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

Royalty Purchase Agreements - Palobiofarma (Details) $ in Thousands		9 Months Ended	12 Months Ended
	Sep. 26, 2019 USD ($) item	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Agreements
Payments to acquire milestones and royalties		$ 20,500
Long-term royalty receivables		55,075	$ 34,575
Impairment of long-term royalty receivable		0	$ 0
Palobiofarma, S.L {Member] \| Royalty Purchase Agreement [Member]
Agreements
Number of drug candidates \| item	6
Payments to acquire milestones and royalties	$ 10,000
Long-term royalty receivables	10,000
Impairment of long-term royalty receivable		$ 0
Palobiofarma, S.L {Member] \| Royalty Purchase Agreement [Member] \| Silicon Valley Bank [Member]
Agreements
Proceeds from issuance of long-term debt	$ 5,000