| Significant Accounting Policies (Policies) | 12 Months Ended |
| Dec. 31, 2023 |
| Accounting Policies [Abstract] | |
| Basis of Accounting, Policy [Policy Text Block] | Basis of Presentation The accompanying consolidated financial statements are presented in U.S. dollars and have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and as amended by Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). |
| Consolidation, Policy [Policy Text Block] | Principles of Consolidation The accompanying consolidated financial statements include the accounts of Compass Therapeutics, Inc., and its wholly-owned subsidiaries, including Compass Therapeutics LLC, Compass Therapeutics Advisors Inc., Trigr Therapeutics, Inc. and Compass Therapeutics Securities Corporation. All intercompany accounts and transactions have been eliminated in consolidation. |
| Use of Estimates, Policy [Policy Text Block] | Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the accrual of research and development expenses, useful lives of equipment, interest rate and term operating lease ROU and liability, the percentage of completion of contractual arrangements, future cash expenditures for liquidity estimates, the valuation of common stock and estimates associated with stock-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from those estimates. Changes in estimates are recorded prospectively in the period that they become known. |
| Segment Reporting, Policy [Policy Text Block] | Segment Information Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company has one |
| Cash and Cash Equivalents, Policy [Policy Text Block] | Cash and Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash with original maturities of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in money market funds or commercial paper. Cash equivalents are stated at cost, which approximates market value. Cash and Cash equivalents were $24.2 million and $34.9 million on December 31, 2023 and 2022, respectively. |
| Marketable Securities, Policy [Policy Text Block] | Marketable Securities All of the Company’s investment securities are debt securities and bank instruments. The Company carries these investments at fair value. Unrealized gains and losses, if any, are reported as a separate component of stockholders’ equity. The cost of investment securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses, if any, are also included in interest income. The cost of securities sold is based on the specific identification method. |
| Concentration Risk, Credit Risk, Policy [Policy Text Block] | Concentrations of Credit Risk Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash equivalents and marketable securities. The Company invests its excess cash primarily in money market funds, U.S. treasury notes, and high quality, marketable debt instruments of corporations in accordance with the Company’s investment policy. The Company’s investment policy defines allowable investments and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. The Company has not experienced any realized losses related to its cash equivalents and marketable securities. |
| Property, Plant and Equipment, Policy [Policy Text Block] | Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and amortization are recorded using the straight-line method over the estimated useful lives of the related assets as follows:
Asset Classification
Estimated Useful Life
Equipment
5 years
Furniture and fixtures
7 years
Software
5 years
Leasehold improvements
Lesser of estimated useful life or lease term Estimated useful lives are periodically assessed to determine if changes are appropriate. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost of these assets and related accumulated depreciation or amortization are eliminated from the consolidated balance sheet and any resulting gains or losses are included in the consolidated statement of operations and comprehensive loss in the period of disposal. Costs for capital assets not yet placed into service are capitalized as construction-in-progress and depreciated once placed into service. |
| Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] | Impairment of Long-Lived Assets Long-lived assets consist of property, equipment and right-of-use (“ROU”) assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized in the consolidated statements of operations when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company did not |
| Fair Value Measurement, Policy [Policy Text Block] | Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:
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Level 1 – Quoted prices in active markets for identical assets or liabilities.
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Level 2 – Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets and liabilities, or other inputs that are observable or can be corroborated by observable market data.
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Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. An entity may choose to measure many financial instruments and certain other items at fair value at specified election dates. Subsequent unrealized gains and losses on items for which the fair value option has been elected are reported in earnings. |
| Research and Development Expense, Policy [Policy Text Block] | Research and Development Costs Costs associated with internal research and development and external research and development services, including drug development and preclinical studies, are expensed as incurred. Research and development expenses include costs for salaries, employee benefits, subcontractors, facility-related expenses, depreciation and amortization, stock-based compensation, third-party license fees, laboratory supplies, and external costs of outside vendors engaged to conduct discovery, preclinical and clinical development activities and clinical trials as well as to manufacture clinical trial materials and other costs. The Company recognizes external research and development costs based on an evaluation of the progress to completion of specific tasks using information provided to the Company by its service providers. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. Such prepaid expenses are recognized as an expense when the goods have been delivered or the related services have been performed, or when it is no longer expected that the goods will be delivered, or the services rendered. Costs associated with licenses of technology acquired as part of collaborative arrangements are expensed as incurred and are generally included in research and development expense in the consolidated statements of operations if it is determined the license has no alternative future use. |
| Accrued Research and Development Expenses [Policy Text Block] | Accrued Research and Development Expenses The Company has entered into various research and development and other agreements with commercial firms, researchers, universities and others for provisions of goods and services. These agreements are generally cancelable, and the related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. |
| Patents Costs [Policy Text Block] | Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expense in the consolidated statements of operations. |
| Share-Based Payment Arrangement [Policy Text Block] | Stock-Based Compensation The Company recognizes the grant‑date fair value of stock‑based awards issued to employees and nonemployee board members as compensation expense on a straight‑line basis over the service period of the award. The Company uses the Black‑Scholes option pricing model to determine the grant‑date fair value of stock options and adjusts expense for forfeitures in the periods they occur. The fair value of each equity award was determined by the Company on the date of grant and by using the methods and assumptions discussed below. Certain of these inputs are subjective and generally require judgment to determine. Stock price: Expected term Expected volatility Risk-free interest rate Expected dividend |
| Earnings Per Share, Policy [Policy Text Block] | Net Loss per Share Basic loss per share is computed by dividing net loss by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as convertible preferred stock, stock options, restricted stock units, unvested restricted stock awards and common stock warrants that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share, the weighted average number of shares remains the same for both calculations due to the fact that when a net loss exists, dilutive shares are not included in the calculation as the impact is anti-dilutive. The following potentially dilutive securities outstanding as of December 31, 2023 and 2022 have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive:
December 31,
2023
2022
(000's)
Restricted stock units 1,500 900
Stock options 7,876 5,378
Nonvested restricted stock — 193
Total 9,376 6,471 |
| Income Tax, Policy [Policy Text Block] | Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, operating losses and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. Deferred tax assets are reduced, as necessary, by a valuation allowance when management determines it is more likely than not that some or all of the deferred tax benefits will not be realized. The Company files income tax returns in the U.S. Federal jurisdiction and in various states. The Company has tax net operating loss carryforwards that are subject to examination for a number of years beyond the year in which they were generated for tax purposes. Since a portion of these net operating loss carryforwards may be utilized in the future, many of these net operating loss carryforwards will remain subject to examination. |
| New Accounting Pronouncements, Policy [Policy Text Block] | New Accounting Pronouncements In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740) Improvements to tax disclosures Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes The Company adopted Accounting Standards Update ASU No. 2016-13, Financial Instruments Credit Losses (Topic 326): Measurement of Credit Losses of Financial Instruments There are no other pending accounting pronouncements that are expected to have a material impact on the Company’s consolidated financial statements. |
