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Net Investment from Former Parent Product and Service [Axis] Document Fiscal Period Focus Document Fiscal Period Focus Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss Amortized Cost Entity Shell Company Entity Shell Company Other accrued liabilities Other Accrued Liabilities, Current Cash and Cash Equivalent Cash and cash equivalents Cash and Cash Equivalent, Total Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Common Stock, Shares, Issued Common stock, shares issued (in shares) Shares of common stock distributed Statement [Table] Statement [Table] Restricted Cash, Noncurrent Restricted cash Restricted cash, net of current portion Restricted cash included in non-current assets Statement [Line Items] Statement [Line Items] External Spend External Spend [Member] External spend. Entity Filer Category Entity Filer Category Liabilities and Equity Total liabilities and Stockholders' equity / Former Parent's deficit Increase (Decrease) in Employee Related Liabilities Increase (Decrease) in Employee Related Liabilities, Total Accrued compensation Research And Development Expense, Adjusted Research And Development Expense, Adjusted Total adjusted research and development Adjusted research and development Adjusted research and development Cash and Cash Equivalents, Fair Value Disclosure Cash equivalents: Cash and Cash Equivalents, Fair Value Disclosure, Total Spin-Off Distribution Ratio, Description Spin-off distribution ratio, description. Spin-off distribution ratio, description Subsequent Event [Line Items] Subsequent Event [Line Items] Outstanding Time-Based Options Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Cash, Cash Equivalents and Restricted Cash Numerator: Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Summary of significant accounting policies table. Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies Milestone Payment Milestone payment. Milestone payment Net Transfers From Former Parent As Reflected In Changes In Deficit Net transfers from former parent as reflected in changes in deficit. Net transfers from Former Parent as reflected in the condensed statement of changes in deficit Collaboration Receivable Outstanding Collaboration Receivable Outstanding Collaboration receivable outstanding Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Computation of Basic and Diluted Net Loss Per Share Cardiology Indication Cardiology Indication [Member] Cardiology indication. Earnings Per Share, Basic Basic net loss per common share Earnings Per Share, Basic, Total Basic net loss per share Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] Schedule of Amortized Costs, Unrealized Gains and Losses and Fair Values of Cash Equivalents and Marketable Securities Schedule of Short-term Investments in Marketable Securities Segment reporting other items amount Segment reporting other items amount. Total other segment items Liabilities, Current Total current liabilities Non Cash Income Tax Expense (Benefit) Non-cash income tax expense Non cash income tax expense (benefit). Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: 2026 Incentive Award Plan Two Thousand Twenty Six Incentive Award Plan [Member] 2026 incentive award plan. Subsegments [Axis] Equity, Attributable to Parent [Abstract] Stockholders' equity/ Former Parent's deficit: Entity Small Business Entity Small Business Increase (Decrease) in Accrued Liabilities Increase (Decrease) in Accrued Liabilities, Total Accrued liabilities Retained Earnings (Accumulated Deficit) Accumulated deficit Accumulated deficit Spin-Off Distribution Ratio Spin-off distribution ratio. Spin-off distribution ratio Summary of significant accounting policies line items. Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Contract with Customer, Liability Ending balance Beginning balance Contract with Customer, Liability, Total Deferred revenue Amendment Flag Amendment Flag Product and Service [Domain] Earnings Per Share, Policy [Policy Text Block] Net Loss Per Share 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 Lease liabilities Increase (Decrease) in Operating Lease Liability Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description Common Stock [Member] Common Stock Maturity Period Maturity Period [Axis] Maturity Period [Axis] Adjusted Net Loss Adjusted net loss Adjusted Net Loss Adjusted net loss Adjusted net loss Debt Securities, Available-for-Sale [Line Items] Schedule Of Available For Sale Securities [Line Items] Business Description and Accounting Policies [Text Block] Significant Accounting Policies Research and Development Arrangement, Contract to Perform for Others, Type [Domain] Entity Address, Address Line One Entity Address, Address Line One Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV Earnings Per Share [Abstract] Operating Lease, Right-of-Use Asset ROU assets Right-of-use asset Debt Securities, Available-for-Sale, Unrealized Loss Position Total Fair Value Payments to Acquire Debt Securities, Available-for-Sale Purchases of short-term investments Purchases of short-term investments OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax, Total Net unrealized loss on short-term investments Document Type Document Type Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative Non Rule 10b5-1 Arr Modified Flag Non Rule 10b5-1 Arr Modified Flag. Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative Entity Central Index Key Entity Central Index Key Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Net increase (decrease) in cash and cash equivalents Net increase in cash, cash equivalents, and restricted cash Subsequent Event Type [Domain] Stock Options [Member] Stock options. Stock Options Two Thousand and Twenty Six Employment Inducement Incentive Award Plan [Member] Two thousand and twenty six employment inducement incentive award plan. 2026 Employment Inducement Incentive Award Plan Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Total Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common stock, par value Common stock distributed Common stock shares distributed Common stock shares distributed Non-cash operating lease costs Operating Lease, Right-of-Use Asset, Periodic Reduction Accrued Liabilities, Current Accrued liabilities Total accrued liabilities 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 Debt Securities, Available-for-Sale, Excluding Accrued Interest, Current Estimated Fair Value, current Marketable securities Marketable securities Document Quarterly Report Issuance of common stock in connection with Spin-Off and reclassification of deficit from Former Parent (in shares) Issuance of common stock in connection with Spin Off and reclassification, shares Issuance of common stock in connection with Spin Off and reclassification, shares. Entity Address, State or Province Entity Address, State or Province Collaboration receivables current. Collaboration Receivables Current Collaboration receivables Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, shares outstanding (in shares) Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Unrealized Gains Common Stock, Capital Shares Reserved for Future Issuance Shares of common stock reserved Shares of common stock reserved for future issuance (in shares) Shares related to Incentive Award Plan Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Contract with Customer, Liability, Revenue Recognized Revenue recognized that was included in the balance at the beginning of the period Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Schedule of Stock-based Compensation Expense Attributed to Company by Classification Included Within Condensed Statements of Operations and Comprehensive Loss Transfers from Former Parent Transfers from former parent. Collaborative Arrangement Disclosure [Text Block] Collaboration, License and Research Agreements Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive loss: Performance stock units Performance Shares [Member] Subsequent Event [Member] Subsequent Event Marketable Securities, Policy [Policy Text Block] Short Term Investments Internal Labor Internal Labor [Member] Internal labor. Antidilutive Securities [Axis] Operating Lease Income Expense Operating lease income expense. Net lease expense for Avidity Rule 10b5-1 Arr Modified Flag Rule 10b5-1 Arr Modified Flag. Proceeds from Sale of Debt Securities, Available-for-Sale Sale of marketable securities Accrued compensation Accrued compensation current Accrued compensation current. AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income Accumulated Other Comprehensive Loss Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Preferred Stock, Value, Issued Preferred stock, $0.001 par value: 40,000 shares authorized; no shares issued and outstanding Available-for-sale investments, impairment Debt Securities, Available for Sale, Impairment Debt securities, Available-for-Sale, impairment. Financial Instrument [Axis] Financial Instrument [Axis] Assets, Current [Abstract] Current assets: Issuance of common stock in connection with Spin-Off and reclassification of Net Investment from Former Parent 1 Issuance of common stock in connection with Spin-Off and reclassification of net investment from former parent 1. Issuance of common stock in connection with Spin-Off and reclassification of Net Investment from Former Parent Fair Value, Inputs, Level 3 [Member] Significant Unobservable Inputs (Level 3) Segment Reporting [Abstract] Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of Financial Assets Measured at Fair Value on Recurring Basis Liabilities, Current [Abstract] Current liabilities: Related Party Transactions [Abstract] Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Schedule of Available-for-sale Securities Schedule of Marketable Securities in Continuous Unrealized Loss Position for Which an Allowance for Credit Losses was Not Recorded Proceeds from Contributions from Affiliates Net transfers from Former Parent Commitments and Contingencies Commitments and contingencies Shareholders' Equity and Share-Based Payments [Text Block] Stockholders' Equity General and Administrative Expense [Member] General and Administrative Expense Operating Lease, Liability Lease, liability Total operating lease liabilities Restricted Cash, Current Restricted cash, current portion Restricted cash included in current assets Shares Distributed In Spin Off Member Shares distributed in spin off. Shares Distributed in Spin-Off Accounting Policies [Line Items] Accounting Policies. Capital Expenditures Incurred but Not yet Paid Costs incurred, but not paid, in connection with purchases of property and equipment included in accounts payable and accrued liabilities Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net loss Accounting Policies [Table] Accounting policies. Reconciliation of Assets from Segment to Consolidated [Table Text Block] Schedule of Measurement of Segment Assets Weighted Average Number of Shares Outstanding, Basic Weighted-average shares outstanding, basic (in shares) Weighted Average Number of Shares Outstanding, Basic, Total Weighted-average common shares outstanding used in the calculation of net loss per common share,basic Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 12 months or Greater, Gross Unrealized Losses Segments [Axis] Segments [Axis] Research collaboration and license agreement with Eli Lilly and company Research Collaboration And License Agreement With Eli Lilly And Company [Member] Research Collaboration and License Agreement with Eli Lilly Avidity Avidity Biosciences, Inc. [Member] Avidity Biosciences, Inc. Subsequent Events [Text Block] Subsequent Events Related Party Transactions Disclosure [Text Block] Related Party Transactions and Transactions with the Former Parent Spin Off common stock granted ratio Spin off common stock granted ratio. Spin-off common stock granted ratio Cash APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Stock-based compensation Reclassification of deficit from Former Parent Reclassifications Of Deficit From Former Parent Reclassifications of deficit from former parent. Equity, Attributable to Parent Ending balance Beginning balance Total stockholders' equity / Former Parent's deficit Preferred Stock, Par or Stated Value Per Share Preferred Stock, par value (in dollars per share) Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss, Noncurrent Amortized Cost, noncurrent Basis of Accounting, Policy [Policy Text Block] Basis of Presentation Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Reclassification of deficit from Former Parent Reclassification of deficit from Former Parent. Reclassification of deficit from Former Parent Debt Securities, Available-for-Sale, Excluding Accrued Interest Marketable securities: Estimated Fair Value Entity Address, Address Line Two Fair Value Measurements Fair Value Disclosures [Text Block] Debt Securities, Available-for-Sale, Accrued Interest Writeoff Debt securities, available-for-sale, accrued interest write off Written off accrued interest receivable Schedule of Accrued Liabilities [Table Text Block] Schedule of Accrued Liabilities Other Assets, Current Other current assets General And Administrative Expense, Adjusted General And Administrative Expense, Adjusted Total adjusted general and administrative Adjusted general and administrative Adjusted general and administrative Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration] Segment Reporting, Other Segment Item, Amount Total other segment items Total other segment items Total other segment items Plan Name [Domain] Plan Name 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] Entity [Domain] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Business Description and Basis of Presentation [Text Block] Description of Business and Basis of Presentation Organization BMS Collaboration Agreement BMS Collaboration Agreement [Member] BMS collaboration agreement. Debt Securities, Available-for-Sale, Excluding Accrued Interest, Noncurrent Estimate Fair Value, noncurrent Related and Nonrelated Parties [Axis] Entity Address, City or Town Entity Address, City or Town Number of reportable segment Number of Reportable Segments Security Exchange Name Security Exchange Name Former Parent Common Stock [Member] Former parent common stock. Former Parent's Common Stock Conversion of Stock, Description Stock description Antidilutive Securities, Name [Domain] Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Cash, cash equivalents and restricted cash, at beginning of period Cash, cash equivalents and restricted cash, at end of period Total cash, cash equivalents and restricted cash Cash, restricted cash and cash equivalents Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Statistical Measurement [Domain] Statistical Measurement Assets, Current Total current assets Total stock-based compensation expense Stock-based compensation Expense related to awards granted Document Period End Date Document Period End Date Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Purchased for Award Shares purchased under 2026 ESPP Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Restricted Stock Units (RSUs) [Member] Restricted Stock Units RSUs Antidilutive Security, Excluded EPS Calculation [Table] Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract] Reconciliation of cash, cash equivalents and restricted cash, at end of period: Net transfers from Former Parent as reflected in the condensed statement of cash flows Net Transfers From Former Parent Per Statement Of Cash Flows Net transfers from former parent per statement of cash flows. Class of Stock [Axis] Realized gains and losses Debt Securities, Available-for-Sale, Realized Gain (Loss) Debt Securities, Available-for-Sale, Realized Gain (Loss), Total Liabilities Total liabilities Financial Instruments [Domain] Financial Instruments [Domain] Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Less Than 12 months, Gross Unrealized Losses Weighted Average Number of Shares Outstanding, Diluted Weighted-average shares outstanding, diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted, Total Weighted-average common shares outstanding used in the calculation of net loss per common share, diluted Entity File Number Entity File Number OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Unrealized gain (loss) on short-term investments Net unrealized loss on short-term investments Cover [Abstract] Cover [Abstract] Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Allowances for credit losses Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance US Treasury Securities [Member] U.S. Treasury Securities Common Shares Outstanding [Member] Common Shares Outstanding. Common Shares Outstanding Number of operating segment Number of Operating Segments Segment Reporting Disclosure [Text Block] Segment Information General and administrative General and Administrative Expense General and Administrative Expense, Total General and administrative expenses Accrued manufacturing and technical development Accrued Manufacturing And Technical Development Accrued Manufacturing And Technical Development Accrued manufacturing and technical development Subsequent Event [Table] Subsequent Event [Table] Equity awards granted to employees Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period Stock granted to employees Research And Development Service [Member] Research and development service. R&D Services Inducement Plan Inducement Plan [Member] Inducement plan. Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss Accrued interest receivable on available-for-sale securities New Accounting Pronouncements, Policy [Policy Text Block] Recently Issued Accounting Pronouncements Not Yet Adopted Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Contract with Customer, Liability, Current Deferred revenue, current portion Schedule of Investments [Text Block] Short-term Investments Contract With Customer, Liability Contract With Customer, Liability [Roll Forward] Contract With Customer, Liability [Roll Forward] Depreciation for Avidity Depreciation Depreciation expenses related to property and equipment Depreciation, Total Depreciation for Avidity Make Whole Awards [Member] Make whole awards. Make Whole Awards Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Unrecognized compensation cost, excluding options Common Stock, Shares, Outstanding Ending balance (in shares) Beginning balance (in shares) Common stock, shares outstanding (in shares) Commons stock outstanding Operating Lease, Liability, Current Lease liabilities, current portion Less lease liabilities, current portion Lease liabilities Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Document Transition Report Document Transition Report Short-Term Investments Short-Term Investments, Total Short term investments Short-term investments Operating Expenses Total operating expenses Accrued Liabilities, Current [Abstract] Research and Development Expense Research and development Research and Development Expense, Total Research and development expenses Schedule of Investments [Abstract] Maturity Period [Domain] Maturity Period [Domain] Maturity Period [Domain] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Earnings Per Share [Text Block] Net Loss Per Share of Common Stock Net loss Net loss Research Collaboration, License Agreement and Securities Purchase Agreement with BMS Research Collaboration, License Agreement and Securities Purchase Agreement with BMS [Member] Research Collaboration, License Agreement and Securities Purchase Agreement with BMS Provision for Loan, Lease, and Other Losses Provision for Loan, Lease, and Other Losses, Total Available-for-sale investments, credit losses Assets [Abstract] Assets Increase (Decrease) in Prepaid Expense and Other Assets Prepaid assets Document Fiscal Year Focus Document Fiscal Year Focus Net Income (Loss) Attributable to Parent, Diluted [Abstract] Denominator: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Cash flows from investing activities Accounts Payable, Current Accrued manufacturing and technical development Accounts payable Research and Development Expense [Member] Research and Development Expense Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Marketable