Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

Document and Entity Information
3 Months Ended
Mar. 31, 2014
May 05, 2014
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 Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   106,898,733
Document Fiscal Year Focus 2014  
Document Fiscal Period Focus Q1  
Document Type 10-Q  
Amendment Flag true  
Amendment Description We are filing this Amended Quarterly Report on Form 10-Q/A (the “Amended Filing”) to correct an error in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2014, which was filed with the Securities and Exchange Commission (“SEC”) on May 7, 2014 (the “Original Filing”), to amend and restate our diluted loss per share for the quarter ended March 31, 2014, as discussed below and in Note 2 to the accompanying restated condensed consolidated financial statements.  
Document Period End Date Mar. 31, 2014