Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Significant Accounting Policies (Details)

v2.4.1.9
Basis of Presentation and Significant Accounting Policies (Details) (USD $)
 12 Months Ended 3 Months Ended
Dec. 31, 2014
Mar. 31, 2015
Customer
Mar. 31, 2014
Customer
Concentration Risk [Line Items]      
Debt issuance costs $ 200,000us-gaap_DebtIssuanceCosts    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Prepaid expenses and other current assets 1,859,000us-gaap_PrepaidExpenseAndOtherAssetsCurrent [1] 1,860,000us-gaap_PrepaidExpenseAndOtherAssetsCurrent  
Total current assets 83,613,000us-gaap_AssetsCurrent [1] 72,622,000us-gaap_AssetsCurrent  
Other assets 669,000us-gaap_OtherAssetsNoncurrent [1] 664,000us-gaap_OtherAssetsNoncurrent  
Total assets 89,402,000us-gaap_Assets [1] 78,069,000us-gaap_Assets  
Interest bearing obligations - current 19,018,000us-gaap_LongTermDebtCurrent [1] 15,605,000us-gaap_LongTermDebtCurrent  
Total current liabilities 36,246,000us-gaap_LiabilitiesCurrent [1] 26,427,000us-gaap_LiabilitiesCurrent  
Interest bearing obligations - long-term 16,290,000us-gaap_LongTermDebtNoncurrent [1] 31,584,000us-gaap_LongTermDebtNoncurrent  
Total liabilities 86,303,000us-gaap_Liabilities [1] 91,453,000us-gaap_Liabilities  
Prior to Adoption of ASU 2015-03 [Member]      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Prepaid expenses and other current assets 2,088,000us-gaap_PrepaidExpenseAndOtherAssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		1,996,000us-gaap_PrepaidExpenseAndOtherAssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Total current assets 83,842,000us-gaap_AssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		72,758,000us-gaap_AssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Other assets 669,000us-gaap_OtherAssetsNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		990,000us-gaap_OtherAssetsNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Total assets 89,631,000us-gaap_Assets
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		78,531,000us-gaap_Assets
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Interest bearing obligations - current 19,247,000us-gaap_LongTermDebtCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		15,741,000us-gaap_LongTermDebtCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Total current liabilities 36,475,000us-gaap_LiabilitiesCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		26,563,000us-gaap_LiabilitiesCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Interest bearing obligations - long-term 16,290,000us-gaap_LongTermDebtNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		31,910,000us-gaap_LongTermDebtNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
Total liabilities 86,532,000us-gaap_Liabilities
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		91,915,000us-gaap_Liabilities
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		 
ASU 2015-03 Adjustment [Member]      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Prepaid expenses and other current assets (229,000)us-gaap_PrepaidExpenseAndOtherAssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(136,000)us-gaap_PrepaidExpenseAndOtherAssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Total current assets (229,000)us-gaap_AssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(136,000)us-gaap_AssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Other assets 0us-gaap_OtherAssetsNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(326,000)us-gaap_OtherAssetsNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Total assets (229,000)us-gaap_Assets
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(462,000)us-gaap_Assets
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Interest bearing obligations - current (229,000)us-gaap_LongTermDebtCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(136,000)us-gaap_LongTermDebtCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Total current liabilities (229,000)us-gaap_LiabilitiesCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(136,000)us-gaap_LiabilitiesCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Interest bearing obligations - long-term 0us-gaap_LongTermDebtNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(326,000)us-gaap_LongTermDebtNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
Total liabilities (229,000)us-gaap_Liabilities
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		(462,000)us-gaap_Liabilities
/ us-gaap_StatementScenarioAxis
= us-gaap_NewAccountingPronouncementMember 		 
As Adopted [Member]      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Prepaid expenses and other current assets 1,859,000us-gaap_PrepaidExpenseAndOtherAssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		1,860,000us-gaap_PrepaidExpenseAndOtherAssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Total current assets 83,613,000us-gaap_AssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		72,622,000us-gaap_AssetsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Other assets 669,000us-gaap_OtherAssetsNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		664,000us-gaap_OtherAssetsNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Total assets 89,402,000us-gaap_Assets
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		78,069,000us-gaap_Assets
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Interest bearing obligations - current 19,018,000us-gaap_LongTermDebtCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		15,605,000us-gaap_LongTermDebtCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Total current liabilities 36,246,000us-gaap_LiabilitiesCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		26,427,000us-gaap_LiabilitiesCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Interest bearing obligations - long-term 16,290,000us-gaap_LongTermDebtNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		31,584,000us-gaap_LongTermDebtNoncurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Total liabilities $ 86,303,000us-gaap_Liabilities
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		91,453,000us-gaap_Liabilities
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		 
Customer Concentration Risk [Member]      
Concentration Risk [Line Items]      
Number of major customers   2xoma_NumberOfMajorCustomers
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember 		3xoma_NumberOfMajorCustomers
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
Revenues [Member] | Customer Concentration Risk [Member] | Customer 1 [Member]      
Concentration Risk [Line Items]      
Concentration risk, percentage (in hundredths)   72.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer1Member 		47.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer1Member
Revenues [Member] | Customer Concentration Risk [Member] | Customer 2 [Member]      
Concentration Risk [Line Items]      
Concentration risk, percentage (in hundredths)   26.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer2Member 		40.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer2Member
Revenues [Member] | Customer Concentration Risk [Member] | Customer 3 [Member]      
Concentration Risk [Line Items]      
Concentration risk, percentage (in hundredths)     13.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer3Member
Trade and Other Receivables [Member] | Customer Concentration Risk [Member] | Customer 1 [Member]      
Concentration Risk [Line Items]      
Concentration risk, percentage (in hundredths)   61.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= xoma_TradeAndOtherReceivablesMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer1Member 		57.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= xoma_TradeAndOtherReceivablesMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer1Member
Trade and Other Receivables [Member] | Customer Concentration Risk [Member] | Customer 2 [Member]      
Concentration Risk [Line Items]      
Concentration risk, percentage (in hundredths)   24.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= xoma_TradeAndOtherReceivablesMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer2Member 		28.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= xoma_TradeAndOtherReceivablesMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer2Member
Trade and Other Receivables [Member] | Customer Concentration Risk [Member] | Customer 3 [Member]      
Concentration Risk [Line Items]      
Concentration risk, percentage (in hundredths)     12.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= xoma_TradeAndOtherReceivablesMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= xoma_Customer3Member
[1] The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited consolidated financial statements as of that date included in the Company 's Annual Report on Form 10-K for the year ended December 31, 2014.