Entity Central Index Key Lessee, operating lease, liability, payments, due year five. Lessee, operating lease, liability, payments, due after year six. Finance lease liability residual values. 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 Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Small Business Entity Small Business Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Shell Company Entity Shell Company Title of 12(b) Security Security12b Title Security Exchange Name Security Exchange Name 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 Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Accrued expenses and other current liabilities. Statement Of Financial Position [Abstract] Statement [Table] Statement [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Redeemable Convertible Preferred Stock Redeemable 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 Held To Maturity 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 Restricted Cash Noncurrent Operating lease right-of-use assets Operating Lease Right Of Use Asset Other assets Other Assets Noncurrent Total assets Assets Liabilities, redeemable convertible preferred stock, and stockholders’ equity (deficit) Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued expenses and other current liabilities Accrued Expenses And Other Current Liabilities Derivative liabilities Derivative Liabilities Current Current portion of lease liability Operating Lease Liability Current Current portion of equipment financing liability Finance Lease Liability Current Total current liabilities Liabilities Current Long-term lease liability Operating Lease Liability Noncurrent Long-term equipment financing liability Finance Lease Liability Noncurrent Other liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and contingencies (See Note 7, Leases, and Note 8, License agreements) Commitments And Contingencies Redeemable convertible preferred stock Temporary Equity Carrying Amount Attributable To Parent Stockholders’ equity (deficit): Stockholders Equity [Abstract] Preferred stock, $0.01 par value; 25,000,000 and no shares authorized at June 30, 2020 and December 31, 2019, respectively, and no shares issued or outstanding at June 30, 2020 and December 31, 2019, respectively Preferred Stock Value Common stock, $0.01 par value; 250,000,000 and 205,000,000 shares authorized, 51,525,807 and 9,981,991 issued, and 49,645,737 and 7,326,185 outstanding at June 30, 2020 and December 31, 2019, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive income Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity (deficit) Stockholders Equity Total liabilities, redeemable convertible preferred stock, and stockholders’ equity (deficit) Liabilities And Stockholders Equity Preferred stock, par or stated value per share Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par or stated value per share 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 Available for sale securities transferred security unrealized gain (loss). Other Operating Income Expense. Reconciliation of net loss to net gain (loss) attributable to common stockholders. Income Statement [Abstract] License revenue Revenues Revenue, Product and Service [Extensible List] Type Of Revenue Extensible List 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 income (expense): Other Operating Income Expense [Abstract] Change in fair value of derivative liabilities Derivative Gain Loss On Derivative Net Interest and other income, net Interest Income Other Total other expense Other Operating Income Expense Net Net loss Net Income Loss Unrealized gain on marketable securities Available For Sale Securities Transferred Security Unrealized Gain Loss Comprehensive loss Comprehensive Income Net Of Tax Reconciliation of net loss to net loss attributable to common stockholders: Reconciliation Of Net Gain Loss To Net Loss Attributable To Common Stockholders [Abstract] Net loss Accretion of redeemable convertible preferred stock to redemption value, including dividends on preferred stock Temporary Equity Accretion To Redemption Value Adjustment Net loss attributable to common stockholders Net Income Loss Available To Common Stockholders Basic Net loss per common share attributable to common stockholders, basic and diluted Earnings Per Share Basic And Diluted Weighted-average common shares used in net loss per share attributable to common stockholders, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Temporary equity stock issued during period shares new issues. Accretion of redeemable convertible preferred stock to redemption value. Temporary equity conversion of redeemable convertible preferred stock to common stock upon closing of initial public offering value. Stock issued during period value Vesting of restricted common stock. Issuance of common stock value related to license agreement. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid In Capital [Member] Accumulated Other Comprehensive (Loss) Income Accumulated Other Comprehensive Income [Member] Accumulated Deficit Retained Earnings [Member] Beginning Balance Beginning Balance, Shares Shares Outstanding Redeemable convertible preferred stock, Beginning Balance Redeemable convertible preferred stock, Beginning Balance, Shares Temporary Equity Shares Outstanding Issuance of Series B redeemable convertible preferred stock, net of issuance costs of $0.1 million Temporary Equity Stock Issued During Period Value New Issues Issuance of Series B redeemable convertible preferred stock, net of issuance costs of $0.1 million, Shares Temporary Equity Stock Issued During Period Shares New Issues Accretion of redeemable convertible preferred stock to redemption value Temporary Equity Accretion To Redemption Value Accretion of redeemable convertible preferred stock to redemption value Accretion Of Redeemable Convertible Preferred Stock To Redemption Value Conversion of preferred stock to common stock upon closing of initial public offering Temporary Equity Conversion Of Redeemable Convertible Preferred Stock To Common Stock Upon Closing Of Initial Public Offering Value Temporary equity conversion of redeemable convertible preferred stock to common stock upon closing of initial public offering shares. Conversion of preferred stock to common stock upon closing of initial public offering, Shares Temporary Equity Conversion Of Redeemable Convertible Preferred Stock To Common Stock Upon Closing Of Initial Public Offering Shares Conversion of preferred stock to common stock upon closing of initial public offering Stock Issued During Period Value Conversion Of Convertible Securities Conversion of preferred stock to common stock upon closing of initial public offering, Shares Stock Issued During Period Shares Conversion Of Convertible Securities Issuance of common stock from initial public offering, net of issuance costs of $18.7 million Stock Issued During Period Value New Issues Issuance of common stock from initial public offering, net of issuance costs of $18.7 million, Shares Stock Issued During Period Shares New Issues Vesting of restricted common stock Stock Issued During Period Value Vesting Of Restricted Common Stock Stock issued during period shares vesting of restricted common stock. Vesting of restricted common stock, Shares Stock Issued During Period Shares Vesting Of Restricted Common Stock Issuance of common stock related to license agreement Issuance Of Common Stock Value Related To License Agreement Issuance of common stock shares related to license agreement. Issuance of common stock related to license agreement, Shares Issuance Of Common Stock Shares Related To License Agreement Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation And Exercise Of Stock Options Exercise of common stock options Stock Issued During Period Value Stock Options Exercised Exercise of common stock options, Shares Stock Issued During Period Shares Stock Options Exercised Other comprehensive income (loss) Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent Redeemable convertible preferred stock, Ending Balance Redeemable convertible preferred stock, Ending Balance, Shares Ending Balance Ending Balance, Shares Temporary equity net issuance cost. Series B redeemable convertible preferred stock. Series B Redeemable Convertible Preferred Stock Series B Redeemable Convertible Preferred Stock [Member] Issuance of Series B redeemable convertible preferred stock, net of issuance costs Temporary Equity Net Issuance Cost Initial public offering, net of issuance costs. Issuance of common stock from initial public offering, net of issuance costs Initial Public Offering Net Of Issuance Costs Change in operating lease right-of-use assets. Non-cash research and development license expense. Change in fair value of derivative liabilities. Increase (decrease) in operating lease liabilities. Increase (decrease) in financing milestone liabilities. Proceeds from equipment financings. Repayment of equipment financings. Receipt of common stock in exchange for technology license. Equity issuance costs in accounts payable and accrued expenses. Statement Of Cash Flows [Abstract] 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] Depreciation Depreciation Amortization of investment premiums Investment Income Net Amortization Of Discount And Premium Stock-based compensation expense Share Based Compensation Change in operating lease right-of-use assets Change In Operating Lease Right Of Use Assets Non-cash research and development license expense Non Cash Research And Development License Expense Change in fair value of derivative liabilities Change In Fair Value Of Derivative Liabilities Other Other Noncash Income Expense Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Other long-term assets Increase Decrease In Other Noncurrent Assets Accounts payable Increase Decrease In Accounts Payable Accrued expenses and other liabilities Increase Decrease In Accrued Liabilities And Other Operating Liabilities Operating lease liabilities Increase Decrease In Operating Lease Liabilities Financing milestone liabilities Increase Decrease In Financing Milestone Liabilities Other long-term liabilities Increase Decrease In Other Noncurrent Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities 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 Held To Maturity Securities Maturities of marketable securities Proceeds From Sale And Maturity Of Held To Maturity Securities Purchase of long-term investment Payments To Acquire Longterm Investments Net cash used in investing activities Net Cash Provided By Used In Investing Activities Financing activities Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from issuance of Series B Preferred Stock, net Proceeds From Issuance Of Preferred Stock And Preference Stock Proceeds from initial public offering, net of underwriting discount Proceeds From Issuance Initial Public Offering Payment of initial public offering costs Payments Of Stock Issuance Costs Proceeds from equipment financings Proceeds From Equipment Financings Repayment of equipment financings Repayment Of Equipment Financings 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 change 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 period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash, cash equivalents and restricted cash—end of period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Income Taxes Paid Net Supplemental disclosure of noncash investing and financing activities: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Conversion of redeemable convertible preferred stock to common stock upon closing of the initial public offering Conversion Of Stock Amount Converted1 Property and equipment additions in accounts payable and accrued expenses Capital Expenditures Incurred But Not Yet Paid Operating lease liabilities arising from obtaining right-of-use assets Right Of Use Asset Obtained In Exchange For Operating Lease Liability Receipt of common stock in exchange for technology license Receipt Of Common Stock In Exchange For Technology License Issuance of common stock for research and development license Stock Issued1 Equity issuance costs in accounts payable and accrued expenses Equity Issuance Costs In Accounts Payable And Accrued Expenses Accretion of redeemable convertible preferred stock to redemption value, including dividends on preferred stock Organization Consolidation And Presentation Of Financial Statements [Abstract] Nature of the Business and Basis of Presentation Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Property Plant And Equipment [Abstract] Property and Equipment, Net Property Plant And Equipment Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Investments Debt And Equity Securities [Abstract] Marketable Securities Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] Payables And Accruals [Abstract] Accrued Expenses and Other Current Liabilities Accounts Payable Accrued Liabilities And Other Liabilities Disclosure Current [Text Block] Leases disclosure. Leases [Abstract] Leases Leases Disclosure [Text Block] License agreement disclosure. License Agreements License Agreement Disclosure [Text Block] Collaboration and License Agreements Collaborative Arrangement Disclosure [Text Block] Preferred and Common Stock Stockholders Equity Note Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock Option and Grant Plan Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Earnings Per Share [Abstract] Net Loss per Share Attributable to Common Stockholders Earnings Per Share [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Use of Estimates Use Of Estimates Cash, Cash Equivalents, and Restricted Cash Cash And Cash Equivalents Restricted Cash And Cash Equivalents Policy Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Reconciliation of Cash, Cash Equivalents, and Restricted Cash Schedule Of Cash And Cash Equivalents Table [Text Block] Schedule of Property and Equipment Property Plant And Equipment [Text Block] Summary of depreciation expense incurred. Summary of Depreciation Expense Incurred Summary Of Depreciation Expense Incurred Table [Text Block] Schedule of Fair Value of Financial Assets and Liabilities Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Schedule of Calculation of Estimated Fair Value of Success Payment Liabilities Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Text Block] Fair value measurement with unobservable inputs reconciliations recurring basis, success payment derivative liabilities. Schedule of Change in Fair Value of Success Payment Liabilities Based on Level 3 Inputs Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Success Payment Derivative Liabilities Table [Text Block] Summary of Marketable Securities Held Held To Maturity Securities [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] Property, Plant and Equipment, Type Property Plant And Equipment By Type [Axis] Property, Plant and Equipment, Type Property Plant And Equipment Type [Domain] Equipment Equipment [Member] Summary of Operating Lease Costs Lease Cost Table [Text Block] Summary of lease term and discount rate. Summary of Lease Term and Discount Rate Summary Of Lease Term And Discount Rate Table [Text Block] Summary of cash paid for amounts included in measurement of lease liabilities. Summary of Cash Paid for Amounts Included in Measurement of Lease Liabilities Summary Of Cash Paid For Amounts Included In Measurement Of Lease Liabilities Table [Text Block] Summary of Future Minimum Lease Payments of Operating Leases Lessee Operating Lease Liability Maturity Table [Text Block] Summary of Future Minimum Payments Related to Equipment Financing Obligations Finance Lease Liability Maturity Table [Text Block] Summary of principal and interest portions. Summary of Principal and Interest Portions Summary Of Principal And Interest Portions Table [Text Block] Schedule of success payment liability. Schedule of Success Payment Liability Schedule Of Success Payment Liability Table [Text Block] Schedule of change in fair value of success payment liability. Schedule of Change in Fair Value of Success Payment Liability Schedule Of Change In Fair Value Of Success Payment Liability Table [Text Block] Summary of Stock-based Compensation Expense Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Summary of Option Activity Under Equity Award Plans Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Summary of Restricted Stock Activity Nonvested Restricted Stock Shares Activity Table [Text Block] Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Summary of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Nature of the business and basis of presentation. Nature of the 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] IPO I P O [Member] Underwriters’ Option Over Allotment Option [Member] Nature Of Business And Basis Of Presentation [Line Items] Nature Of Business And Basis Of Presentation [Line Items] Reverse stock split ratio Stockholders Equity Note Stock Split Conversion Ratio1 Reverse stock split Stockholders Equity Reverse Stock Split Shares issued and sold Sale Of Stock Number Of Shares Issued In Transaction Public offering price per share Sale Of Stock Price Per Share Gross proceeds from sale of common stock Net proceeds from sale of common stock Sale Of Stock Consideration Received On Transaction Shares issued upon conversion of preferred stock Convertible Preferred Stock Shares Issued Upon Conversion Accumulated deficit Cash, cash equivalents, and marketable securities Cash Cash Equivalents And Short Term Investments Total cash, cash equivalents, and restricted cash Schedule Of Property Plant And Equipment [Table] Schedule Of Property Plant And Equipment [Table] Lab equipment. Lab Equipment Lab Equipment [Member] Leasehold Improvements Leasehold Improvements [Member] Furniture and Fixtures Furniture And Fixtures [Member] Computer Equipment Computer Equipment [Member] Construction in Process Construction In Progress [Member] Property Plant And Equipment [Line Items] Property Plant And Equipment [Line Items] Total property and equipment Property Plant And Equipment Gross Less accumulated depreciation Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Property and equipment, net Depreciation expense Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Table] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Interest and other income, net. Interest and Other Income, Net Interest And Other Income Net [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] Investments in privately issued corporate equity securities Equity Securities Fv Ni 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 Frequency Fair Value By Measurement Frequency [Axis] Measurement Frequency Fair Value Measurement Frequency [Domain] Recurring Fair Value Measurements Recurring [Member] Collaborative Arrangement and Arrangement Other than Collaborative Type Of Arrangement [Axis] Collaborative Arrangement and Arrangement Other than Collaborative Arrangements And Nonarrangement Transactions [Member] Harvard license agreement. Harvard Harvard License Agreement [Member] Broad license agreement. Broad Institute Broad License Agreement [Member] Measurement Basis Fair Value By Measurement Basis [Axis] Fair Value Disclosure Item Amounts [Default] Portion At Fair Value Fair Value Disclosure [Member] Fair Value Measurement Fair Value Disclosure Item Amounts [Domain] Carrying Amount Carrying Reported Amount Fair Value Disclosure [Member] Fair Value Estimate Of Fair Value Fair Value Disclosure [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] Commercial Paper Commercial Paper [Member] Corporate Notes Corporate Debt Securities [Member] U.S. Treasury Securities U S Treasury 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] Assets Assets Fair Value Disclosure [Abstract] Cash equivalents Cash And Cash Equivalents Fair Value Disclosure Marketable securities Held To Maturity Securities Fair Value Total assets Assets Fair Value Disclosure Liabilities Liabilities Fair Value Disclosure [Abstract] Success payment liability Derivative Fair Value Of Derivative Liability Total liabilities Liabilities Fair Value Disclosure Measurement Input Type Measurement Input Type [Axis] Measurement Input Type Measurement Input Type [Domain] Measurement input fair value of preferred stock. Fair Value of Series A Preferred Stock Measurement Input Fair Value Of Preferred Stock [Member] Measurement input fair value of common stock. Fair Value of Common Stock Measurement Input Fair Value Of Common Stock [Member] Expected Volatility Measurement Input Price Volatility [Member] Expected Term (years) Measurement Input Expected Term [Member] Statistical Measurement Range [Axis] Statistical Measurement Range [Member] Minimum Minimum [Member] Maximum Maximum [Member] Success payment liability, measurement input Derivative Liability Measurement Input Success payment liability, term Derivative Term Of Contract Fair value of preferred stock price per share after adjusted reverse stock split. Fair value of preferred stock price per share after adjusted reverse stock split Fair Value Of Preferred Stock Price Per Share After Adjusted Reverse Stock Split Fair value measurement with unobservable inputs reconciliations recurring basis success payment liability value. Fair value measurement with unobservable inputs reconciliation recurring basis success payment liability period increase (decrease). Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] 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 at December 31, 2019 Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Success Payment Liability Value Changes in fair value Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Success Payment Liability Period Increase Decrease Balance at June 30, 2020 Schedule Of Held To Maturity Securities [Table] Schedule Of Held To Maturity Securities [Table] Financial Instrument Financial Instrument [Axis] Financial Instruments Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain] Schedule Of Held To Maturity Securities [Line Items] Schedule Of Held To Maturity Securities [Line Items] Marketable securities held, Amortized Cost Held To Maturity Securities Marketable securities held, Gross Unrealized Gains Held To Maturity Securities Accumulated Unrecognized Holding Gain Marketable securities held, Gross Unrealized Losses Held To Maturity Securities Accumulated Unrecognized Holding Loss Marketable securities held, Fair Value Realized gains or losses recognized on sale or maturity of marketable securities Heldtomaturity Securities Sold Security Realized Gain Loss Excluding Other Than Temporary Impairments Number of unrealized loss position held in debt securities Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Accrued research cost. Other accrued expenses and other current liabilities. Research costs Accrued Research Cost Employee compensation and related benefits Employee Related Liabilities Current Professional fees Accrued Professional Fees Current Other Other Accrued Expenses And Other Current Liabilities Total Operating lease, commencement month and year. Operating lease, termination month and year. Lessee Lease Description [Table] Lessee Lease Description [Table] Office and laboratory space. Office and Laboratory Space Office And Laboratory Space [Member] Laboratory space. Laboratory Space Laboratory Space [Member] Lessee Lease Description [Line Items] Lessee Lease Description [Line Items] Square feet of office and laboratory space Area Of Land Operating lease, commencement month and year Operating Lease Commencement Month And Year Operating lease, termination month and year Operating Lease Termination Month And Year Tenant improvements Tenant Improvements Operating lease, amendment month and year. Operating lease, amendment month and year Operating Lease Amendment Month And Year Operating lease, option to extend Lessee Operating Lease Option To Extend Operating lease, existence of option to extend Lessee Operating Lease Existence Of Option To Extend Operating lease right-of-use asset Lease liability Operating Lease Liability Operating lease costs Operating Lease Cost Variable lease costs Variable Lease Cost Short-term lease costs Short Term Lease Cost Sublease income Sublease Income Total Lease Cost Operating leases, Weighted-average remaining lease term (years) Operating Lease Weighted Average Remaining Lease Term1 Operating leases, Weighted-average discount rate Operating Lease Weighted Average Discount Rate Percent Operating cash flows used for operating leases Operating Lease Payments Operating Lease Liabilities Payments Due [Abstract] Remainder of 2020 Lessee Operating Lease Liability Payments Remainder Of Fiscal Year 2021 Lessee Operating Lease Liability Payments Due Year Two 2022 Lessee Operating Lease Liability Payments Due Year Three 2023 Lessee Operating Lease Liability Payments Due Year Four 2024 Lessee Operating Lease Liability Payments Due Year Five 2025 Lessee Operating Lease Liability Payments Due Year Six Thereafter Lessee Operating Lease Liability Payments Due After Year Six Undiscounted lease payments Lessee Operating Lease Liability Payments Due Less: imputed interest Lessee Operating Lease Liability Undiscounted Excess Amount Total operating lease liabilities Lessee, operating lease, lease not yet commenced, expiration term. Lessee, operating lease, lease not yet commenced tenant improvement. Lessee, operating lease, lease not yet commenced, security deposit. Lessee, operating lease, lease not yet commenced anticipated undiscounted lease payments due. Lessee, operating lease, lease not yet commenced, description Lessee Operating Lease Lease Not Yet Commenced Description Lessee, operating lease, lease not yet commenced, existence of option to terminate Lessee Operating Lease Lease Not Yet Commenced Existence Of Option To Terminate Lessee, operating lease, lease not yet commenced, expiration term Lessee Operating Lease Lease Not Yet Commenced Expiration Term Lessee, operating lease, lease not yet commenced tenant improvement Lessee Operating Lease Lease Not Yet Commenced Tenant Improvement Lessee, operating lease, lease not yet commenced, existence of option to extend Lessee Operating Lease Lease Not Yet Commenced Existence Of Option To Extend Lessee, operating lease, lease not yet commenced, option to extend Lessee Operating Lease Lease Not Yet Commenced Option To Extend Lessee, operating lease, lease not yet commenced, security deposit Lessee Operating Lease Lease Not Yet Commenced Security Deposit Lessee, operating lease, lease not yet commenced anticipated undiscounted lease payments due Lessee Operating Lease Lease Not Yet Commenced Anticipated Undiscounted Lease Payments Due Financing obligations, leased back description Lessee Finance Lease Description Financing obligations, leased back equipment term of contract Lessee Finance Lease Term Of Contract1 Finance lease additional equipment sold amount. Financing obligations lease back equipment annual rent amount. Financing obligations, additional equipment sold Finance Lease Additional Equipment Sold Amount Financing obligations, lease back equipment annual rent Financing Obligations Lease Back Equipment Annual Rent Amount Finance lease liability payments. Finance lease liability payments. Finance Lease Liability Payments [Table] Finance Lease Liability Payments [Table] Finance Lease Liability Payments [Line Items] Finance Lease Liability Payments [Line Items] Remainder of 2020 Finance Lease Liability Payments Remainder Of Fiscal Year 2021 Finance Lease Liability Payments Due Year Two 2022 Finance Lease Liability Payments Due Year Three 2023 Finance Lease Liability Payments Due Year Four 2024 Finance Lease Liability Payments Due Year Five Total Finance Lease Liability Payments Due Less: amounts representing interest at 8.64% Finance Lease Liability Undiscounted Excess Amount Plus: residual values Finance Lease Liability Residual Values Financing obligations Finance Lease Liability Finance lease liability payments interest percentage. Finance lease liability payments interest percentage Finance Lease Liability Payments Interest Percentage Paydown of principal Finance Lease Principal Payments Paydown of interest Finance Lease Interest Expense Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Agreement description Collaborative Arrangement Nature And Purpose Success payment liability Success payment paid or due. Success payments paid or due Success Payment Paid Or Due Product development and regulatory approval milestones and royalties recognized. Product development, regulatory approval milestones and royalties recognized Product Development And Regulatory Approval Milestones And Royalties Recognized Commitments And Contingencies Disclosure [Abstract] Broad License Agreement Development regulatory and commercial milestone payments. Editas License Agreement. Editas License Agreement Editas License Agreement [Member] Development, regulatory and commercial milestone payments Development Regulatory And Commercial Milestone Payments Payment of upfront fee. Payment of milestone amount. Bio Palette License Agreement. Bio Palette License Agreement Bio Palette License Agreement [Member] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] Bio Palette Patent. Bio Palette Patent Bio Palette Patent [Member] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Upfront fee paid Payment Of Upfront Fee Milestone payment shares issued Milestone payment value of stock issued Milestone payment paid Payment Of Milestone Amount Collaboration arrangement extend term. Prime medicine Inc. Prime Medicine Inc Prime Medicine Inc [Member] Common stock, value Collaboration arrangement extend term Collaboration Arrangement Extend Term Schedule Of Stock By Class [Table] Schedule Of Stock By Class [Table] Class Of Stock [Line Items] Class Of Stock [Line Items] Preferred stock, shares authorized Preferred stock, par value per share Common stock, shares authorized Common stock, par value per share 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 nineteen equity incentive plan. 2019 Plan Two Thousand Nineteen Equity Incentive Plan [Member] Award Type Award Type [Axis] Award Type Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Unvested Stock Options Employee Stock Option [Member] Restricted Stock Restricted Stock [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Number of shares reserved for future issuance Common Stock Capital Shares Reserved For Future Issuance Number of shares available for future issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant 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] 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 Number of options Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward Outstanding at December 31, 2019 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 Forfeitures Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Outstanding at June 30, 2020 Exercisable as of June 30, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Weighted average exercise price Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward Outstanding at December 31, 2019 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 Forfeitures Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price Outstanding at June 30, 2020 Exercisable as of June 30, 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Weighted-average grant date fair value per share of options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Unrecognized compensation cost related to unvested stock options Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options Unrecognized compensation cost, expected to recognize over a weighted-average period Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Shares Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward Unvested as of December 31, 2019 Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Issued 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 Unvested as of June 30, 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 Unvested as of December 31, 2019 Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Issued 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 Unvested as of June 30, 2020 Unrecognized stock-based compensation expense, expected to vest Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options 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] Unvested Restricted Stock Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive shares excluded from computation of diluted net loss per share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Numerator: Net Income Loss [Abstract] Net loss attributable to common stockholders Denominator: Weighted Average Number Of Shares Outstanding [Abstract] Weighted average number of common shares, basic and diluted Number of founder shareholders. Schedule Of Related Party Transactions By Related Party [Table] Schedule Of Related Party Transactions By Related Party [Table] Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] Founder Shareholders. Founder Shareholders Founder Shareholders [Member] Related Party Transaction Related Party Transaction [Axis] Related Party Transaction Related Party Transaction [Domain] Scientific consulting and other expenses. Scientific Consulting and Other Expenses Scientific Consulting And Other Expenses [Member] Verve Therapeutics, Inc. Verve Therapeutics, Inc. Verve Therapeutics Inc [Member] Series A Preferred Stock Shares Series A Preferred Stock [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Payments made to related parties Related Party Transaction Amounts Of Transaction Number of founder shareholders Number Of Founder Shareholders Purchased shares from related party Related Party Transaction Purchases From Related Party Unrealized gains on investment Equity Securities Fv Ni Unrealized Gain Loss Manufacturing facility number of square feet. Expects to investment in lease amount. Maximum period of amount expected to invest in lease. Number of operating lease renewal options. Subsequent Event [Table] Subsequent Event [Table] Alexandria Real Estate Equities, Inc. Alexandria Real Estate Equities, Inc. Alexandria Real Estate Equities Inc [Member] Manufacturing Facility Manufacturing Facility [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Manufacturing facility, number of square feet Manufacturing Facility Number Of Square Feet Operating lease term Lessee Operating Lease Term Of Contract Operating lease, number of renewal options Number Of Operating Lease Renewal Options Operating lease, option to extend term Lessee Operating Lease Renewal Term Expects to investment in lease amount Expects To Investment In Lease Amount Maximum period of amount expected to invest in lease Maximum Period Of Amount Expected To Invest In Lease