Securities Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Schedule of Reconciliation of Deferred Revenue Collaboration Receivable Current Collaboration receivable current Collaboration receivable Accrued research Accrued research. Fair Value Measurement, Policy [Policy Text Block] Fair Value of Measurements Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Percentage of Shares of Common Stock Outstanding including any Shares Issuable Pursuant to Pre-funded Warrants on Immediately Preceding December 31 Percentage of shares of common stock outstanding including any shares issuable pursuant to pre-funded warrants on immediately preceding December 31. Percentage of shares of common stock outstanding (including any shares issuable pursuant to pre-funded warrants) on immediately preceding December 31 Net assets distributed from Former Parent Fair Value of Assets Acquired Debt Securities, Available-for-Sale [Abstract] Debt Securities, Available-for-Sale [Abstract] Total Assets, Fair Value Disclosure Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Net cash used in investing activities Title of 12(b) Security Title of 12(b) Security Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Ownership Interest Ownership interest. Ownership interest Subsegments [Domain] Money Market Funds [Member] Money Market Funds Related and Nonrelated Parties [Domain] Number Of Financial Instruments Held Number of financial instruments held. Number of financial instruments held Collaborative Arrangement and Arrangement Other than Collaborative [Table] Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Issuance of common stock in connection with Spin-Off and reclassification of deficit from Former Parent Issuance of common stock in connection with Spin Off and reclassification Issuance of common stock in connection with spin off and reclassification. Other Liabilities, Noncurrent Other long-term liabilities 2026 Employee Stock Purchase Plan Two Thousand Twenty Six Employee Stock Purchase Plan [Member] 2026 employee stock purchase plan. Legal Entity [Axis] Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: Fair Value, Recurring and Nonrecurring [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Additional Paid-in Capital [Member] Additional Paid-in Capital Statement of Income Location, Balance [Axis] Statement of Income Location, Balance Trading Symbol Trading Symbol Related Party Transaction [Table] Reportable Segment Reportable Segment [Member] Reportable Segment One Year Or Less One Year Or Less [Member] 1 or Less Subsequent Event Type [Axis] Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Cash flows from financing activities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Accrued Liabilities Entity Ex Transition Period Lessee, Operating Lease, Liability, to be Paid Aggregate future lease payments Total lease payments Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract] Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract] Lessee, Operating Lease, Liability, Undiscounted Excess Amount Less imputed interest Equity Components [Axis] Equity Components Nonoperating Income (Expense) Other income, net Total other income (expense) Equity Component [Domain] Equity Component Other current assets Increase (Decrease) in Other Current Assets Stock Issued During Period, Shares, Employee Stock Purchase Plans Issuance of common stock related to the 2026 Incentive Award Plan Statistical Measurement [Axis] Statistical Measurement Contract with Customer, Liability, Noncurrent Deferred revenue, net of current portion Prepaid Expense, Current Prepaid assets Prepaid Expense, Current, Total Common Stock, Value, Issued Common stock, $0.001 par value: 400,000 shares authorized; 17,106 shares issued and outstanding as of June 30, 2026, and no shares authorized, issued, or outstanding as of December 31, 2025 Stock Issued During Period, Value, Employee Benefit Plan Issuance of common stock related to the 2026 Employment Inducement Incentive Award Plan Net Investment from Former Parent Net investment from former parent. Net investment from Former Parent Other income (expense) Preferred Stock, Shares Authorized Preferred stoc, shares authorized (in shares) One To Two Years One To Two Years [Member] 1 - 2 Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Total Gross Unrealized Losses Total Gross Unrealized Losses Marketable securities Related Party Transaction [Line Items] Employee Stock [Member] ESPP shares pending issuance Entity Registrant Name Entity Registrant Name Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Unrealized Losses Other income (expense), net Other Nonoperating Income (Expense) Other Nonoperating Income (Expense), Total Additional Paid in Capital, Total Additional Paid in Capital Additional paid-in capital Subsequent Events [Abstract] Subsequent Events [Abstract] Issuance Of Common Stock In Connection With Spin Off Issuance of common stock in connection with spin off. Issuance of common stock in connection with Spin-Off Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Concentration Risk, Credit Risk, Policy [Policy Text Block] Concentration of Risk Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Accumulated other comprehensive loss, net Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment Net Asset Value Per Share Net Asset Value Per Share, Ending Balance Net Asset Value Per Share, Beginning Balance Net asset value per share Issuance of common stock in connection with Spin-Off and reclassification of Net Investment from Former Parent Shares Issuance of common stock in connection with spin-off and reclassification of net investment from former parent shares. Issuance of common stock in connection with Spin-Off and reclassification of Net Investment from Former Parent (in shares) Assets Total assets Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss, Current Amortized Cost, current Income Statement [Abstract] Income Statement [Abstract] Share-Based Payment Arrangement [Policy Text Block] Stock-Based Compensation Weighted Average [Member] Weighted Average Stock Issued During Period, Shares, New Issues Common stock issued in settlement in connection with the Spin-Off Earnings Per Share, Diluted Earnings Per Share, Diluted, Total Diluted net loss per common share Diluted net loss per share Summary of allocations of expenses [Table Text Block] Summary of allocations of expenses. Summary of Allocations of Certain Expenses Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Segment Reporting Information, by Segment City Area Code City Area Code Issuance Of Common Stock In Connection With Spin Off Shares Issuance of common stock in connection with spin off shares. Issuance of common stock in connection with Spin-Off (in shares) Total cost allocations Total cost allocations. Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Stockholders' Equity Note, Stock Split, Conversion Ratio Stock conversion ratio Property, Plant and Equipment, Net Property and equipment, net Total property and equipment, net Net assets distributed Net assets distributed. Net assets distributed from Avidity Operating Income (Loss) Loss from operations Loss from operations Retained Earnings [Member] Retained Earnings Retained Earnings / Accumulated Deficit Stock Issued During Period, Shares, Employee Benefit Plan Issuance of common stock related to the 2026 Employment Inducement Incentive Award Plan (in shares) Collaboration, license and research agreements. Collaboration License And Research Agreements [Abstract] Collaboration License And Research Agreements [Abstract] Share-Based Payment Arrangement, Noncash Expense Stock-based compensation expense Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Less Than 12 months, Fair Value Operating Lease, Liability, Noncurrent Lease liabilities, net of current portion Fair Value, Inputs, Level 1 [Member] Quoted Prices in Active Markets for Identical Assets (Level 1) Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Net cash provided by financing activities Investments, Fair Value Disclosure Investments, Fair Value Disclosure, Total Short term investments: Earnings Per Share Reconciliation [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Potential Shares of Common stock Excluded from Calculation of Diluted Net Loss Per Share Common Shares Not Issued and Outstanding [Member] Common Shares Not Issued and Outstanding. Common Shares not Issued and Outstanding Debt Securities, Available-for-Sale [Table] Debt Securities Available For Sale [Table] Entity Interactive Data Current Entity Interactive Data Current Increase (Decrease) in Contract with Customer, Liability Deferred revenues Statement of Income Location, Balance [Domain] Statement of Income Location, Balance Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Cash flows from operating activities Transfers from (to) Former Parent Transfers from (to) Former Parent. Accretion (Amortization) of Discounts and Premiums, Investments Amortization of premiums and discounts on short-term investments, net Amortization of premiums and discounts on short-term investments, net Increase (Decrease) in Other Noncurrent Liabilities Other long-term liabilities Entity Tax Identification Number Entity Tax Identification Number Shares of Common Stock Received in Connection with Separation Agreement Shares of common stock received in connection with separation agreement. Shares of common stock received in connection with separation agreement Interest Income, Other Interest income Local Phone Number Local Phone Number Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Unrecognized compensation cost, options Accounting Policies [Abstract] Accounting Policies [Abstract] Collaboration revenue Revenue from Contract with Customer, Excluding Assessed Tax Class of Stock [Domain] Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Shares remaining available for issuance Shares remaining available for grant Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Weighted-average period of unrecognized compensation cost Entity Emerging Growth Company Entity Emerging Growth Company