Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.3.0.814
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2015
Nov. 02, 2015
Document And Entity Information [Abstract]    
Entity Registrant Name XOMA Corp  
Entity Central Index Key 0000791908  
Current Fiscal Year End Date --12-31  
Entity Well-known Seasoned Issuer No  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   118,814,763
Document Fiscal Year Focus 2015  
Document Fiscal Period Focus Q3  
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2015