Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	13,374	62,397
Common stock issued for cashless exercise	27,507	3,693
Cashless exercise of stock options	71,294	5,524

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