Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2023

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Basis of PresentationThe accompanying unaudited interim consolidated financial statements of the Company have been prepared in accordance with GAAP for interim financial information as found in the ASC and ASUs of the FASB, and with the instructions to Form 10-Q and Article 10 of Regulation S-X promulgated by the SEC. In the opinion of management, the accompanying unaudited interim consolidated financial statements of the Company include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the unaudited interim consolidated financial statements) considered necessary to present fairly the Company’s financial position as of March 31, 2023, and its results of operations and cash flows for the three months ended March 31, 2023 and 2022. Operating results for the three months ended March 31, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023. The unaudited interim consolidated financial statements presented herein do not contain the required disclosures under GAAP for annual financial statements. The accompanying unaudited interim consolidated financial statements should be read in conjunction with the annual audited financial statements and related notes as of and for the year ended December 31, 2022 filed with the SEC as part of the Annual Report.

Use of Estimates, Policy [Policy Text Block]

Use of EstimatesThe preparation of financial statements in conformity with GAAP requires the Company 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.On an ongoing basis, the Company evaluates its estimates using historical experience and other factors, including the current economic environment. Significant items subject to such estimates are assumptions used for purposes of determining stock-based compensation. Management believes its estimates to be reasonable under the circumstances. Actual results could differ significantly from those estimates.

Fair Value of Financial Instruments, Policy [Policy Text Block]

Fair Value of Financial InstrumentsThe carrying amounts of the Company’s financial instruments, including cash, cash equivalents, and accounts payable approximate fair value due to the short-term nature of those instruments.

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of Credit RiskFinancial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents, and marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash, cash equivalents, and marketable securities.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash EquivalentsThe Company considers any highly-liquid investments, such as money market funds, with an original maturity of three months or less to be cash equivalents.

Marketable Securities, Policy [Policy Text Block]

Marketable securitiesThe Company classifies its marketable securities as available-for-sale, which include commercial paper and U.S. government debt securities with original maturities of greater than three months from date of purchase. The Company considers its marketable securities as available for use in current operations, and therefore classifies these securities as current assets on the consolidated balance sheet. These securities are carried at fair value, with unrealized gains and losses reported in comprehensive loss and accumulated other comprehensive loss within stockholders’ equity. Gains or losses on marketable securities sold will be based on the specific identification method.The Company routinely monitors the difference between cost and the estimated fair value of its investments. Each reporting period, securities with unrealized losses are reviewed to determine whether the decline in fair value requires the recognition of an allowance for credit losses. Factors considered in the review include (i) current market interest rates, (ii) general financial condition of the issuer, (iii) issuer's industry and future business prospects, (iv) issuer's past defaults in principal and interest payments, and (v) the payment structure of the investment and the issuer's ability to make contractual payments on the investment.

Research and Development Expense, Policy [Policy Text Block]

Research and DevelopmentMajor components of research and development costs include internal research and development (such as salaries and related employee benefits, equity-based compensation, supplies and allocated facility costs) and contracted services (research and development activities performed on the Company’s behalf). Costs incurred for research and development are expensed as incurred.Upfront payments made to third parties who perform research and development services on the Company’s behalf are expensed as services are rendered.

Legal Costs, Policy [Policy Text Block]

Patent CostsPatent costs, including related legal costs, are expensed as incurred and are recorded within general and administrative expenses in the consolidated statements of operations and comprehensive loss.

Share-Based Payment Arrangement [Policy Text Block]

Stock-based CompensationThe Company measures stock-based awards at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the award. The Company uses the Black-Scholes Model to value its stock option awards. Estimating the fair value of stock option awards requires management to apply judgment and make estimates, including the volatility of the Company’s common stock, the expected term of the Company’s stock options, the expected dividend yield and the fair value of the Company’s common stock on the measurement date. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards.For certain stock option grants, the expected term was estimated using the “simplified method” for employee options as the Company has limited historical information to develop reasonable expectations about future exercise patterns and post vesting employment termination behavior for its stock option grants. The simplified method is based on the average of the vesting tranches and the contractual life of each grant. The Company uses the simplified method to estimate the expected term.For stock price volatility, the Company uses a combination of its own historical stock price and comparable public companies as a basis for its expected volatility to calculate the fair value of option grants. The Company assumes no dividend yield because dividends are not expected to be paid in the near future, which is consistent with the Company’s history of not paying dividends. The risk-free interest rate is based on U.S. Treasury notes with a term approximating the expected term of the option. The Company accounts for forfeitures in the periods they occur.

Earnings Per Share, Policy [Policy Text Block]

Net Loss Per Common ShareBasic net loss per share is computed by dividing net loss by the weighted average number of shares of common stock outstanding during each period. Diluted net loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as common stock warrants, stock options and unvested restricted stock that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share applicable to common stockholders, 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 have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive:

	March 31,
	2023		2022
Common stock warrants		88,252		111,891
Stock options		104,047		116,564
Unvested restricted stock awards		2,910		5,182
		195,209		233,637

New Accounting Pronouncements, Policy [Policy Text Block]

Recently Adopted Accounting PronouncementsIn June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses, Measurement of Credit Losses on Financial Instruments (Topic 326). The standard amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses for most financial assets and certain other instruments that aren’t measured at fair value through net income. For available-for-sale debt securities, entities will be required to recognize an allowance for credit losses rather than a reduction in carrying value of the asset. Entities will no longer be permitted to consider the length of time that fair value has been less than amortized cost when evaluating when credit losses should be recognized. The Company adopted the guidance using a modified retrospective approach as of January 1, 2023 which resulted in no cumulative-effect adjustment to retained earnings.

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DIFFUSION PHARMACEUTICALS INC.

NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS

The updated guidance in ASU 2016-13 also amended the previous other-than-temporary impairment (“OTTI”) model for available-for-sale fixed income securities by requiring the recognition of impairments relating to credit losses through an allowance account and limits the amount of credit loss to the difference between a security’s amortized cost basis and its fair value. In addition, the length of time a security has been in an unrealized loss position will no longer impact the determination of whether a credit loss exists. The Company adopted the guidance related to available-for-sale fixed income securities on January 1, 2023 using a prospective transition approach for available-for-sale fixed income securities that were purchased with credit deterioration or had recognized an OTTI write-down prior to the effective date. The effect of the prospective transition approach was to maintain the same amortized cost basis before and after the effective date.