Trading Arrangements, by Individual
Trading Arrangements, by Individual [Table]
Trading Arrangement:
Trading Arrangement [Axis]
Maximum
Maximum [Member]
Statistical Measurement [Domain]
Statistical Measurement [Domain]
Proceeds from sale of common stock and pre-funded warrants in 2026 private placement
Proceeds From Sale Of Common Stock and Pre-Funded Warrants In Private Placement
Proceeds From Sale Of Common Stock and Pre-Funded Warrants In Private Placement
Title of 12(b) Security
Title of 12(b) Security
Subsequent Event
Subsequent Event [Member]
Document Fiscal Year Focus
Document Fiscal Year Focus
Payments on issuance cost from registration statement
Payments on Issuance Cost from Registration Statement
Payments on Issuance Cost from Registration Statement
Adjustment to Compensation, Amount
Adjustment to Compensation Amount
Purchase Agreement [Domain]
Purchase Agreement [Domain]
Purchase Agreement
Shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
ALTO-207
Alto-207 [Member]
Alto-207
Segment Reporting [Abstract]
Prepayment fee, percent of outstanding principal, applicable on or before 24 months after initial funding date
Debt Instrument, Prepayment Penalty Fee, On Or Before 24 Months After Initial Funding Date, Percent Of Outstanding Principal
Debt Instrument, Prepayment Penalty Fee, On Or Before 24 Months After Initial Funding Date, Percent Of Outstanding Principal
Payment of withholding taxes for stock-based compensation
Payment, Tax Withholding, Share-Based Payment Arrangement
Accrued payroll, vacation and employee-related expenses
Employee-related Liabilities, Current
Retention period
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Requisite Service Period
Retirement Plan
Retirement Benefits [Text Block]
Restatement Determination Date
Restatement Determination Date
Issuance of common stock for conversion of the K2 term loan, net of issuance (in shares)
Stock Issued During Period, Share, Conversion Of Term Loan
Stock Issued During Period, Share, Conversion Of Term Loan
Class of Warrant or Right [Domain]
Class of Warrant or Right [Domain]
Amount of debt convertible to equity at election of lender
Debt Instrument, Additional Amount Convertible To Equity At Election Of Lender
Debt Instrument, Additional Amount Convertible To Equity At Election Of Lender
Weighted –
average
remaining
contractual
term (in
years)
Share-Based Compensation Arrangement By Share Based Payment Award, Options, Weighted Average Contractual Term [Abstract]
Share-Based Compensation Arrangement By Share Based Payment Award, Options, Weighted Average Contractual Term
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of shares called by warrants (in shares)
Class of Warrant or Right, Number of Securities Called by Warrants or Rights
Conversion price per share
Debt Instrument, Convertible, Conversion Price
Amendment Flag
Amendment Flag
Current liabilities:
Liabilities, Current [Abstract]
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Issuance of new tranches
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances
Stock issued during period (in shares)
Stock Issued During Period, Shares, Other
Other, net
Fair Value Adjustment of Warrants
Non-cash interest expense related to term loan
Interest Expense, Noncash
Interest Expense, Noncash
New Warrant
New K2 Warrant [Member]
New K2 Warrant
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Annual increase, percentage of outstanding shares
Common Stock, Capital Shares Reserved for Future Issuance, Annual Increase, Percentage of Outstanding Stock
Common Stock, Capital Shares Reserved for Future Issuance, Annual Increase, Percentage of Outstanding Stock
Adjustment to Non-PEO NEO Compensation Footnote
Adjustment to Non-PEO NEO Compensation Footnote [Text Block]
Amended Loan Agreement
Amended Loan Agreement [Member]
Amended Loan Agreement
Entity Address, State or Province
Entity Address, State or Province
Granted (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross
Foreign currency translation
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent
PEO Total Compensation Amount
PEO Total Compensation Amount
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Maximum shares issuable (in shares)
Debt Instrument, Convertible, Maximum Shares Issuable
Debt Instrument, Convertible, Maximum Shares Issuable
Outstanding, beginning balance (in shares)
Outstanding, ending balance (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Accrued liabilities and other liabilities
Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities
Weighted-average number of common shares outstanding, basic (in shares)
Weighted Average Number of Shares Outstanding, Basic
Vested after 18 months
Share-Based Payment Arrangement, Tranche One [Member]
Retirement Benefits [Abstract]
Outstanding Aggregate Erroneous Compensation Amount
Outstanding Aggregate Erroneous Compensation Amount
Number of reportable segments
Number of Reportable Segments
Total current liabilities
Liabilities, Current
Increase or decrease the beneficial ownership limitation
Class Of Warrants Or Rights, Notice Period For Beneficial Ownership Limitation
Class Of Warrants Or Rights, Notice Period For Beneficial Ownership Limitation
Entity Address, City or Town
Entity Address, City or Town
Asset purchase agreement, expenses reimbursed
Asset Purchase Agreement, Expenses Reimbursed
Asset Purchase Agreement, Expenses Reimbursed
Granted (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]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Disclosure [Line Items]
Statement of Financial Position [Abstract]
Award Timing MNPI Disclosure
Award Timing MNPI Disclosure [Text Block]
Vested (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period
Variable rate threshold for potential adjustment
Debt Instrument, Variable Interest Rate, Threshold For Potential Adjustment
Debt Instrument, Variable Interest Rate, Threshold For Potential Adjustment
Class of Stock [Axis]
Class of Stock [Axis]
Basis of Presentation
Basis of Accounting, Policy [Policy Text Block]
Peer Group Total Shareholder Return Amount
Peer Group Total Shareholder Return Amount
Level 2
Fair Value, Inputs, Level 2 [Member]
Total Shareholder Return Vs Peer Group
Total Shareholder Return Vs Peer Group [Text Block]
Aggregate principle amount (up to)
Line of Credit Facility, Maximum Borrowing Capacity
Comprehensive loss
Other Comprehensive Income (Loss), Net of Tax
Non-Rule 10b5-1 Arrangement Terminated
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Term loan, current
Less: Term loan, current portion
Long-Term Debt, Current Maturities
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Restricted stock units vesting (in shares)
Stock Issued During Period, Shares, Restricted Stock Award, Gross
Schedule of Long-Term Debt Instruments [Table]
Schedule of Long-Term Debt Instruments [Table]
Preferred stock conversion, number of common stock (in shares)
Temporary Equity, Shares, Conversion Of Convertible Securities
Temporary Equity, Shares, Conversion Of Convertible Securities
Recently Adopted and Recently Issued Accounting Pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Conversion of K2 term loan into shares of common stock
Capital Expenditures Incurred but Not yet Paid
Segment Reporting
Segment Reporting [Table Text Block]
Loss on disposal of assets
Gain (Loss) on Disposition of Property Plant Equipment
Use of Estimates
Use of Estimates, Policy [Policy Text Block]
Issuance of K2 warrants
APIC Increase For Reclassification Of Warrants For Conversion Of Convertible Securities To Common Stock
APIC Increase For Reclassification Of Warrants For Conversion Of Convertible Securities To Common Stock
Total other comprehensive income (loss)
Other comprehensive income
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Schedule of accrued liabilities
Schedule of Accrued Liabilities [Table Text Block]
Warrant exercise price (in dollars per share)
Class of Warrant or Right, Exercise Price of Warrants or Rights
Term loan, non-current
Long-Term Debt
Exercise prices, upper range (in dollars per share)
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit
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]
Forfeited and cancelled (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period
Net cash used in 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]
Preferred stock, outstanding (in shares)
Preferred Stock, Shares Outstanding
Term loan
Debt Instrument, Face Amount
Stockholders’ Equity
Equity [Text Block]
Third tranche, available from October 1, 2023 and March 1, 2024
Debt Instrument, Tranche Three [Member]
Debt Instrument, Tranche Three
Security Exchange Name
Security Exchange Name
Granted (in dollars per share)
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Payments of issuance cost and underwriting fees related to the sale of common stock and pre-funded warrants in 2026 private placement
Payments Of Costs From Sale Of Common Stock And Pre-Funded Warrants In Private Placement
Payments Of Costs From Sale Of Common Stock And Pre-Funded Warrants In Private Placement
Convertible Grant Agreement
Convertible Debt
Value of the RSUs vested
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss), Net of Tax
Entity Shell Company
Entity Shell Company
Changes in fair value reported in statements of operations
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings
Term of weighted average price for share conversion
Debt Instrument, Convertible, Conversion Price, Term Of Weighted Average Price Measurement
Debt Instrument, Convertible, Conversion Price, Term Of Weighted Average Price Measurement
Number of shares approved, initially reserved for issuance under plan (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized
Lease liability, short term
Operating Lease, Liability, Current
Accrued interest, short term
Interest Payable, Current
Schedule of property and equipment, net
Property, Plant, and Equipment [Table Text Block]
Loss Per Share
Earnings Per Share [Text Block]
Name
Outstanding Recovery, Individual Name
Earnings Per Share [Abstract]
Award Timing, How MNPI Considered
Award Timing, How MNPI Considered [Text Block]
Document Fiscal Period Focus
Document Fiscal Period Focus
Discount on shares
Debt Instrument, Convertible, Discount On Shares Converted
Debt Instrument, Convertible, Discount On Shares Converted
Peer Group Issuers, Footnote
Peer Group Issuers, Footnote [Text Block]
Total liabilities
Liabilities
Trading Symbol
Trading Symbol
Measurement Input, Discount Rate
Measurement Input, Discount Rate [Member]
Debt Instrument, Tranche [Domain]
Debt Instrument, Tranche [Domain]
Debt Instrument, Tranche [Domain]
Capital expenditures
Payments to Acquire Property, Plant, and Equipment
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]
Unrecognized stock-based compensation
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount
Employer matching contribution, percent of employees' gross pay
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
Company Selected Measure Name
Company Selected Measure Name
Sale of Stock [Domain]
Sale of Stock [Domain]
Computer software and equipment
Computer Software And Equipment [Member]
Computer Software And Equipment
Income Tax Disclosure [Abstract]
Purchase Agreement [Axis]
Purchase Agreement [Axis]
Purchase Agreement
Number of shares called by warrants, multiplier
Class of Warrant or Right, Number of Securities Called by Warrants or Rights, Multiplier
Class of Warrant or Right, Number of Securities Called by Warrants or Rights, Multiplier
Total principal payments
Long-Term Debt, Gross
Amount of debt convertible to equity at election of lender
Debt Instrument, Portion Convertible To Equity At Election Of Lender
Debt Instrument, Portion Convertible To Equity At Election Of Lender
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]
Weighted-average number of common shares 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]
Schedule of prepaid expenses and other current assets
Schedule of Other Current Assets [Table Text Block]
Underlying Security Market Price Change
Underlying Security Market Price Change, Percent
Exercise prices, lower range (in dollars per share)
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit
Percentage vested in year one
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage
Exercise price (in dollars per share)
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
General and administrative
Other General and Administrative Expense
Award Timing Predetermined
Award Timing Predetermined [Flag]
Exercised
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value
Adjustment To PEO Compensation, Footnote
Adjustment To PEO Compensation, Footnote [Text Block]
Stock compensation expense
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition
Level 1
Fair Value, Inputs, Level 1 [Member]
Fixed rate, paid-in-kind
Debt Instrument, Fixed Rate, Paid-In-Kind
Debt Instrument, Fixed Rate, Paid-In-Kind
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Asset purchase agreement, milestone payments
Asset Purchase Agreement, Milestone Payments
Asset Purchase Agreement, Milestone Payments
Outstanding, beginning balance (in dollars per share)
Outstanding, 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
All Executive Categories
All Executive Categories [Member]
Pension Adjustments Service Cost
Pension Adjustments Service Cost [Member]
Weighted-
average
exercise
price per share
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Weighted Average Exercise Price [Roll Forward]
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Weighted Average Exercise Price
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share
Subsidiary of LLC or LP [Table]
Subsidiary of LLC or LP [Table]
Depreciation
Depreciation
ALTO-101
Alto-101 [Member]
Alto-101
Vesting [Domain]
Vesting [Domain]
Plan Name [Domain]
Plan Name [Domain]
Antidilutive Securities [Axis]
Antidilutive Securities [Axis]
Outstanding, beginning balance (in dollars per share)
Outstanding, ending balance (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Operating right-of-use asset
Operating Lease, Right-of-Use Asset
Fair Value Disclosures [Abstract]
Debt Disclosure [Abstract]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Segments
Segment Reporting [Text Block]
Minimum
Minimum [Member]
Expiration Date
Trading Arrangement Expiration Date
Liabilities:
Liabilities [Abstract]
Class of Warrant or Right [Axis]
Class of Warrant or Right [Axis]
Effect of exchange rate changes on cash, cash equivalents and restricted cash
Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation
Location, Statement of Income, Balance [Axis]
Location, Statement of Income, Balance [Axis]
Non-Rule 10b5-1 Arrangement Adopted
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Outstanding
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted-Average Remaining Contractual Term
Fair value of common stock (in dollars per share)
Share Based Compensation By Share Based Payment Award, Fair Value Assumptions, Fair Value Of Award
Share Based Compensation By Share Based Payment Award, Fair Value Assumptions, Fair Value Of Award, Per Share
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
Total liabilities
Financial Liabilities Fair Value Disclosure
Convertible Grant Agreement
Convertible Debt, Fair Value Disclosures
Exercisable at period end (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number
Issuance costs related to the 2026 private placement
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs
Aggregate Pension Adjustments Service Cost
Aggregate Pension Adjustments Service Cost [Member]
Other income (expense):
Other Income and Expenses [Abstract]
Common stock, authorized (in shares)
Common Stock, Shares Authorized
Antidilutive Security, Excluded EPS Calculation [Table]
Antidilutive Security, Excluded EPS Calculation [Table]
Accrued research
Accrued Research Expense
Accrued Research Expense
Sale of stock, number of shares issued in transaction (in shares)
Sale of Stock, Number of Shares Issued in Transaction
Share-based payment arrangement, restricted stock unit, activity
Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]
Exercise Price
Award Exercise Price
Cash Flows from Investing Activities:
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]
Segment Reporting [Line Items]
Segment Reporting [Line Items]
Weighted-average
grant date fair value per share
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Rollforward [Roll Forward]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Rollforward
RSU unrecognized compensation
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
