Non-cash operating lease expense Operating Lease, Right-of-Use Asset, Periodic Reduction Number of platforms Number Of Platforms Number Of Platforms Over-Allotment Option Over-Allotment Option [Member] Issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Issued in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Issued in Period Summary of Accrued Expenses Schedule of Accrued Liabilities [Table Text Block] Accrued expenses Total accrued expenses Accrued Liabilities, Current Statistical Measurement [Domain] Statistical Measurement [Domain] Total current assets Assets, Current Research and development Research and Development Expense Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Revenue from Contract with Customer [Abstract] Restricted cash Restricted Cash Award Type [Domain] Award Type [Domain] Beginning balance (in shares) Ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Other income, net Other Nonoperating Income (Expense) Entity Filer Category Entity Filer Category Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Investments, Debt and Equity Securities [Abstract] Current Fiscal Year End Date Current Fiscal Year End Date Net Loss per Share Earnings Per Share, Policy [Policy Text Block] Accounts payable Accounts Payable, Current Weighted average remaining contractual term exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Corporate debt securities Corporate Debt Securities [Member] Total other income Nonoperating Income (Expense) Preferred stock, authorized (in shares) Preferred Stock, Shares Authorized Commitments and contingencies (Note 6) Commitments and Contingencies Common Stock Warrants Common Stock, Warrants [Policy Text Block] Common Stock, Warrants Number of shares exercisable (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number Preferred stock, outstanding (in shares) Preferred Stock, Shares Outstanding Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Summary of Restricted Stock Activity Nonvested Restricted Stock Shares Activity [Table Text Block] Schedule Of Common Stock Reserved For Future Issuance [Line Items] Schedule Of Common Stock Reserved For Future Issuance [Line Items] Schedule Of Common Stock Reserved For Future Issuance Line items Proceeds from issuance or sale of equity Proceeds from Issuance or Sale of Equity Common Stock and Preferred Stock Equity [Text Block] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Aggregate intrinsic value vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Aggregate intrinsic value exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value Proceeds from stock offerings, net of issuance costs Proceeds from Issuance of Common Stock Summary of Common Stock Reserved For Future Issuance Schedule Of Common Stock Reserved For Future Issuance [Table Text Block] Schedule Of Common Stock Reserved For Future Issuance Estimated fair value, available-for-sale, current Debt Securities, Available-for-Sale, Current Deferred revenue Increase (Decrease) in Contract with Customer, Liability Accrued other expenses Other Accrued Liabilities, Current Expected dividend yield Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Available-for-sale, gross unrealized loss, current, before tax Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, Current, before Tax Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, Current, before Tax Issued (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Issued in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Issued in Period, Weighted Average Grant Date Fair Value Nature of the Business Nature of Operations [Text Block] Current liabilities: Liabilities, Current [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Total stockholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Preferred stock, $0.0001 par value; 10,000,000 shares authorized and no shares issued or outstanding as of June 30, 2023 and December 31, 2022 Preferred Stock, Value, Issued Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Net loss per share attributable to common stockholders, diluted (in dollars per share) Earnings Per Share, Diluted Shares reserved for vesting of restricted stock units Unvested restricted stock units Restricted Stock [Member] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Milestone payments Revenue, Remaining Performance Obligation, Variable Consideration Amount Revenue, Remaining Performance Obligation, Variable Consideration Amount Supplemental disclosures of non-cash activities: Supplemental Cash Flow Elements [Abstract] Vested and expected to vest (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Expected term (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Treasury stock (in shares) Treasury Stock, Common, Shares Level 3 Fair Value, Inputs, Level 3 [Member] Subsequent Events [Abstract] Subsequent Events [Abstract] Beginning balance (in shares) Ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Percentage increase in annual base rent Percentage Increase In Annual Base Rent Percentage Increase In Annual Base Rent. Issuance of common stock upon exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Trading Symbol Trading Symbol Debt securities issued by U.S. government agencies US Government Agencies Debt Securities [Member] Restructuring Restructuring and Related Activities Disclosure [Text Block] Preferred stock, issued (in shares) Preferred Stock, Shares Issued Granted (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Investments Investments, Fair Value Disclosure Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Weighted average grant-date fair value per share (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Level 2 Fair Value, Inputs, Level 2 [Member] Net loss Net loss Net loss Net loss Net Income (Loss) Total current liabilities Liabilities, Current Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Entity Emerging Growth Company Entity Emerging Growth Company Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Potential shares issuable under the 2020 ESPP Employee Stock [Member] Available-for-sale, cost, current Debt Securities, Available-for-Sale, Amortized Cost, Current Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Stockholders’ equity: Equity, Attributable to Parent [Abstract] Total available-for-sale, gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Upfront payment Contract with Customer, Liability Issuance of common stock upon exercise of stock options (in shares) Exercised (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Document Fiscal Period Focus Document Fiscal Period Focus Antidilutive Securities [Axis] Antidilutive Securities [Axis] Share-based payment arrangement Share-Based Payment Arrangement [Member] Beginning balance (in dollars per share) Ending balance (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Common Stock Common Stock [Member] Exercised (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Level 1 Fair Value, Inputs, Level 1 [Member] City Area Code City Area Code Entity Address, Postal Zip Code Entity Address, Postal Zip Code Product and Service [Axis] Product and Service [Axis] Net Loss per Share Earnings Per Share [Text Block] Income Statement Location [Domain] Income Statement Location [Domain] Equity Components [Axis] Equity Components [Axis] Warrants (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Financial Instruments [Domain] Financial Instruments [Domain] Accrued expenses Increase (Decrease) in Accrued Liabilities Document Fiscal Year Focus Document Fiscal Year Focus Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Entity Small Business Entity Small Business Remaining restructuring costs Restructuring and Related Cost, Incurred Cost Local Phone Number Local Phone Number Property and equipment, net Property, Plant and Equipment, Net Summary of Stock Option Activity Share-Based Payment Arrangement, Option, Activity [Table Text Block] Change in unrealized losses on marketable securities, net of tax Change in unrealized loss on marketable securities, net of tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Measurement Frequency [Axis] Measurement Frequency [Axis] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Warrant Warrant [Member] Assets Assets [Abstract] Non-current portion of operating lease liabilities Operating Lease, Liability, Noncurrent Payments of tax withholdings related to vesting of restricted stock units Payment, Tax Withholding, Share-Based Payment Arrangement Payments of stock issuance costs Payment of issuance costs for at-the-market offerings Payments of Stock Issuance Costs Depreciation expense Depreciation Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Summary of Financial Assets Measured At Fair Value On A Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Income Statement Location [Axis] Income Statement Location [Axis] Pre-Funded Warrant Pre-Funded Warrant [Member] Pre-Funded Warrant Accumulated Deficit Retained Earnings [Member] Summary of Stock-Based Compensation Expense Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Amortization of premiums and discounts on marketable securities, net Accretion (Amortization) of Discounts and Premiums, Investments Shares withheld for taxes for vesting of restricted stock units Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Total liabilities and stockholders’ equity Liabilities and Equity Total available-for-sale securities, cost Debt Securities, Available-for-Sale, Amortized Cost Other income: Nonoperating Income (Expense) [Abstract] Other non-current assets Other Assets, Noncurrent Risk-free interest rate Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Net loss per share attributable to common stockholders, basic (in dollars per share) Earnings Per Share, Basic Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Number of product candidates Number Of Product Candidates Number Of Product Candidates Unrecognized compensation expense related to unvested stock based awards Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Issuance of common stock under employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Accounting Policies [Abstract] Accounting Policies [Abstract] Sale of Stock [Domain] Sale of Stock [Domain] Number of shares issued in transaction Sale of Stock, Number of Shares Issued in Transaction Payables and Accruals [Abstract] Payables and Accruals [Abstract] Collaboration revenue Revenues Aggregate intrinsic value exercised Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value Shares reserved for future awards under the 2020 Stock Option and Incentive Plan Twenty Twenty Employee Stock Incentive Plan [Member] Twenty Twenty Employee Stock Incentive Plan Warrants (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Product and Service [Domain] Product and Service [Domain] Summary of Antidilutive Securities Excluded From Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] At-The-Market Offering At-the-market Offering [Member] At-the-market Offering Entity Address, City or Town Entity Address, City or Town Research and development Research and Development Research and Development Expense [Member] Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Unvested Restricted Stock Units Unvested Restricted Stock Units [Member] Unvested Restricted Stock Units Office Space in Boston Massachusetts Office Space in Boston Massachusetts [Member] Office Space in Boston Massachusetts Weighted average remaining contractual term vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Antidilutive securities (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Award Type [Axis] Award Type [Axis] Available-for-sale, gross unrealized gain, current, before tax Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, Current, before Tax Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, Current, before Tax Plan Name [Domain] Plan Name [Domain] Document Quarterly Report Document Quarterly Report Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Document Transition Report Document Transition Report General and administrative General and Administrative Expense General and Administrative Expense [Member] Number of shares authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Weighted average remaining contractual term outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Accrued personnel-related expenses Accrued Personnel Related Expenses Current Accrued Personnel Related Expenses, Current. Related Party Transactions Related Party Transactions Disclosure [Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Maturities of marketable securities Proceeds from Sale and Maturity of Marketable Securities Accounts payable Increase (Decrease) in Accounts Payable Common stock, authorized (in shares) Common Stock, Shares Authorized Marketable securities Total available-for-sale securities, estimated fair value Debt Securities, Available-for-Sale Entity File Number Entity File Number Loss Contingencies [Table] Loss Contingencies [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Operating lease liabilities Operating Lease, Liability, Current License License [Member] 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] Total available-for-sale securities, gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Issuance of common stock under employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Entity Shell Company Entity Shell Company Adjustments to reconcile net loss to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Recently Adopted Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Change in ownership notice, term Notice of Change, Term Notice of Change, Term Accrued external research and development expenses Accrued External Research And Development Expenses Current Accrued External Research And Development Expenses, Current. Counterparty Name [Domain] Counterparty Name [Domain] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Cash, cash equivalents and restricted cash, beginning of period Cash, cash equivalents and restricted cash, end of period Total cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Asset Class [Axis] Asset Class [Axis] Sale of stock (in USD per share) Sale of Stock, Price Per Share Additional paid-in capital Additional Paid in Capital Common stock, issued (in shares) Common Stock, Shares, Issued Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Current portion of deferred revenue Contract with Customer, Liability, Current Schedule Of Common Stock Reserved For Future Issuance [Table] Schedule Of Common Stock Reserved For Future Issuance [Table] Schedule Of Common Stock Reserved For Future Issuance Table Schedule of Fair Value of Stock Option Awards on the Grant Date Using the Black-Scholes Option Valuation Model Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Forfeitures (in dollars per shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Security Exchange Name Security Exchange Name Assets Assets, Fair Value Disclosure Statement of Comprehensive Income [Abstract] Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax UCB Option and License Agreement Collaborative Arrangement Disclosure [Text Block] Shares reserved for exercise of outstanding stock options Outstanding stock options Employee Stock Option [Member] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Cancelled or forfeited (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Weighted-average period (in years) Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Maximum Maximum [Member] Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total unrecognized compensation cost related to unvested restricted stock units Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Document Type Document Type Aggregate intrinsic value outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Entity Registrant Name Entity Registrant Name Percentage change in ownership Change in Percentage of Ownership Change in Percentage of Ownership Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock-Based Compensation Share-Based Payment Arrangement [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Purchases of marketable securities Payments to Acquire Debt Securities, Available-for-Sale Document Period End Date Document Period End Date Weighted Average Exercise Price per Share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Accrued milestone expense Accrued Milestone Expense, Current Accrued Milestone Expense, Current Exercisable (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price Entity Central Index Key Entity Central Index Key Follow-On Offering Follow-On Offering [Member] Follow-On Offering Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Total stock-based compensation expense Share-Based Payment Arrangement, Expense Income Statement [Abstract] Income Statement [Abstract] Issuance of common stock from at-the-market public offerings, net of issuance and offering costs (in shares) Stock Issued During Period, Shares, New Issues Canceled or forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period Title of 12(b) Security Title of 12(b) Security Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Fair Value Measurements Fair Value Disclosures [Text Block] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Operating lease liabilities Increase (Decrease) in Operating Lease Liabilities Increase (Decrease) in Operating Lease Liabilities. Issuance of common stock from at-the-market public offerings, net of issuance costs Stock Issued During Period, Value, New Issues Unvested beginning balance (in dollars per share) Unvested ending balance (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Amendment Flag Amendment Flag Money market funds Money Market Funds [Member] Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Entity Tax Identification Number Entity Tax Identification Number 2020 Employee Stock Incentive Plan 2020 Employee Stock Incentive Plan [Member] 2020 Employee Stock Incentive Plan Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Shares withheld for taxes for vesting of restricted stock units (in shares) Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Statistical Measurement [Axis] Statistical Measurement [Axis] Financial Instrument [Axis] Financial Instrument [Axis] Entity Interactive Data Current Entity Interactive Data Current Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Shares reserved for future awards under the 2020 Employee Stock Purchase Plan 2020 Employee Stock Purchase Plan 2020 Employee Stock Purchase Plan [Member] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Reconciliation of cash, cash equivalents and restricted cash: Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents [Abstract] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested, Number of Shares [Roll Forward] Weighted average common shares outstanding, diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] UCB UCB [Member] UCB Accumulated deficit Accumulated deficit Retained Earnings (Accumulated Deficit) Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Vesting of restricted stock awards (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Operating expenses: Operating Expenses [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Additional Paid-In Capital Additional Paid-in Capital [Member] Current assets: Assets, Current [Abstract] Total assets Assets Entity Address, State or Province Entity Address, State or Province 2017 Stock Incentive Plan 2017 Employee Stock Incentive Plan [Member] Counterparty Name [Axis] Counterparty Name [Axis] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Cover [Abstract] Cover [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Subsequent Events Subsequent Events [Text Block] Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Fair Value, Recurring Fair Value, Recurring [Member] Common stock, outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Restructuring and Related Activities [Abstract] Vested (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Transaction price Revenue, Remaining Performance Obligation, Amount Offering costs included in accrued expenses Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction Total operating expenses Operating Expenses Other Other Operating Activities, Cash Flow Statement Increase (decrease) in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Asset Class [Domain] Asset Class [Domain] Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Sale of Stock [Axis] Sale of Stock [Axis] Equity Component [Domain] Equity Component [Domain] Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities Number of securities Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Weighted average common shares outstanding, basic (in shares) Weighted Average Number of Shares Outstanding, Basic Name of Property [Domain] Name of Property [Domain] Entity Current Reporting Status Entity Current Reporting Status Loss from operations Operating Income (Loss) Ionis Ionis [Member] Ionis Total liabilities Liabilities Expected volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Securities, unrealized loss position, fair value Debt Securities, Available-for-Sale, Unrealized Loss Position Total shares of authorized common stock reserved for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Measurement Frequency [Domain] Measurement Frequency [Domain] Non-current portion of deferred revenue Contract with Customer, Liability, Noncurrent Long-term liabilities: Liabilities, Noncurrent [Abstract] Proceeds from exercise of stock options and employee stock purchase plan purchases Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Including Option Exercised Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Statement [Line Items] Statement [Line Items] Plan Name [Axis] Plan Name [Axis] Accrued Expenses Accounts Payable and Accrued Liabilities Disclosure [Text Block] Vested and expected to vest (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract] Maximum percentage of voting power Percentage of Ownership Held by Sole Owner Percentage of Ownership Held by Sole Owner Earnings Per Share [Abstract] Earnings Per Share [Abstract] Summary of Investment Portfolio Debt Securities, Available-for-Sale [Table Text Block] Name of Property [Axis] Name of Property [Axis] Common stock, $0.0001 par value; 150,000,000 shares authorized; 128,540,223 shares issued and outstanding as of June 30, 2023, and 49,382,453 shares issued and outstanding as of December 31, 2022 Common Stock, Value, Issued Unaudited Interim Condensed Consolidated Financial Information Unaudited Interim Condensed Consolidated Financial Information [Policy Text Block] Unaudited interim condensed consolidated financial information General and administrative General and Administrative Expense Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract]