Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	63,425	30,176
Common stock issued for cashless exercise	4,405	27,421
Cashless exercise of stock options	7,581	42,365

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