Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	41,507	63,425
Common stock issued for cashless exercise	103,189	4,405
Cashless exercise of stock options	196,341	7,581

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