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Reverse Merger - Summary of Pro Forma Results of Operation (Detail) - OncoGenex Pharmaceuticals, Inc [Member] - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Business Acquisition [Line Items] |  |  |
Net loss applicable to common shareholders | $ (16,395) | $ (12,687) | $ (20,111)
Net loss per share-basic and diluted | $ (1.99) | $ (3.61) | $ (41.95)
Weighted average shares | 8,246,400 | 3,510,217 | 479,442

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