v3.7.0.1
Document And Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Mar. 03, 2017
Jun. 30, 2016
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   17,935,982  
Entity Public Float     $ 81.1
Amendment Flag false    
Trading Symbol XENE    
Entity Central Index Key 0001582313    
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, 2016    
Document Fiscal Year Focus 2016    
Document Fiscal Period Focus FY