Document Quarterly Report
Document Quarterly Report
Debt Instrument, Tranche [Axis]
Debt Instrument, Tranche [Axis]
Debt Instrument, Tranche
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]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Second tranche, available between October 1, 2023 and March 1, 2024
Debt Instrument, Tranche Two [Member]
Debt Instrument, Tranche Two
Debt
Debt Disclosure [Text Block]
Number of tranches
Debt Instrument, Number Of Tranches
Debt Instrument, Number Of Tranches
Repayment of former term loan
Repayments of Long-Term Debt
Debt issuance costs and discount
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net
Awards Close in Time to MNPI Disclosures, Table
Awards Close in Time to MNPI Disclosures [Table Text Block]
Issuance of common stock for conversion of the K2 term loan, net of issuance
Stock Issued During Period, Value, Conversion Of Term Loan
Stock Issued During Period, Value, Conversion Of Term Loan
Prepayment fee, percent of outstanding principal, applicable on or before 36 months after initial funding date
Debt Instrument, Prepayment Penalty Fee, On Or Before 36 Months After Initial Funding Date, Percent Of Outstanding Principal
Debt Instrument, Prepayment Penalty Fee, On Or Before 36 Months After Initial Funding Date, Percent Of Outstanding Principal
K2 Healthventures LLC
K2 Healthventures LLC [Member]
K2 Healthventures LLC
Equity Component [Domain]
Equity Component [Domain]
PEO Actually Paid Compensation Amount
PEO Actually Paid Compensation Amount
Interest rate increase in event of default
Debt Instrument, Interest Rate Increase In Event Of Default
Debt Instrument, Interest Rate Increase In Event Of Default
Measurement Input Type [Domain]
Measurement Input Type [Domain]
ALTO-203
Alto-203 [Member]
Alto-203
Secured Debt
Secured Debt [Member]
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]
Sale of stock, consideration received on transaction
Sale of Stock, Consideration Received on Transaction
Adoption Date
Trading Arrangement Adoption Date
First tranche, funded on December 16, 2022
Debt Instrument, Tranche One [Member]
Debt Instrument, Tranche One
Total stockholders’ equity
Beginning balance
Ending balance
Equity, Attributable to Parent
Total other income, net
Nonoperating Income (Expense)
Asset purchase agreement, potential milestone payments tied to commercial success
Asset Purchase Agreement, Potential Milestone Payments Tied To Commercial Success
Asset Purchase Agreement, Potential Milestone Payments Tied To Commercial Success
Prepaid insurance
Prepaid Insurance
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
Stock options issued and outstanding from 2024, 2019 Equity Incentive Plan and Inducement Plan
Employee Stock Options Issued And Outstanding [Member]
Employee Stock Options Issued And Outstanding
One-time facility fee
Debt Instrument, Fee Amount
Accounting Policies [Abstract]
Restatement does not require Recovery
Restatement Does Not Require Recovery [Text Block]
Risk-free rate
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate
Insider Trading Policies and Procedures [Line Items]
Outstanding, beginning balance (in shares)
Outstanding, ending balance (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]
Performance Shares
Performance Shares [Member]
Prepaid expenses and other current assets
Total 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]
Private Placement
Private Placement [Member]
Balance Sheet Components
Supplemental Balance Sheet Disclosures [Text Block]
Exit Fee
Debt Instrument, Exit Fee
Debt Instrument, Exit Fee
Forfeited and cancelled (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Compensation Actually Paid vs. Net Income
Compensation Actually Paid vs. Net Income [Text Block]
Reportable segment
Reportable Segment [Member]
Reportable Segment
Antidilutive securities excluded from computation of earnings per share (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Restricted Stock Units
Restricted Stock Units (RSUs) [Member]
Schedule of antidilutive securities excluded from computation of earnings per share
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Entity Central Index Key
Entity Central Index Key
Common stock (par value $0.0001), 500,000 shares authorized; 35,094 and 31,924 shares issued and outstanding as of June 30, 2026 and December 31, 2025, respectively
Common Stock, Value, Outstanding
Less: accumulated depreciation
Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization
All Adjustments to Compensation
All Adjustments to Compensation [Member]
Equity [Abstract]
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
2026 (remainder of year)
Long-Term Debt, Maturity, Remainder of Fiscal Year
ALTO-100
Alto-100 [Member]
Alto-100
Income Statement [Abstract]
Document Transition Report
Document Transition Report
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Interest rate floor
Debt Instrument, Interest Rate Floor
Debt Instrument, Interest Rate Floor
Operating expenses:
Operating Expenses [Abstract]
Stock Appreciation Rights (SARs)
Stock Appreciation Rights (SARs) [Member]
Schedule of share-based payment award, stock options, valuation assumptions
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Interest rate, basis spread (greater of)
Debt Instrument, Basis Spread on Variable Rate
Other Commitments [Domain]
Other Commitments [Domain]
City Area Code
City Area Code
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent [Member]
All Individuals
All Individuals [Member]
Subsequent Events
Subsequent Events [Text Block]
Non-cash lease expense
Operating Lease, Right-of-Use Asset, Periodic Reduction
Securities Purchase Agreement
Securities Purchase Agreement [Member]
Securities Purchase Agreement
Price volatility
Measurement Input, Price Volatility [Member]
Name
Forgone Recovery, Individual Name
Period for recognition of unrecognized share based compensation
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition
Non-GAAP Measure Description
Non-GAAP Measure Description [Text Block]
Statement [Line Items]
Statement [Line Items]
Total assets
Assets
Defined Benefit Plan [Table]
Defined Benefit Plan [Table]
Nicholas Smith [Member]
Nicholas Smith
Preferred stock, issued (in shares)
Preferred Stock, Shares Issued
Shares reserved for issuance under ESPP plan (in shares)
Common Stock, Capital Shares Reserved for Future Issuance
Asset purchase agreement, milestone payments, maximum shares to be issued
Asset Purchase Agreement, Milestone Payments, Maximum Shares To Be Issued
Asset Purchase Agreement, Milestone Payments, Maximum Shares To Be Issued
Convertible debt
Convertible Debt [Member]
Sale of stock conversion of outstanding loan
Sale Of Stock, Conversion Of Outstanding Loan
Sale Of Stock, Conversion Of Outstanding Loan
Weighted average grant date fair value (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value
Deferred interest
Debt Instrument, Deferred Interest
Debt Instrument, Deferred Interest
Interest expense
Interest Expense, Nonoperating
Stock-Based Plans
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]
Proceeds from Convertible Grant Agreement
Proceeds from Convertible Debt
PEO
PEO [Member]
2028
Long-Term Debt, Maturity, Year Two
Cash and Cash Equivalents [Domain]
Cash and Cash Equivalents [Domain]
Stock-based compensation expenses
Total stock-based compensation expense
Share-Based Payment Arrangement, Expense
Forgone Recovery due to Violation of Home Country Law, Amount
Forgone Recovery due to Violation of Home Country Law, Amount
Exercise of common stock options (in shares)
Exercised (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period
Granted (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
Shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Asset purchase agreement, milestone payment achieved and paid in cash
Asset Purchase Agreement, Milestone Payment Achieved and Paid In Cash
Asset Purchase Agreement, Milestone Payment Achieved and Paid In Cash
Accumulated Deficit
Retained Earnings [Member]
Lease liability, long-term
Operating Lease, Liability, Noncurrent
Total operating expenses
Operating Expenses
Money Market Funds
Money Market Funds [Member]
Weighted average interest rate
Long-Term Debt, Weighted Average Interest Rate, over Time
Forfeited and cancelled (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value
Erroneously Awarded Compensation Recovery
Erroneously Awarded Compensation Recovery [Table]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)
Beginning balance (in shares)
Ending balance (in shares)
Common Stock, Shares, Outstanding
Award Timing Disclosures [Line Items]
Payment of loan financing cost
Payments of Debt Issuance Costs
Net loss per share attributable to common stockholders, diluted (in dollars per share)
Earnings Per Share, Diluted
Entity Current Reporting Status
Entity Current Reporting Status
Net cash provided by financing activities
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation
Total Shareholder Return Amount
Total Shareholder Return Amount
The 2024 Equity Incentive Plan
The 2024 Equity Incentive Plan [Member]
The 2024 Equity Incentive Plan
Number of wholly owned subsidiaries
Number of Wholly Owned Subsidiaries
Number of Wholly Owned Subsidiaries
Prepaid expenses and other assets
Increase (Decrease) in Prepaid Expense and Other Assets
Schedule of change in the air value of the Convertible Grant Agreement
Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]
Stockholders’ equity:
Stockholders' Equity Note [Abstract]
Asset purchase agreement, milestone payments, maximum shares to be issued, percentage of outstanding shares
Asset Purchase Agreement, Milestone Payments, Maximum Shares To Be Issued, Percentage Of Outstanding Shares
Asset Purchase Agreement, Milestone Payments, Maximum Shares To Be Issued, Percentage Of Outstanding Share
Proceeds from issuance of term loan, net
Proceeds from Long-Term Lines of Credit
Research and development
Direct external program expenses:
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]
2029
Long-Term Debt, Maturity, Year Three
IPO
IPO [Member]
Share-Based Payment Arrangement [Abstract]
Cash Flows from Financing Activities:
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Property and equipment, net
Property and equipment, net
Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization
Shares underlying repriced options, (in shares)
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding
Aggregate
intrinsic
value
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Aggregate Intrinsic Value [Abstract]
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Aggregate Intrinsic Value
Exercise of common stock options
Stock Issued During Period, Value, Stock Options Exercised
Underwriting Agreement
Underwriting Agreement [Member]
Underwriting Agreement
Equity Awards Adjustments, Footnote
Equity Awards Adjustments, Footnote [Text Block]
RSUs issued (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted
Underlying Securities
Award Underlying Securities Amount
Over-Allotment Option
Over-Allotment Option [Member]
