Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum Maximum [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Title of 12(b) Security Title of 12(b) Security Debt Securities, Available-for-Sale [Table] Debt Securities, Available-for-Sale [Table] Subsequent Events Subsequent Event [Member] Document Fiscal Year Focus Document Fiscal Year Focus Adjustment to Compensation, Amount Adjustment to Compensation Amount 2016 Equity Incentive Plan Stock Options Granted Two Thousand And Sixteen Equity Incentive Plan [Member] Two thousand and sixteen equity incentive plan. Financial Instrument [Axis] Financial Instrument [Axis] Segment Reporting [Abstract] Common stock, $0.0001 par value; 400,000,000 shares authorized as of September 30, 2026 and December 31, 2025; 89,953,997 shares and 78,189,811 shares issued and outstanding as of September 30, 2026 and December 31, 2025, respectively. Common Stock, Value, Issued Decrease in fair value of contingent value rights liability Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease) Restatement Determination Date Restatement Determination Date Payment for sublicensing fee Payment For Sublicensing Fee Payment For Sublicensing Fee Preferred stock issued and outstanding (as percent) Preferred Stock Remains Issued and Outstanding Percentage. Preferred stock remains issued and outstanding percentage. Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Derivative Instrument [Axis] Derivative Instrument [Axis] Warrants to purchase shares (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Amendment Flag Amendment Flag CURRENT LIABILITIES Liabilities, Current [Abstract] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Fairmount Funds Management LLC Fairmount Funds Management LLC [Member] Fairmount Funds Management LLC. Disposal Group Classification [Axis] Disposal Group Classification [Axis] Marketable securities, gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Sale of stock, remaining authorized amount Sale of Stock, Remaining Authorized Amount Sale of Stock, Remaining Authorized Amount License Agreements milestone and sublicensing fees Paragon Agreement, License Agreement, Milestone And Sublicensing Fees [Member] Paragon Agreement, License Agreement, Milestone And Sublicensing Fees Related Party Transactions Related Party Transactions Disclosure [Text Block] Total related party accounts payable Accounts Payable, Other, Current Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Royalty step-down (as percent) Royalty Step-Down, Percent Royalty Step-Down, Percent Entity Address, State or Province Entity Address, State or Province Total, unrealized losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Options granted to purchase (in shares) Stock options, Grants (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Fair Value Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract] PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Financial Assets: Assets, Fair Value Disclosure [Abstract] Asset Acquisition [Axis] Asset Acquisition [Axis] Cash and Cash Equivalents [Abstract] Accrued and other liabilities Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Weighted-average common stock outstanding, basic (in shares) Weighted Average Number of Shares Outstanding, Basic Share-Based Payment Arrangement, Tranche One Share-Based Payment Arrangement, Tranche One [Member] Schedule of Expenses Related to Related Party Which are Settled in Cash Schedule of Related Party Transactions [Table Text Block] Net accretion of discount on marketable securities Accretion (Amortization) of Discounts and Premiums, Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Number of reportable segments Number of Reportable Segments Total current liabilities Liabilities, Current CVR liability Derivative Liability, Current 2016 Employee Stock Purchase Plan 2016 ESPP Two Thousand And Sixteen Employee Stock Purchase Plan [Member] Two thousand and sixteen employee stock purchase plan. Entity Address, City or Town Entity Address, City or Town Restricted stock units, Grants (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Vesting of restricted stock units (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Class of Stock [Axis] Class of Stock [Axis] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Interest proceeds from maturities of zero coupon U.S. Treasury Bills Interest Proceeds, Debt Securities Interest Proceeds, Debt Securities Level 2 Fair Value, Inputs, Level 2 [Member] Other income (expense): Nonoperating Income (Expense) [Abstract] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Net Loss Per Share Earnings Per Share, Policy [Policy Text Block] Recently Adopted Accounting Pronouncements and Not Yet Adopted Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Weighted-average shares outstanding (in shares) Weighted Average Number of Shares Issued, Basic Related and Nonrelated Parties [Axis] Related and Nonrelated Parties [Axis] Schedule of Accrued and Other Current Liabilities Schedule of Accrued Liabilities [Table Text Block] Schedule of Changes in CVR Liability Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Exercise price per warrant (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Document