Note 1 - Organization and Description of Business	12 Months Ended
Dec. 31, 2017
Notes to Financial Statements
Nature of Operations [Text Block]	1. Organization and Description of Business Diffusion Pharmaceuticals Inc. “Diffusion” or “the Company” 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 is developing its lead product candidate, transcrocetinate sodium, also known as trans sodium crocetinate (“TSC”), for use in the many cancer types in which tumor oxygen deprivation (“hypoxia”) is known to diminish the effectiveness of current treatments. TSC is designed to target the cancer ’s hypoxic micro-environment, re-oxygenating treatment-resistant tissue and making the cancer cells more susceptible to the therapeutic effects of standard-of-care radiation therapy and chemotherapy. On December 15, 2015, the Company ’s predecessor for accounting purposes, Diffusion Pharmaceuticals LLC (“Diffusion LLC”) entered into a definitive merger agreement with the Company, then known as “RestorGenex Corporation” and traded on the over-the-counter stock exchange under the ticker symbol “RESX.” On January 8, 2016 the Company completed the merger with Diffusion LLC under which a newly formed subsidiary of the Company merged with and into Diffusion LLC in an all-stock transaction, with Diffusion LLC surviving as a wholly-owned subsidiary of the Company. Subsequent to the merger, the Company was renamed “Diffusion Pharmaceuticals Inc.” and the Company’s ticker symbol was changed to “DFFN.” On November 9, 2016, the Company’s common stock (“Common Stock”) began trading on the NASDAQ Capital Market exchange. 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 RestorGenex for accounting purposes (See Note 4 ). The Company ’s members’ capital at January 1, 2016 has been recast as common stock and additional paid in capital. On August 17, 2016, the Company effected a 1 -for- 10 reverse split of its common stock. The accompanying consolidated financial statements and these notes give retroactive effect to this reverse stock split. Each outstanding unit of membership interest of Diffusion LLC (the “Diffusion Units”) was converted into the right to receive 0.3652658 shares of Common Stock (the “Exchange Ratio”). Additionally, the right of holders of $1.1 million outstanding convertible notes of Diffusion LLC to convert such notes into Diffusion Units was converted into the right to convert such notes into a number of shares of Common Stock equal to the number of Diffusion Units into which such notes would have been convertible under the original terms of the notes multiplied by the Exchange Ratio. In addition, all outstanding options to purchase Diffusion Units were assumed by the Company and the right to exercise converted into 1,495,615 options to purchase Common Stock on terms substantially identical to those in effect prior to the merger transaction, except for adjustments to the underlying number of shares and the exercise price based on the Exchange Ratio.

Organization and Description of Business

Diffusion Pharmaceuticals Inc. “Diffusion” or “the Company” 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 is developing its lead product candidate, transcrocetinate sodium, also known as trans sodium crocetinate (“TSC”), for use in the many cancer types in which tumor oxygen deprivation (“hypoxia”) is known to diminish the effectiveness of current treatments. TSC is designed to target the cancer

’s hypoxic micro-environment, re-oxygenating treatment-resistant tissue and making the cancer cells more susceptible to the therapeutic effects of standard-of-care radiation therapy and chemotherapy.

December 15, 2015,

the Company

’s predecessor for accounting purposes, Diffusion Pharmaceuticals LLC (“Diffusion LLC”) entered into a definitive merger agreement with the Company, then known as “RestorGenex Corporation” and traded on the over-the-counter stock exchange under the ticker symbol “RESX.” On

January 8, 2016

the Company completed the merger with Diffusion LLC under which a newly formed subsidiary of the Company merged with and into Diffusion LLC in an all-stock transaction, with Diffusion LLC surviving as a wholly-owned subsidiary of the Company. Subsequent to the merger, the Company was renamed “Diffusion Pharmaceuticals Inc.” and the Company’s ticker symbol was changed to “DFFN.” On

November 9, 2016,

the Company’s common stock (“Common Stock”) began trading on the NASDAQ Capital Market exchange.

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 RestorGenex for accounting purposes (See Note

The Company

’s members’ capital at

January 1, 2016

has been recast as common stock and additional paid in capital. On

August 17, 2016,

the Company effected a

-for-

reverse split of its common stock. The accompanying consolidated financial statements and these notes give retroactive effect to this reverse stock split.

Each outstanding unit of membership interest of Diffusion LLC (the “Diffusion Units”) was converted into the right to receive

0.3652658

shares of Common Stock (the “Exchange Ratio”). Additionally, the right of holders of

$1.1

million outstanding convertible notes of Diffusion LLC to convert such notes into Diffusion Units was converted into the right to convert such notes into a number of shares of Common Stock equal to the number of Diffusion Units into which such notes would have been convertible under the original terms of the notes multiplied by the Exchange Ratio. In addition, all outstanding options to purchase Diffusion Units were assumed by the Company and the right to exercise converted into

1,495,615

options to purchase Common Stock on terms substantially identical to those in effect prior to the merger transaction, except for adjustments to the underlying number of shares and the exercise price based on the Exchange Ratio.