PCL and HEK293 Platform PCL and HEK293 Platforms [Member] PCL and HEK293 Platforms. Balance of contract assets (liabilities) at end of period Deductions Contract with customer (assets) liability deductions during period. Contract With Customer assets Liability Deductions During Period Balance of contract liabilities at beginning of period Balance of contract liabilities at beginning of period Contract With Customer Assets Liability Current Contract with customer assets (liability) current. Additions Contract With Customer Assets Liability Additions During Period Other Other Member Other member. Common stock - 250,000,000 shares authorized; 67,961,963 and 66,818,520 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively Other liabilities Other Liabilities, Noncurrent Other Liabilities, Noncurrent, Total Contract assets and liabilities, net Contract assets and liabilities, net Increase Decrease In Contract Assets and Contract Liabilities Net Increase (decrease) in contract assets and contract liabilities net. Proceeds from sale of equity investment Proceeds From Sale Of Equity Investment Proceeds from sale of equity investment. Prepaid Expenses and Other Current Assets Realized gain (loss) Realized Investment Gains (Losses) Realized Investment Gains (Losses), Total Additional option to purchase common stock value per share Option To Purchase Additional Common Stock Value Per Share Option to purchase additional common stock value per share. Additional option to purchase common stock Option To Purchase Additional Common Stock Option to purchase additional common stock. Number of disease targets Number Of Disease Targets Number of disease targets. Mahzi Therapeutics, Inc. Mahzi Therapeutics Inc [Member] Mahzi Therapeutics Inc. Subsequent Event Subsequent Event [Member] Subsequent Event Type [Domain] Subsequent Event Type [Axis] Preferred Stock Preferred Stock [Member] Debt conversion, converted instrument, shares issued Debt Conversion, Converted Instrument, Shares Issued Total operating expenses Cost Of Sales And Operating Expenses Cost of sales and operating expenses. 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Issuance Of Common Stock Value In Connection With License Agreement Issuance of common stock in connection with license agreement, net of issuance costs Stock issued during period value at market offering. 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Arcturus Research Collaboration And License Agreement [Member] Arcturus Arcturus Counterparty Name [Axis] Counterparty Name Counterparty Name [Domain] Counterparty Name Solid Biosciences, Inc. Solid Biosciences Inc [Member] Solid Biosciences, Inc. Schedule of cost sharing payments. Schedule Of Cost Sharing Payments Table [Text Block] Schedule of Cost Sharing Payments Schedule of changes in fair value of equity investment. Schedule Of Changes In Fair Value Of Equity Investment Table [Text Block] Schedule of Changes in Fair Value of Equity Investment Schedule of changes in fair value of investment in securities. Schedule Of Changes In Fair Value Of Investment In Securities Table [Text Block] Schedule of Changes in Fair Value of Investment in Securities Schedule of activity within liability related to sale of future royalties. 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Liability Related To Sale Of Future Royalties Liability related to the sale of future royalties at end of year Liability related to the sale of future royalties at beginning of year Liability related to the sale of future royalties Statement of Financial Position [Abstract] Assets [Abstract] Assets Net income (loss) per share: Statement of Comprehensive Income [Abstract] Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Foreign currency translation adjustments OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Unrealized gain (loss) on available-for-sale securities Other Comprehensive Income (Loss), Net of Tax Other comprehensive income (loss) Other comprehensive income (loss): Comprehensive Income (Loss), Net of Tax, Attributable to Parent Issuance of common stock under equity plan awards, net of tax, shares. Issuance Of Common Stock Under Equity Plan Awards Net Of Tax Shares Issuance of common stock under equity plan awards, net of tax, shares Issuance of common stock under equity plan awards, net of tax. Issuance Of Common Stock Under Equity Plan Awards Net Of Tax Issuance of common stock under equity plan awards, net of tax Retained Earnings [Member] Accumulated Deficit Issuance of common stock in connection with license agreement net of issuance costs shares. Issuance Of Common Stock In Connection With License Agreement Net Of Issuance Costs Shares Issuance of common stock in connection with license agreement, net of issuance costs, shares Stock issued during period shares at market offering. Stock Issued During Period Shares At Market Offering Issuance of common stock in connection with at-the-market offering, net of issuance costs, shares APIC, Share-based Payment Arrangement, Increase for Cost Recognition Stock-based compensation Issuance of common stock upon exercise of warrants and under equity plan awards, net of tax, shares. Issuance Of Common Stock Upon Exercise Of Warrants And Under Equity Plan Awards Net Of Tax Shares Issuance of common stock upon exercise of warrants and under equity plan awards, net of tax, shares Allocated share based compensation expense net of capitalized inventory cost. Allocated Share Based Compensation Expense Net Of Capitalized Inventory Cost Stock-based compensation Non cash collaboration royalty revenue. Non Cash Collaboration Royalty Revenue Non-cash collaboration royalty revenue Increase decrease in accounts payable accrued liabilities and other operating liabilities. Increase Decrease In Accounts Payable Accrued Liabilities And Other Operating Liabilities Accounts payable, accrued, and other liabilities Proceeds from issuance of common stock in connection with license agreement. Proceeds From Issuance Of Common Stock In Connection With License Agreement Proceeds from the issuance of common stock in connection with the license agreement, net Proceeds from issuance of common stock in connection with license agreement Proceeds from issuance of common stock at market offering. Proceeds From Issuance Of Common Stock At Market Offering Proceeds from the issuance of common stock in connection with at-the-market offering, net Operating and finance lease liability from obtaining right of use assets. 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Dojolvi [Member] Dojolvi Disaggregation of Revenue [Line Items] Disaggregation Of Revenue [Line Items] North America [Member] North America Europe [Member] Europe Latin America [Member] Latin America Percentage of gross accounts receivable balance. Percentage Of Gross Accounts Receivable Balance Percentage of gross accounts receivable balance Percentage of cost for developing activities. Percentage Of Cost For Developing Activities Percentage of cost for developing activities Collaborative Arrangement and Arrangement Other than Collaborative [Table] Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Kyowa Kirin Collaboration. Kyowa Kirin Collaboration [Member] Kyowa Kirin Collaboration Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Forecast [Member] Scenario Forecast Profit share revenue and royalties. Profit Share Revenue And Royalties [Member] Profit Share Revenue Commercial and development activity reimbursements. Commercial And Development Activity Reimbursements [Member] Commercial and Development Activity Reimbursements Balance Sheet Location [Axis] Balance Sheet Location Balance Sheet Location [Domain] Balance Sheet Location Prepaid Expenses and Other Current Assets [Member] Legal Entity [Axis] Legal Entity Entity [Domain] Entity Bayer Health Care LLC. Bayer Health Care L L C [Member] Bayer HealthCare LLC Research, development and commercialize AAV Gene therapy products agreement. Research Development And Commercialize A A V Gene Therapy Products Agreement [Member] Research, Develop and Commercialize AAV Gene Therapy Products Program agreement and unitholder option agreement. Program Agreement And Unitholder Option Agreement [Member] Program Agreement and Unitholder Option Agreement GeneTx Biotherapeutics LLC. Gene Tx Biotherapeutics L L C [Member] GeneTx Biotherapeutics LLC REGENXBIO, incorporated. R E G E N X B I O Incorporated [Member] REGENXBIO, Inc. License agreement. License Agreement [Member] License Agreement License and technology access agreement. License And Technology Access Agreement [Member] License and Technology Access Agreement HeLA PCL platform. He L A P C L Platform [Member] HeLA PCL Platform Stock purchase agreement. Stock Purchase Agreement [Member] Stock Purchase Agreement Sublicense agreement. Sublicense Agreement [Member] Sublicense Agreement Collaboration and license agreement. Collaboration And License Agreement [Member] Collaboration and License Agreement Collaboration agreement. Collaboration Agreement [Member] Automatic increases in shares available for grant effective date Share based compensation arrangement by share based payment award shares available for grant ending date. Share Based Compensation Arrangement By Share Based Payment Award Shares Available For Grant Ending Date Shares available for grant, ending date 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 [Axis] Plan Name Plan Name [Domain] Plan Name 2014 Incentive plan. Two Thousand Fourteen Incentive Plan [Member] 2014 Incentive Plan Two thousand fourteen employee stock purchase plan. Two Thousand Fourteen Employee Stock Purchase Plan [Member] 2014 Employee Stock Purchase Plan Employment inducement plan. 