XML 59 R37.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Contract Revenues [Abstract] |  |  |
Decrease in Previously Invoiced Balances from NIAID |  | $ 1,800,000 |
Research and Development Expense [Abstract] |  |  |
Adjustment to the Company's accrued estimates for clinical trial activities from inception of the trials |  | 200,000 |
Impairment loss recognized | $ 0 | $ 0 | $ 0
Unrecognized tax benefits, income tax penalties or interest charged | $ 0 |  |
Equipment [Member] | Minimum [Member] |  |  |
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |  |
Useful lives | 3 years |  |
Equipment [Member] | Maximum [Member] |  |  |
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |  |
Useful lives | 7 years |  |
Leasehold Improvements, Buildings and Building Improvements [Member] | Minimum [Member] |  |  |
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |  |
Useful lives | 1 year |  |
Leasehold Improvements, Buildings and Building Improvements [Member] | Maximum [Member] |  |  |
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |  |
Useful lives | 15 years |  |

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 958 -SubTopic 225 -Section 45 -Paragraph 11 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51659069&loc=d3e92212-112881 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Impairment -URI http://asc.fasb.org/extlink&oid=6515133 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2921-110230 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=51824106&loc=d3e2420-110228 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Basis of presentation and significant accounting policies. + References No definition available. + Details
Name: | xoma_BasisOfPresentationAndSignificantAccountingPoliciesLineItems
Namespace Prefix: | xoma_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of changes in accounting estimate related to adjustment accrual during the period. + References No definition available. + Details
Name: | xoma_ChangesInAccountingEstimateRelatedToAdjustmentAccrual
Namespace Prefix: | xoma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition Refers to the decrease in previously invoiced balances from NIAID. + References No definition available. + Details
Name: | xoma_DecreaseInPreviouslyInvoicedBalancesFromNIAID
Namespace Prefix: | xoma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_EquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |