XML 67 R53.htm IDEA: XBRL DOCUMENT
v3.22.1

Summary of Significant Unobservable Inputs Used in Fair Value Measurements Categorized Within Level 3 of Fair Value Hierarchy (Detail) - Level 3 - Option Pricing Method | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Discount for Lack of Marketability (“DLOM”) |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Sensitivity of the input to fair value | 1% increase or decrease in DLOM would result in a variation in the debt investment’s fair value by approximately $93 thousand and in the equity investment’s fair value by approximately $26 thousand. | 1% increase or decrease in DLOM would result in a variation in the debt investment’s fair value by approximately $120 thousand.
Volatility |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Sensitivity of the input to fair value | 1% increase or decrease in volatility would result in a variation in the debt investment's fair value by approximately $9 thousand and in the equity investment's fair value by approximately $13 thousand. | 1% increase or decrease in volatility would result in a variation in the debt investment’s fair value by less than $30 thousand.
Rate for Debt Investment |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Volatility | 36.0 | 41.0
Rate for Debt Investment | Minimum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Discount for lack of marketability (“DLOM”) | 9.0 | 13.50
Rate for Debt Investment | Maximum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Discount for lack of marketability (“DLOM”) | 18.0 | 26.00
Rate for Equity Investment |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Volatility | 36.0 |
Rate for Equity Investment | Minimum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Discount for lack of marketability (“DLOM”) | 11.0 |
Rate for Equity Investment | Maximum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Discount for lack of marketability (“DLOM”) | 18.0 |

X
- Definition Discount for lack of marketability measurement input. + References No definition available. + Details
Name: | gigm_DiscountForLackOfMarketabilityMeasurementInput
Namespace Prefix: | gigm_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Sensitivity of the input to fair value. + References No definition available. + Details
Name: | gigm_SensitivityOfInputToFairValue
Namespace Prefix: | gigm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Volatility measurement input. + References No definition available. + Details
Name: | gigm_VolatilityMeasurementInput
Namespace Prefix: | gigm_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- 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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueOptionPricingModelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputOptionVolatilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=gigm_RateForDebtInvestmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=gigm_RateForEquityInvestmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |