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

Common Stock Warrants - Summary of Common Stock Warrants Outstanding (Details) - $ / shares	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Class Of Warrant Or Right [Line Items]
Warrant outstanding (in shares)	17,312	17,312
Five Year Warrants Issued in February 2015 [Member] \| Stockholders' Equity [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2015-02
Expiration Date	2020-02
Exercise price of warrants (in dollars per share)	$ 66.20
Warrant outstanding (in shares)	9,063	9,063
Five Year Warrants Issued in February 2016 [Member] \| Stockholders' Equity [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2016-02
Expiration Date	2021-02
Exercise price of warrants (in dollars per share)	$ 15.40
Warrant outstanding (in shares)	8,249	8,249