Note 12 - Subsequent Events (Details Textual) - Subsequent Event [Member] - Warrants Attached to Series A Convertible Preferred Stock [Member] $ in Millions	Nov. 01, 2017 USD ($)
Amount of Warrant Liability Removed from Total Liabilities	$ 16.3
Fair Value of Warrants Reclassified to Additional Paid in Capital During the Period	13.2
Adjustment of Accumulated Deficit Balance for the Change in Fair Value of Warrants	$ 3.2

Represents the fair value of warrants (previously classified as liabilities) that were reclassified to additional paid in capital during the period.

No definition available.

Name:	dffn_FairValueOfWarrantsReclassifiedToAdditionalPaidInCapitalDuringThePeriod
Namespace Prefix:	dffn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration