Exercise price per share or per unit of warrants or rights outstanding.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123467658&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123467658&loc=d3e12317-112629

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt instrument commencing year and month.

+ References

No definition available.

+ Details

Name:	xene_DebtInstrumentCommencingYearAndMonth
Namespace Prefix:	xene_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument, final payment fee, amount.

+ References

No definition available.

+ Details

Name:	xene_DebtInstrumentFinalPaymentFeeAmount
Namespace Prefix:	xene_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt instrument final payment fee percentage.

+ References

No definition available.

+ Details

Name:	xene_DebtInstrumentFinalPaymentFeePercentage
Namespace Prefix:	xene_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument interest only payment end date.

+ References

No definition available.

+ Details

Name:	xene_DebtInstrumentInterestOnlyPaymentEndDate
Namespace Prefix:	xene_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument Prepayment Fee.

+ References

No definition available.

+ Details

Name:	xene_DebtInstrumentPrepaymentFee
Namespace Prefix:	xene_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt instrument principal payment term after interest only period expires.

+ References

No definition available.

+ Details

Name:	xene_DebtInstrumentPrincipalPaymentTermAfterInterestOnlyPeriodExpires
Namespace Prefix:	xene_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term loan facility maximum borrowing capacity.

+ References

No definition available.

+ Details

Name:	xene_TermLoanFacilityMaximumBorrowingCapacity
Namespace Prefix:	xene_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=xene_TermLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=xene_SiliconValleyBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=xene_LoanAndSecurityAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Term Loan (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		9 Months Ended
	May 31, 2020	Aug. 31, 2018	Sep. 30, 2020	Sep. 30, 2021
Debt Instrument [Line Items]
Loss on repayment of term loan			$ (988)
Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, commencing period		2018-08
Debt instrument, interest only payment end date		Mar. 31, 2020
Debt instrument principal repayment period		30 months
Debt instrument, maturity date		Sep. 01, 2022
Debt instrument, final payment fee percentage		6.50%
Debt instrument, final payment fee	$ 1,008
Debt instrument prepayment fee	225
Warrants outstanding to purchase common stock				40,000
Warrants exercise price per common share				$ 9.79
Loss on repayment of term loan	$ 988
Term Loan [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Debt instrument, floating interest rate		0.50%
Silicon Valley Bank [Member] \| Term Loan [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt instrument		$ 15,500