Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Laboratory equipment Laboratory Equipment [Member] Represents information pertaining to laboratory equipment. Computer equipment and software Computer Equipment [Member] Leasehold improvements Leasehold Improvements [Member] Furniture and fixtures Furniture and Fixtures [Member] Office equipment Office 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 Property, Plant and Equipment, Net Revenue from Contract with Customer [Abstract] Revenue Arrangements Revenue from Contract with Customer [Text Block] Accounting Policies [Abstract] Concentration Risk [Table] Concentration Risk [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Russian subsidiary RUSSIAN FEDERATION Concentration Risk [Line Items] Concentration Risk [Line Items] Cash maintained in Russian bank accounts Cash Laboratory equipment, software and office equipment Equipment [Member] Computer equipment Estimated useful life Property, Plant and Equipment, Useful Life Property and Equipment Property, Plant and Equipment Disclosure [Text Block] Share-based Payment Arrangement [Abstract] 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 [Axis] Plan Name [Domain] Plan Name [Domain] The 2008 Plan and the 2016 Plan The 2008 Plan And The 2016 Plan [Member] The 2008 Plan And The 2016 Plan [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Employee awards Share-based Payment Arrangement [Member] Non‑employee awards Non Employee Stock Option [Member] An arrangement whereby a non-employee is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Ending balance (in shares) Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares Vested and expected to vest (in shares) 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 [Abstract] Beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Ending balance (in dollars per share) Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Exercise Price Vested and expected to vest (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted-average remaining contractual term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term [Abstract] n/a Outstanding, term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Vested, term Share-based Compensation Arrangement By Share-based Payment Award, Options, Vested, Outstanding, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement By Share-based Payment Award, Options, Vested, Outstanding, Weighted Average Remaining Contractual Term Vested and expected to vest, term Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value [Abstract] n/a Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Vested Share-based Compensation Arrangement By Share-based Payment Award, Options, Vested, Outstanding, Intrinsic Value Share-based Compensation Arrangement By Share-based Payment Award, Options, Vested, Outstanding, Intrinsic Value Vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Valuation Technique, Option Pricing Model Valuation Technique, Option Pricing Model [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Risk-free interest rate Measurement Input, Risk Free Interest Rate [Member] Expected life (in years) Measurement Input, Expected Term [Member] Expected volatility Measurement Input, Price Volatility [Member] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Warrants and rights outstanding, measurement input Warrants and Rights Outstanding, Measurement Input Warrants and rights outstanding, term Warrants and Rights Outstanding, Term Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] At-The-Market Offering At-The-Market Offering [Member] At-The-Market Offering [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Sale of stock, number of shares issued in transaction (in shares) Sale of Stock, Number of Shares Issued in Transaction Share price (in dollars per share) Sale of Stock, Price Per Share Net proceeds on shares issued Proceeds From Issuance Of Common Stock, Net Proceeds From Issuance Of Common Stock, Net Organization, Consolidation and Presentation of Financial Statements [Abstract] Accumulated deficit Retained Earnings (Accumulated Deficit) Schedule of Cash and Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Russian subsidiary Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Unrestricted cash Unrestricted Cash [Member] Unrestricted Cash [Member] Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Cash, cash equivalents, and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Restricted cash and cash equivalents Restricted Cash and Cash Equivalents Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Research and development Research And Development [Member] Represents the information pertaining to research and development expenses included in the income statement. General and administrative General and Administrative Expense [Member] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Total stock-based compensation expense Share-based Payment Arrangement, Expense Statement of Financial Position [Abstract] Preferred stock, par value (in dollars 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 value (in dollars 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 Statement of Comprehensive Income [Abstract] Grant and collaboration revenue Revenue from Contract with Customer, Excluding Assessed Tax Operating