XOMA Corporation Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Income Taxes (Details)

Income Taxes (Details) (USD $)	3 Months Ended								12 Months Ended
Income Taxes (Details) (USD $)	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal income tax (benefit) provision									$ 0	$ (14,000)	$ (74,000)
Total	0us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	1,000us-gaap_IncomeTaxExpenseBenefit	(15,000)us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	(14,000)us-gaap_IncomeTaxExpenseBenefit	(74,000)us-gaap_IncomeTaxExpenseBenefit
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal tax at statutory rate (in hundredths)									34.00%	34.00%	34.00%
Warrant valuation (in hundredths)									40.00%	(17.00%)	(4.00%)
Permanent items and other (in hundredths)									(1.00%)	0.00%	(1.00%)
Valuation allowance (in hundredths)									(73.00%)	(17.00%)	(29.00%)
Total (in hundredths)									0.00%	0.00%	0.00%
Significant components of net deferred tax assets [Abstract]
Capitalized research and development expenses	50,900,000				49,400,000				50,900,000	49,400,000
Net operating loss carryforwards	105,000,000				78,400,000				105,000,000	78,400,000
Research and development and other credit carryforwards	12,100,000				8,800,000				12,100,000	8,800,000
Other	22,100,000us-gaap_DeferredTaxAssetsOther				23,500,000us-gaap_DeferredTaxAssetsOther				22,100,000us-gaap_DeferredTaxAssetsOther	23,500,000us-gaap_DeferredTaxAssetsOther
Total deferred tax assets	190,100,000us-gaap_DeferredTaxAssetsGross				160,100,000us-gaap_DeferredTaxAssetsGross				190,100,000us-gaap_DeferredTaxAssetsGross	160,100,000us-gaap_DeferredTaxAssetsGross
Valuation allowance	(190,100,000)				(160,100,000)				(190,100,000)	(160,100,000)
Net deferred tax assets	0us-gaap_DeferredTaxAssetsNet				0us-gaap_DeferredTaxAssetsNet				0us-gaap_DeferredTaxAssetsNet	0us-gaap_DeferredTaxAssetsNet
Increase (decrease) in the valuation allowance									30,000,000	(74,000,000)	(6,000,000)
Unrecognized Tax Benefits [Roll Forward]
Beginning Balance				4,274,000us-gaap_UnrecognizedTaxBenefits				4,104,000us-gaap_UnrecognizedTaxBenefits	4,274,000us-gaap_UnrecognizedTaxBenefits	4,104,000us-gaap_UnrecognizedTaxBenefits	0us-gaap_UnrecognizedTaxBenefits
Increase related to current year tax position									720,000	164,000	49,000
Increase related to prior year tax position									509,000	6,000	4,055,000
Ending Balance	5,503,000us-gaap_UnrecognizedTaxBenefits				4,274,000us-gaap_UnrecognizedTaxBenefits				5,503,000us-gaap_UnrecognizedTaxBenefits	4,274,000us-gaap_UnrecognizedTaxBenefits	4,104,000us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	4,000,000								4,000,000
Stock Option [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carry-forwards	5,200,000								5,200,000
State [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carry-forwards	132,300,000								132,300,000
California [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carry-forward expired									54,300,000	16,800,000	10,400,000
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carry-forwards	292,300,000								292,300,000
Net operating loss carry-forward expired									$ 0	$ 0	$ 0