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Reverse Merger - Summary of Pro Forma Results of Operation (Detail) - OncoGenex Pharmaceuticals, Inc [Member] - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended
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Mar. 31, 2018 | Mar. 31, 2017
Business Acquisition [Line Items] |  |
Net loss applicable to common shareholders | $ (3,022) | $ (3,474)
Net loss per share-basic and diluted | $ (0.24) | $ (1.27)
Weighted average shares | 12,431,488 | 2,734,196

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