Other prepaid expenses
Prepaid Expense, Current
Number of clinical-stage assets
Number Of Clinical-Stage Assets
Number Of Clinical-Stage Assets
Additional Warrants
Additional K2 Warrants [Member]
Additional K2 Warrants
ALTO-300
Alto-300 [Member]
Alto-300
Segment Reporting [Table]
Segment Reporting [Table]
Schedule of future principal debt payments and exit fee
Schedule of Maturities of Long-Term Debt [Table Text Block]
Final payment, percentage of amount borrowed
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid, Percentage Of Amount Borrowed
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid, Percentage Of Amount Borrowed
Sale of Stock [Axis]
Sale of Stock [Axis]
Commitments and Contingencies Disclosure [Abstract]
All Trading Arrangements
All Trading Arrangements [Member]
Loan at fair value
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)
Supplemental Disclosure of Cash Flow Information
Interest Paid, Including Capitalized Interest, Operating and Investing Activities [Abstract]
Current Fiscal Year End Date
Current Fiscal Year End Date
Non-PEO NEO Average Total Compensation Amount
Non-PEO NEO Average Total Compensation Amount
Asset purchase agreement, potential milestone payments
Asset Purchase Agreement, Potential Milestone Payments
Asset Purchase Agreement, Potential Milestone Payments
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]
Fourth tranche, available through January 1, 2025
Debt Instrument, Tranche Four [Member]
Debt Instrument, Tranche Four
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]
Asset purchase agreement, consecutive trading day period
Asset Purchase Agreement, Consecutive Trading Day Period
Asset Purchase Agreement, Consecutive Trading Day Period
Common stock, issued (in shares)
Common Stock, Shares, Issued
Measure:
Measure [Axis]
Incremental stock-based compensation expense
Share-Based Payment Arrangement, Plan Modification, Incremental Cost
Equity Components [Axis]
Equity Components [Axis]
Product and Service [Domain]
Product and Service [Domain]
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]
Defined contribution plan, cost
Defined Contribution Plan, Cost
Entity Small Business
Entity Small Business
Termination Date
Trading Arrangement Termination Date
Other Commitments [Axis]
Other Commitments [Axis]
Property, Plant, and Equipment [Line Items]
Property, Plant, and Equipment [Line Items]
Subsequent Events [Abstract]
Fair Value, Recurring and Nonrecurring [Table]
Fair Value, Recurring and Nonrecurring [Table]
Principal payments
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements
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 period of options
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]
Loss on debt extinguishment
Loss on extinguishment of debt
Loss on debt extinguishment
Gain (Loss) on Extinguishment of Debt
Accrued expenses and other current liabilities
Total accrued expenses and other current liabilities
Accrued Liabilities, Current
Fair Value as of Grant Date
Award Grant Date Fair Value
Chase Asset Purchase Agreement
Chase Asset Purchase Agreement [Member]
Chase Asset Purchase Agreement
Summary of Significant Accounting Policies and Basis of Presentation
Significant Accounting Policies [Text Block]
Exercisable
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value
Pay vs Performance Disclosure, Table
Pay vs Performance [Table Text Block]
Arrangement Duration
Trading Arrangement Duration
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Statement of Stockholders' Equity [Abstract]
Local Phone Number
Local Phone Number
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
Entity Registrant Name
Entity Registrant Name
Two Thousand Twenty Five Pre Funded Warrants
Two Thousand Twenty Five Pre Funded Warrants [Member]
Two Thousand Twenty Five Pre Funded Warrants
Warrant in excess percentage
Class Of Warrants Or Rights, Warrant Excess Percentage
Warrent in excess percentage
Fair value of warrants
Warrants Not Settleable in Cash, Fair Value Disclosure
Insider Trading Policies and Procedures Not Adopted
Insider Trading Policies and Procedures Not Adopted [Text Block]
Warrants, expected life
Warrants and Rights Outstanding, Term
Commitments and contingencies (Note 11)
Commitments and Contingencies
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name [Domain]
Property equipment, gross
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization
Changed Peer Group, Footnote
Changed Peer Group, Footnote [Text Block]
Warrants, measurement input
Warrants and Rights Outstanding, Measurement Input
Forgone Recovery due to Expense of Enforcement, Amount
Forgone Recovery due to Expense of Enforcement, Amount
Executive Category:
Executive Category [Axis]
Vesting period
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period
Office equipment and furniture
Furniture and Fixtures [Member]
Liabilities and stockholders’ equity
Liabilities and Equity [Abstract]
Other Commitments [Table]
Other Commitments [Table]
Exercisable
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted-Average Remaining Contractual Term
Prepayment fee, percent of outstanding principal, applicable 36 months after initial funding date
Debt Instrument, Prepayment Penalty Fee, After 36 Months After Initial Funding Date, Percent Of Outstanding Principal
Debt Instrument, Prepayment Penalty Fee, After 36 Months After Initial Funding Date, Percent Of Outstanding Principal
Schedule of classes 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
Award Type [Domain]
Non-PEO NEO Average Compensation Actually Paid Amount
Non-PEO NEO Average Compensation Actually Paid Amount
Number of warrants or rights outstanding (in shares)
Class of Warrant or Right, Outstanding
Fair Value
Fair Value Disclosures [Text Block]
Level 3
Fair Value, Inputs, Level 3 [Member]
Supplemental Disclosure of Non-cash Activities
Supplemental Cash Flow Information [Abstract]
401(k) Plan
401(k) Plan [Member]
401(k) Plan
Grant Agreement
Grant Agreement [Member]
Grant Agreement
Expected term (in years)
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term
PEO Name
PEO Name
Restricted cash
Restricted Cash
Leasehold improvements
Leasehold Improvements [Member]
Loan and Security Agreement
Loan And Security Agreement [Member]
Loan And Security Agreement
Retirement Plan Name [Domain]
Retirement Plan Name [Domain]
Long-Lived Asset, Class [Axis]
Long-Lived Asset, Class [Axis]
Other assets
Other Assets
Stock Price or TSR Estimation Method
Stock Price or TSR Estimation Method [Text Block]
Entity Tax Identification Number
Entity Tax Identification Number
Interest expense
Interest Expense, Debt
Liability Class [Axis]
Liability Class [Axis]
Other Commitments [Line Items]
Other Commitments [Line Items]
Exercised (in dollars per share)
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price
Cash, cash equivalents and restricted cash at the beginning of the period
Cash, cash equivalents and restricted cash at the end of the period
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation
Accounts payable
Increase (Decrease) in Accounts Payable
Other accruals and current liabilities
Other Accrued Liabilities, Current
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]
Description of the Business
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Debt Instrument [Axis]
Debt Instrument [Axis]
Subsequent Event [Table]
Subsequent Event [Table]
Stock-based compensation expense
Share-Based Payment Arrangement, Noncash Expense
Personnel expenses excluding stock-based compensation
Labor and Related Expense
K2 Common Stock Warrants
K2 Common Stock Warrants [Member]
K2 Common Stock Warrants
2027
Long-Term Debt, Maturity, Year One
Long-Term Debt, Type [Domain]
Long-Term Debt, Type [Domain]
Net loss per share attributable to common stockholders, basic (in dollars per share)
Earnings Per Share, Basic
Measurement Input Type [Axis]
Measurement Input Type [Axis]
Disclosure of share-based compensation arrangements by share-based payment award
Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block]
Risk free interest rate
Measurement Input, Risk Free Interest Rate [Member]
Total current assets
Assets, Current
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Insider Trading Arrangements [Line Items]
Term loan, non-current
Term loan, non-current
Long-Term Debt, Excluding Current Maturities
Pre-Funded Warrants
Pre-Funded Warrants [Member]
Pre-Funded Warrants
Award Type
Award Type [Axis]
Named Executive Officers, Footnote
Named Executive Officers, Footnote [Text Block]
Less: unamortized debt discount
Debt Instrument, Unamortized Exit Fee
Debt Instrument, Unamortized Exit Fee
Issuance of warrants in connection with term loan agreement
Adjustments to Additional Paid in Capital, Warrant Issued
Accumulated deficit
Accumulated deficit
Retained Earnings (Accumulated Deficit)
Product and Service [Axis]
Product and Service [Axis]
Restricted cash
Restricted Cash, Noncurrent
Performance awards outstanding (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested, Number of Shares
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]
Awards Close in Time to MNPI Disclosures
Awards Close in Time to MNPI Disclosures [Table]
Proceeds from issuance of debt
Proceeds from Issuance of Secured Debt
Common Stock
Common Stock [Member]
Change in other, net
Gain (Loss) In Other Operating Activities, Net
Gain (Loss) In Other Operating Activities, Net
Compensation Actually Paid vs. Company Selected Measure
Compensation Actually Paid vs. Company Selected Measure [Text Block]
Cover [Abstract]
Dividend yield
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate
Purchase price (in dollars per share)
Class Of Warrant Or Right, Purchase Price Of Warrants Or Rights
Class Of Warrant Or Right, Purchase Price Of Warrants Or Rights
Restricted stock units vesting
APIC, Share-Based Payment Arrangement, Recognition and Exercise
Equity Awards Adjustments
Equity Awards Adjustments [Member]
Asset Purchase and License Agreements
Collaborative Arrangement Disclosure [Text Block]
Total liabilities and stockholders’ equity
Liabilities and Equity
Stock options issued and outstanding
Stock Options
Share-Based Payment Arrangement, Option [Member]
Segments [Axis]
Segments [Axis]
Additional 402(v) Disclosure
Additional 402(v) Disclosure [Text Block]
Maximum percentage of outstanding stock
Debt Instrument, Convertible, Percentage Of Outstanding Stock, Maximum
Debt Instrument, Convertible, Percentage Of Outstanding Stock, Maximum
Plan Name [Axis]
Plan Name [Axis]
Tabular List, Table
Tabular List [Table Text Block]
Vesting [Axis]
Vesting [Axis]
Additional paid-in capital
Additional Paid in Capital
Share-based payment arrangement, cost by plan
Share-Based Payment Arrangement, Cost by Plan [Table Text Block]
Volatility
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Weighted Average Volatility Rate
Name
Awards Close in Time to MNPI Disclosures, Individual Name
Performance awards vested (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested, Number of Shares
Issuance of common stock and pre-funded warrants in 2026 private placement, net of issuance costs (in shares)
Issuance Of Common Stock And Pre Funded Warrants In Private Placement Net Of Issuance Costs In Common Stock
Issuance Of Common Stock And Pre Funded Warrants In Private Placement Net Of Issuance Costs In Common Stock
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]
Outstanding
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value
Forfeited and cancelled (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period
General and administrative
General and Administrative Expense
Long-Lived Asset, Class [Domain]
Long-Lived Asset, Class [Domain]
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
Preferred stock, authorized (in shares)
Preferred Stock, Shares Authorized
Asset purchase agreement, initial payment made
Asset Purchase Agreement, Initial Payment Made
Asset Purchase Agreement, Initial Payment Made
Property, Plant, and Equipment [Table]
Property, Plant, and Equipment [Table]
Measurement input
Debt Instrument, Measurement Input
Adjustment to Compensation:
Adjustment to Compensation [Axis]
Registered Direct Offering (RDO)
Registered Direct Offering (RDO) [Member]
Registered Direct Offering (RDO)
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
Cash paid for interest
Interest Paid, Excluding Capitalized Interest, Operating Activity
Statement of Cash Flows [Abstract]
Extinguishment of debt, amount
Extinguishment of Debt, Amount
Change in fair value attributable to instrument specific credit risk
OCI, Market Risk Benefit, Instrument-Specific Credit Risk, Gain (Loss), after Adjustments and Tax, Parent
Aggregate Available
Trading Arrangement, Securities Aggregate Available Amount
Total assets
Assets, Fair Value Disclosure
Total principal payments and Exit Fee
Long-Term Debt, Principal Payments And Exit Fee
Long-Term Debt, Principal Payments And Exit Fee
Name
Measure Name
Income Taxes
Income Tax Disclosure [Text Block]
Accounts payable
Accounts Payable, Current
Pay vs Performance Disclosure [Line Items]
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV [Domain]
Alto 401(k) Plan
Alto 401(k) Plan [Member]
Alto 401(k) Plan
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Pay vs Performance Disclosure
Pay vs Performance Disclosure [Table]
2025 Inducement Plan
2025 Inducement Plan [Member]
2025 Inducement Plan
Additional Paid-in Capital
Additional Paid-in Capital [Member]
Entity Filer Category
Entity Filer Category
Minimum market capitalization
Debt Instrument, Next Fiscal Year Covenant, Market Capitalization, Minimum Amount
Debt Instrument Covenant, Minimum Market Capitalization
Name
Trading Arrangement, Individual Name
Funding fee multiplier
Debt Instrument, Funding Fee Multiplier
Debt Instrument, Funding Fee Multiplier
Cash and cash equivalents
Cash and Cash Equivalent
Expected term
Measurement Input, Expected Term [Member]
Performance awards issued (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures
Company Selected Measure Amount
Company Selected Measure Amount
Laboratory equipment
Laboratory Equipment [Member]
Laboratory Equipment
Retirement Plan Name [Axis]
Retirement Plan Name [Axis]
Stock, Class of Stock [Table]
Stock, Class of Stock [Table]
Current assets:
Assets, Current [Abstract]
Non-PEO NEO
Non-PEO NEO [Member]
Entity Address, Address Line One
Entity Address, Address Line One
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
Award Timing Method
Award Timing Method [Text Block]
Net (decrease) increase in cash, cash equivalents and restricted cash
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation
Other research and development
Other Research and Development Expense
Forgone Recovery, Explanation of Impracticability
Forgone Recovery, Explanation of Impracticability [Text Block]
Final fee, percent of loan funded
Debt Instrument, Exit Fee, Percent Of Loans Funded
Debt Instrument, Exit Fee, Percent Of Loans Funded
Shares available for future grant from 2024 Equity Incentive Plan and Inducement Plan
Employee Stock Options Available For Future Grant [Member]
Employee Stock Options Available For Future Grant
Net loss
Net loss
Net Income (Loss) Attributable to Parent
Long-Term Debt, Type [Axis]
Long-Term Debt, Type [Axis]
Erroneous Compensation Analysis
Erroneous Compensation Analysis [Text Block]
Statement [Table]
Statement [Table]
Vested after 24 months
Share-Based Payment Arrangement, Tranche Two [Member]
Issuance of common stock and pre-funded warrants in 2026 private placement, net of issuance costs
Stock And Pre Funded Warrants Issued During Period Value
Stock And Pre Funded Warrants Issued During Period Value
Restatement Determination Date:
Restatement Determination Date [Axis]
Minimum number of months of cash runway
Debt Instrument, Next Fiscal Year Covenant, Cash Runway Period, Minimum
Debt Instrument, Next Fiscal Year Covenant, Cash Runway Period, Minimum
Proceeds from exercise of stock options
Proceeds from Stock Options Exercised
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Interest income
Investment Income, Interest
Exercisable at period end (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price
Changes in fair value reported in other comprehensive loss
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)
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]
K2 Warrants
K2 Warrant [Member]
K2 Warrant
Pension Benefits Adjustments, Footnote
Pension Benefits Adjustments, Footnote [Text Block]
Schedule of stock reserved for issuance
Schedule of Stock Reserved for Issuance [Table Text Block]
Schedule of Stock Reserved for Issuance