Related parties - Schedule of Disclosure of Transactions Between Liabilities and Receivables (Details) - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Related party transactions [abstract]
Collections	€ 13,196	€ 24,978
Payments	(5,486)	0
Net collections	7,710	24,978
Receivables	2,136	2,974
Liabilities	(5,431)	(35,990)
Net receivables (liabilities)	€ (3,295)	€ (33,016)

The amounts payable resulting from related party transactions. [Refer: Total for all related parties [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2025-01-01
-Paragraph 20
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_20&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2025-01-01
-Paragraph 18
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_18_b&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 230
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_230_b&doctype=Standard
-URIDate 2025-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 230
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_230_b&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_AmountsPayableRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amounts receivable resulting from related party transactions. [Refer: Total for all related parties [member]]

+ References

+ Details

Name:	ifrs-full_AmountsReceivableRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow for loans and advances made to related parties. [Refer: Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2025-01-01
-Paragraph 16
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_16&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_CashAdvancesAndLoansMadeToRelatedParties
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from repayment to the entity of loans and advances made to related parties. [Refer: Total for all related parties [member]]

+ References

+ Details

Name:	ifrs-full_CashReceiptsFromRepaymentOfAdvancesAndLoansMadeToRelatedParties
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	ifrs-full_RelatedPartyTransactionsAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Net Amounts Receivable Payable Related Party Transactions

+ References

No definition available.

+ Details

Name:	nbx_NetAmountsReceivablePayableRelatedPartyTransactions
Namespace Prefix:	nbx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Net Collections (Payments) From Related Party

+ References

No definition available.

+ Details

Name:	nbx_NetCollectionsPaymentsFromRelatedParty
Namespace Prefix:	nbx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration