Estimated year of patent expiration.

No definition available.

Name:	evok_EstimatedYearOfPatentExpiration
Namespace Prefix:	evok_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Milestone payment.

+ References

No definition available.

+ Details

Name:	evok_MilestonePayment
Namespace Prefix:	evok_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Milestone payments contingent amount.

+ References

No definition available.

+ Details

Name:	evok_MilestonePaymentsContingentAmount
Namespace Prefix:	evok_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of milestone payments.

+ References

No definition available.

+ Details

Name:	evok_NumberOfMilestonePayments
Namespace Prefix:	evok_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of material contingencies of the registrant unless separately disclosed in the consolidated statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph a
-Subsection 04

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24072-122690

+ Details

Name:	srt_DescriptionOfMaterialContingenciesOfParentCompany
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of long-term loans payable classified as other.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_OtherLoansPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of cash paid for royalties during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3536-108585

+ Details

Name:	us-gaap_PaymentsForRoyalties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_ResearchAndDevelopmentAssetsAcquiredOtherThanThroughBusinessCombinationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 730
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6472174&loc=d3e58812-109433

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 985
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373

+ Details

Name:	us-gaap_ResearchAndDevelopmentExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of purchased research and development assets that are acquired in a business combination have no alternative future use and are therefore written off in the period of acquisition.

+ References

No definition available.

+ Details

Name:	us-gaap_ResearchAndDevelopmentInProcess
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	srt_CounterpartyNameAxis=evok_MallinckrodtPlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ResearchAndDevelopmentAssetsAcquiredOtherThanThroughBusinessCombinationByTransactionAxis=evok_RightsAndPatentsAcquiredFromQuestcorPharmaceuticalsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=evok_GimotiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=evok_DevelopmentTargetOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=evok_DevelopmentTargetFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_PatentedTechnologyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Technology Acquisition Agreement - Additional Information (Detail)	1 Months Ended			9 Months Ended
	Jul. 31, 2021 USD ($)	May 31, 2014 USD ($)	Jun. 30, 2007 USD ($)	Sep. 30, 2021 USD ($) Milestone	Sep. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)
Technology Acquisition Agreement [Line Items]
Payment expensed as in-process research and development			$ 650,000
Milestone payment				$ (5,000,000)	$ 5,000,000
Mallinckrodt Plc [Member]
Technology Acquisition Agreement [Line Items]
Milestone payments contingent amount				$ 5,000,000
Number of milestone payments \| Milestone				1
Mallinckrodt Plc [Member] \| Rights and Patents Acquired from Questcor Pharmaceuticals Inc [Member] \| Maximum [Member]
Technology Acquisition Agreement [Line Items]
Milestone payments contingent amount				$ 52,000,000
Gimoti [Member] \| Mallinckrodt Plc [Member]
Technology Acquisition Agreement [Line Items]
Milestone payment	$ 5,000,000
Research and development expense payable				$ 5,000,000
Amount payable to Mallinckrodt						$ 5,000,000
Development Target One [Member] \| Rights and Patents Acquired from Questcor Pharmaceuticals Inc [Member]
Technology Acquisition Agreement [Line Items]
Milestone payment		$ 500,000
Development targets description				Upon the initiation of the first patient dosing in the Company’s Phase 3 clinical trial for Gimoti.
Development Target Four [Member] \| Mallinckrodt Plc [Member] \| Patented Technology [Member]
Technology Acquisition Agreement [Line Items]
Development targets description				Depend on Gimoti’s commercial success. The Company is also required to pay Mallinckrodt a low single digit royalty percentage on net sales of Gimoti.
Milestone payments contingent amount				$ 47,000,000
Royalties on net sales				$ 14,000
Expected expiration of patent right				2030