v3.8.0.1
Document And Entity Information - USD ($)
12 Months Ended
Dec. 31, 2017
Mar. 06, 2018
Jun. 30, 2017
Document and Entity Information [Abstract]      
Entity Registrant Name Arbutus Biopharma Corp    
Document Type 10-K    
Current Fiscal Year End Date --12-31    
Entity Common Stock, Shares Outstanding   55,070,037  
Entity Public Float     $ 198,187,182
Amendment Flag false    
Entity Central Index Key 0001447028    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Accelerated Filer    
Entity Well-known Seasoned Issuer No    
Document Period End Date Dec. 31, 2017    
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY