XML 77 R57.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Long-Term Debt and Other Financings - Interest Expense and Amortization of Debt Issuance Costs (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Interest expense and amortization of debt issuance costs [Abstract] |  |  |
Interest expense | $ 1,238 | $ 3,946 | $ 3,765
Hercules Loan [Member] |  |  |
Interest expense and amortization of debt issuance costs [Abstract] |  |  |
Interest expense | 311 | 2,628 | 2,223
Servier Loan [Member] |  |  |
Interest expense and amortization of debt issuance costs [Abstract] |  |  |
Interest expense | 431 | 892 | 1,083
Novartis Note [Member] |  |  |
Interest expense and amortization of debt issuance costs [Abstract] |  |  |
Interest expense | 490 | 405 | 329
Other [Member] |  |  |
Interest expense and amortization of debt issuance costs [Abstract] |  |  |
Interest expense | $ 6 | $ 21 | $ 130

X
- References No definition available. + Details
Name: | us-gaap_InterestExpenseAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_InterestExpenseDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=xoma_HerculesLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=xoma_ServierLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=xoma_NovartisNoteMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=xoma_OtherFinancingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |