Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	46,296	1,972
Common stock issued for cashless exercise	36,159	55,885
Cashless exercise of stock options	76,107	96,354

Number of common stock issued in exchange for share options (or share units) exercised via net exercise (cashless) method during the current period.

No definition available.

Name:	xene_CommonStockIssuedForCashlessExercise
Namespace Prefix:	xene_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration