Losses Unrealized Losses Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Repurchased in Period Share-based compensation arrangement by share-based payment award, equity instruments other than options, repurchased in period. Restricted Stock Awards, repurchased Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Other Nonoperating Income (Expense) Other Nonoperating Income (Expense), Total Other income, net Additional Paid in Capital Additional Paid in Capital, Ending Balance Additional Paid in Capital, Beginning Balance Additional paid-in capital Additional Paid in Capital, Total Subsequent Events [Abstract] Stock Repurchased During Period, Value Repurchase of common shares, value Repurchase of common stock in connection with the royalty agreement Repurchase of common stock in connection with the royalty agreement Accrued patent reimbursement costs Accrued Patent Reimbursement Costs Accrued patent reimbursement costs. Proceeds from issuance of common stock in registered direct offering, net of issuance costs Proceeds from Issuance of Common Stock Aggregate gross proceeds of common stock Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Summary of Estimated Fair Value Cash acquired in connection with the Merger Proceeds From Cash Acquired In Connection With Merger Proceeds from cash acquired in connection with merger. Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Concentration Risk, Credit Risk, Policy [Policy Text Block] Concentrations of Credit Risk and Other Risks and Uncertainties Non Cash Operating Lease Income (Expense) Non cash operating lease income (expense). Non-cash operating lease expense Liability Class [Axis] Adjustment to Additional Paid-in Capital, Convertible Debt Instrument Issued at Substantial Premium Premium on issuance of convertible promissory notes Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive income Commitments and Contingencies, Policy [Policy Text Block] Commitments and Contingencies Restricted Stock Awards, granted Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Temporary Equity, by Class of Stock [Table] Assets Total assets Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Weighted Average Remaining Contractual Term (in years), Exercisable, March 31, 2026 Loss Contingency, Settlement Agreement, Date Date of settlement agreement executed Percentage of maximum discount on purchase of shares of common stock Percentage of Maximum Discount Price on Purchase of Shares of Common Stock Percentage of maximum discount price on purchase of shares of common stock. Income Statement [Abstract] Sale of Stock, Number of Shares Issued in Transaction Common stock, shares issued Common stock shares issued Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Restricted Stock Awards, Vested Annual increase in number of shares reserved for issuance Maximum Annual Increase Of Common Stock Reserved For Issuance Maximum annual increase of common stock reserved for issuance. Business Combination [Abstract] Net loss per share - diluted Earnings Per Share, Diluted, Total Net loss per share - diluted Net loss per share attributable to common stockholders - diluted Debt Conversion, Original Debt, Amount Conversion of convertible promissory notes and accrued interest in connection with the Merger Schedule of Segment Reporting Information, by Segment [Table Text Block] Summary of Segment Loss Title and Position [Domain] City Area Code City Area Code Debt instrument, issued, principal amount Debt Instrument, Issued, Principal Other Comprehensive Income (Loss), Net of Tax Total other comprehensive loss Debt Instrument, Face Amount Outstanding principal amount Line of Credit Facility, Maximum Borrowing Capacity Additional draw up amount Business Combination [Line Items] Business Acquisition [Line Items] Change in Accounting Principle, Accounting Standards Update, Early Adoption [true false] Counterparty Name [Domain] Variable lease cost Variable Lease, Cost Operating Lease, Weighted Average Remaining Lease Term Weighted-average remaining lease term Stock Issued During Period, Shares, Restricted Stock Award, Gross Issuance of restricted stock awards Lease, Cost Total lease cost Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Including Discontinued Operation Cash and cash equivalents and restricted cash, at end of the period Cash and cash equivalents and restricted cash, at beginning of the period Operating Income (Loss) Loss from operations Reduction in Letter of Credit Reduction in letter of credit. Reduction in letter of credit Retained Earnings [Member] Accumulated Deficit Cash and Cash Equivalents [Axis] Cash and Cash Equivalents Share-Based Payment Arrangement, Noncash Expense Stock-based compensation expense Share-based Payment Arrangement, Noncash Expense, Total License fees, milestone payments, and annual maintenance fees related to acquired technologies License Fees, Milestone Payments, and Annual Maintenance Fees Related to