Commitment and Contingencies (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Other Commitments [Line Items]
Contingent value rights liability, current	$ 1,388	$ 281
Contingent value rights liability, non-current	717	1,006
Lease CVR
Other Commitments [Line Items]
Contingent value rights liability, current	536	281
Contingent value rights liability, non-current	717	1,006
Intellectual Property CVR
Other Commitments [Line Items]
Contingent value rights liability, current	520	0
Contingent value rights liability, non-current	0	0
Sales Tax CVR
Other Commitments [Line Items]
Contingent value rights liability, current	332	0
Contingent value rights liability, non-current	$ 0	$ 0

Amount of liability recognized from contingent consideration in asset acquisition, classified as current.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 15
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480123/805-50-15-3

+ Details

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

- Definition

Amount of liability recognized from contingent consideration in asset acquisition, classified as noncurrent.

+ References

+ Details

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

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

- Details

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

- Details

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

- Details

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