Entity Central Index Key Cover [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity File Number Entity File Number Entity Incorporation, State or Country Code Entity Incorporation State Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address Address Line1 Entity Address, City or Town Entity Address City Or Town Entity Address, State or Province Entity Address State Or Province Entity Address, Postal Zip Code Entity Address Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Shell Company Entity Shell Company Document Annual Report Document Annual Report Document Transition Report Document Transition Report Title of 12(b) Security Security12b Title Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers ICFR Auditor Attestation Flag Icfr Auditor Attestation Flag Entity Public Float Entity Public Float Restricted cash and other assets noncurrent. Statement Of Financial Position [Abstract] Statement [Table] Statement [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Convertible Preferred Stock Convertible Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Marketable securities Available For Sale Securities Debt Securities Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Restricted cash and other assets Restricted Cash And Other Assets Noncurrent Total assets Assets Liabilities and Stockholders’ Equity Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued expenses and other current liabilities Accrued Liabilities And Other Liabilities Total current liabilities Liabilities Current Deferred rent Deferred Rent Credit Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 12) Commitments And Contingencies Stockholders’ equity Stockholders Equity [Abstract] Preferred stock Preferred Stock Value Common stock, $0.0001 par value; 200,000,000 and 68,000,000 shares authorized at December 31, 2020 and 2019, respectively; 45,446,903 and 3,239,017 shares issued and 45,076,574 and 2,586,535 shares outstanding at December 31, 2020 and 2019, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity Stockholders Equity Total liabilities and stockholders’ equity Liabilities And Stockholders Equity Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Changes in fair value of preferred stock tranche obligations. Changes in success fee obligation. Income Statement [Abstract] Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Expenses Loss from operations Operating Income Loss Other (expense) income: Other Nonoperating Income Expense [Abstract] Interest income Interest Income Other Interest expense Interest Expense Other Change in fair value of preferred stock tranche obligations Changes In Fair Value Of Preferred Stock Tranche Obligations Change in success fee obligation Changes In Success Fee Obligation Total other (expense) income, net Other Nonoperating Income Expense Net loss Net Income Loss Net loss per share, basic and diluted Earnings Per Share Basic And Diluted Weighted average common shares outstanding, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Comprehensive loss: Comprehensive Income Net Of Tax [Abstract] Net loss Other comprehensive loss: Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent [Abstract] Unrealized losses on marketable securities Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Reclassifications of temporary to permanent equity, shares. Stock issued during period shares restricted stock vested. Settlement of tranche right one. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Convertible Preferred Stock Preferred Stock [Member] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid In Capital [Member] Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income [Member] Accumulated Deficit Retained Earnings [Member] Redeemable Convertible Preferred Stock Redeemable Convertible Preferred Stock [Member] Series A Convertible Preferred Stock Preferred Class A [Member] Series B Convertible Preferred Stock Preferred Class B [Member] Beginning Balance Beginning Balance, Shares Shares Outstanding Beginning Balance Temporary Equity Carrying Amount Attributable To Parent Beginning Balance, Shares Temporary Equity Shares Outstanding Issuance of Series A redeemable convertible preferred stock, net of issuance costs of $0.1 million Temporary Equity Stock Issued During Period Value New Issues Temporary equity stock issued during period shares new issues. Issuance of Series A redeemable convertible preferred stock, net of issuance costs of $0.1 million, Shares Temporary Equity Stock Issued During Period Shares New Issues Settlement of Tranche Right I Settlement Of Tranche Right One Reclassification of redeemable convertible preferred stock and preferred stock tranche obligations Reclassifications Of Temporary To Permanent Equity Reclassification of redeemable convertible preferred stock and preferred stock tranche obligations, Shares Reclassifications Of Temporary To Permanent Equity Shares Issuance of stock, net of issuance costs Stock Issued During Period Value New Issues Issuance of stock, net of issuance costs, Shares Stock Issued During Period Shares New Issues Conversion of convertible preferred stock into common stock upon initial public offering Stock Issued During Period Value Conversion Of Convertible Securities Conversion of convertible preferred stock into common stock upon initial public offering, Shares Stock Issued During Period Shares Conversion Of Convertible Securities Exercise of stock options Stock Issued During Period Value Stock Options Exercised Exercise of stock options, Shares Stock Issued During Period Shares Stock Options Exercised Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Vesting of restricted shares Stock Issued During Period Shares Restricted Stock Vested Unrealized gains on marketable securities Ending Balance Ending Balance, Shares Ending Balance Ending Balance, Shares Stock issuance costs. Series A redeemable convertible preferred stock. Series A Redeemable Convertible Preferred Stock Series A Redeemable Convertible Preferred Stock [Member] Stock issuance costs Stock Issuance Costs Amortization (accretion) of premium (discount) on marketable securities. Payments for settlement of success fee obligation. Cash paid for interest and income taxes. Reclassification of preferred stock tranche obligation liability to permanent equity. Settlements of tranche right one. Operating Cash Flows Direct Method [Abstract] Cash flows from operating activities: Net Cash Provided By Used In Operating Activities [Abstract] Net loss Profit Loss Adjustments to reconcile net loss to net cash used in operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Stock-based compensation expense Share Based Compensation Depreciation and amortization expense Depreciation Depletion And Amortization Amortization of debt discount Amortization Of Debt Discount Premium Amortization (accretion) of premium (discount) on marketable securities Amortization Accretion Of Premium Discount On Marketable Securities Changes in fair value of preferred stock tranche obligations Changes in success fee obligation Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable and other liabilities Increase Decrease In Accounts Payable And Other Operating Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities Cash flows from investing activities: Net Cash Provided By Used In Investing Activities [Abstract] Purchases of property and equipment Payments To Acquire Property Plant And Equipment Purchases of marketable securities Payments To Acquire Marketable Securities Net cash used in investing activities Net Cash Provided By Used In Investing Activities Cash flows from financing activities: Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from initial public offering of common stock, net of issuance costs Proceeds From Issuance Initial Public Offering Settlement of success fee obligation Payments For Settlement Of Success Fee Obligation Proceeds from issuance of convertible preferred stock, net of issuance costs Proceeds From Issuance Of Convertible Preferred Stock Proceeds from issuance of debt, net of issuance costs Proceeds From Issuance Of Long Term Debt Repayment of debt Repayments Of Debt Proceeds from exercise of stock options Proceeds From Stock Options Exercised Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Net increase in cash, cash equivalents and restricted cash Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash, cash equivalents and restricted cash, beginning of year Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations Cash, cash equivalents and restricted cash, end of year Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest and taxes Cash Paid For Interest And Income Taxes Supplemental disclosure of non-cash investing and financing information: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Reclassification of preferred stock tranche obligation liability to permanent equity Reclassification Of Preferred Stock Tranche Obligation Liability To Permanent Equity Conversion of convertible preferred stock to common stock Conversion Of Stock Amount Converted1 Settlement of Tranche Right I Settlements Of Tranche Right One Documents Incorporated by Reference Documents Incorporated By Reference [Text Block] Accounting Policies [Abstract] Nature of Business and Basis of Presentation Business Description And Basis Of Presentation [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Marketable securities and fair value measurements. Marketable securities and fair value measurements. Marketable Securities And Fair Value Measurements [Abstract] Marketable Securities and Fair Value Measurements Marketable Securities And Fair Value Measurements [Text Block] Property Plant And Equipment [Abstract] Property and Equipment Property Plant And Equipment Disclosure [Text Block] Payables And Accruals [Abstract] Accrued Expenses and Other Current Liabilities Accounts Payable Accrued Liabilities And Other Liabilities Disclosure Current [Text Block] Debt Disclosure [Abstract] Debt Financing Debt Disclosure [Text Block] Equity [Abstract] Convertible Preferred Stock Preferred Stock [Text Block] Equity Stockholders Equity Note Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock-based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Earnings Per Share [Abstract] Net Loss per Share Earnings Per Share [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Use of Estimates Use Of Estimates Concentrations of Credit Risk and of Significant Suppliers Concentration Risk Credit Risk Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Restricted Cash Cash And Cash Equivalents Restricted Cash And Cash Equivalents Policy Marketable Securities Marketable Securities Policy Deferred Rent Deferred Charges Policy [Text Block] Property and Equipment Property Plant And Equipment Policy [Text Block] Impairment of Long-Lived Assets Impairment Or Disposal Of Long Lived Assets Policy [Text Block] Segment Information Segment Reporting Policy Policy [Text Block] Research and Development Costs Research And Development Expense Policy Research and manufacturing contract costs and accruals policy. Research and Manufacturing Contract Costs and Accruals Research And Manufacturing Contract Costs And Accruals Policy [Text Block] Patent costs policy. Patent Costs Patent Costs Policy [Text Block] Income Taxes Income Tax Policy [Text Block] Fair Value Measurements Fair Value Measurement Policy Policy [Text Block] Net Loss Per Share Earnings Per Share Policy [Text Block] Redeemable Convertible Preferred Stock Stockholders Equity Note Redeemable Preferred Stock Issue Policy Stock-Based Compensation Compensation Related Costs Policy [Text Block] Success Fee Obligation Policy[Text Block] Success Fee Obligation Success Fee Obligation Policy [Text Block] Comprehensive Loss Comprehensive Income Policy Policy [Text Block] Accounting Pronouncements Issued and Not Adopted New Accounting Pronouncements Policy Policy [Text Block] Schedule Of Property Plant And Equipment Estimated Useful Lives [Table Text Block] Schedule Of Property Plant And Equipment Estimated Useful Lives Schedule Of Property Plant And Equipment Estimated Useful Lives Table [Text Block] Summary of Marketable Securities by Security Type Debt Securities Available For Sale Table [Text Block] Summary of Assets Carried at Fair Value on Recurring Basis Fair Value Assets Measured On Recurring Basis [Text Block] Summary of Scheduled Maturity for Marketable Securities Investments Classified By Contractual Maturity Date Table [Text Block] Roll-forward of Aggregate Fair Values of Liabilities Determined by Level 3 Inputs Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Text Block] Schedule of Property and Equipment Property Plant And Equipment [Text Block] Schedule of accrued expenses and other current liabilities. Schedule of Accrued Expenses and Other Current Liabilities Schedule Of Accrued Expenses And Other Current Liabilities Table [Text Block] Summary of Assumptions Used to Determine Grant-Date Fair Value of Options Granted Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Stock Option Activity and Related Information Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Summary of RSU Activity Schedule Of Nonvested Restricted Stock Units Activity Table [Text Block] Summary of Restricted Common Stock Award Activity Nonvested Restricted Stock Shares Activity Table [Text Block] Summary of Stock-based Compensation Expense Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule Of Effective Income Tax Rate Reconciliation Table [Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule Of Deferred Tax Assets And Liabilities Table [Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Potential Dilutive Securities Excluded From Calculation Of Net Loss Per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Schedule of Future Minimum Lease Payments under Non-Cancelable Operating Leases Schedule Of Future Minimum Rental Payments For Operating Leases Table [Text Block] Nature of business and basis of presentation. Nature of business and basis of presentation. Nature Of Business And Basis Of Presentation [Table] Nature Of Business And Basis Of Presentation [Table] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] Initial Public Offering I P O [Member] Follow-on public offering. Follow-on Public Offering Follow On Public Offering [Member] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Nature Of Business And Basis Of Presentation [Line Items] Nature Of Business And Basis Of Presentation [Line Items] Entity incorporation date Entity Incorporation Date Of Incorporation Underwriters option to purchase additional shares. Number of shares issued and sold Sale Of Stock Number Of Shares Issued In Transaction Underwriters option to purchase additional shares Underwriters Option To Purchase Additional Shares Public offering price Sale Of Stock Price Per Share Net proceeds from issuance of common stock Proceeds From Issuance Of Common Stock Cash And Cash Equivalents Maturity Period Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Loan Agreement [Member] Loan Agreement Loan Agreement [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Pacific Western Bank. Pacific Western Bank Pacific Western Bank [Member] Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Cash and cash equivalent maturity period Cash And Cash Equivalents Maturity Period Restricted cash Restricted Cash Schedule Of Property Plant And Equipment [Table] Schedule Of Property Plant And Equipment [Table] Long-Lived Tangible Asset Property Plant And Equipment By Type [Axis] Long-Lived Tangible Asset Property Plant And Equipment Type [Domain] Laboratory equipment. Laboratory Equipment Laboratory Equipment [Member] Furnitures and Fixtures Furniture And Fixtures [Member] Computer Equipment Computer Equipment [Member] Leasehold Improvements Leasehold Improvements [Member] Property Plant And Equipment [Line Items] Property Plant And Equipment [Line Items] Property, plant and equipment, useful life Property Plant And Equipment Useful Life Property, plant and equipment, useful life Property Plant And Equipment Estimated Useful Lives Impairment charges Asset Impairment Charges Number of operating segment Number Of Operating Segments Success fee paid. Success fee paid Success Fee Paid Debt Securities Available For Sale [Table] Debt Securities Available For Sale [Table] Financial Instrument Financial Instrument [Axis] Financial Instruments Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain] Commercial Paper Commercial Paper [Member] Certificates of Deposit Certificates Of Deposit [Member] Corporate Debt Securities Corporate Debt Securities [Member] Schedule Of Available For Sale Securities [Line Items] Schedule Of Available For Sale Securities [Line Items] Amortized Cost Available For Sale Debt Securities Amortized Cost Basis Unrealized Gains Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Unrealized Losses Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax Total Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Measurement Input Type Measurement Input Type [Axis] Measurement Input Type Measurement Input Type [Domain] Discount Rate Measurement Input Discount Rate [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Marketable securities Measurement Frequency Fair Value By Measurement Frequency [Axis] Measurement Frequency Fair Value Measurement Frequency [Domain] Fair Value, Recurring Fair Value Measurements Recurring [Member] Investment Type Investment Type [Axis] Investments Investment Type Categorization [Member] Cash Equivalents Cash And Cash Equivalents [Member] Marketable securities. Marketable Securities Marketable Securities [Member] Fair Value Hierarchy and NAV Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV Fair Value Measurements Fair Value Hierarchy [Domain] Level 1 Fair Value Inputs Level1 [Member] Level 2 Fair Value Inputs Level2 [Member] Level 3 Fair Value Inputs Level3 [Member] Cash and Cash Equivalents Cash And Cash Equivalents [Axis] Cash and Cash Equivalents Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Member] Asset Class Fair Value By Asset Class [Axis] Asset Class Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] Money Market Funds Money Market Funds [Member] Assets: Assets Fair Value Disclosure [Abstract] Total Assets Fair Value Disclosure Fair value assets transfers amount. Fair value assets, transfers among level 1, level 2 or level 3 Fair Value Assets Transfers Amount Available-for-sale debt securities maturity after year one through two years fair value. Available-for-sale debt securities maturity after two years fair value. Maturing in one year or less Available For Sale Securities Debt Maturities Within One Year Fair Value Maturing after one year through two years Available For Sale Debt Securities Maturity After Year One Through Two Years Fair Value Maturing after two years Available For Sale Debt Securities Maturity After Year Two Years Fair Value Total Available For Sale Securities Debt Securities Sales of marketable securities Proceeds From Sale And Maturity Of Marketable Securities Fair value liability, payment percentage. Fair value liability, payment percentage Fair Value Liability Payment Percentage Measurement input Derivative Liability Measurement Input Fair value of derivative liability Derivative Liabilities Fair value measurement with unobservable inputs reconciliation recurring basis reclassification of tranche right two to equity. Fair value measurement with unobservable inputs reconciliation recurring basis initial fair value of success fee obligation. Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Liability Class Fair Value By Liability Class [Axis] Fair Value by Liability Class Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation By Liability Class [Domain] Preferred Stock Tranche Obligations. Preferred Stock Tranche Obligations Preferred Stock Tranche Obligations [Member] Success fee obligation. Success Fee Obligation Success Fee Obligation [Member] Vesting Vesting [Axis] Vesting Vesting [Domain] Tranche right one. Tranche Right I Tranche Right One [Member] Derivative Instrument Derivative [Member] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Balance—January 1, 2019 Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value Settlement Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements Change in fair value Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings Reclassification of Tranche Right II to equity Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Reclassification Of Tranche Right Two To Equity Balance—December 31, 2019 Initial fair value of success fee obligation Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Initial Fair Value Of Success Fee Obligation Office and computer equipment. Office and Computer Equipment Office And Computer Equipment [Member] Construction in Process Construction In Progress [Member] Property and equipment—at cost Property Plant And Equipment Gross Less accumulated depreciation and amortization Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Property and equipment—net Accrued consulting services current. Accrued research and development expenses current. Accrued facility costs current. Payroll and benefits Employee Related Liabilities Current Consulting services Accrued Consulting Services Current Legal services Accrued Professional Fees Current Research and development Accrued Research And Development Expenses Current Facility costs Accrued Facility Costs Current Total Line Of Credit Facility [Table] Line Of Credit Facility [Table] Term loan. Term Loan Term Loan [Member] Line Of Credit Facility [Line Items] Line Of Credit Facility [Line Items] Credit facility, maximum borrowing capacity under loan agreement Line Of Credit Facility Maximum Borrowing Capacity Credit facility, interest rate description Line Of Credit Facility Interest Rate Description Debt instrument, frequency of periodic payment of interest Debt Instrument Frequency Of Periodic Payment Credit facility, variable interest rate spread Debt Instrument Basis Spread On Variable Rate1 Credit facility, interest rate during period Line Of Credit Facility Interest Rate During Period Debt instrument success fee paid. Success fee required to pay in the event of liquidation, including IPO Debt Instrument Fee Amount Success fee paid after IPO Debt Instrument Success Fee Paid Temporary Equity By Class Of Stock [Table] Temporary Equity By Class Of Stock [Table] Tranche Right [Member] Tranche Right Tranche Right [Member] Tranche Right Two [Member] Tranche Right II Tranche Righttwo [Member] Statistical Measurement Range [Axis] Statistical Measurement Range [Member] Maximum Maximum [Member] Minimum [Member] Minimum [Member] Temporary Equity [Line Items] Temporary Equity [Line Items] Convertible preferred stock, shares issued upon conversion Convertible Preferred Stock Shares Issued Upon Conversion Purchases Of Shares Value Preferred Stock Fair Value Stock Issuance Cost Purchase of share Purchases Of Shares Value Shares issued Convertible preferred stock, price per share Share Price Fair value Preferred Stock Fair Value Issuance costs Stock Issuance Cost Sale of stock Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Two thousand eighteen stock incentive plan. 2018 Plan Two Thousand Eighteen Stock Incentive Plan [Member] Two thousand twenty stock incentive plan. 2020 Plan Two Thousand Twenty Stock Incentive Plan [Member] 2020 ESPP Employee Stock [Member] Award Type Award Type [Axis] Award Type Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Stock Option Employee Stock Option [Member] Restricted Stock Units ("RSUs") Restricted Stock Units R S U [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Total number of shares of common stock authorized Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized Number of shares available for future issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Number of shares initially reserved for issuance Common Stock Capital Shares Reserved For Future Issuance Percentage of outstanding shares increased annually under the plan Share Based Compensation Arrangement By Share Based Payment Award Percentage Of Outstanding Stock Maximum Threshold limit for increase in common stock reserved for future issuance. Increase in common stock reserved for future issuance Threshold Limit For Increase In Common Stock Reserved For Future Issuance Expected volatility Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Risk-free interest rate, minimum Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Minimum Risk-free interest rate, maximum Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Maximum Expected term (in years) Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 Expected dividend yield Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate Options Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward Outstanding, beginning of period Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Exercised Canceled Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Outstanding, end of period Options exercisable— December 31, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Options vested or expected to vest— December 31, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number Weighted Average Exercise Price Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward Outstanding, beginning of period Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Granted Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Exercised Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price Canceled Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price Outstanding, end of period Options exercisable— December 31, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Options vested or expected to vest— December 31, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price Share based compensation arrangement by share based payment award options weighted average remaining contractual term. Weighted Average Remaining Life (in years) Share Based Compensation Arrangement By Share Based Payment Award Options Weighted Average Remaining Contractual Term [Abstract] Outstanding Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 Options exercisable— December 31, 2020 Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 Options vested or expected to vest— December 31, 2020 Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 Aggregate Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract] Outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Options exercisable— December 31, 2020 Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 Options vested or expected to vest— December 31, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Aggregate Intrinsic Value Employee service share based compensation nonvested awards compensation cost not yet recognized performance conditions not probable. Weighted-average grant date fair value of options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Unrecognized compensation expense Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Unrecognized share based compensation expense, recognition period Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Unrecognized compensation cost related to unvested stock-based awards with performance-based vesting conditions for which performance conditions not deemed probable Employee Service Share Based Compensation Nonvested Awards Compensation Cost Not Yet Recognized Performance Conditions Not Probable Share based compensation arrangement by share based payment award, number of shares of common stock receivable upon vesting. Sharebased compensation arrangement by sharebased payment award grant service conditions to vest number of annual installments. Number of share of common stock receivable upon vesting Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Of Common Stock Receivable Upon Vesting Share-based Compensation Arrangement By Share-based Payment Award Grant Service Conditions to Vest Number of Annual Installments Share Based Compensation Arrangement By Share Based Payment Award Grant Service Conditions To Vest Number Of Annual Installments Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Rights Number of Shares Underlying RSUs Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward Issued and unvested as of January 1, 2020 Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Forfeited Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period Issued and unvested as of December 31, 2020 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 Roll Forward Issued and unvested as of January 1, 2020 Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value 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 Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures Weighted Average Grant Date Fair Value Issued and unvested as of December 31, 2020 Restricted Common Stock Restricted Stock [Member] Number of Restricted Shares Vested Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Research and Development Research And Development Expense [Member] General and Administrative General And Administrative Expense [Member] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Stock-based compensation expense Allocated Share Based Compensation Expense Effective Income Tax Rate Reconciliation, Change in Fair Value of Preferred Stock Tranche Obligations Effective Income Tax Rate Reconciliation, Permanent Differences Effective income tax rate reconciliation Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract] Federal income tax expense at statutory rate Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate State taxes—net of federal benefit Effective Income Tax Rate Reconciliation State And Local Income Taxes Change in fair value of preferred stock tranche obligations Effective Income Tax Rate Reconciliation Change In Fair Value Of Preferred Stock Tranche Obligations Other permanent differences Effective Income Tax Rate Reconciliation Permanent