v2.4.0.8
Document And Entity Information (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Mar. 09, 2015
Nov. 05, 2014
Document And Entity Information [Abstract]      
Entity Registrant Name Xenon Pharmaceuticals Inc.    
Document Type 10-K    
Current Fiscal Year End Date --12-31    
Entity Common Stock, Shares Outstanding   14,221,600  
Entity Public Float     $ 111
Amendment Flag false    
Trading Symbol XENE    
Entity Central Index Key 0001582313    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Non-accelerated Filer    
Entity Well-known Seasoned Issuer No    
Document Period End Date Dec. 31, 2014    
Document Fiscal Year Focus 2014    
Document Fiscal Period Focus FY