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

Common Stock Warrants - Summary of Common Stock Warrants Outstanding (Details) - $ / shares	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Class Of Warrant Or Right [Line Items]
Warrant outstanding (in shares)	28,489	23,644
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
Five 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	6,332
Five Year Warrants Issued in March 2019 [Member] \| Stockholders' Equity [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2019-03
Expiration Date	2029-03
Exercise price of warrants (in dollars per share)	$ 14.71
Warrant outstanding (in shares)	4,845