Period End Date Document Period End Date Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Net cash (used in) provided by investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Compensation Compensation Expense, Excluding Cost of Good and Service Sold Number of monthly installments Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Monthly Installments Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Monthly Installments Preferred stock, outstanding (in shares) Beginning balance, preferred stock (in shares) Ending balance, preferred stock (in shares) Preferred Stock, Shares Outstanding Series B Non Voting Convertible Preferred Stock Series B Non-Voting Convertible Preferred Stock Series B Preferred Stock Series B Non Voting Convertible Preferred Stock [Member] Series B Non Voting Convertible Preferred Stock Security Exchange Name Security Exchange Name Stock options, Weighted Average Grant Date Fair Value (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Paragon Agreement Paragon Agreement [Member] Paragon agreement. Convertible Preferred Stock and Stockholders' Equity Preferred Stock [Text Block] Total liabilities Liabilities, Fair Value Disclosure Accumulated other comprehensive (loss) income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Changes in the fair value of the CVR liability Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings 12 Months or Longer Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Net Loss Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Earnings Per Share [Abstract] Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Schedule of Computation of Basic and Diluted Net Loss Per Share Schedule of Weighted Average Number of Shares [Table Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] TOTAL LIABILITIES Liabilities Trading Symbol Trading Symbol Risk-adjusted discount rate Measurement Input, Discount Rate [Member] Converted at the option of the holder (in shares) Convertible Preferred Stock, Shares Issued upon Conversion Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Denominator Weighted Average Number of Shares Outstanding, Basic [Abstract] Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Purchases of marketable securities Payments to Acquire Debt Securities, Available-for-Sale At-The-Market Offering, 2024 Sales Agreement At-The-Market Offering, 2024 Sales Agreement [Member] At-The-Market Offering, 2024 Sales Agreement Supplemental Disclosure of Non-Cash Financing Information: Noncash Investing and Financing Items [Abstract] U.S. government agency securities U.S. government agency securities U.S. government agency securities US Government Corporations and Agencies Securities [Member] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] CVR liability CVR Liability Contingent Value Right Liability [Member] Contingent Value Right Liability April 2026 Underwriting Agreement April 2026 Underwriting Offering [Member] April 2026 Underwriting Offering Schedule of Estimated Fair Value of Cash Equivalents and Marketable Securities and Gross Unrealized Gains and Losses Cash, Cash Equivalent, and Investment [Table Text Block] Related Party Transactions [Abstract] Related Party Transactions [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Campaign timeline, minimum term (in years) Campaign Timeline, Minimum Term Campaign Timeline, Minimum Term Weighted-average common stock outstanding, diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Disposal Group Name [Domain] Disposal Group Name [Domain] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Commercial paper Commercial paper Commercial paper Commercial Paper [Member] U.S. government treasury securities U.S. government treasury securities U.S. government treasury securities US Treasury Securities [Member] Vesting percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Payment of deferred offering costs in connection with shelf registration Payment For Deferred Offering Costs Payment For Deferred Offering Costs Award Timing Predetermined Award Timing Predetermined [Flag] Debt Securities, Available-for-Sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] All Executive Categories All Executive Categories [Member] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Realized gains or losses on marketable securities Marketable Security, Realized Gain (Loss) Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Plan Name [Domain] Plan Name [Domain] Vesting [Domain] Vesting [Domain] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Asset Acquisition [Domain] Asset Acquisition [Domain] 2015 and 2016 and 2018 Equity Inducement Plan Two Thousand And Fifteen And Two Thousand And Sixteen Equity Incentive Plan And Two Thousand And Eighteen Equity Inducement Plan [Member] Two thousand and fifteen and two thousand and sixteen equity incentive plan and two thousand and eighteen equity inducement plan. Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] License Agreement Paragon Agreement, License Milestone Payments [Member] Paragon Agreement, License Milestone Payments Segment Reporting Segment Reporting [Text Block] Minimum Minimum [Member] Expiration Date Trading Arrangement Expiration Date Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Location, Statement of Income, Balance [Axis] Location, Statement of Income, Balance [Axis] Unrealized Losses Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract] October 2026 Underwriting Offering October 2026 Underwriting Offering [Member] October 2026 Underwriting Offering Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Cash equivalents, estimated fair value Cash and Cash Equivalents, Fair Value Disclosure Company and Basis of Presentation [Line Items] Company and Basis of Presentation [Line Items] Company and basis of presentation. Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Exercise price (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Exercise Price Nonrelated Party Nonrelated Party [Member] Disposal Group, Including Discontinued Operations [Line Items] Disposal Group, Including Discontinued Operations [Line Items] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Common stock, authorized (in shares) Common Stock, Shares Authorized Net loss per share, basic and diluted: Earnings Per Share Reconciliation [Abstract] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Number of shares of common stock sold (in shares) Number of shares sold (in shares) Sale of Stock, Number of Shares Issued in Transaction Percentage of ownership held in third party Minority Interest Ownership Percentage By Noncontrolling Owners Held In Third Party Minority interest ownership percentage by noncontrolling owners held in third party. Exercise Price Award Exercise Price SPY002 and SPY072 License Agreement SPY002 And SPY 072 License Agreement [Member] SPY002 And SPY 072 License Agreement CASH FLOWS FROM INVESTING ACTIVITIES Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Related Party Transaction [Axis] Related Party Transaction [Axis] Segment Reporting [Line Items] Segment Reporting [Line Items] Cash Equivalents And Marketable Securities [Line Items] Cash Equivalents And Marketable Securities [Line Items] Cash equivalents and marketable securities. Appoint Of Board Members Appoint Of Board Members [Member] Appoint Of Board Members Proceeds from maturities and sales of marketable securities Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Document Quarterly Report Document Quarterly Report Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] October 2025 Underwritten Offering October 2025 Underwritten Offering [Member] October 2025 Underwritten Offering Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] U.S. Banking Institution U.S. Banking Institution [Member] U.S. Banking Institution [Member] Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Issuance of common stock in connection with exercise of warrants (in shares) Stock Issued During Period Shares Of Common Stock Upon Warrant Exercises Stock Issued During Period Shares Of Common Stock Upon Warrant Exercises Disposal Group Classification [Domain] Disposal Group Classification [Domain] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Contingent consideration Disposal Group, Including Discontinued Operation, Contingent Consideration Disposal Group, Including Discontinued Operation, Contingent Consideration Asset acquisition, stockholder payment period (in years) Asset Acquisition, Stockholder Payment Period Asset Acquisition, Stockholder Payment Period Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Measurement Input Type [Domain] Measurement Input Type [Domain] Sale of stock, proceeds received Sale of Stock, Consideration Received on Transaction Adoption Date Trading Arrangement Adoption Date Receivable outstanding Disposal Group, Including Discontinued Operation, Consideration TOTAL STOCKHOLDERS’ EQUITY Beginning balance Ending balance Equity, Attributable to Parent Total other income (expense) Nonoperating Income (Expense) Disposal Group, Disposed of by Sale, Not Discontinued Operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Global Rights to Pegzilarginase Global Rights To Pegzilarginase [Member] Global Rights To Pegzilarginase ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Service Based Awards Service Based Awards [Member] Service-based awards. Marketable securities, amortized cost Debt Securities, Available-for-Sale, Amortized Cost Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Risk-free interest rate Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Placement agent and other offering costs Payments of Stock Issuance Costs Insider Trading Policies and Procedures [Line Items] Outstanding option awards (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] SPY003 License Agreement SPY003 License Agreement [Member] SPY003 License Agreement Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Number of operating segments Number of Operating Segments Restricted Stock Units (RSUs) Unvested restricted stock units Restricted Stock Units (RSUs) [Member] Schedule of Weighted-Average Equity Instruments Excluded from Calculation of Diluted Net Loss Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Entity Central Index Key Entity Central Index Key Additional paid-in capital Additional Paid in Capital, Common Stock All Adjustments to Compensation All Adjustments to Compensation [Member] Accrued contracted research and development