Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	49,502	63,425
Common stock issued for cashless exercise	106,474	4,405
Cashless exercise of stock options	201,661	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