XOMA Corporation Quarterly report pursuant to Section 13 or 15(d)

Royalty and Commercial Payment Purchase Agreements - Agenus (Details) $ in Thousands		1 Months Ended	9 Months Ended		12 Months Ended
	Sep. 20, 2018 USD ($) item	Nov. 30, 2020 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Agreements
Payments related to purchase of royalty rights and other commercial payment rights				$ 20,500
Long-term royalty and commercial payment receivables			$ 66,049		$ 69,075
Impairment of long-term royalty receivable			0		0
Royalty Purchase Agreement \| Merck Immuno-Oncology Product \| Agenus
Agreements
Amount of milestone achieved		$ 10,000
Agenus \| Royalty Purchase Agreement
Agreements
Payments related to purchase of royalty rights and other commercial payment rights	$ 15,000
Long-term royalty and commercial payment receivables	$ 15,000
Impairment of long-term royalty receivable			$ 0		$ 0
Agenus \| Royalty Purchase Agreement \| Incyte Immuno-Oncology Assets
Agreements
Royalties entity has right to receive (as a percent)	33.00%
Number of licensed products related to milestone and royalties \| item	6
Purchased percentage of milestones	10.00%
Agenus \| Royalty Purchase Agreement \| Merck Immuno-Oncology Product
Agreements
Royalties entity has right to receive (as a percent)	33.00%
Purchased percentage of milestones	10.00%
Purchased eligible milestone payments receivable upon achievement of potential development, regulatory and commercial milestones	$ 59,500
Amount of milestone achieved		1,000
Cash receipts for achievement of contractual milestones		$ 1,000