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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 | 9 Months Ended
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Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017
Business Acquisition [Line Items] |  |  |  |
Net loss applicable to common shareholders | $ (3,240) | $ (9,730) | $ (9,050) | $ (10,100)
Net loss per share-basic and diluted | $ (0.71) | $ (13.47) | $ (3.70) | $ (41.48)
Weighted average shares | 4,533,943 | 722,583 | 2,448,962 | 243,510

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