costs Accrued Contracted Research And Development Costs Accrued contracted research and development costs. Equity [Abstract] Equity [Abstract] Proceeds from issuance of common stock in connection with follow-on offering, net of issuance costs Proceeds from Issuance of Private Placement Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash used in operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Income Statement [Abstract] Income Statement [Abstract] CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY Equity, Attributable to Parent [Abstract] Preferred Stock, Excluding Series A Non Voting Convertible Preferred Stock Preferred Stock, Excluding Series A and B Non Voting Convertible Preferred Stock [Member] Preferred Stock, Excluding Series A and B Non Voting Convertible Preferred Stock Document Transition Report Document Transition Report Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Operating expenses: Operating Expenses [Abstract] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Schedule of Weighted-Average Assumptions Used in Calculating Fair Value of Awards Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] City Area Code City Area Code Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Consulting Agreement Consulting Agreement [Member] Consulting Agreement All Individuals All Individuals [Member] Due in 1-2 years Debt Securities, Available-For-Sale, Fair Value, Maturity, Allocated And Single Maturity Date, After Year One Debt Securities, Available-For-Sale, Fair Value, Maturity, Allocated And Single Maturity Date, After Year One Termination notice period (in days) Termination Notice Period Termination Notice Period Name Forgone Recovery, Individual Name Contingent Value Rights Commitments and Contingencies, Policy [Policy Text Block] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] TOTAL ASSETS Assets Interest income Investment Income, Net Preferred stock, issued (in shares) Preferred Stock, Shares Issued Common stock available for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Operating Segments Operating Segments [Member] Number of board seats held by related party Related Party Transaction, Number Of Board Seats Related Party Transaction, Number Of Board Seats Conversion of Series B non-voting convertible preferred stock into common stock Conversion of Stock, Amount Converted Marketable securities, gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Stock-based Compensation Share-Based Payment Arrangement [Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Issuance of common stock in connection with at-the-market offering programs, net of financing costs (in shares) Stock Issued During Period, Shares, New Issues Related party accounts payable Accounts Payable and Other Accrued Liabilities, Current PEO PEO [Member] Proceeds from raising capital Proceeds From Raising Capital Proceeds From Raising Capital Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Stock-based compensation expense Total stock-based compensation expense Share-Based Payment Arrangement, Expense Other non-current liabilities Other Liabilities, Noncurrent Common stock available for future issuance, additional amount authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Restricted stock units, Weighted Average Grant Date Fair Value (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Money market funds Cash equivalents, amortized cost Cash Equivalents, at Carrying Value Due in one year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Subsequent Event Type [Domain] Subsequent Event Type [Domain] Payables and Accruals [Abstract] Accumulated Deficit Retained Earnings [Member] Total operating expenses Operating Expenses Money market funds Money market funds Money Market Funds [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Schedule of Significant Inputs Used to Estimate the Fair Value of CVR Liability Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Unrealized (loss) gain on marketable securities OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Common stock, outstanding (in shares) Beginning balance, common stock (in shares) Ending balance, common stock (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Net loss per share, diluted (in dollars per share) Earnings Per Share, Diluted Royalty term expiration period (in years) Royalty Term, Expiration Period Royalty Term, Expiration Period Entity Current Reporting Status Entity Current Reporting Status Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Liabilities: Liabilities, Fair Value Disclosure [Abstract] 2018 Equity Inducement Plan Two Thousand And Eighteen Equity Inducement Plan [Member] 2018 equity inducement plan. Ownership [Domain] Ownership [Domain] Research and development, excluding compensation and share-based compensation Research and Development Expense Adjustments to reconcile net loss to net cash used in operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Share-Based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] CASH FLOWS FROM FINANCING ACTIVITIES Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Contingent obligation based on milestones Amount To Be Paid Under Agreement Amount to be paid under agreement. Financial Instruments [Domain] Financial Instruments [Domain] Numerator Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Annual percentage of additional shares Annual Percentage Of Additional Shares Which Equals To Issued And Outstanding Shares Annual percentage of additional shares which equals to the issued and outstanding shares. Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Issuance of common stock in connection with at-the-market offering programs, net of financing costs Stock Issued During Period, Value, New Issues Over-Allotment Option Over-Allotment Option [Member] Proceeds from employee stock option exercises and employee stock plan purchases Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Including Option Exercised Preferred Stock Preferred Stock [Member] Segment Reporting [Table] Segment Reporting [Table] Related Party Transaction [Table] Related Party Transaction [Table] Sale of Stock [Axis] Sale of Stock [Axis] All Trading Arrangements All Trading Arrangements [Member] Less Than 12 Months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Beginning balance Ending balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Loss from operations Operating Income (Loss) Reportable Segment Reportable Segment [Member] Reportable Segment Allocation of deferred offering costs against proceeds of issuance of common stock Deferred Offering Costs, Allocated Amount of Proceeds of Issuance of Common Stock Deferred Offering Costs, Allocated Amount of Proceeds of Issuance of Common Stock Current Fiscal Year End Date Current Fiscal Year End Date Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Related Party Transaction [Domain] Related Party Transaction [Domain] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Stock-based compensation expense Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Schedule of Contractual Maturities of Marketable Securities at Estimated Fair Value Investments Classified by Contractual Maturity Date [Table Text Block] Corporate bonds Corporate bonds Corporate bonds Corporate Bond Securities [Member] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Common stock, issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Sublicensing fee Sublicensing Fee Sublicensing Fee 2016 ESPP 2016 ESPP [Member] 2016 ESPP 12 Months or Longer Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Marketable securities Marketable securities, estimated fair value Total marketable securities Debt Securities, Available-for-Sale, Current Sale of stock, authorized amount Sale of Stock, Authorized Amount Sale of Stock, Authorized Amount Equity Components [Axis] Equity Components [Axis] Issuance of common stock in connection with exercise of stock options and employee stock purchase plan (in shares) Stock Issued During Period, Shares, Options Exercised And Employee Stock Ownership Plan Stock Issued During Period, Shares, Options Exercised And Employee Stock Ownership Plan Related Party Related Party [Member] Class of Stock [Line Items] Class of Stock [Line Items] Entity Interactive Data Current Entity Interactive Data Current Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Cash Equivalents And Marketable Securities [Table] Cash Equivalents And Marketable Securities [Table] Cash equivalents and marketable securities. Entity Small Business Entity Small Business Total comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Termination Date Trading Arrangement Termination Date Accounts payable Increase (Decrease) in Accounts Payable, Trade Payments Payments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Sale of Pegzilarginase to Immedica Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Expiration term (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period Document Type Document Type 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] Asset acquisition, cash payment, threshold period (in years) Asset Acquisition, Cash Payment, Threshold Period Asset Acquisition, Cash Payment, Threshold Period Fair Value as of Grant Date Award Grant Date Fair Value Allowance for credit loss Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Schedule of Available-for-Sale Securities in an Unrealized Loss Position Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table] Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table] CASH AND CASH EQUIVALENTS Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Foreign currency translation adjustment Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Milestone payments, outstanding and payable License Agreement, Milestone Payments Outstanding and Payable License Agreement, Milestone Payments Outstanding and Payable Local Phone Number Local Phone Number Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Less Than 12 Months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Series A Non Voting Convertible Preferred Stock Series A Non-Voting Convertible Preferred Stock Series A Preferred Stock Series A Non Voting Convertible Preferred Stock [Member] Series A non voting convertible preferred stock. Loss before income tax benefit Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Commitments and Contingencies (Notes 6 and 7) Commitments and Contingencies Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Vest period grant date (in years) Share-based award, vesting period (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Other Paragon Reimbursable Expenses Other Paragon Reimbursable Expenses [Member] Other Paragon Reimbursable Expenses Schedule of Fair Value of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Number of warrants outstanding (in shares) Class of Warrant or Right, Outstanding Fair Value Measurements Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] US Government Agencies Debt Securities US Government Agencies Debt Securities [Member] Paragon and License Agreement Paragon and License Agreement [Member] Paragon and License Agreement Expected term (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Cash equivalents, gross unrealized losses Cash Equivalents Unrealized Losses Cash equivalents unrealized losses. Percentage of ownership by noncontrolling owner Subsidiary, Ownership Percentage, Noncontrolling Owner PEO Name PEO Name Accrued and other current liabilities Total accrued and other current liabilities Accrued Liabilities and Other Liabilities Impairment of marketable securities Impairment Of Marketable Securities Impairment of marketable securities. Cash, cash equivalents, and marketable securities Cash, Cash Equivalents, and Short-Term Investments Other segment items Segment Reporting, Other Segment Item, Amount Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number SPY001 License Agreement SPY001 License Agreement [Member] SPY001 License Agreement. Liability Class [Axis] Liability Class [Axis] Proceeds from issuance of common stock in connection with at-the-market offering program, net of issuance costs Proceeds From Issuance of Common Stock, At-The-Market Offerings, Net Proceeds From Issuance of Common Stock, At-The-Market Offerings, Net At-The-Market Offering, 2026 Sales Agreement At-The-Market Offering, 2026 Sales Agreement [Member] At-The-Market Offering, 2026 Sales Agreement Beginning of period End of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Accrued professional and consulting fees Accrued Professional Fees, Current Accrued other Other Accrued Liabilities, Current Accrued and Other Current Liabilities Accrued And Other Current Liabilities [Text Block] The entire disclosure for accrued expenses, and other liabilities that are classified as current at the end of the reporting period. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] The Company and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Stock-based compensation Share-Based Payment Arrangement, Noncash Expense Disposal Group Name [Axis] Disposal Group Name [Axis] Conversion of Series B Non-Voting Convertible Preferred Stock to common stock (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Employee Stock Employee Stock [Member] Amount of related party transaction Related Party Transaction, Amounts of Transaction Net loss per share, basic (in dollars per share) Earnings Per Share, Basic Cash equivalents, gross unrealized gains Cash Equivalents Unrealized Gains Cash equivalents unrealized gains. Measurement Input Type [Axis] Measurement Input Type [Axis] Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Cash milestone payments License Agreement, Milestone Payments License Agreement, Milestone Payments Award Type [Axis] Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Licensing Agreements [Abstract] Licensing Agreements Accumulated deficit Accumulated deficit Retained Earnings (Accumulated Deficit) Schedule of Stock Awards Granted Under all Equity Incentive and Inducement Plans Schedule of Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value [Table Text Block] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Proceeds from stock option exercises received in subsequent period Issuance of Convertible Preferred Stock Related to Private Placement, Unpaid Amount Issuance of Convertible Preferred Stock Related to Private Placement, Unpaid Amount Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Stock Common Stock Common Stock [Member] Gain on sale of in-process research and development asset Gain on sale of in-process research and development asset Gain on sale of in-process research and development asset Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Financial assets Debt Securities, Available-for-Sale Expected volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Related party accounts payable Increase (Decrease) in Other Accounts Payable Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Dividend yield Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Derivative Contract [Domain] Derivative Contract [Domain] Equity Awards Adjustments Equity Awards Adjustments [Member] Licensing Agreements Collaborative Arrangement Disclosure [Text Block] TOTAL LIABILITIES, CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY Liabilities and Equity Non-current CVR liability Derivative Liability, Noncurrent Accrued compensation Accrued Salaries, Current Options to purchase common stock Stock Options Share-Based Payment Arrangement, Option [Member] Number of common shares issuable upon conversion (in shares) Preferred Stock, Convertible, Shares Issuable Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Plan Name [Axis] Plan Name [Axis] Related and Nonrelated Parties [Domain] Related and Nonrelated Parties [Domain] Derivative liability, measurement input (as percent) Derivative Liability, Measurement Input Tabular List, Table Tabular List [Table Text Block] Vesting [Axis] Vesting [Axis] Schedule of Stock-Based Compensation Expense Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Other (expense) income, net Other Nonoperating Income (Expense) Name Awards Close in Time to MNPI Disclosures, Individual Name Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] General and administrative General and Administrative Expense Payments related to contingent value rights liability Payments Related To Contingent Value Rights Liability Payments Related To Contingent Value Rights Liability Number of domestic banking institutions (in banks) Number Of Domestic Banking Institutions Number Of Domestic Banking Institutions Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Sale of stock, price per share (in dollars per share) Sale of Stock, Price Per Share Conversion of Series B Non-Voting Convertible Preferred Stock to common stock Stock Issued During Period, Value, Conversion of Convertible Securities Preferred stock, authorized (in shares) Preferred Stock, Shares Authorized First milestone payment Payment Of Milestone Payment of milestone. Outstanding Parapyre warrants Parapyre Warrants [Member] Parapyre Warrants Preferred stock Preferred Stock, Value, Issued Adjustment to Compensation: Adjustment to Compensation [Axis] Company and Basis of Presentation [Table] Company and Basis of Presentation [Table] Company and basis of presentation. Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Sublicensing fee, outstanding and payable Sublicensing Fee, Outstanding And Payable Sublicensing Fee, Outstanding And Payable Issuance of common stock in connection with exercise of stock options and employee stock purchase plan Stock Issued During Period, Value, Options Exercised And Employee Stock Ownership Plan Stock Issued During Period, Value, Options Exercised And Employee Stock Ownership Plan Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Total financial assets Assets, Fair Value Disclosure Discontinued Operations and Disposal Groups [Abstract] Name Measure Name Accounts payable Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Additional Paid-In Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Total, fair value Debt Securities, Available-for-Sale, Unrealized Loss Position Proceeds from sale of in-process research and development asset Proceeds from sale of in-process research and development asset Proceeds from Sale of Intangible Assets Spyre Therapeutics, Inc. Spyre Therapeutics, Inc. [Member] Spyre Therapeutics, Inc. Accrued interest receivable on available-for-sale debt securities Interest Receivable Name Trading Arrangement, Individual Name Sale of stock, aggregate offering price Sale of Stock, Aggregate Offering Price Sale of Stock, Aggregate Offering Price Cash and cash equivalents Cash and Cash Equivalent Change in fair value of CVR liability Gain (Loss) on Derivative Instruments, Net, Pretax Company Selected Measure Amount Company Selected Measure Amount Schedule of Significant Expenses Provided to the CODM on a Regular Basis Segment Reporting, Reconciliation of Profit (Loss) by Segment to Consolidated [Table Text Block] Entity Address, Address Line Three Entity Address, Address Line Three Entity Address, Address Line Two Entity Address, Address Line Two Stock, Class of Stock [Table] Stock, Class of Stock [Table] Increase (decrease) in fair value of contingent value right liability Increase (Decrease) In Fair Value Of Contingent Value Right Liability Increase (Decrease) In Fair Value Of Contingent Value Right Liability Commercial paper Commercial Paper, Not Included with Cash and Cash Equivalents [Member] CURRENT ASSETS Assets, Current [Abstract] CVR liability Derivative Liability Non-PEO NEO Non-PEO NEO [Member] Entity Address, Address Line One Entity Address, Address Line One Income tax benefit Income Tax Expense (Benefit) Additional number of shares available for issuance (in shares) Share Based Compensation Arrangement By Share Based Payment Award Additional Number Of Shares Available For Grant Share-based compensation arrangement by share-based payment award, additional number of shares available for grant. Paragon Therapeutics Inc Paragon Therapeutics Inc [Member] Paragon therapeutics, Inc. Award Timing Method Award Timing Method [Text Block] NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Cash Equivalents and Marketable Securities Cash, Cash Equivalent, and Marketable Security [Text Block] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Research and development Total related party expense Research and Development Expense (Excluding Acquired in Process Cost) Net loss Net loss Net loss Allocation of losses Net Income (Loss) Attributable to Parent Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Cash, FDIC insured amount (up to) Cash, FDIC Insured Amount Statement [Table] Statement [Table] Restatement Determination Date: Restatement Determination Date [Axis] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]