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Lease Arrangements - Summary of Right of Use Assets (Detail) $ in Thousands | Dec. 31, 2019 USD ($)
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Recognition of Right-of-Use Assets |
Lessee Lease Description [Line Items] |
Cost | $ 1,056
Net | 1,056
Recognition of Impairment |
Lessee Lease Description [Line Items] |
Cost | (1,056)
Net | $ (1,056)

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- Definition Right of use assets cost. + References No definition available. + Details
Name: | gigm_RightOfUseAssetsCost
Namespace Prefix: | gigm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Right of use assets net. + References No definition available. + Details
Name: | gigm_RightOfUseAssetsNet
Namespace Prefix: | gigm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LesseeLeaseDescriptionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis=gigm_RecognitionOfRightOfUseAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis=gigm_RecognitionOfImpairmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |