Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v3.20.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2019
Mar. 05, 2020
Jun. 30, 2019
Document And Entity Information [Abstract]      
Document Type 10-K    
Document Period End Date Dec. 31, 2019    
Entity Registrant Name XOMA Corp    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 93,973,763
Entity Common Stock, Shares Outstanding   9,761,901  
Entity Central Index Key 0000791908    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Amendment Flag false