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

Capital Stock - Common Stock Warrants - Additional Information (Details)

Capital Stock - Common Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended
	May 07, 2018	May 31, 2018	Feb. 29, 2016	Feb. 28, 2015
Loan and Security Agreement [Member] \| Silicon Valley Bank [Member] \| Warrants for Common Stock [Member]
Class Of Warrant Or Right [Line Items]
Aggregate number of unregistered shares of common stock called by warrants (in shares)	6,332
Exercise price of warrants (in dollars per share)	$ 23.69
Exercisable period of warrants	10 years
Estimated fair value of warrants	$ 0.1
Five Year Warrants Issued in February 2016 [Member] \| Third-Party Consultant [Member]
Class Of Warrant Or Right [Line Items]
Aggregate number of unregistered shares of common stock called by warrants (in shares)			8,249
Exercise price of warrants (in dollars per share)			$ 15.40
Exercisable period of warrants			5 years
Warrants expiration period			2021-02
Estimated fair value of warrants			$ 0.1
Five Year Warrants Issued in February 2015 [Member] \| Hercules Loan [Member]
Class Of Warrant Or Right [Line Items]
Aggregate number of unregistered shares of common stock called by warrants (in shares)				9,063
Exercise price of warrants (in dollars per share)				$ 66.20
Exercisable period of warrants				5 years
Ten Year Warrants Issued in May 2018 [Member] \| Loan and Security Agreement [Member] \| Silicon Valley Bank [Member] \| Warrants for Common Stock [Member]
Class Of Warrant Or Right [Line Items]
Aggregate number of unregistered shares of common stock called by warrants (in shares)		6,332
Exercise price of warrants (in dollars per share)		$ 23.69
Exercisable period of warrants		10 years
Estimated fair value of warrants		$ 0.1