0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 0000002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 0000003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 0000004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS link:presentationLink link:calculationLink link:definitionLink 0000005 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS link:presentationLink link:calculationLink link:definitionLink 0000006 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY link:presentationLink link:calculationLink link:definitionLink 0000007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS link:presentationLink link:calculationLink link:definitionLink 0000008 - Disclosure - Organization and Description of Business link:presentationLink link:calculationLink link:definitionLink 0000009 - Disclosure - Summary of Significant Accounting Policies link:presentationLink link:calculationLink link:definitionLink 0000010 - Disclosure - Fair Value Measurements link:presentationLink link:calculationLink link:definitionLink 0000011 - Disclosure - Balance Sheet Components link:presentationLink link:calculationLink link:definitionLink 0000012 - Disclosure - Research Collaboration and License Agreements link:presentationLink link:calculationLink link:definitionLink 0000013 - Disclosure - Commitments and Contingencies link:presentationLink link:calculationLink link:definitionLink 0000014 - Disclosure - Stockholders' Equity link:presentationLink link:calculationLink link:definitionLink 0000015 - Disclosure - Income Taxes link:presentationLink link:calculationLink link:definitionLink 0000016 - Disclosure - Summary of Significant Accounting Policies (Policies) link:presentationLink link:calculationLink link:definitionLink 0000017 - Disclosure - Summary of Significant Accounting Policies (Tables) link:presentationLink link:calculationLink link:definitionLink 0000018 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 0000019 - Disclosure - Balance Sheet Components (Tables) link:presentationLink link:calculationLink link:definitionLink 0000020 - Disclosure - Research Collaboration and License Agreements (Tables) link:presentationLink link:calculationLink link:definitionLink 0000021 - Disclosure - Commitments and Contingencies (Tables) link:presentationLink link:calculationLink link:definitionLink 0000022 - Disclosure - Stockholders' Equity (Tables) link:presentationLink link:calculationLink link:definitionLink 0000023 - Disclosure - Summary of Significant Accounting Policies - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 0000024 - Disclosure - Summary of Significant Accounting Policies - Estimated Useful Life of Asset (Details) link:presentationLink link:calculationLink link:definitionLink 0000025 - Disclosure - Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) link:presentationLink link:calculationLink link:definitionLink 0000026 - Disclosure - Summary of Significant Accounting Policies - Computation of Net Loss Per Common Share (Details) link:presentationLink link:calculationLink link:definitionLink 0000027 - Disclosure - Summary of Significant Accounting Policies - Potentially Dilutive Securities Not Included in the Diluted Net Loss Per Share Calculations (Details) link:presentationLink link:calculationLink link:definitionLink 0000028 - Disclosure - Fair Value Measurements - Summary of Cash and Cash Equivalents and Marketable Securities Classified as Available-for-sale Securities (Details) link:presentationLink link:calculationLink link:definitionLink 0000029 - Disclosure - Fair Value Measurements - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 0000030 - Disclosure - Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) link:presentationLink link:calculationLink link:definitionLink 0000031 - Disclosure - Balance Sheet Components - Schedule of Reconciliation of Cash, Cash Equivalent and Restricted Cash (Details) link:presentationLink link:calculationLink link:definitionLink 0000032 - Disclosure - Balance Sheet Components - Schedule of Property and Equipment (Details) link:presentationLink link:calculationLink link:definitionLink 0000033 - Disclosure - Balance Sheet Components - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 0000034 - Disclosure - Balance Sheet Components - Schedule of Accrued Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 0000035 - Disclosure - Research Collaboration and License Agreements - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 0000036 - Disclosure - Research Collaboration and License Agreements - Schedule of Milestone Payments by Indications (Details) link:presentationLink link:calculationLink link:definitionLink 0000037 - Disclosure - Research Collaboration and License Agreements - Schedule of Recognized Revenue from Collaboration and License Agreements (Details) link:presentationLink link:calculationLink link:definitionLink 0000038 - Disclosure - Commitments and Contingencies - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 0000039 - Disclosure - Commitments and Contingencies - Components of Lease Costs (Details) link:presentationLink link:calculationLink link:definitionLink 0000040 - Disclosure - Commitments and Contingencies - Operating Lease Liability Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 0000040 - Disclosure - Commitments and Contingencies - Operating Lease Liability Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 0000041 - Disclosure - Stockholders' Equity - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 0000042 - Disclosure - Stockholders' Equity - Schedule of Shares of Common Stock Reserved for Issuance (Details) link:presentationLink link:calculationLink link:definitionLink 0000043 - Disclosure - Stockholders' Equity - Summary of Activity under 2008 Plan and 2018 Plan (Details) link:presentationLink link:calculationLink link:definitionLink 0000044 - Disclosure - Stockholders' Equity - Summary of Stock Based Compensation Expense (Details) link:presentationLink link:calculationLink link:definitionLink