Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Summary of Stock Options Activity (Detail)

v3.8.0.1
Common Stock - Summary of Stock Options Activity (Detail) - $ / shares
9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Number of Optioned Common Shares, Additions from OncoGenex Plans 113,451  
Number of Optioned Common Shares, Granted 1,052,200 0
Number of Optioned Common Shares, Expired (19,544)  
Number of Optioned Common Shares, Ending Balance 1,146,107  
Weighted Average Exercise Price, Additions from OncoGenex Plans $ 92.61  
Weighted Average Exercise Price, Granted 2.89  
Weighted Average Exercise Price, Expired 114.53  
Weighted Average Exercise Price, Ending Balance $ 9.87