Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 11, 2022
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
Document Transition Report	false
Entity File Number	001-32295
Entity Registrant Name	FENNEC PHARMACEUTICALS INC.
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	20-0442384
Entity Address, Address Line One	PO Box 13628, 68 TW Alexander Drive
Entity Address, City or Town	Research Triangle Park
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27709
City Area Code	919
Local Phone Number	636-4530
Title of 12(b) Security	Common Shares, no par value
Trading Symbol	FENCF
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		26,067,283
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001211583
Amendment Flag	false