Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	1,972	20,576
Common stock issued for cashless exercise	55,885	657
Cashless exercise of stock options	96,354	1,826

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