expenses: Cost of Revenue [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) Investment income Investment Income, Net Foreign currency transaction (loss), net Foreign Currency Transaction Gain (Loss), before Tax Interest expense Interest Expense Change in fair value of warrant liabilities Fair Value Adjustment of Warrants Other (expense), net Other Nonoperating Income (Expense) Net loss Net Income (Loss) Attributable to Parent Stock‑based compensation expense APIC, Share-based Payment Arrangement, Increase for Cost Recognition Other comprehensive loss: Other Comprehensive Income (Loss), Tax [Abstract] Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized gain on securities Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Total comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net loss per share: Earnings Per Share, Basic and Diluted [Abstract] Net loss per share attributable to common stockholders—basic and diluted (in dollars per share) Earnings Per Share, Basic and Diluted Weighted average common shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic and diluted (in shares) Weighted Average Number of Shares Outstanding, Basic and Diluted Impairment of intangible assets, finite-lived Impairment of Intangible Assets, Finite-lived Leases [Abstract] Schedule of Lease, Cost Lease, Cost [Table Text Block] Schedule of Lessee, Operating Lease, Liability, Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Subsequent Events Subsequent Events [Text Block] Retirement Benefits [Abstract] Defined Contribution Plan Pension and Other Postretirement Benefits Disclosure [Text Block] Debt Disclosure [Abstract] Line of Credit Facility [Table] Line of Credit Facility [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] 2017 Term Loans 2017 Term Loans [Member] 2017 Term Loans [Member] Term Loans Term Loan [Member] Represents information pertaining to term loan member. Debt Covenant Period [Axis] Debt Covenant Period [Axis] Debt Covenant Period [Axis] Debt Covenant Period [Domain] Debt Covenant Period [Domain] [Domain] for Debt Covenant Period [Axis] Prepaid after second anniversary Term Loan Prepaid After Second Anniversary [Member] Represents information pertaining to prepayment of term loan after second anniversary. Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Base Rate Base Rate [Member] Outstanding Balances Outstanding Balances [Member] Outstanding Balances [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Term loan facility Long-term Line of Credit Repayments of debt Repayments of Lines of Credit Loss on extinguishment of debt Gain (Loss) on Extinguishment of Debt Debt issuance costs, line of credit arrangements (less than) Debt Issuance Costs, Line of Credit Arrangements, Net Prepayment fee (as a percent) Early Extinguishment Of Debt, Prepayment Fee Percentage Percentage of fee payable on early extinguishment of debt. Interest rate per annum Line of Credit Facility, Interest Rate During Period Minimum assets trigger Debt Instrument, Event Of Default, Minimum Assets Trigger Debt Instrument, Event Of Default, Minimum Assets Trigger Minimum amount in excess of indebtedness trigger Debt Instrument, Event Of Default, Minimum Amount In Excess Of Indebtedness Trigger Debt Instrument, Event Of Default, Minimum Amount In Excess Of Indebtedness Trigger Final payment fee (as a percent) Final Payment Fee Percentage Percentage of final fee payment payable on aggregate principal amounts borrowed. Final payment fee Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid Debt instrument, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Interest expense Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Warrant Warrant [Member] Shares available for future stock incentive awards Unvested restricted stock units Restricted Stock Units (RSUs) [Member] Outstanding common stock options Share-based Payment Arrangement, Option [Member] Class of Stock [Line Items] Class of Stock [Line Items] Total (in shares) Common Stock, Capital Shares Reserved for Future Issuance Payables and Accruals [Abstract] Schedule of Accrued Expenses Schedule of Accrued Liabilities [Table Text Block] Earnings Per Share [Abstract] Net Loss Per Share Earnings Per Share [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Recurring Fair Value, Recurring [Member] Money market funds Money Market Funds [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] (Level 1) Fair Value, Inputs, Level 1 [Member] (Level 2) Fair Value, Inputs, Level 2 [Member] (Level 3) Fair Value, Inputs, Level 3 [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] Assets: Assets, Fair Value Disclosure [Abstract] Cash and cash equivalents, fair value disclosure Cash and Cash Equivalents, Fair Value Disclosure Total Assets, Fair Value Disclosure Liabilities: Liabilities, Fair Value Disclosure [Abstract] Warrant liabilities Warrants and Rights Outstanding Total Financial and Nonfinancial Liabilities, Fair Value Disclosure Schedule of Changes in Contract Liabilities Contract with Customer, Asset and Liability [Table Text Block] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Cash Equivalents, Current Long-term restricted cash Restricted Cash and Cash Equivalents, Noncurrent Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Common stock Common Stock [Member] Additional