v3.26.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2026
May 12, 2026
Document and Entity Information    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Document Transition Report false  
Securities Act 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 FENC  
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   34,737,030
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Entity Central Index Key 0001211583  
Amendment Flag false