Document and Entity Information Document Information [Table] Document Information [Line Items] Document Type Document Annual Report Document Transition Report Document Period End Date Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company ICFR Auditor Attestation Flag Entity Shell Company Entity Central Index Key Amendment Flag Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Public Float Entity Common Stock, Shares Outstanding Auditor Name Auditor Firm ID Auditor Location Consolidated Balance Sheets Statement [Table] Statement [Line Items] Assets Abstract Assets Assets, Current Abstract Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Marketable Securities, Current. Marketable securities Contract with Customer, Asset, Net, Current Related party collaboration receivables, ending balance Related party collaboration receivables, beginning balance Related party collaboration receivable Prepaid expenses and other current assets Total Assets, Current Total current assets Property, Plant and Equipment, Net Property and equipment, net Property and equipment, net Deposits and other assets that are expected to be realized or consumed after one year. Deposits And Other Non-Current Assets Deposits and other non-current assets Operating Lease, Right-of-Use Asset Operating lease, right-of-use assets Assets Total assets Liabilities and Equity Abstract Liabilities and stockholders' equity Liabilities, Current Abstract Current liabilities: Accounts payable Accrued Liabilities, Current Accrued expenses Total Other Liabilities, Current Other current liabilities Total other current liabilities Contract with Customer, Liability, Current Deferred revenue, current Liabilities, Current Total current liabilities Contract with Customer, Liability, Noncurrent Deferred revenue, non-current Other Liabilities, Noncurrent Total other non-current liabilities Other non-current liabilities Liabilities Total liabilities Commitments and contingencies (see note 7) Commitments and contingencies (see note 9) Stockholders' Equity Attributable to Parent Abstract Stockholders' equity: Preferred stock $0.001 par value: 5,000,000 shares authorized at June 30, 2019 and December 31, 2018; no shares issued and outstanding at June 30, 2019 and December 31, 2018 Preferred stock, $0.001 par value: 5,000,000 shares authorized; no shares issued and outstanding at December 31, 2022 and 2021 Common stock, $0.001 par value: 120,000,000 shares authorized at June 30, 2019 and December 31, 2018; 36,677,608 and 32,364,895 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively Common stock, $0.001 par value: 120,000,000 shares authorized; 38,613,891 and 37,918,395 shares issued and outstanding at December 31, 2022 and 2021, respectively Additional paid in capital Additional paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive loss Retained Earnings (Accumulated Deficit) Accumulated deficit Stockholders' Equity Attributable to Parent Stockholders' Equity, Ending Balance Stockholders' Equity, Beginning Balance Total stockholders' equity Liabilities and Equity Total liabilities and stockholders' equity Preferred Stock, Par or Stated Value Per Share Preferred Stock, par value (in dollars per share) Preferred Stock, Shares Authorized Preferred Stock, Shares Issued Preferred Stock, Shares Outstanding Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common Stock, Shares Authorized Common Stock, Shares, Issued Common Stock, Shares, Outstanding Consolidated Statements of Operations and Comprehensive (Loss) Income Revenue from Contract with Customer, Excluding Assessed Tax Collaboration revenue Collaboration revenue Operating expenses: Research and development expense Research and development General and Administrative Expense General and administrative Operating Expenses Total operating expenses Operating Income (Loss) Operating (loss) income Interest and Debt Expense [Abstract] Other income, net: Interest income (expense) Other financing expense Other income Interest and Debt Expense Total other income, net Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest (Loss) income before income taxes Income Tax Expense (Benefit) Total tax expense Income tax provision Net Income (Loss) Attributable to Parent Net (loss) income Net income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Other comprehensive (loss) income Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Net unrealized loss on available-for-sale-securities Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Total other comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive (loss) income Earnings Per Share, Basic Net (loss) income per share, basic Earnings Per Share, Diluted Net (loss) income per share, diluted Weighted Average Number of Shares Outstanding, Basic Weighted-average common shares outstanding, basic Weighted average shares outstanding-basic Weighted Average Number of Shares Outstanding, Diluted Weighted-average common shares outstanding, diluted Weighted average shares outstanding-diluted Consolidated Statements of Stockholders' Equity Equity Components [Axis] Equity Component [Domain] Common Stock Additional Paid-in Capital Accumulated Other Comprehensive Loss Accumulated Deficit Shares, Outstanding Shares, Outstanding, Ending Balance Shares, Outstanding, Beginning Balance Stock Issued During Period, Value, Stock Options Exercised Exercises of vested stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercised (in shares) Exercises of vested stock options (in shares) Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Vesting of restricted stock units Vesting of restricted stock units (in shares) Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Issuance of common stock under ESPP Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Issuance of common stock under ESPP (in shares) Adjustments to Additional Paid in Capital, Share-based Compensation, Stock Options, Requisite Service Period Recognition Stock based compensation expense Consolidated Statement of Cash Flows Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Cash flow from operating activities Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net (loss) income Adjustments to reconcile net loss to net cash provided by operating activities: Adjustments to reconcile net (loss) income to net cash used in operating activities: Stock-based compensation expense Depreciation Depreciation expense Accretion (Amortization) of Discounts and Premiums, Investments Amortization of premiums and discounts on marketable securities Gain (Loss) on Termination of Lease Gain on Lease Termination Gain on termination of lease Amount of change in fair value for common stock and warrants to purchase equity securities. Common Stock And Warrants To Purchase Equity Securities Change in fair value of common stock and warrants to purchase equity securities Gain (Loss) on Disposition of Property Plant Equipment Loss on disposal of fixed assets Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: The increase (decrease) during the reporting period of the sum of amounts due within one year (or one business cycle) from Collaboration agreements. Increase (Decrease) in Collaboration Receivables Related party collaboration receivable Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other assets The increase (decrease) during the reporting period in operating lease, right-of-use assets. Increase Decrease In Right Of Use Assets Operating lease, right-of-use assets Change in operating lease, right-of-use assets Increase (Decrease) in Other Noncurrent Assets Other non-current assets Increase (Decrease) in Accounts Payable Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expenses Increase (Decrease) in Operating Lease Liability Operating lease liabilities Change in operating lease liabilities Increase (Decrease) in Contract with Customer, Liability Deferred revenue Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash used in operating activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Cash flow from investing activities Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment Payments to Acquire Marketable Securities Purchases of marketable securities Proceeds from Sale and Maturity of Marketable Securities Proceeds from sales and maturities of marketable securities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Cash flow from financing activities Proceeds from Stock Options Exercised Proceeds from the exercise of stock options Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Excluding Stock Options Proceeds from the purchase of common stock under ESPP Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Net (decrease) increase in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents, and restricted cash end of period Cash, cash equivalents, and restricted cash beginning of period Total cash, cash equivalents, and restricted cash Supplemental Cash Flow Elements [Abstract] Supplemental disclosure of cash and non-cash activities Represents the cash or non-cash activities surrounding lease arrangements. Lease Exchange Cash Flow Amount Operating lease right-of-use assets obtained in exchange for operating lease liabilities Capital Expenditures Incurred but Not yet Paid Capital expenditures incurred but not yet paid Nature of business Nature of Operations [Text Block] Nature of business Summary of significant accounting policies Significant Accounting Policies [Text Block] Summary of significant accounting policies Fair value measurements Fair Value Disclosures [Text Block] Fair value measurements Prepaid expense and other current assets Prepaid expenses and other current assets disclosure text block Prepaid expenses and other current assets Property and equipment, net Property, Plant and Equipment Disclosure [Text Block] Property and equipment, net Accrued expenses Accrued Liabilities Disclosure [Text Block] Accrued expenses Lease obligation The entire disclosure of information about leases. Lease Disclosure [Text Block] Lease obligation Other liabilities Other Liabilities Disclosure [Text Block] Other liabilities Commitments and contingencies Commitments and Contingencies Disclosure [Text Block] Commitments and contingencies Common stock. Stockholders' Equity Note Disclosure [Text Block] Common stock Stock-based compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-based compensation 401(k) Savings plan Pension and Other Postretirement Benefits Disclosure [Text Block] 401(k) Savings plan Income taxes Income Tax Disclosure [Text Block] Income taxes Related party transactions Related Party Transactions Disclosure [Text Block] Related party transactions Subsequent event Subsequent Events [Text Block] Subsequent event Basis of Presentation Use of Estimates Fair Value of Financial Instruments Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Marketable Securities, Policy [Policy Text Block] Marketable Securities Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash Property and Equipment Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Impairment of Long-Lived Assets Revenue from Contract with Customer [Policy Text Block] Revenue Recognition Research and Development Expense, Policy [Policy Text Block] Research and Development Lessee, Leases [Policy Text Block] Leases Disclosure of accounting policy for research contract costs and accruals. Research Contract Costs And Accruals [Policy Text Block] Research Contract Costs and Accruals Patent Costs Policy [Text Block] Patent Costs Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Stock-Based Compensation Expense Income Tax, Policy [Policy Text Block] Income Taxes Comprehensive Income (Loss) Comprehensive (Loss) Income