Stock Option Plan - Stock Option Activity (Parenthetical) (Details) - shares	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	29,270	53,442
Common stock issued for cashless exercise	741	32,399
Cashless exercise of stock options	1,259	46,369

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