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Change In Fair Value Of Additional Common Stock Fair value of option to purchase additional shares of common stock, Change in fair value Transfer of fair value on additional exercise of options. Transfer Of Fair Value On Additional Exercise Of Options Fair value of option to purchase additional shares of common stock, Transfer of value upon option exercise Option to purchase additional sale of shares. Option To Purchase Additional Sale Of Shares Fair value of option to purchase additional shares of common stock, Sale of shares Transfer of fair value on exercise of options. Transfer Of Fair Value On Exercise Of Options Common stock, Transfer of value upon option exercise Fair value of sale of shares. Fair Value Of Sale Of Shares Common stock, Sale of shares Fair Value, Option, Changes in Fair Value, Gain (Loss) Common stock, Change in fair value Unrealized Gain (Loss) on Investments Unrealized gain (loss) Business combination upfront payment. Business Combination Upfront Payment Upfront payment for exclusive option to acquisition Exclusive options subject to option exercise period. Exclusive Options Subject To Option Exercise Period Business acquisition option exercise period, description Option extension right to acquire subject to description. Option Extension Right To Acquire Subject To Description Exercise of option extension, right to acquire condition Business acquisition number of quarters available for extension. Business Acquisition Number Of Quarters Available For Extension Extension period available for right to acquisition Option extension premium. Option Extension Premium Option extension Premium Business Combination, Consideration Transferred Business acquisition, consideration transferred Annual fees payable. Annual Fees Payable Annual fees payable Upfront payment for in process research and development expense. 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Remaining Business Combination Consideration Transferred1 Remaining consideration paid Acquisition of investment in common stock. Acquisition Of Investment In Common Stock Common stock, Acquisition of investment in securities Deferred Income Tax Liabilities, Net, Total Payments made under agreement. Payments Made Under Agreement Payments made under agreement Proceeds from sale of future royalties. Proceeds From Sale Of Future Royalties Proceeds from sale of future royalties Royalty agreement termination threshold amount. Royalty Agreement Termination Threshold Amount Royalty agreement termination threshold amount Royalty agreement termination description. Royalty Agreement Termination Description Royalty payment termination description Liability related to sale of future royalties. Liability Related To Sale Of Future Royalties [Line Items] Liability Related To Sale Of Future Royalties [Line Items] Liability related to sale of future royalties. Liability Related To Sale Of Future Royalties [Table] Liability Related To Sale Of Future Royalties [Table] Royalty purchase agreement. Royalty Purchase Agreement [Member] Royalty Purchase Agreement RPI Finance Trust. R P I Finance Trust [Member] RPI Finance Trust (RPI) Royalties transaction costs net. Royalties Transaction Costs Net Royalties transaction costs net Proceeds from royalties received financing activities. Proceeds From Royalties Received Financing Activities Proceeds from the sale of future royalties, net Debt Instrument, Interest Rate, Effective Percentage Effective annual interest rate Share based compensation arrangement by share based payment award shares available for grant beginning date. Share Based Compensation Arrangement By Share Based Payment Award Shares Available For Grant Beginning Date Selling, General and Administrative Expense, Total Increase (Decrease) in Prepaid Expense and Other Assets, Total Common Stock, Value, Issued, Total Common Stock, Value, Issued, Beginning Balance Common Stock, Value, Issued, Ending Balance Research and Development Expense, Total Common Stock, Shares, Issued, Total Unrealized Gain (Loss) on Investments, Total Equity Securities, FV-NI, Gain (Loss), Total Other Noncash Income (Expense), Total Increase (Decrease) in Inventories, Total Accounts Payable, Current, Total Preferred Stock, Value, Issued, Total Preferred Stock, Value, Issued, Beginning Balance Preferred Stock, Value, Issued, Ending Balance Income Tax Expense (Benefit), Total Other Assets, Noncurrent, Total Mereo