Agreements with Horizon - Additional Information (Detail) $ in Millions	6 Months Ended
Jun. 30, 2025 USD ($)
Horizon collaboration agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement, transaction price	$ 55.0
Collaboration agreement, Aggregate amount of sales milestone	75.1
Received amount from Horizon	55.0
Collaboration agreement, contingent payment	75.1
Refund liability	55.0
Payment to horizon	20.1
Legacy Q32
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Business combination, intial consideration	55.0
Sales-based milestone \| Horizon collaboration agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement, contingent payment	75.1
Collaboration agreement, contingent payment payable excess of cash received	$ 20.1

Amount of refund liability.

No definition available.

Name:	qttb_AmountOfRefundLiability
Namespace Prefix:	qttb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Collaboration agreement contingent payment.

+ References

No definition available.

+ Details

Name:	qttb_CollaborationAgreementContingentPayment
Namespace Prefix:	qttb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Collaboration agreement contingent payment payable excess of cash received.

+ References

No definition available.

+ Details

Name:	qttb_CollaborationAgreementContingentPaymentPayableExcessOfCashReceived
Namespace Prefix:	qttb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Collaboration agreement transaction price.

+ References

No definition available.

+ Details

Name:	qttb_CollaborationAgreementTransactionPrice
Namespace Prefix:	qttb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Collaborative arrangement milestone payments.

+ References

No definition available.

+ Details

Name:	qttb_CollaborativeArrangementMilestonePayments
Namespace Prefix:	qttb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Payment To Horizon

+ References

No definition available.

+ Details

Name:	qttb_PaymentToHorizon
Namespace Prefix:	qttb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of asset recognized arising from contingent consideration in a business combination, expected to be realized within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationAssetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

+ Details

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

- Definition

Cash received from collaborators during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

+ Details

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

- Details

Name:	us-gaap_TypeOfArrangementAxis=qttb_HorizonCollaborationAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=qttb_LegacyQ32Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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