Significant Accounting Policies | Note 2 - Significant Accounting Policies Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and notes required by GAAP for complete financial statements. Therefore, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2020, which were included in the Company’s Form 10-K, and filed with the SEC on March 12, 2021. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period. 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. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Other Receivables - Related Party Other receivables consist of amounts due to the Company from TG Therapeutics, Inc. (“TGTX”), a related party, and are recorded at the invoiced amount. Research and Development Costs Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved. Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies. In accordance with Accounting Standards Codification (“ASC”) 730-10-25-1, Research and Development Annual Equity Fee Under the Founders Agreement with Checkpoint dated March 17, 2015, and amended and restated in July 2016 and October 2017 (the “Founders Agreement”), Fortress is entitled to an annual equity fee on January 1 of each year equal to 2.5% of fully diluted outstanding equity, payable in Checkpoint common shares (“Annual Equity Fee”). The Annual Equity Fee was part of the consideration payable for formation of the Company, identification of certain assets, including the license contributed to Checkpoint by Fortress (see Note 4). The Company records the Annual Equity Fee in connection with the Founders Agreement with Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. Due to the nature of the Company’s assets and stage of development, future share prices and shares outstanding cannot be estimated prior to the issuance of the Annual Equity Fee. Due to these uncertainties, the Company has concluded that it is unable to reasonably estimate the contingent consideration until shares are actually issued on January 1 of each year. Pursuant to the Founders Agreement, the Company issued 1,742,449 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2021. Because the number of outstanding shares issuable to Fortress was determinable on January 1, 2021 prior to the issuance of the December 31, 2020 financial statements, the Company recorded approximately $4.6 million in research and development expense and a credit to Common shares issuable - Founders Agreement during the year ended December 31, 2020. Stock-Based Compensation Expenses The Company expenses stock-based compensation over the requisite service period based on the estimated grant-date fair value of the awards and forfeiture rates. The Company accounts for forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the Condensed Statements of Operations based upon the underlying individual’s role at the Company. Fair Value Measurement The Company follows the accounting guidance in ASC 820 for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to their liquid or short-term nature, such as accounts payable and accrued expenses. Revenue from Contracts with Customers The Company recognizes revenue under ASC 606, “ Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer. ● Step 2: Identify the performance obligations in the contract. ● Step 3: Determine the transaction price. ● Step 4: Allocate the transaction price to the performance obligations in the contract. ● Step 5: Recognize revenue when the company satisfies a performance obligation. In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct); and ● the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. When determining the transaction price, an entity must consider the effects of all of the following: ● variable consideration; ● constraining estimates of variable consideration; ● the existence of a significant financing component in the contract; ● noncash consideration; and ● consideration payable to a customer. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. Revenue for a sales-based or usage-based royalty promised in exchange for a license of intellectual property is recognized only when (or as) the later of the following events occurs: a. the subsequent sale or usage occurs; and b. the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). Incremental contract costs are expensed when incurred when the amortization period of the asset that would have been recognized is one year or less; otherwise, incremental contract costs are recognized as an asset and amortized over time as services are provided to a customer. Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if management believes it is more likely than not that the deferred tax assets will not be recovered based on an evaluation of objective verifiable evidence. For tax positions that are more likely than not to be sustained upon audit, the Company recognizes the largest amount with a greater than 50% likelihood of being realized. The Company does not recognize any portion of the benefit for tax positions that are not more likely than not to be sustained upon audit. As of September 30, 2021 and December 31, 2020, the Company determined, based upon available evidence, that it is more likely than not that the net deferred tax asset will not be realized and, accordingly, has provided a full valuation allowance against its net deferred tax asset. Net Loss per Share Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Since dividends are declared, paid and set aside among the holders of shares of common stock and Class A common stock pro-rata on an as-if-converted basis, the two-class method of computing net loss per share is not required. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of stock options and warrants, as their inclusion would be anti-dilutive. The following table summarizes potentially dilutive securities outstanding at September 30, 2021 and 2020 that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive: September 30, 2021 2020 Warrants (Note 6) 13,191 3,224,455 Stock options (Note 6) 270,000 220,000 Unvested restricted stock (Note 6) 4,240,868 4,013,199 Total 4,524,059 7,457,654 Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) In response to the COVID-19 pandemic, the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) was signed into law on March 27, 2020. The CARES Act, among other things, includes tax provisions relating to refundable payroll tax credits, deferment of employer’s social security payments, net operating loss utilization and carryback periods and modifications to the net interest deduction limitations. The CARES Act did not have a material impact on the Company’s income tax provision. The Company will continue to evaluate the impact of the CARES Act on its financial position, results of operations and cash flows. On December 27, 2020, the President of the United States signed the Consolidated Appropriations Act, 2021 (“Consolidated Appropriations Act”) into law. The Consolidated Appropriations Act is intended to enhance and expand certain provisions of the CARES Act, allows for the deductions of expenses related to the Payroll Protection Program funds received by companies, and provides an update to meals and entertainment expensing for 2021. The Consolidated Appropriations Act did not have a material impact to the Company’s income tax provision for 2020 and the Company does not believe it will have a material impact on its income tax provision for 2021. The Company will continue to evaluate the impact of the Consolidated Appropriations Act on its financial position, results of operations and cash flows. Recently Issued Accounting Standards In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “ Financial Instruments – Credit Losses In August 2020, the FASB issued ASU No. 2020-06, “ Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity Recently Adopted Accounting Standards In December 2019, the FASB issued ASU No. 2019-12, “ Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes |