XOMA Corporation Annual report pursuant to Section 13 and 15(d)

Capital Stock - Summary of Common Stock Warrants Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Class Of Warrant Or Right [Line Items]
Warrant outstanding (in shares)	23,644	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
Ten Year Warrants Issued in May 2018 [Member] \| Stockholders' Equity [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2018-05
Expiration Date	2028-05
Exercise price of warrants (in dollars per share)	$ 23.69
Warrant outstanding (in shares)	6,332