The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

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- Definition

Number of non-transferable contractual contingent value rights (CVR) each acquiree share has right to receive. representing right to receive one or more potential cash payments.

+ References

No definition available.

+ Details

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- Definition

Amount of arranger fee receivable for the acquisition related services rendered.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Price of a single share of a number of saleable stocks paid in asset acquisition.

+ References

No definition available.

+ Details

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Namespace Prefix:	xoma_
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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Subsequent Events (Details)	1 Months Ended
Subsequent Events (Details)	Feb. 28, 2026 USD ($) $ / shares	Jan. 27, 2026	Oct. 31, 2025 USD ($)
Xeno
Subsequent Events
Acquisition service, arranger fee, receivable			$ 3,000,000
Subsequent Event \| BVF \| Investor \| Repare Therapeutics, Inc
Subsequent Events
Ownership interest (as a percent)		24.00%
Subsequent Event \| Generation Bio Co
Subsequent Events
Asset acquisition, share price (in dollars per share) \| $ / shares	$ 4.2913
Number of non-transferable contractual CVR per share	1