0001001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 1001002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 1002003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 1003004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS link:presentationLink link:calculationLink link:definitionLink 1004005 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS link:presentationLink link:calculationLink link:definitionLink 1005006 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY link:presentationLink link:calculationLink link:definitionLink 1006007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS link:presentationLink link:calculationLink link:definitionLink 2101101 - Disclosure - Organization and Description of Business link:presentationLink link:calculationLink link:definitionLink 2102102 - Disclosure - Summary of Significant Accounting Policies link:presentationLink link:calculationLink link:definitionLink 2203201 - Disclosure - Summary of Significant Accounting Policies (Policies) link:presentationLink link:calculationLink link:definitionLink 2304301 - Disclosure - Summary of Significant Accounting Policies (Tables) link:presentationLink link:calculationLink link:definitionLink 2405401 - Disclosure - Summary of Significant Accounting Policies - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2406402 - Disclosure - Summary of Significant Accounting Policies - Estimated Useful Life of Asset (Details) link:presentationLink link:calculationLink link:definitionLink 2407403 - Disclosure - Summary of Significant Accounting Policies - Computation of Net Loss Per Common Share (Details) link:presentationLink link:calculationLink link:definitionLink 2408404 - 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 2109103 - Disclosure - Fair Value Measurements link:presentationLink link:calculationLink link:definitionLink 2310302 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 2411405 - 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 2412406 - Disclosure - Fair Value Measurements - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2413407 - Disclosure - Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) link:presentationLink link:calculationLink link:definitionLink 2114104 - Disclosure - Balance Sheet Components link:presentationLink link:calculationLink link:definitionLink 2315303 - Disclosure - Balance Sheet Components (Tables) link:presentationLink link:calculationLink link:definitionLink 2416408 - Disclosure - Balance Sheet Components - Schedule of Reconciliation of Cash, Cash Equivalent and Restricted Cash (Details) link:presentationLink link:calculationLink link:definitionLink 2417409 - Disclosure - Balance Sheet Components - Schedule of Property and Equipment (Details) link:presentationLink link:calculationLink link:definitionLink 2418410 - Disclosure - Balance Sheet Components - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2419411 - Disclosure - Balance Sheet Components - Schedule of Accrued Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 2120105 - Disclosure - Research Collaboration and License Agreements link:presentationLink link:calculationLink link:definitionLink 2321304 - Disclosure - Research Collaboration and License Agreements (Tables) link:presentationLink link:calculationLink link:definitionLink 2422412 - Disclosure - Research Collaboration and License Agreements - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2423413 - Disclosure - Research Collaboration and License Agreements - Schedule of Milestone Payments by Indications (Details) link:presentationLink link:calculationLink link:definitionLink 2424414 - Disclosure - Research Collaboration and License Agreements - Schedule of Recognized Revenue from Collaboration and License Agreements (Details) link:presentationLink link:calculationLink link:definitionLink 2125106 - Disclosure - Commitments and Contingencies link:presentationLink link:calculationLink link:definitionLink 2326305 - Disclosure - Commitments and Contingencies (Tables) link:presentationLink link:calculationLink link:definitionLink 2427415 - Disclosure - Commitments and Contingencies - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2428416 - Disclosure - Commitments and Contingencies - Future Minimum Commitments under Unassigned Lease Obligations (Details) link:presentationLink link:calculationLink link:definitionLink 2129107 - Disclosure - Stockholders' Equity link:presentationLink link:calculationLink link:definitionLink 2330306 - Disclosure - Stockholders' Equity (Tables) link:presentationLink link:calculationLink link:definitionLink 2431417 - Disclosure - Stockholders' Equity - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2432418 - Disclosure - Stockholders' Equity - Schedule of Shares of Common Stock Reserved for Issuance (Details) link:presentationLink link:calculationLink link:definitionLink 2433419 - Disclosure - Stockholders' Equity - Summary of Activity under 2008 Plan and 2018 Plan (Details) link:presentationLink link:calculationLink link:definitionLink 2434420 - Disclosure - Stockholders' Equity - Summary of Stock Based Compensation Expense (Details) link:presentationLink link:calculationLink link:definitionLink 2135108 - Disclosure - Income Taxes link:presentationLink link:calculationLink link:definitionLink