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

Royalty Purchase Agreements - Aronora (Details)

Royalty Purchase Agreements - Aronora (Details) $ in Thousands		1 Months Ended	9 Months Ended	12 Months Ended
	Apr. 07, 2019 USD ($) item	Sep. 30, 2019 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Agreements
Long-term royalty receivables			$ 55,075	$ 34,575
Contingent consideration under royalty purchase agreements			75	75
Impairment of long-term royalty receivable			0	$ 0
Aronora [Member] \| Royalty Purchase Agreement [Member]
Agreements
Number of drug candidates \| item	5
Non-royalties to be received (as a percent)	10.00%
Future non-royalty payments to be received (as a percent)	5.00%
Multiplier for cumulative amount of consideration paid \| item	2
Upfront payment	$ 6,000
Threshold amount of cumulative royalties on net sales per product	250,000
Aggregate milestones payments per product	85,000
Long-term royalty receivables	9,000
Contingent consideration under royalty purchase agreements	3,000		0
Payments of contingent consideration		$ 3,000
Impairment of long-term royalty receivable			$ 0
Aronora [Member] \| Royalty Purchase Agreement [Member] \| Silicon Valley Bank [Member]
Agreements
Upfront payment	$ 3,000
Aronora [Member] \| Royalty Purchase Agreement [Member] \| Bayer Products [Member]
Agreements
Number of drug candidates \| item	3
Number of drug candidates subject to exclusive license option \| item	1
Royalties entity has right to receive (as a percent)	100.00%
Non-royalties to be received (as a percent)	10.00%
Contingent future cash payment for each product	$ 1,000
Potential future cash payments	$ 3,000
Aronora [Member] \| Royalty Purchase Agreement [Member] \| Non-Bayer Products [Member]
Agreements
Number of drug candidates \| item	2
Non-royalties to be received (as a percent)	10.00%