paid-In Capital Additional Paid-in Capital [Member] Accumulated deficit Retained Earnings [Member] Accumulated other comprehensive loss AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance (in shares) Beginning balance Stockholders' Equity Attributable to Parent Issuance of common stock under Employee Stock Purchase Plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Issuance of common stock under Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Issuance of common stock upon exercise of options (in shares) Issuance of common stock upon exercise of options Stock Issued During Period, Value, Stock Options Exercised Issuance of vested restricted stock units (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Issuance of common stock through at-the-market offering, net (in shares) Stock Issued During Period, Shares, Other Issuance of common stock through at-the-market offering, net Stock Issued During Period, Value, Other Other financing fees Adjustments to Additional Paid in Capital, Other Net loss Issuance of common stock, net of issuance costs (in shares) Stock Issued During Period, Shares, New Issues Issuance of common stock, net of issuance costs Stock Issued During Period, Value, New Issues Ending balance (in shares) Ending balance Summary of Assets Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Fair Value Measurement Inputs and Valuation Techniques Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Schedule Of Changes In The Warrant Liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] 2020 (remainder) 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 Thereafter Lessee, Operating Lease, Liability, Payments, Due after Year Five Total future minimum lease payments Lessee, Operating Lease, Liability, Payments, Due Less imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Total operating lease liabilities Operating Lease, Liability Current operating lease liabilities Operating Lease, Liability, Current Non-current operating lease liabilities Operating Lease, Liability, Noncurrent Operating lease, weighted average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Operating lease, weighted average discount rate, percent Operating Lease, Weighted Average Discount Rate, Percent Stock Incentive Plans Share-based Payment Arrangement [Text Block] Equity Stockholders' Equity Note Disclosure [Text Block] Class of Warrant or Right [Table] Class of Warrant or Right [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Class of Warrant or Right [Line Items] Class of Warrant or Right [Line Items] Class of warrant or right, outstanding (in shares) Class of Warrant or Right, Outstanding Exercise price (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights ESPP Employee Stock Purchase Plan2016 [Member] Represent information pertaining to the 2016 Employee Stock Purchase Plan. Number of offering periods under the ESPP Number Of Offering Periods Number Of Offering Periods Eligible compensation withheld for use (up to) (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate Purchase price of shares (not less than) (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent Common stock authorized and reserved for future issuance (in shares) Number of shares of common stock outstanding (as a percent) Employee Stock Purchase Plan Maximum Percentage Of Shares Reserved Based On Shares Outstanding The maximum percentage increase in the shares reserved for future issuance each year based on the number of common stock outstanding at the last day of the year. Number of shares authorized, increase (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Shares Available For Grant, Increase (Decrease) Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Shares Available For Grant, Increase (Decrease) Shares of common stock issued to employees under the ESPP (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Stock-based compensation expense 2008 Plan Stock Incentive Plan2008 [Member] Represents the information pertaining to the 2008 stock incentive plan, which provides for the granting of stock based awards to employees, directors, and consultants under terms and provisions established by the board of directors. 2016 Plan Stock Incentive Plan2016 [Member] Represents the information pertaining to the 2016 stock incentive plan, which provides for the granting of stock based awards to employees, directors, and consultants under terms and provisions established by the board of directors. Employment Inducement Incentive Award Plan Employment Inducement Incentive Award Plan [Member] Employment Inducement Incentive Award Plan [Member] Employee stock option grants Non-employee stock options Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Tranche One Share-based Payment Arrangement, Tranche One [Member] Tranche Two Share-based Payment Arrangement, Tranche Two [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Number of shares authorized for grants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Automatic increase in the number of shares that may be issued (as a percent) Exercise price of incentive stock options (not less than) Combined voting power of participants (as a percent) Share-based Compensation Arrangement By Share-based Payment Award, Voting Rights of Common Stock, Holding Percentage Represents the percentage of voting rights of all classes of stock held by the employees. Award vesting term Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Award expiration term Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Grants in period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested in period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Grants in period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Estimated forfeitures rate Share-based Compensation Arrangement By Share-based Payment Award Forfeitures Rate Represents the percentage of forfeitures rate of the stock options based on the historical trends. Weighted average grant date fair value of stock options (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Aggregate intrinsic value of stock options exercised Unrecognized compensation expense related to unvested employee stock options Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Weighted average period for recognition Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Unrecognized compensation expense related to unvested non-employee stock options Share-Based Goods And Non Employee Services Transaction, Compensation Not Yet Recognized, Stock Options Share-Based Goods And Non Employee Services Transaction, Compensation Not Yet Recognized, Stock Options Unrecognized compensation expense related to unvested non-employee stock options, period Share-Based Goods And Non Employee Services Transaction, Compensation Not Yet Recognized, Stock Options, Period Share-Based Goods And Non Employee Services Transaction, Compensation Not Yet Recognized, Stock Options, Period Unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Schedule of Restricted Cash and Cash Equivalents Restrictions on Cash and Cash Equivalents [Table Text Block] Contract liabilities: Change In Contract With Customer, Liability [Roll Forward] Change In Contract With Customer, Liability [Roll Forward] Deferred revenue, beginning of period Contract with Customer, Liability, Deferred Revenue Contract with Customer, Liability, Deferred Revenue Contract liabilities, beginning of period Contract with Customer, Liability Deferred revenue, additions Contract with Customer, Liability, Deferred Revenue, Increase From Cash Receipts Contract with Customer, Liability, Deferred Revenue, Increase From Cash Receipts Contract liabilities, additions Contract with Customer, Liability, Increase From Cash Receipts Contract with Customer, Liability, Increase From Cash Receipts Deferred revenue, deductions Contract with Customer, Liability, Deferred Revenue, Revenue Recognized Contract with Customer, Liability, Deferred Revenue, Revenue Recognized Contract liabilities, deductions Contract with Customer, Liability, Revenue Recognized Deferred revenue, end of period Contract liabilities, end of period Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] 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 premiums (accretion of discounts) on investments Accretion (Amortization) of Discounts and Premiums, Investments Non-cash lease expense Finance Lease, Right-of-Use Asset, Amortization Loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Stock‑based compensation expense Share-based Payment Arrangement, Noncash Expense Non‑cash interest expense Paid-in-Kind Interest Warrant liabilities revaluation Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Prepaid expenses, deposits and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable Increase (Decrease) in Accounts Payable Deferred revenue Increase (Decrease) in Contract with Customer, Liability Accrued expenses and other liabilities Increase (Decrease) in Accrued Liabilities 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, Continuing Operations [Abstract] Purchases of short-term investments Payments to Acquire Short-term Investments Sale of short term investments Proceeds from Sale of Short-term Investments Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from the sale of property and equipment Proceeds from Sale of Property, Plant, and Equipment 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, Continuing Operations [Abstract] Repayments of principal on outstanding debt Repayments of Long-term Debt Net proceeds from issuance of common stock Proceeds from Issuance of Common Stock Issuance costs paid for December 2019 financing Payments of Financing Costs Other financing fees Proceeds from (Payments for) Other Financing Activities Proceeds from exercise of stock options Proceeds from Stock Options Exercised Proceeds from issuance of common stock under Employee Stock Purchase Plan Proceeds from Stock Plans Net cash (used in) provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents 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 at beginning of period Cash, cash equivalents, and restricted cash at end of period Supplement cash flow information Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Noncash investing and financing activities Noncash Investing and Financing Items [Abstract] Purchase of property and equipment not yet paid Capital Expenditures Incurred but Not yet Paid Equity offering costs in accrued liabilities Equity Offering Costs In Accrued Liabilities Equity Offering Costs In Accrued Liabilities Unrealized gain on marketable securities Marketable Securities, Unrealized Gain (Loss) Accrued Expenses Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Remaining performance obligation Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Research and Development Arrangement, Contract to Perform for Others, Type [Domain] Research and Development Arrangement, Contract to Perform for Others, Type [Domain] Spark License Agreement License Agreement Terms [Member] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] License and Supply Obligation License And Supply Obligation [Member] License And Supply Obligation [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Remaining performance obligation, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Principles of Consolidation Consolidation, Policy [Policy Text Block] Foreign Currency Foreign Currency Transactions and Translations Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Segment Information Segment Reporting, Policy [Policy Text Block] Cash Equivalents, Short-term Investments and Restricted Cash Cash Equivalents And Short Term Investments [Policy Text Block] Disclosure of accounting policy for cash equivalents and short term investments. Concentrations of Credit Risk and Off-Balance Sheet Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Impairment of Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Debt Issuance Costs Debt, Policy [Policy Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income, Policy [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Research and Development Costs Research and Development Expense, Policy [Policy Text Block] Clinical Trial Costs Clinical Trial Costs [Policy Text Block] Disclosure of accounting policy for clinical trial costs. Income Taxes Income Tax, Policy [Policy Text Block] Warrants Warrants [Policy Text Block] Disclosure of accounting policy for warrants. Stock-Based Compensation Share-based Payment Arrangement [Policy Text Block] Net Loss Per Share Earnings Per Share, Policy [Policy Text Block] Contingent Liabilities Contingent Liability Reserve Estimate, Policy [Policy Text Block] Leases Lessee, Leases [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Letter of credit Letter of Credit [Member] Lease Arrangement [Axis] Lease Arrangement [Axis] Lease Arrangement [Axis] Lease Arrangement [Domain] Lease Arrangement [Domain] [Domain] for Lease Arrangement [Axis] Laboratory and office space Laboratory And Office Space [Member] Represents information pertaining to laboratory and office space member. 75 North Beacon, Watertown, MA 75 North Beacon, Watertown, MA [Member] 75 North Beacon, Watertown, MA [Member] 65 Grove Street, Watertown,MA 65 Grove Street, Watertown,MA [Member] 65 Grove Street, Watertown,MA [Member] Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Right of use asset, net Operating Lease, Right-of-Use Asset Lease liabilities Term of contract Lessee, Operating Lease, Term of Contract Leasehold improvements gross Leasehold Improvements, Gross Restricted cash Restricted Cash Area of additional office space leased Area of Real Estate Property Lessee-paid construction costs Lease, Cost Operating lease, expense Operating Lease, Expense operating lease payments due Schedule of Future Minimum Payments on the Term Loans Schedule of Maturities of Long-term Debt [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] 3SBio License License Agreement With Shenyang Sunshine Pharmaceutical Company Limited [Member] Represents information pertaining to License agreement with Shenyang Sunshine Pharmaceutical co., ltd. Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Aggregate amount of upfront and milestone-based payments Aggregate Amount Of Upfront And Milestone Based Payments Paid Aggregate Amount Of Upfront And Milestone Based Payments Paid Aggregate amount for future payments upon achievement of clinical and regulatory approval milestones for products containing ImmTOR platform Aggregate Amount For Future Payments Upon Achievement Of Clinical And Regulatory Approval Milestones For Products Containing ImmTOR Platform Aggregate Amount For Future Payments Upon Achievement Of Clinical And Regulatory Approval Milestones For Products Containing ImmTOR Platform Aggregate amount for future payments upon achievement of clinical and regulatory approval milestones for products without ImmTOR Platform Aggregate Amount For Future Payments Upon Achievement Of Clinical And Regulatory Approval Milestones For Products Without ImmTOR Platform Aggregate Amount For Future Payments Upon Achievement Of Clinical And Regulatory Approval Milestones For Products Without ImmTOR Platform Vesting period Defined Contribution Plan Employers Matching Contribution Vesting Period Period which an employee's right to exercise a plan is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. 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" Consideration for Promises Consideration For Promises [Member] Consideration For Promises [Member] Development Milestones Development Milestones [Member] Development Milestones [Member] Regulatory Milestones Regulatory Milestones [Member] Regulatory Milestones [Member] Commercial Milestones Commercial Milestones [Member] Commercial Milestones [Member] Discount on Option Obligation Discount On Option Obligation [Member] Discount On Option Obligation [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Long-term contract liability Upfront cash payment License And Option Agreement, Upfront Cash Payment License And Option Agreement, Upfront Cash Payment Initial Up-front cash payment License And Option Agreement, Initial Up-Front Cash Payment License And Option Agreement, Initial Up-Front Cash Payment Initial Upfront execution fee payment License And Option Agreement, Execution Fee Payment License And Option Agreement, Execution Fee Payment Short-term contract liability Aggregate additional payments due within twelve months License And Option Agreement, Aggregate Additional Payments Due Within Twelve Months Of Contract Date License And Option Agreement, Aggregate Additional Payments Due Within Twelve Months Of Contract Date Term loan number of payments Term Loan Number of Payments Term Loan Number of Payments Two payments due within 12 months of contract date License And Option Agreement, Two Payments Due Within Twelve Months Of Contract Date License And Option Agreement, Two Payments Due Within Twelve Months Of Contract Date Number of additional targets License And Option Agreement, Number Of Additional Targets For Which Other Party May Exercise Options For Additional Licenses License And Option Agreement, Number Of Additional Targets For Which Other Party May Exercise Options For Additional Licenses Variable fee the Company is eligible to receive for each additional target option elected License And Option Agreement, Variable Fee To Be Received For Each Additional Target Option Elected License And Option Agreement, Variable Fee To Be Received For Each Additional Target Option Elected Election period to exercise additional targets License And Option Agreement, Period For Other Party To Exercise Options For Additional Licenses License And Option Agreement, Period For Other Party To Exercise Options For Additional Licenses Additional development and regulatory milestone payments License And Option Agreement, Additional Development And Regulatory Milestone Payments That May Be Received License And Option Agreement, Additional Development And Regulatory Milestone Payments That May Be Received Commercialization milestone payments License And Option Agreement, Commercialization Milestone Payments That May Be Received License And Option Agreement, Commercialization Milestone Payments That May Be Received Sales milestone payments License And Option Agreement, Sales Milestone Payments That May Be Received License And Option Agreement, Sales Milestone Payments That May Be Received Number of obligations Revenue, Number Of Performance Obligations Revenue, Number Of Performance Obligations Period after first commercial sale when the Company is eligible to receive royalties Eligible Period To Receive Royalties Eligible Period To Receive Royalties Period for prior written notice to terminate license Period For Prior Written Notice To Terminate License Represents information pertaining to period for prior written notice to terminate license. Premium of average daily VWAP (as a percent) Premium Of Average Daily Volume Weighted Average Price Of Common Stock, Percent Premium Of Average Daily Volume Weighted Average Price Of Common Stock, Percent Deferred revenue related to agreement Aggregate purchase price Aggregate Purchase Price Aggregate Purchase Price Aggregate price of shares Spark will have the right to purchase Stock Purchase Agreement, Authorized Amount Of Stock To Sell Stock Purchase Agreement, Authorized Amount Of Stock To Sell Number of shares authorized to be issued pursuant to the Stock Purchase Agreement (in shares) Stock Purchase Program, Number Of Shares Authorized To Be Sold Stock Purchase Program, Number Of Shares Authorized To Be Sold License and option agreement, additional sub-license payment received liability License And Option Agreement, Additional Sub-License Payment Received Liability License And Option Agreement, Additional Sub-License Payment Received Liability License and option agreement, payments made relative to calculated premium paid for initial equity investment made under the purchase agreement License And Option Agreement, Calculated Premium Paid For Equity Investment Under Purchase Agreement License And Option Agreement, Calculated Premium Paid For Equity Investment Under Purchase Agreement Number of agreements combined and evaluated into a single agreement Number Of Agreements Combined Into Single Agreement For Evaluation Number Of Agreements Combined Into Single Agreement For Evaluation Fair value of initial purchase of common stock combined with the embedded future stock Acquisition Rights Stock Issued During Period, Value, Purchase of Assets Performance obligation per each option Revenue, Remaining Performance Obligation, Each Option Revenue, Remaining Performance Obligation, Each Option Revenue recognized Aggregate purchase price per share (in dollar per share) Stock Purchase Program, Aggregate Purchase Price Per Share Stock Purchase Program, Aggregate Purchase Price Per Share Payments received Increase Decrease In Contingently Repayable Grant Funding The increase (decrease) during the reporting period in contingently repayable grant funding that are used in an entity's business. 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