Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	10,715	23,625
Common stock issued for cashless exercise	85,816	94,248
Cashless exercise of stock options	142,702	151,186

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