Annual report pursuant to Section 13 and 15(d)

Common Stock - Summary of Stock Options Activity (Detail)

v3.8.0.1
Common Stock - Summary of Stock Options Activity (Detail) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 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  
Number of Optioned Common Shares, Expired (19,543)  
Number of Optioned Common Shares, Exercised 0 0
Number of Optioned Common Shares, Forfeited (30,461)  
Number of Optioned Common Shares, Ending Balance 1,115,647  
Weighted Average Exercise Price, Additions from OncoGenex Plans $ 96.38  
Weighted Average Exercise Price, Granted 2.89  
Weighted Average Exercise Price, Expired 114.53  
Weighted Average Exercise Price, Forfeited 92.72  
Weighted Average Exercise Price, Ending Balance $ 7.99