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

Subsequent Events - Additional Information (Details)

Subsequent Events - Additional Information (Details) - Subsequent Events [Member] $ in Millions	Apr. 07, 2019 USD ($) Number
Aronora [Member]
Subsequent Event [Line Items]
Percentage of future developmental regulatory and sales milestones reduced	5
Aronora [Member] \| Bayer Licensed Products [Member]
Subsequent Event [Line Items]
Percentage of future developmental regulatory and sales milestones	10
Aronora [Member] \| Non Bayer Licensed Products [Member]
Subsequent Event [Line Items]
Percentage of future developmental regulatory and sales milestones	10
Aronora [Member] \| Royalty Purchase Agreement [Member]
Subsequent Event [Line Items]
Number of hematology drug products in development \| Number	5
Number of anti thrombotic candidates \| Number	3
Initial amount payable	$ 6.0
Additional amount payable	$ 1.0
Agreement termination notice period	90 days
Received cumulative royalties on net sales per product amount	$ 250.0
Milestones payments to aggregate amount of per product	$ 85.0
Agreement termination period	6 months
Aronora [Member] \| Royalty Purchase Agreement [Member] \| Maximum [Member]
Subsequent Event [Line Items]
Additional amount payable	$ 3.0
Aronora [Member] \| Royalty Purchase Agreement [Member] \| Bayer Licensed Products [Member]
Subsequent Event [Line Items]
Number of anti thrombotic candidates subject to option by bayer \| Number	1
Aronora [Member] \| Royalty Purchase Agreement [Member] \| Non Bayer Licensed Products [Member]
Subsequent Event [Line Items]
Number of aditional early clinical hematology candidates \| Number	2