BioPharma 3 Limited. Mereo Bio Pharma3 Limited [Member] Mereo Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Profit loss sharing percentage on commercializing products. Profit Loss Sharing Percentage On Commercializing Products Remaining profit or loss share percentage on commercializing products Revenue share percentage on commercialized products range mid to high. Revenue Share Percentage On Commercialized Products Range Mid To High Tiered double-digit revenue share percentage entitled to receive Profit loss sharing percentage on net sales. Profit Loss Sharing Percentage On Net Sales Profit loss sharing percentage on net sales Royalty percentage on net sales. Royalty Percentage On Net Sales Percentage of royalty on net sales receives Collaboration and royalty. Collaboration And Royalty [Member] Collaboration and Royalty Collaborative arrangements effective reduction of expense in research and development expenses. Collaborative Arrangements Effective Reduction Of Expense In Research And Development Expenses Research and development Collaborative arrangements effective reduction of expense in selling, general and administrative expenses. Collaborative Arrangements Effective Reduction Of Expense In Selling General And Administrative Expenses Selling, general and administrative Cost Sharing Payments [Table] Cost Sharing Payments [Table] Accounts Receivable, after Allowance for Credit Loss License agreement accounts receivable Other Receivables License agreement other receivables Accrued Liabilities License agreement accrued liabilities Future contingent milestone payments. Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Beginning Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Ending Balance Payments for (Proceeds from) Other Investing Activities Other Amortization of premium on marketable debt securities, net Other Contract with Customer, Asset, after Allowance for Credit Loss Contract with Customer, Asset, after Allowance for Credit Loss, Total Investments, Fair Value Disclosure, Total Retained Earnings (Accumulated Deficit), Total Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Ending Balance Other Nonoperating Income (Expense), Total Available-for-sale Securities, Gross Realized Gain (Loss), Total Goodwill, Total Goodwill, Beginning Balance Goodwill, Ending Balance Employee-related Liabilities, Current, Total Accounts Receivable, after Allowance for Credit Loss, Total APIC, Share-based Payment Arrangement, Increase for Cost Recognition, Total Debt Securities, Available-for-sale, Current, Total Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax, Total Payments to Acquire Property, Plant, and Equipment, Total Inventory, Finished Goods, Gross, Total Available-for-sale Securities, Total Cash and Cash Equivalents, at Carrying Value, Total Cash and Cash Equivalents, at Carrying Value, Beginning Balance Cash and Cash Equivalents, at Carrying Value, Ending Balance AOCI, Debt Securities, Available-for-sale, Adjustment, after Tax, Total Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Total Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised, Total Intangible Assets, Net (Excluding Goodwill), Total Depreciation, Depletion and Amortization, Total Accrued Liabilities, Total Property, Plant and Equipment, Net, Total Property, Plant and Equipment, Net, Beginning Balance Property, Plant and Equipment, Net, Ending Balance Additional Paid in Capital, Total Additional Paid in Capital, Beginning Balance Additional Paid in Capital, Ending Balance Business Combination, Consideration Transferred, Total Contract with Customer, Liability, Total Preferred Stock, Shares Outstanding, Beginning Balance Preferred Stock, Shares Outstanding, Ending Balance Revenue from Contract with Customer, Excluding Assessed Tax, Total Accounts Receivable, after Allowance for Credit Loss, Current, Total Amortization of premium on marketable debt securities, net Contract assets Investment Income Interest, Total Earnings Per Share, Basic and Diluted Earnings Per Share, Basic and Diluted, Total Weighted Average Number of Shares Outstanding, Basic and Diluted Net loss per share, basic and diluted Weighted-average shares used in computing net loss per share, basic and diluted Loss before income taxes Net loss Net loss Common stock equivalents excluded from computation of diluted net loss per share Total comprehensive loss Net Loss Per Share Other Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share Minimum License Agreement Sublicense Agreement Licenses Agreement. Licenses Agreement [Member] Sublicenses Agreement. Sublicenses Agreement [Member] License Agreement Sublicense Agreement Number of common stock held. Number Of Common Stock Held Number of common stock held