XOMA Corporation Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Servier Loan Agreement - Additional Information (Details)

Long-Term Debt - Servier Loan Agreement - Additional Information (Details)			1 Months Ended			3 Months Ended		6 Months Ended		9 Months Ended
	Aug. 25, 2017 USD ($) € / $	Jan. 09, 2015 USD ($) Tranche	Jan. 31, 2017 USD ($)	Jan. 31, 2016 EUR (€)	Jan. 31, 2011 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Jan. 31, 2018	Jul. 31, 2017	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 EUR (€)	Jan. 31, 2017 EUR (€)	Dec. 31, 2016 USD ($) € / $	Jan. 09, 2015 EUR (€) Tranche
Debt Instrument [Line Items]
Accrued interest paid										$ 518,000	$ 1,724,000
Carrying value of the loan						$ 14,300,000				14,300,000
Loss on extinguishment of debt						135,000				$ 650,000
Servier Loan [Member]
Debt Instrument [Line Items]
Date of agreement										Dec. 30, 2010
Maximum borrowing capacity under loan agreement \| €												€ 15,000,000
Proceeds from loan					$ 19,500,000
Date of loan amendment										Jan. 09, 2015
Date of agreement, after amendment										Aug. 12, 2013
Number of tranches \| Tranche		3													3
Principal payment amount \| €				€ 3,000,000
Accrued interest paid \| €				€ 200,000
Unamortized discount on debt		$ 1,900,000			$ 8,900,000
Amortization of debt discount						200,000	$ 200,000			$ 400,000	500,000
Carrying value of the loan														$ 12,200,000
Unrealized foreign exchange gains (loss) related to re-measurement of loan discount						4,000	6,000			25,000	26,000
Outstanding principal balance														$ 12,600,000
Euro to US Dollar exchange rates \| € / $	1.1932													1.052
Unrealized foreign exchange gains (losses) related to re-measurement of loan						(600,000)	$ (100,000)			(1,700,000)	$ (400,000)
Payment of debt through cash by NIBR	$ 14,300,000
Loss on extinguishment of debt						$ 100,000				$ 100,000
Servier Loan [Member] \| Tranche One [Member]
Debt Instrument [Line Items]
Maturity date		Jan. 15, 2016
Principal payment amount \| €															€ 3,000,000
Servier Loan [Member] \| Tranche Two [Member]
Debt Instrument [Line Items]
Maturity date		Jan. 15, 2017
Principal payment amount \| €															5,000,000
Servier Loan [Member] \| Tranche Three [Member]
Debt Instrument [Line Items]
Maturity date		Jan. 15, 2018
Principal payment amount \| €															€ 7,000,000
Servier Loan [Member] \| Mid-January 2017 Through Mid-July 2017 [Member]
Debt Instrument [Line Items]
Period of interest resetting									6 months
Interest rate during period									1.77%
Servier Loan [Member] \| Amendment No.3 [Member] \| Tranche Two [Member]
Debt Instrument [Line Items]
Maturity date			Jul. 15, 2017
Principal payment amount \| €													€ 5,000,000
Unamortized discount on debt			$ 400,000
Servier Loan [Member] \| Forecast [Member] \| Mid-July 2017 Through Mid-January 2018 [Member]
Debt Instrument [Line Items]
Period of interest resetting								6 months
Interest rate during period								1.73%