Note 1 - Organization and Description of Business	3 Months Ended
Mar. 31, 2016
Notes to Financial Statements
Nature of Operations [Text Block]	1. Organization and Description of Business Diffusion Pharmaceuticals Inc. (“Diffusion” or the “Company”), a Delaware Corporation, is a clinical stage biotechnology company focused on extending the life expectancy of cancer patients by improving the effectiveness of current standard-of-care treatments, including radiation therapy and chemotherapy. The Company’s lead product candidate, trans sodium crocetinate (“TSC”), uses a novel mechanism to re-oxygenate the microenvironment of solid cancerous tumors, thereby enhancing tumor cells’ response to conventional treatment without additional side effects. TSC has received orphan drug designations for the treatment of glioblastoma multiforme (“GBM”) and metastatic brain cancer, and the Company expects to enter a Phase III study in newly diagnosed GBM patients in the next twelve months, assuming the availability of financial resources. On January 8, 2016, the Company completed a merger (the “Merger”) of a wholly-owned subsidiary with Diffusion Pharmaceuticals LLC (“Diffusion LLC”) pursuant to an Agreement and Plan of Merger, dated December 15, 2015, by and among the Company, Arco Merger Sub LLC and Diffusion LLC (the “Merger Agreement”) and, as a result, Diffusion LLC became a wholly-owned subsidiary of the Company. At the effective time of the Merger, each outstanding unit of membership interest of Diffusion LLC (“Diffusion Units”) was converted into the right to receive 3.652658 shares of the Company’s common stock, as determined pursuant to the Merger Agreement (“Exchange Ratio”). Also at the effective time of the Merger, $1,125,000 of Diffusion LLC convertible notes were outstanding and the rights of the holders of each outstanding convertible promissory note convertible into Diffusion Units (“Diffusion Convertible Notes”) was converted into the right to convert such securities into a number of shares of the Company’s common stock equal to the number of Diffusion Units such Diffusion Convertible Note would be convertible into pursuant to its terms multiplied by the Exchange Ratio. In addition, at the effective time of the Merger and as a result of the Merger, all outstanding options to purchase Diffusion Units were converted into and became options to purchase the Company’s common stock on terms substantially identical to those in effect prior to the effective time of the Merger, except for adjustments to the underlying number of shares and the exercise price based on the Exchange Ratio. Through December 2015, the Company issued options to purchase Diffusion Units which converted into options to purchase an aggregate of 14,952,101 shares of the Company’s common stock with a weighted average exercise price of $0.40 per share. No fractional shares of the Company’s common stock were issued in connection with the Merger, and holders of Diffusion Units received cash in lieu thereof. The merger transaction was accounted for as a reverse acquisition under the acquisition method of accounting. Because Diffusion LLC’s pre-transaction owners held an 84.1% economic and voting interest in the combined company immediately following the closing of the merger, Diffusion LLC is considered to be the acquirer of the Company for accounting purposes. Accordingly, the historical financial statements of Diffusion LLC became the Company’s historical financial statements including the comparative prior periods. All references in the unaudited condensed consolidated financial statements to the number of shares and per-share amounts of common stock have been retroactively restated to reflect the Exchange Ratio. In connection with the Merger, the Company issued 18,614,968 shares of its common stock to its former shareholders, or approximately 15.9% of the common stock of the combined company, in each case, on a fully-diluted basis (subject to certain exceptions and adjustments).

1. Organization and Description of Business

Diffusion Pharmaceuticals Inc. (“Diffusion” or the “Company”), a Delaware Corporation, is a clinical stage biotechnology company focused on extending the life expectancy of cancer patients by improving the effectiveness of current standard-of-care treatments, including radiation therapy and chemotherapy. The Company’s lead product candidate, trans sodium crocetinate (“TSC”), uses a novel mechanism to re-oxygenate the microenvironment of solid cancerous tumors, thereby enhancing tumor cells’ response to conventional treatment without additional side effects. TSC has received orphan drug designations for the treatment of glioblastoma multiforme (“GBM”) and metastatic brain cancer, and the Company expects to enter a Phase III study in newly diagnosed GBM patients in the next twelve months, assuming the availability of financial resources.

On January 8, 2016, the Company completed a merger (the “Merger”) of a wholly-owned subsidiary with Diffusion Pharmaceuticals LLC (“Diffusion LLC”) pursuant to an Agreement and Plan of Merger, dated December 15, 2015, by and among the Company, Arco Merger Sub LLC and Diffusion LLC (the “Merger Agreement”) and, as a result, Diffusion LLC became a wholly-owned subsidiary of the Company.

At the effective time of the Merger, each outstanding unit of membership interest of Diffusion LLC (“Diffusion Units”) was converted into the right to receive 3.652658 shares of the Company’s common stock, as determined pursuant to the Merger Agreement (“Exchange Ratio”). Also at the effective time of the Merger, $1,125,000 of Diffusion LLC convertible notes were outstanding and

the rights of the holders of each outstanding convertible promissory note convertible into Diffusion Units (“Diffusion Convertible Notes”) was converted into the right to convert such securities into a number of shares of the Company’s common stock equal to the number of Diffusion Units such Diffusion Convertible Note would be convertible into pursuant to its terms multiplied by the Exchange Ratio. In addition, at the effective time of the Merger and as a result of the Merger, all outstanding options to purchase Diffusion Units were converted into and became options to purchase the Company’s common stock on terms substantially identical to those in effect prior to the effective time of the Merger, except for adjustments to the underlying number of shares and the exercise price based on the Exchange Ratio. Through December 2015, the Company issued options to purchase Diffusion Units which converted into options to purchase an aggregate of 14,952,101 shares of the Company’s common stock with a weighted average exercise price of $0.40 per share. No fractional shares of the Company’s common stock were issued in connection with the Merger, and holders of Diffusion Units received cash in lieu thereof.

The merger transaction was accounted for as a reverse acquisition under the acquisition method of accounting. Because Diffusion LLC’s pre-transaction owners held an 84.1% economic and voting interest in the combined company immediately following the closing of the merger, Diffusion LLC is considered to be the acquirer of the Company for accounting purposes. Accordingly,

the historical financial statements of Diffusion LLC became the Company’s historical financial statements including the comparative prior periods. All references in the unaudited condensed consolidated financial statements to the number of shares and per-share amounts of common stock have been retroactively restated to reflect the Exchange Ratio.

In connection with the Merger, the Company issued 18,614,968 shares of its common stock to its former shareholders, or approximately 15.9% of the common stock of the combined company, in each case, on a fully-diluted basis (subject to certain exceptions and adjustments).