Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2020
Mar. 05, 2021
Jun. 30, 2020
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2020    
Document Transition Report false    
Entity File Number 0-14710    
Entity Registrant Name XOMA CORPORATION    
Entity Incorporation State Country Code DE    
Entity Tax Identification Number 52-2154066    
Entity Address Address Line1 2200 Powell Street    
Entity Address Address Line2 Suite 310    
Entity Address City Or Town Emeryville    
Entity Address State Or Province CA    
Entity Address Postal Zip Code 94608    
City Area Code 510    
Local Phone Number 204-7200    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Public Float     $ 136,774,906
Entity Common Stock, Shares Outstanding   11,240,057  
Entity Central Index Key 0000791908    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Amendment Flag false    
Common Stock      
Security12b Title Common Stock    
Trading Symbol XOMA    
Security Exchange Name NASDAQ    
8.625% Series A Cumulative, Perpetual Preferred Stock      
Security12b Title 8.625% Series A Cumulative, Perpetual Preferred Stock    
Trading Symbol XOMAP    
Security Exchange Name NASDAQ