Basis of Presentation	12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	2. Basis of presentation: These consolidated financial statements are presented in U.S. dollars and have been prepared in accordance with generally accepted accounting principles in the United States ("GAAP"). The Company has one wholly-owned subsidiary as of December 31, 2024, Xenon Pharmaceuticals USA Inc., which was incorporated in Delaware on December 2, 2016. These consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany transactions and balances have been eliminated on consolidation. Certain information has been reclassified to conform with the financial presentation adopted for the current year. Correction of prior period error During the year ended December 31, 2024, the Company identified a presentation error related to the accretion of discounts on marketable securities, which was incorrectly presented within proceeds from marketable securities as part of net cash provided by (used in) investing activities in the consolidated statements of cash flows. As a result, a correction was made to the prior periods to reclassify the amount of accretion of discounts on marketable securities within net cash used in operating activities, resulting in an increase in net cash used in operating activities and a corresponding decrease in net cash used in investing activities for the years ended December 31, 2023 and 2022 of $5,785 and $2,598, respectively, from the previously reported amounts. The Company evaluated the materiality of the presentation error, both quantitatively and qualitatively, and concluded it was not material to the consolidated financial statements for any prior period. These presentation changes had no effect on the previously reported consolidated balance sheets, consolidated statements of operations and comprehensive loss, or consolidated statements of shareholders’ equity.

Basis of Presentation

12 Months Ended

Dec. 31, 2024

Basis of presentation:

These consolidated financial statements are presented in U.S. dollars and have been prepared in accordance with generally accepted accounting principles in the United States ("GAAP").

The Company has one wholly-owned subsidiary as of December 31, 2024, Xenon Pharmaceuticals USA Inc., which was incorporated in Delaware on December 2, 2016.

These consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany transactions and balances have been eliminated on consolidation. Certain information has been reclassified to conform with the financial presentation adopted for the current year.

Correction of prior period error

During the year ended December 31, 2024, the Company identified a presentation error related to the accretion of discounts on marketable securities, which was incorrectly presented within proceeds from marketable securities as part of net cash provided by (used in) investing activities in the consolidated statements of cash flows. As a result, a correction was made to the prior periods to reclassify the amount of accretion of discounts on marketable securities within net cash used in operating activities, resulting in an increase in net cash used in operating activities and a corresponding decrease in net cash used in investing activities for the years ended December 31, 2023 and 2022 of $5,785 and $2,598, respectively, from the previously reported amounts. The Company evaluated the materiality of the presentation error, both quantitatively and qualitatively, and concluded it was not material to the consolidated financial statements for any prior period. These presentation changes had no effect on the previously reported consolidated balance sheets, consolidated statements of operations and comprehensive loss, or consolidated statements of shareholders’ equity.