Quarterly report pursuant to Section 13 or 15(d)

Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details)

v2.4.1.9
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) (USD $)
9 Months Ended 0 Months Ended 9 Months Ended 0 Months Ended
Dec. 28, 2013
Nov. 10, 2011
Dec. 27, 2014
Feb. 19, 2013
Jul. 08, 2013
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Preferred Stock, Shares Issued (in Shares)     18,533.51us-gaap_PreferredStockSharesIssued    
Proceeds from Issuance of Preferred Stock and Preference Stock $ 817,000us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock        
Series B Preferred Stock [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Proceeds from Issuance of Preferred Stock, Preference Stock, and Warrants   2,199,000us-gaap_ProceedsFromIssuanceOfPreferredStockPreferenceStockAndWarrants
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesBPreferredStockMember
     
Preferred Stock, Shares Issued (in Shares)   9,997us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesBPreferredStockMember
9,997.00us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesBPreferredStockMember
   
Sale of Stock, Price Per Share (in Dollars per share)   $ 220us-gaap_SaleOfStockPricePerShare
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesBPreferredStockMember
     
Preferred Stock, Value, Issued     2,000,000us-gaap_PreferredStockValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesBPreferredStockMember
   
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs     202,000us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesBPreferredStockMember
   
Series C Preferred Stock [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Preferred Stock, Shares Issued (in Shares)     3,424.65us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesCPreferredStockMember
3,424.65us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesCPreferredStockMember
 
Sale of Stock, Price Per Share (in Dollars per share)       $ 146.00us-gaap_SaleOfStockPricePerShare
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesCPreferredStockMember
 
Preferred Stock, Value, Issued     457,000us-gaap_PreferredStockValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesCPreferredStockMember
   
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs     43,000us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesCPreferredStockMember
   
Proceeds from Issuance of Preferred Stock and Preference Stock       500,000us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesCPreferredStockMember
 
Series D Preferred Stock [Member] | SPA [Member] | Unallocated [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Proceeds from Issuance of Convertible Preferred Stock         817,000us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
/ us-gaap_StatementScenarioAxis
= giga_UnallocatedMember
/ us-gaap_TransactionTypeAxis
= giga_SPAMember
Series D Preferred Stock [Member] | SPA [Member] | Allocated [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Proceeds from Issuance of Convertible Preferred Stock         498,000us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
/ us-gaap_StatementScenarioAxis
= giga_AllocatedMember
/ us-gaap_TransactionTypeAxis
= giga_SPAMember
Proceeds from Issuance of Common Stock         360,000us-gaap_ProceedsFromIssuanceOfCommonStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
/ us-gaap_StatementScenarioAxis
= giga_AllocatedMember
/ us-gaap_TransactionTypeAxis
= giga_SPAMember
Debt Instrument, Convertible, Conversion Price (in Dollars per share)         $ 0.97us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
/ us-gaap_StatementScenarioAxis
= giga_AllocatedMember
/ us-gaap_TransactionTypeAxis
= giga_SPAMember
Series D Preferred Stock [Member] | SPA [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Debt Issuance Cost         41,000us-gaap_DebtIssuanceCosts
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
/ us-gaap_TransactionTypeAxis
= giga_SPAMember
Series D Preferred Stock [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Preferred Stock, Shares Issued (in Shares)     5,111.86us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
  5,111.86us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
Proceeds from Issuance of Convertible Preferred Stock         858,000us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
Debt Instrument, Convertible, Beneficial Conversion Feature         $ 238,000us-gaap_DebtInstrumentConvertibleBeneficialConversionFeature
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesDPreferredStockMember
New Warrant [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in Shares)         511,186us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_ClassOfWarrantOrRightAxis
= giga_NewWarrantMember
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)         $ 1.43us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_ClassOfWarrantOrRightAxis
= giga_NewWarrantMember
Alara Capital AVI II, LLC [Member]          
Note 15 - Series B, C, D Convertible Voting Perpetual Preferred Stock and Warrants (Details) [Line Items]          
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in Shares)     1,017,405us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis
= giga_AlaraCapitalAVIIILLCMember
   
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)     $ 1.43us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis
= giga_AlaraCapitalAVIIILLCMember