75000 - Document - Document and Entity Information
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75010 - Statement - Condensed Consolidated Balance Sheets (unaudited)
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75020 - Statement - Condensed Consolidated Balance Sheets (Parenthetical) (unaudited)
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75030 - Statement - Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited)
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75040 - Statement - Condensed Consolidated Statements of Stockholders' Equity (Unaudited)
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75050 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited)
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995455 - Disclosure - The Company
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995465 - Disclosure - Summary of Significant Accounting Policies
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995475 - Disclosure - Accrued and Other Current Liabilities
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995485 - Disclosure - Fair Value Measurements
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995505 - Disclosure - Derivatives
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995515 - Disclosure - Commitments and Contingencies
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995525 - Disclosure - Stock-Based Compensation
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995535 - Disclosure - Segment Information
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995545 - Disclosure - Net Loss per Common Share
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995555 - Disclosure - Subsequent Events
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995565 - Disclosure - Summary of Significant Accounting Policies (Policies)
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995575 - Disclosure - Accrued and Other Current Liabilities (Tables)
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995585 - Disclosure - Fair Value Measurements (Tables)
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995605 - Disclosure - Stock-Based Compensation (Tables)
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995615 - Disclosure - Segment Information (Tables)
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995625 - Disclosure - Net Loss per Common Share (Tables)
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995635 - Disclosure - The Company - Additional Information (Details)
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995645 - Disclosure - Summary of Significant Accounting Policies (Additional Information) (Details)
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995655 - Disclosure - Accrued and Other Current Liabilities - Schedule of Accrued and Other Current Liabilities (Details)
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995665 - Disclosure - Fair Value Measurements - Summary of Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis (Details)
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995675 - Disclosure - Fair Value Measurements (Additional Information) (Details)
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995705 - Disclosure - Commitments and Contingencies - Additional Information (Details)
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995715 - Disclosure - Stock-Based Compensation - Additional Information (Details)
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995725 - Disclosure - Stock-Based Compensation - Schedule Of Common Stock Available For Issuance Under The Equity Incentive Plans (Details)
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995735 - Disclosure - Stock-Based Compensation - Summary of Stock Options Activity Under 2018 Plan and 2015 Equity Incentive Plan (Details)
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995745 - Disclosure - Stock-Based Compensation - Summary of Restricted Shares (Details)
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995755 - Disclosure - Stock-Based Compensation - Summary of stock-based compensation is classified in the consolidated statements of operations and comprehensive loss (Details)
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995765 - Disclosure - Stock-Based Compensation - Summary of stock-based compensation expense by award type (Details)
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995775 - Disclosure - Segment information - Schedule Of research and development expenses have been disaggregated (Details)
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995785 - Disclosure - Segment information (Additional Information) (Details)
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995795 - Disclosure - Net Loss per Common Share - Summary of Anti-dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share (Details)
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995805 - Disclosure - Subsequent Events - Additional Information (Details)
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Vested
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value
Forfeited or canceled
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Preferred Stock, Shares Issued
Preferred Stock, shares issued
Preferred Stock, Shares Issued, Total
Increase (Decrease) in Accounts Payable
Accounts payable
Increase (Decrease) in Accounts Payable, Total
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Supplemental disclosures of non-cash investing and financing information:
Plan Name [Axis]
Plan Name
Entity Current Reporting Status
Entity Current Reporting Status
Operating Expenses [Abstract]
Operating expenses
Fair Value, Inputs, Level 2 [Member]
Fair Value Inputs Level 2[Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price
Commitments and Contingencies Disclosure [Text Block]
Commitments and Contingencies
Common Stock, Shares Authorized
Common stock, shares authorized
Settlement of derivative contracts
Settlement of derivative contracts
Settlement of derivative contracts
Lease agreement on April two thousand and twenty.
Lease Agreement On April Two Thousand And Twenty [Member]
Lease Agreement on April 2020
Document Fiscal Period Focus
Document Fiscal Period Focus
Entity Shell Company
Entity Shell Company
Other Accrued Liabilities, Current
Accrued other liabilities
Cash and Cash Equivalent
Cash and cash equivalents
Cash and Cash Equivalents, at Carrying Value, Beginning Balance
Cash and Cash Equivalents, at Carrying Value, Ending Balance
Total cash and cash equivalents
Plan description
Long-Term Performance Incentive Plan Description
Long-Term Performance Incentive Plan Description
Unrealized Gains, Non Current
Debt Securities Available For Sale Unrealized Gains, Non Current
Debt Securities Available For Sale Unrealized Gains, Non Current
Common Stock, Shares, Issued
Common stock, shares issued
Common Stock, Shares, Issued, Total
Asset Class [Domain]
Asset Class
Statement [Table]
Statement [Table]
Restricted Cash, Noncurrent
Restricted cash
Share-Based Compensation Arrangement by Share-Based Payment Award, Purchase Price of Common Stock, Percent
Common stock purchase price percentage
Statement [Line Items]
Statement [Line Items]
Entity Filer Category
Entity Filer Category
Reclassification
Reclassification, Comparability Adjustment [Policy Text Block]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Liabilities and Equity
Total liabilities and stockholders’ equity
Total liabilities and stockholders' equity
Manufacturing agreement expense
Manufacturing Agreement Expense
Manufacturing Agreement Expense
Long-Lived Tangible Asset [Axis]
Employee Stock Purchase Plan [Member]
Employee Stock Purchase Plan [Member]
Employee stock purchase plan
ESPP
Lessee operating lease monthly rent expense.
Lessee Operating Lease Monthly Rent Expense
Monthly rent expense
Cash and Cash Equivalents, Fair Value Disclosure
Cash equivalents
Tenant improvement allowance.
Tenant Improvement Allowance
Tenant improvement allowance
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Outstanding stock options
Investment Income, Interest
Interest income
Geographical [Domain]
Debt Securities, Available-for-Sale, Term
Marketable securities, effective maturities
Additional Paid in Capital, Common Stock
Additional paid-in capital
Additional Paid in Capital, Common Stock, Beginning Balance
Additional Paid in Capital, Common Stock, Ending Balance
Building two.
Building Two [Member]
1250 Page Mill Road in Palo Alto
Payment For Sublease
Payment For Sublease
Payment for sublease
Significant Accounting Policies [Text Block]
Summary of Significant Accounting Policies
Accounts Payable and Accrued Liabilities, Current [Abstract]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross
Granted
Stock options, granted
Liability related to sale of future royalties.
Liability Related To Sale Of Future Royalties
Liability related to sale of future royalties
Earnings Per Share, Basic
Earnings Per Share, Basic, Total
Net loss per share, basic
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number
Ending balance
Beginning balance
Commitments and contingencies disclosure.
Commitments And Contingencies Disclosure [Line Items]
Commitments And Contingencies Disclosure [Line Items]
Schedule of accrued and other current liabilities.
Schedule Of Accrued And Other Current Liabilities Table [Text Block]
Schedule of Accrued and Other Current Liabilities
Impairment of Leasehold
Non-cash lease impairment expense
Liabilities, Current
Total current liabilities
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]
Adjustments to reconcile net loss to net cash used in operating activities:
Equity, Attributable to Parent [Abstract]
Stockholders’ equity:
Entity Small Business
Entity Small Business
Retained Earnings (Accumulated Deficit)
Accumulated deficit
Retained Earnings (Accumulated Deficit), Total
Retained Earnings (Accumulated Deficit), Beginning Balance
Retained Earnings (Accumulated Deficit), Ending Balance
Sales
Sales Forecasting
Sales Forecasting
Sale of Stock, Price Per Share
Stock Price
Manufacturing agreement, extended term
Manufacturing agreement term that can be extended.
Manufacturing Agreement Term That Can Be Extended
Automatic renewal interval.
Automatic Renewal Interval
Automatic renewal interval
Share-Based Payment Arrangement [Text Block]
Stock-Based Compensation
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Lease Contractual Term [Axis]
Amendment Flag
Amendment Flag
Liabilities and Equity [Abstract]
Liabilities and stockholders’ equity
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation
Net cash used in operating activities
Net cash used in operating activities
Increase (Decrease) in Operating Lease Liability
Operating lease liability
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description
CODM Information, Description
Common Stock [Member]
Common Stock
Subordinated borrowing, interest rate
Subordinated Borrowing, Interest Rate
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Granted
Entity Address, Address Line One
Entity Address, Address Line One
Marketable Securities [Table]
Marketable Securities [Table]
Fair Value Hierarchy and NAV [Axis]
Significant Observable Inputs (Level 2)
Earnings Per Share [Abstract]
Consecutive Trading Days
Consecutive Trading Days
Consecutive Trading days
Payroll And Personnel Expenses [Member]
Payroll And Personnel Expenses [Member]
Payroll And Personnel Expenses
Operating Lease, Right-of-Use Asset
Operating lease right-of-use asset
Foreign Currency Fair Value Hedge Derivative at Fair Value, Net, Total
Foreign Currency Fair Value Hedge Derivative at Fair Value, Net
Recognized fair value of foreign currency of derivative instruments
Document Type
Document Type
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Entity Central Index Key
Entity Central Index Key
Entity Central Index Key
John Borgeson [Member]
John Borgeson [Member]
Investments, Debt and Equity Securities [Abstract]
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation
Net decrease in cash, cash equivalents and restricted cash
Subsequent Event Type [Domain]
Subsequent Event Type
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Anti-dilutive securities excluded from the computation of diluted net loss per common share
SWITZERLAND
Switzerland
Common Stock, Par or Stated Value Per Share
Common stock, par value
Amortization of operating lease right-of-use asset
Operating Lease, Right-of-Use Asset, Periodic Reduction
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term (in years)
Weighted Average Remaining Contractual Term (in years)
Debt Securities, Available-for-Sale
Marketable securities
Debt Securities, Available-for-sale, Total
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period
Exercised
Exercise of stock options, shares
Marketable Securities
Availability of Marketable Securities
Marketable Securities, Total
Accrued Liabilities, Current
Accrued and other current liabilities
Total accrued and other current liabilities
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Current Fiscal Year End Date
Current Fiscal Year End Date
Cash-collateralized letter of credit.
Cash Collateralized Letter Of Credit
Cash-collateralized letter of credit
Document Quarterly Report
Document Quarterly Report
CALIFORNIA
California
Entity Address, State or Province
Entity Address, State or Province
Unvested, beginning balance
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Unvested, ending balance
Tarcocimab Program Expenses [Member]
Tarcocimab program expenses [Member]
Tarcocimab Program Expenses
Preferred Stock, Shares Outstanding
Preferred Stock, shares outstanding
Preferred Stock, Shares Outstanding, Beginning Balance
Preferred Stock, Shares Outstanding, Ending Balance
Common Stock, Capital Shares Reserved for Future Issuance
Reserved for future award grants
Geographical [Axis]
Number of options to extend lease term.
Number Of Options To Extend Lease Term
Number of options to extend lease term
Stock Issued During Period, Value, Stock Options Exercised
Exercise of stock options
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]
Accrued and Other Current Liabilities
Performance Shares [Member]
Unrealized Losses, Non Current
Debt Securities Available For Sale Unrealized Losses, Non Current
Debt Securities Available For Sale Unrealized Losses, Non Current
Subsequent Event [Member]
Subsequent Event
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized
Number of common stock available for issuance increased
Other Assets, Noncurrent
Other assets
Other Assets, Noncurrent, Total
Debt Securities, Available-for-Sale, Current
Fair Value, current
Debt Securities, Available-for-sale, Current, Total
Antidilutive Securities [Axis]
Antidilutive Securities
Amortized Cost, Non Current
Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage
Percentage of vested of award under performance based award
Share-Based Payment Arrangement, Cost by Plan [Table Text Block]
Summary of stock-based compensation is classified in the consolidated statements of operations and comprehensive loss
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss)
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name
Cash
Cash [Member]
Lessee, Operating Lease, Option to Extend
Lessee operating lease option to extend
Deposits on property and equipment
Deposits On Property And Equipment
Deposits on property and equipment.
Preferred Stock, Value, Issued
Preferred Stock, Value, Issued, Total
Preferred Stock, Value, Issued, Beginning Balance
Preferred Stock, Value, Issued, Ending Balance
Preferred stock, $0.0001 par value, 10,000,000 shares authorized: 0 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively
Preferred stock, $0.0001 par value - 10,000,000 shares authorized; none issued
Minimum [Member]
Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value
Granted
Financial Instrument [Axis]
Assets, Current [Abstract]
Current assets:
Gain (Loss) on Foreign Currency Fair Value Hedge Derivatives
Change in fair value recognized in other income (expense)
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs Level3 [Member]
Segment Reporting [Abstract]
Summary of Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
Summary of Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis
Liabilities, Current [Abstract]
Current liabilities:
KSI-501 Program Expenses [Member]
KSI-501 Program Expenses [Member]
KSI-501 Program Expenses
Shares, Outstanding
Ending balance, shares
Beginning balance, shares
Sublease Income
Sublease Income
Commitments and Contingencies
Commitments and contingencies (Note 5)
Commitments and contingencies disclosure.
Commitments And Contingencies Disclosure [Table]
Commitments And Contingencies Disclosure [Table]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value
Unvested, ending balance
Unvested, beginning balance
General and Administrative Expense [Member]
General and Administrative
Operating Lease, Liability
Lease liabilities
Operating Lease, Liability, Total
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value [Abstract]
Aggregate Intrinsic Value
Gain (Loss) on Derivative Instruments, Net, Pretax, Total
Gain (Loss) on Derivative Instruments, Net, Pretax
Settlement of derivative contracts
Settlement of derivative contracts
Lease Contractual Term [Domain]
Weighted Average Number of Shares Outstanding, Basic
Weighted Average Number of Shares Outstanding, Basic, Total
Weighted-average shares outstanding used, basic
Accrued manufacturing and research & development costs
Accrued research and development current.
Accrued Research And Development Current
Risk and uncertainties.
Risk And Uncertainties Policy [Text Block]
Risk and Uncertainties
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]
Long-Lived Tangible Asset [Domain]
Subsequent Events [Text Block]
Subsequent Events
Cash
Cash
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition
Stock-based compensation expense
APIC, Share-based Payment Arrangement, Increase for Cost Recognition, Total
Lessee operating lease rent abatement.
Lessee Operating Lease Rent Abatement
Total rent abatement
Equity, Attributable to Parent
Ending Balance
Beginning Balance
Total stockholders’ equity
Preferred Stock, Par or Stated Value Per Share
Preferred stock, par value
Statement of Stockholders' Equity [Abstract]
Corporate Note Securities [Member]
Corporate Notes
Equity Incentive Plan
Equity Incentive Plan
Total
Equity incentive plans
Manufacturing agreement capital contributions fixed assets
Manufacturing Agreement Capital Contributions Fixed Assets
Manufacturing agreement capital contributions fixed assets.
Use of Estimates, Policy [Policy Text Block]
Use of Estimates
Non-cash lease impairment expense
Finance Lease, Impairment Loss
Fair Value Disclosures [Text Block]
Fair Value Measurements
Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block]
Summary of stock-based compensation expense by award type
LT Program Implementation Plan [Member]
LT Program Implementation Plan [Member]
Number of Options
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Term of offering period
Term of offering period.
Term Of Offering Period
Plan Name [Domain]
Plan Name
Increase (Decrease) in Other Operating Assets
Other assets
Increase (Decrease) in Other Operating Assets, Total
Office and laboratory space.
Office And Laboratory Space [Member]
Rottenstrasse 5 in Visp
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]
Performance-based stock options.
Performance Based Stock Options [Member]
Performance-based Stock Options
Property, Plant and Equipment, Policy [Policy Text Block]
Property and Equipment, Net
Entity Address, City or Town
Entity Address, City or Town
Building one.
Building One [Member]
1200 Page Mill Road in Palo Alto
Security Exchange Name
Security Exchange Name
Two thousand eighteen employee share purchase plan.
Two Thousand Eighteen Employee Share Purchase Plan [Member]
2018 Employee Share Purchase Plan
Accrued legal fees and professional fees
Accrued legal fees and professional fees
Accrued legal fees and professional fees
Counterparty Name [Axis]
Counterparty Name
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name
Number of leased buildings.
Number Of Leased Buildings
Number of buildings leased
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table]
Statistical Measurement [Domain]
Statistical Measurement
Assets, Current
Total current assets
Share-Based Payment Arrangement, Expense
Stock-based compensation expense recognized
Total stock-based compensation
Noncash or Part Noncash Acquisition, Fixed Assets Acquired
Purchase of property and equipment under accounts payable and accruals
Document Period End Date
Document Period End Date
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV
Statement of Financial Position [Abstract]
Restricted Stock Units (RSUs) [Member]
Performance based equity awards.
Performance Based Equity Awards [Member]
Performance Based Equity Awards
Schedule Of Common Stock Available For Issuance Under The Equity Incentive Plans
Schedule Of Common Stock Available For Issuance Under The Equity Incentive Plans
Schedule Of Common Stock Available For Issuance Under The Equity Incentive Plans
Antidilutive Security, Excluded EPS Calculation [Table]
Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table]
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract]
Reconciliation of cash, cash equivalents and restricted cash to consolidated balance sheets
Debt Securities, Available-for-Sale, Realized Gain (Loss)
Realized gains or losses recognized on sale or maturity of available-for-sale debt securities
Debt Securities, Available-for-sale, Realized Gain (Loss), Total
Liabilities
Total liabilities
Financial Instruments [Domain]
Other-than-temporary Impairment Loss, Debt Securities, Available-for-Sale
Impairment charges or recoveries related to marketable securities
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total
Manufacturing agreement.
Manufacturing Agreement [Member]
Manufacturing Agreement
Unvested restricted shares
Restricted Stock [Member]
Restricted Shares
Weighted Average Number of Shares Outstanding, Diluted
Weighted Average Number of Shares Outstanding, Diluted, Total
Weighted-average shares outstanding used, diluted
Securities Act File Number
Entity File Number
Non Cash Lease Impairment Expense
Non Cash Lease Impairment Expense
Non Cash Lease Impairment Expense
Cover [Abstract]
Share based compensation arrangement by share based payment award options performance period expiration.
Share Based Compensation Arrangement By Share Based Payment Award Options Performance Period Expiration
Performance expiration date
Prepaid Expense and Other Assets, Current
Prepaid expenses and other current assets
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period
Canceled
Long Term Deposit
Long Term Deposit
Long-term deposit
US Treasury Securities [Member]
U.S. Treasury Securities
Issuance of common stock pursuant to employee stock purchase plans
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized
Number of Operating Segments
Number of operating segments
Segment Reporting Disclosure [Text Block]
Segment Information
General and Administrative Expense
General and administrative
General and Administrative Expense, Total
Operating lease right-of-use asset obtained in exchange for operating lease liability
Operating lease right-of-use asset obtained in exchange for operating lease liability
Operating lease right-of-use asset obtained in exchange for operating lease liability
Operating lease right-of-use asset obtained in exchange for operating lease liability
Annual rent year over year increase percentage.
Annual Rent Year Over Year Increase Percentage
Annual rent year-over-year increase percentage
Stock options, vested
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested, Number of Shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period
Forfeited or canceled
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Total
Subsequent Event [Table]
Subsequent Event [Table]
Variable Sublease Income
Variable Sublease Income
Variable sublease income
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Term (in years)
New Accounting Pronouncements, Policy [Policy Text Block]
Recent Accounting Pronouncements
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]
Summary of Restricted Shares
Gain (Loss) on Disposition of Assets
Gain (Loss) on Disposition of Assets, Total
Loss on disposal of long-lived assets
Two thousand eighteen equity incentive plan.
Two Thousand Eighteen Equity Incentive Plan [Member]
2018 Equity Incentive Plan
Depreciation
Depreciation
Depreciation, Total
Lessee, Operating Lease, Term of Contract
Lessee, operating lease, term of contract
Common Stock, Shares, Outstanding
Common stock, shares outstanding
Common Stock, Shares, Outstanding, Beginning Balance
Common Stock, Shares, Outstanding, Ending Balance
Operating Lease, Liability, Current
Operating lease liability
Document Transition Report
Document Transition Report
Operating Expenses
Total operating expenses
Research and Development Expense, Total
Research and Development Expense
Research and development
Amortized Cost, current
Amortized Cost, current
Debt Securities, Available-for-Sale, Amortized Cost, Current
Statement of Cash Flows [Abstract]
Weighted Average Grant Date Fair Value
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
Summary of Stock Options Activity under 2018 Plan and 2015 Equity Incentive Plan
Summary of stock options and performance-based stock options under 2021 LTPIP, 2018 Plan and 2015 Plan.
Two thousand eighteen and two thousand fifteen equity incentive plan.
Two Thousand Eighteen And Two Thousand Fifteen Equity Incentive Plan [Member]
2018 Plan and 2015 Equity Incentive Plan
Earnings Per Share [Text Block]
Net Loss per Common Share
Net loss
Net loss and comprehensive loss
Net loss
Aggregate Intrinsic Value ending balance
Aggregate Intrinsic Value Beginning balance
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value
Aggregate Intrinsic Value
Operating lease cost
Operating Lease, Cost
Assets [Abstract]
Assets
Increase (Decrease) in Prepaid Expense and Other Assets, Total
Increase (Decrease) in Prepaid Expense and Other Assets
Prepaid expenses and other current assets
Document Fiscal Year Focus
Document Fiscal Year Focus
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]
Cash flows from investing activities
Accounts Payable, Current
Accounts payable
Accounts Payable, Current, Total
Research and Development Expense [Member]
Research and Development
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]
Marketable Securities
Sahre Based Compensation Arrangement By Share Based Payment Award Awards Outstanding
Sahre Based Compensation Arrangement By Share Based Payment Award Awards Outstanding
Outstanding stock awards
Facilities And Other Research And Development Expenses [Member]
Facilities And Other Research And Development Expenses [Member]
Facilities And Other Research And Development Expenses
Performance Based Restricted Stock Units
Performance Based Restricted Stock Units [Member]
Performance Based Restricted Stock Units [Member]
Proceeds from Stock Options Exercised
Proceeds from stock options exercises
Proceeds from stock option exercises
Fair Value Disclosures [Abstract]
Commitments and Contingencies Disclosure [Abstract]
ABC Platform And Other Program Expenses [Member]
ABC Platform And Other Program Expenses [Member]
ABC Platform And Other Program Expenses
Share-Based Payment Arrangement [Abstract]
Payment of Public Offering Costs
Payment of Public Offering Costs
Payment of public offering costs
Payment of public offering costs
Assets, Fair Value Disclosure
Total
Total cash equivalents
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation
Net cash used in investing activities
Title of 12(b) Security
Title of 12(b) Security
Schedule of Segment Reporting Information, by Segment [Table]
Derivatives
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value
Canceled
Money Market Funds [Member]
Money Market Funds
Debt Securities, Available-for-Sale, Allowance for Credit Loss
Allowance for credit losses for available-for-sale debt securities
Debt Securities, Available-for-sale, Allowance for Credit Loss, Total
Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance
Debt Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]
Changes in assets and liabilities:
Beginning balance
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Ending balance
Fair Value, Recurring and Nonrecurring [Table]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table]
Additional Paid-in Capital [Member]
Additional Paid-In Capital
Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities
Accrued and other current liabilities
Measurement Frequency [Domain]
Measurement Frequency
Clinical and commercial supply.
Clinical And Commercial Supply [Member]
Clinical and Commercial Supply of Drug Substance
Statement of Income Location, Balance [Axis]
Income Statement Location
Trading Symbol
Trading Symbol
Subsequent Event Type [Axis]
Subsequent Event Type
Employee-related Liabilities, Current
Accrued salaries and benefits
Employee-related Liabilities, Current, Total
Manufacturing agreement, initial term
Manufacturing agreement initial term.
Manufacturing Agreement Initial Term
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Cash flows from financing activities
Fair Value, Recurring [Member]
Fair Value, Measurements, Recurring
Lonza.
Lonza [Member]
Lonza
Equity Components
Equity Components [Axis]
Equity Component [Domain]
Equity Component
Asset Class
Asset Class [Axis]
Leasehold improvements and machinery and equipment
Leasehold Improvements, Gross
Common Stock Shares Reserved For Future Grants Award
Common Stock Shares Reserved For Future Grants Award
Reserved for future award grants
Schedule Of Expense Segment Reporting Information Table Text Block
Schedule Of Expense Segment Reporting Information Table Text Block
Schedule Of research and development expenses have been disaggregated
Common Stock ShareReserved For Future Issuance ESPP
Common Stock ShareReserved For Future Issuance ESPP
Reserved for future ESPP
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures, Total
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures
Restricted stock units vested, shares
Issuance of common stock pursuant to employee stock purchase plan, shares
Stock Issued During Period, Shares, Employee Stock Purchase Plans
Proceeds from ESPP , Share
Maximum [Member]
Maximum
Maximum
Share based compensation arrangement by share based payment award vesting period for achievement of specific milestone.
Share Based Compensation Arrangement By Share Based Payment Award Vesting Period For Achievement Of Specific Milestone
Vesting period for achievement of specific milestone
Statistical Measurement [Axis]
Statistical Measurement
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price
Exercised
Common Stock, Value, Issued
Common Stock, Value, Issued, Total
Common Stock, Value, Issued, Beginning Balance
Common Stock, Value, Issued, Ending Balance
Common stock, $0.0001 par value, 490,000,000 shares authorized at March 31, 2024 and December 31, 2023; XX and 52,333,850 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively
Common stock, $0.0001 par value - 490,000,000 shares authorized; 62,155,685 and 61,758,454 shares issued and outstanding, respectively
KSI-101 Program Expenses [Member]
KSI-101 Program Expenses [Member]
KSI-101 Program Expenses
Long-term deposit
Long-term deposit
Long-term deposit
Impairment of Long-Lived Assets
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]
Marketable Securities [Line Items]
Marketable Securities [Line Items]
The entire disclosure for the company.
The Company [Text Block]
The Company
Preferred Stock, Shares Authorized
Preferred stock, shares authorized
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class
Employee Stock [Member]
Entity Registrant Name
Entity Registrant Name
Other Nonoperating Income (Expense)
Other Nonoperating Income (Expense), Total
Other income (expense), net
Subsequent Events [Abstract]
Unrealized Losses, Current
Debt Securities, Available-for-Sale, Unrealized Loss
Measurement Frequency [Axis]
Measurement Frequency
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Two Thousand Twenty One Long-Term Performance Incentive Plan [Member]
Two Thousand Twenty One Long-Term Performance Incentive Plan [Member]
2021 LTPIP
Payments to Acquire Property, Plant, and Equipment
Purchase of property and equipment
Payments to Acquire Property, Plant, and Equipment, Total
Summary of Significant Accounting Policies [Policy Text Block]
Summary of Significant Accounting Policies [Policy Text Block]
Summary of Significant Accounting Policies
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period
Granted
Assets
Total assets
Income Statement [Abstract]
Vested
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period
Awards vested
Earnings Per Share, Diluted
Earnings Per Share, Diluted, Total
Net loss per share, diluted
Lessee operating lease initial term of contract.
Lessee Operating Lease Initial Term Of Contract
Initial lease term
City Area Code
City Area Code
Lease Agreement
Lease Agreements [Member]
Non Cash Lease Impairment Expenses
Non Cash Lease Impairment Expenses
Non-cash lease impairment expense
Lease Agreement on June two thousand and twenty
Lease Agreement On June Two Thousand And Twenty [Member]
Lease Agreement on June 2020
Counterparty Name [Domain]
Counterparty Name
Proceeds from ESPP
Stock Issued During Period, Value, Employee Stock Purchase Plan
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net
Property and equipment, net
Property, Plant and Equipment, Net, Total
Property, Plant and Equipment, Net, Beginning Balance
Property, Plant and Equipment, Net, Ending Balance
Cash, cash equivalents and restricted cash in consolidated balance sheets
Total cash, cash equivalents and restricted cash in consolidated balance sheets
Cash, cash equivalents and restricted cash, at end of period
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Including Discontinued Operation
Cash, cash equivalents and restricted cash, at end of period
Cash, cash equivalents and restricted cash, at beginning of period
Operating Income (Loss)
Loss from operations
Loss from operations
Number of purchase periods.
Number Of Purchase Periods
Number of purchase periods
Retained Earnings [Member]
Accumulated Deficit
Share-Based Payment Arrangement, Noncash Expense
Stock-based compensation
Share-based Payment Arrangement, Noncash Expense, Total
Operating Lease, Liability, Noncurrent
Long-term operating lease liability
Fair Value, Inputs, Level 1 [Member]
Fair Value Inputs Level1 [Member]
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation
Net cash provided by financing activities
Marketable Securities [Table Text Block]
Summary of Marketable Securities
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Summary of Anti-dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share
Entity Interactive Data Current
Entity Interactive Data Current
Statement of Income Location, Balance [Domain]
Income Statement Location
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]
Cash flows from operating activities
Accrued clinical trial and related costs current.
Accrued Clinical Trial And Related Costs Current
Accrued clinical trial and related costs
Fair Value, Non Current
Available For Sale Debt Securities , Non Current
Available For Sale Debt Securities , Non Current
2018 Plan, 2015 Equity Incentive Plan and 2021 LTPIP
Two Thousand Eighteen And Two Thousand Fifteen Equity Incentive Plan And Two Thousand Twenty One Long Performance Incentive Plan [Member]
Two Thousand Eighteen And Two Thousand Fifteen Equity Incentive Plan And Two Thousand Twenty One Long Performance Incentive Plan [Member]
Entity Tax Identification Number
Entity Tax Identification Number
Local Phone Number
Local Phone Number
Unrealized Gains, Current
Debt Securities, Available-for-Sale, Unrealized Gain
Basis of presentation and principles of consolidation [Policy Text Block]
Basis Of Presentation And Principles Of Consolidation [Policy Text Block]
Basis of Presentation and Principles of Consolidation
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount
Unrecognized compensation cost related to unvested share based awards
Accounting Policies [Abstract]
Cash, cash equivalents and marketable securities
Investments and Cash
Investments and Cash, Total
New Tax Laws [Policy Text Block]
New Tax Laws [Policy Text Block]
New Tax Laws
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition
Unrecognized compensation weighted-average period expected for recognition
Entity Emerging Growth Company
Entity Emerging Growth Company
Area of Land
Lease area