Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	23,625	41,507
Common stock issued for cashless exercise	94,248	103,189
Cashless exercise of stock options	151,186	196,341

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