Basis of Presentation	3 Months Ended
Mar. 31, 2025
Accounting Policies [Abstract]
Basis of Presentation	2. Basis of presentation: These unaudited interim condensed consolidated financial statements are presented in U.S. dollars and include the accounts of the Company and its wholly-owned subsidiary, Xenon Pharmaceuticals USA Inc., a Delaware corporation. All intercompany transactions and balances have been eliminated on consolidation. The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim financial information. Certain information has been reclassified to conform with the financial presentation adopted for the current year. Accordingly, these condensed consolidated financial statements do not include all of the information and footnotes required for complete consolidated financial statements and should be read in conjunction with the audited consolidated financial statements and notes for the year ended December 31, 2024 included in the Company’s 2024 Annual Report on Form 10-K filed with the SEC and with the securities commissions in British Columbia, Alberta and Ontario on February 27, 2025. These unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, which, in the opinion of management, are necessary for a fair presentation of results for the interim periods presented. The results of operations for the three months ended March 31, 2025 and 2024 are not necessarily indicative of results that can be expected for a full year. These unaudited interim condensed consolidated financial statements follow the same significant accounting policies as those described in the notes to the audited consolidated financial statements of the Company included in the Company’s 2024 Annual Report on Form 10-K for the year ended December 31, 2024, with the exception of the policy described in note 3 below. 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 period 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 three months ended March 31, 2024 of $3,009 from the previously reported amount. 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 the 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

3 Months Ended

Mar. 31, 2025

Basis of presentation:

These unaudited interim condensed consolidated financial statements are presented in U.S. dollars and include the accounts of the Company and its wholly-owned subsidiary, Xenon Pharmaceuticals USA Inc., a Delaware corporation. All intercompany transactions and balances have been eliminated on consolidation.

The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim financial information. Certain information has been reclassified to conform with the financial presentation adopted for the current year. Accordingly, these condensed consolidated financial statements do not include all of the information and footnotes required for complete consolidated financial statements and should be read in conjunction with the audited consolidated financial statements and notes for the year ended December 31, 2024 included in the Company’s 2024 Annual Report on Form 10-K filed with the SEC and with the securities commissions in British Columbia, Alberta and Ontario on February 27, 2025.

These unaudited interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, which, in the opinion of management, are necessary for a fair presentation of results for the interim periods presented. The results of operations for the three months ended March 31, 2025 and 2024 are not necessarily indicative of results that can be expected for a full year. These unaudited interim condensed consolidated financial statements follow the same significant accounting policies as those described in the notes to the audited consolidated financial statements of the Company included in the Company’s 2024 Annual Report on Form 10-K for the year ended December 31, 2024, with the exception of the policy described in note 3 below.

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 period 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 three months ended March 31, 2024 of $3,009 from the previously reported amount. 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 the 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.