Differences Federal & state R&D credits Effective Income Tax Rate Reconciliation Tax Credits Research Increase in valuation allowance Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance Effective income tax rate Effective Income Tax Rate Continuing Operations Deferred tax assets: Deferred Tax Assets Net [Abstract] Stock-based compensation Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost Net operating loss carryforwards Deferred Tax Assets Operating Loss Carryforwards Credit carryforwards Deferred Tax Assets Tax Credit Carryforwards Intangible assets Deferred Tax Assets Goodwill And Intangible Assets Accrued expenses Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities Total deferred tax assets Deferred Tax Assets Gross Valuation allowance Deferred Tax Assets Valuation Allowance Total net deferred tax assets Deferred Tax Assets Net Deferred tax liabilities: Deferred Tax Liabilities [Abstract] Fixed assets Deferred Tax Liabilities Property Plant And Equipment Total deferred tax liability Deferred Income Tax Liabilities Total deferred tax assets (liabilities) Deferred Tax Assets Liabilities Net Operating Loss Carryforwards, Expiration Year Tax Credit Carryforward, Expiration Year Income Tax Disclosure [Line Items] Income Tax Disclosure [Table] Income Tax Disclosure [Table] Income Tax Disclosure [Table] Income Tax Authority Income Tax Authority [Axis] Income Tax Authority Income Tax Authority [Domain] U.S. Federal Domestic Country [Member] State and Local Jurisdiction State And Local Jurisdiction [Member] Tax Credit Carryforward Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name Tax Credit Carryforward Name [Domain] Research and Developments Tax Credit Carryforwards Research [Member] Income Tax Disclosure [Line Items] Income Tax Disclosure [Line Items] Net operating loss carryforwards Operating Loss Carryforwards Net operating loss carryforwards expiration year Operating Loss Carryforwards Expiration Year Research and development tax credit carryforwards Tax Credit Carryforward Amount Research and development tax credit carryforwards expiration year Tax Credit Carryforward Expiration Year Increase in valuation allowance for deferred tax assets Valuation Allowance Deferred Tax Asset Change In Amount Unrecognized tax positions, accrued interest or penalties Unrecognized Tax Benefits Income Tax Penalties And Interest Expense Tax returns open year Open Tax Year Weighted average number of shares outstanding basic and diluted. Numerator: Net Income Loss [Abstract] Denominator: Weighted Average Number Of Shares Outstanding Basic And Diluted [Abstract] Weighted-average common shares outstanding—basic and diluted Net loss per share—basic and diluted Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Options to Purchase Common Stock Unvested Restricted Common Stock Unvested Restricted Stock Units Convertible Preferred Stock (As Converted to Common Stock) Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Total Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Lease executed date. Leases [Abstract] Lease executed date Lease Executed Date Lease expiration date Lease Expiration Date1 Facility additional area leased. Operating lease monthly rent expense. Operating lease increase in monthly rent expense. Operating lease period of extension. Additional leased office space Facility Additional Area Leased Lease term Lessee Operating Lease Term Of Contract Lease, description Lessee Operating Lease Description Monthly rent expense Operating Lease Monthly Rent Expense Increase in monthly rent expense Operating Lease Increase In Monthly Rent Expense Existence of option to extend lease Lessee Operating Lease Existence Of Option To Extend Option to extend lease Lessee Operating Lease Option To Extend Additional period of lease Operating Lease Period Of Extension Rent expense Operating Lease Expense Operating Leases Future Minimum Payments Due [Abstract] Operating Lease Liabilities Payments Due [Abstract] 2021 Lessee Operating Lease Liability Payments Due Next Twelve Months 2022 Lessee Operating Lease Liability Payments Due Year Two 2023 Lessee Operating Lease Liability Payments Due Year Three 2024 Lessee Operating Lease Liability Payments Due Year Four 2025 Lessee Operating Lease Liability Payments Due Year Five Thereafter Lessee Operating Lease Liability Payments Due After Year Five Total Lessee Operating Lease Liability Payments Due Collaborative agreement upfront payments. Contractual agreements milestone payment. Contractual agreements possible second milestone payment. Upfront payment Collaborative Agreement Upfront Payments Development and regulatory milestones payment Contractual Agreements Milestone Payment Development and regulatory possible second milestones payment Contractual Agreements Possible Second Milestone Payment Accrued milestone payment obligation. Accrued milestone payment obligation Accrued Milestone Payment Obligation Accrued royalty obligation Accrued Royalties Current And Noncurrent