Acquired Technologies License fees, milestone payments, and annual maintenance fees related to acquired technologies Derivative Liability Fair Value Assignment Fee Derivative liability fair value assignment fee. Derivative liability fair value assignment fee Operating Lease, Weighted Average Discount Rate, Percent Weighted-average discount rate Operating Lease, Liability, Noncurrent Operating lease liability, long-term Operating lease liabilities, long-term Fair Value, Inputs, Level 1 [Member] Level 1 Gain (Loss) on Extinguishment and on Issuance of Convertible Promissory Notes Gain (loss) on extinguishment and on issuance of convertible promissory notes Loss on extinguishment and on issuance of convertible promissory notes Loss on extinguishment and on issuance of convertible promissory notes Loss on extinguishment and on issuance of convertible promissory notes (including $0 and $169 for a related party) Loss on extinguishment and on issuance of convertible promissory notes (including $0 and $169 for a related party) Class of Stock [Line Items] Class Of Stock [Line Items] Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Net cash (used in) provided by financing activities Short-Term Debt [Line Items] Schedule of Components of Lease Cost Lease, Cost [Table Text Block] Change in Accounting Principle, Accounting Standards Update, Adopted [true false] Significant Agreements [Line Items] Significant agreements. Prepaid Expenses and Other Current Assets [Table Text Block] Prepaid expenses and other current assets. Schedule of Prepaid Expenses and Other Current Assets Nonoperating Income (Expense) [Abstract] Other income (expense), net: Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Potential Dilutive Securities Excluded From Computation Of Diluted Net Loss Per Share Attributable To Common Stockholders Debt Securities, Available-for-Sale [Table] Entity Interactive Data Current Entity Interactive Data Current Statement of Income Location, Balance [Domain] Income Statement Location Royalty Agreement [Member] Royalty Agreement. Royalty Agreement Contractual Interest Expense on Prepetition Liabilities Not Recognized in Statement of Operations Contractual interest expense Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Cash flows from operating activities: Accretion (Amortization) of Discounts and Premiums, Investments Net amortization of premiums and accretion of discounts on marketable securities Percentage Of The Number Of Shares Outstanding Percentage of the number of shares outstanding. Shares outstanding percentage Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares Common stock shares issued Common stock issued to Legacy Kalaris' securityholders at the Effective Time Pre Funded Warrant [Member] Pre funded warrant. Entity Tax Identification Number Entity Tax Identification Number Share Price Purchase price per share Prepaid Taxes Prepaid taxes Debt Instrument, Term Expected term (in years) Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Maturities of marketable securities Marketable Security, Unrealized Gain (Loss) Unrealized gain (loss) on marketable securities Local Phone Number Local Phone Number Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Unrecognized stock-based compensation expenses Weighted Average Number of Shares Outstanding, Diluted [Abstract] Denominator: Transaction costs related to the Merger Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Options to purchase common stock. Options To Purchase Common Stock [Member] Options To Purchase Common Stock Accounting Policies [Abstract] Derivative liabilities for a related party Related party Derivative liabilities Fair Value Disclosure Related party derivative liabilities fair value disclosure. Lessee, Operating Lease, Liability, to be Paid, Year Four 2030 Class of Stock [Domain] Commercial Paper [Member] Commercial paper Commercial Paper Sale of Stock, Transaction Date Sale of stock, effective Date Shares available for future grants Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Weighted average period of cost expected to be recognized Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Long-Term Investments [Abstract] Long-term marketable securities: Cash, Cash Equivalents, and Short-Term Investments Cash, Cash Equivalents, and Short-Term Investments, Total Cash, cash equivalents and marketable securities Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Numerator: Accrued Transaction Expenses Accrued transaction expenses. Accrued transaction expenses Schedule Of Stock By Class [Table] Stock, Class of Stock [Table] Non Cash Interest Expense Non-cash interest expense. Non-cash interest expense Non-cash interest expense (including $0 and $1,384 for a related party) Entity Emerging Growth Company Entity Emerging Growth Company Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Weighted Average Remaining Contractual Term (in years), Vested and expected to vest, March 31, 2026