Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	61,072	10,715
Common stock issued for cashless exercise	196,206	85,816
Cashless exercise of stock options	325,636	142,702

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