Stock Option Plan - Stock Option Activity (Parenthetical) (Details)	3 Months Ended
Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock options exercised for number of common shares for cash	26,910
Common stock issued for cashless exercise	14,032
Cashless exercise of stock options	17,746xene_CashlessExerciseOfStockOptions

Stock options exercised for number of common shares for cash.

No definition available.

Name:	xene_StockOptionsExercisedForNumberOfCommonSharesForCash
Namespace Prefix:	xene_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration