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		9 Months Ended
	Dec. 21, 2016 USD ($) agreement period	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Licensing and other arrangements
Unearned revenue recognized under units-of-revenue method				$ (1,121)	$ (1,052)
Revenue recognized under units-of-revenue method		$ 390	$ 357	1,121	1,051
Unearned revenue recognized under units-of-revenue method, current		1,541		1,541		$ 1,452
Unearned revenue recognized under units-of-revenue method, noncurrent		12,306		12,306		13,516
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		400	$ 400	1,100	$ 1,100
Unearned revenue recognized under units-of-revenue method, current		1,500		1,500		1,500
Unearned revenue recognized under units-of-revenue method, noncurrent		$ 12,300		$ 12,300		$ 13,500
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