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

Licensing and Other Arrangements - Sale of Future Revenue Streams (Details) $ in Thousands		3 Months Ended
	Dec. 21, 2016 USD ($) agreement period	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Licensing and other arrangements
Unearned revenue recognized under units-of-revenue method		$ (356)	$ (304)
Revenue recognized under units-of-revenue method		356	304
Unearned revenue recognized under units-of-revenue method, current		1,482		$ 1,452
Unearned revenue recognized under units-of-revenue method, noncurrent		13,130		$ 13,516
HealthCare Royalty Partners II, L.P
Licensing and other arrangements
Revenue recognized under units-of-revenue method		400
Unearned revenue recognized under units-of-revenue method, current		1,500
Unearned revenue recognized under units-of-revenue method, noncurrent		$ 13,100
HealthCare Royalty Partners II, L.P \| Royalty Sale Agreements
Licensing and other arrangements
Number of agreements \| agreement	2
Unearned revenue recognized under units-of-revenue method	$ 18,000
Revenue recognized under units-of-revenue method			$ 300
HealthCare Royalty Partners II, L.P \| First Royalty Sale Agreement
Licensing and other arrangements
Cash payment received	6,500
Eligible potential additional payments receivable upon achievement of specified net sales milestones in future years	$ 4,000
Number of milestone periods \| period	3
HealthCare Royalty Partners II, L.P \| Second Royalty Sale Agreement
Licensing and other arrangements
Cash payment received	$ 11,500