Quarterly report pursuant to Section 13 or 15(d)

Note 13 - Line of Credit (Details)

v2.4.1.9
Note 13 - Line of Credit (Details) (USD $)
0 Months Ended
Jun. 11, 2013
Dec. 27, 2014
Mar. 29, 2014
Note 13 - Line of Credit (Details) [Line Items]      
Line of Credit Facility, Collateral Fees, Percent of Outstanding Financed Receivables 0.10%giga_LineOfCreditFacilityCollateralFeesPercentOfOutstandingFinancedReceivables    
Line of Credit, Current   $ 1,622,000us-gaap_LinesOfCreditCurrent $ 1,165,000us-gaap_LinesOfCreditCurrent
Line of Credit Facility, Remaining Borrowing Capacity   0us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity 0us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
New Amended Credit Facility [Member] | Foreign Accounts Receivable [Member]      
Note 13 - Line of Credit (Details) [Line Items]      
Advance Rate 70.00%giga_AdvanceRate
/ us-gaap_BalanceSheetLocationAxis
= giga_ForeignAccountsReceivableMember
/ us-gaap_CreditFacilityAxis
= giga_NewAmendedCreditFacilityMember
   
New Amended Credit Facility [Member]      
Note 13 - Line of Credit (Details) [Line Items]      
Line of Credit Facility, Initiation Date Jun. 11, 2013    
Advance Rate 80.00%giga_AdvanceRate
/ us-gaap_CreditFacilityAxis
= giga_NewAmendedCreditFacilityMember
   
Line of Credit Facility, Maximum Borrowing Capacity 3,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= giga_NewAmendedCreditFacilityMember
   
Line of Credit Facility, Covenant Terms, Minimum Cash Balance 750,000giga_LineOfCreditFacilityCovenantTermsMinimumCashBalance
/ us-gaap_CreditFacilityAxis
= giga_NewAmendedCreditFacilityMember
   
Line of Credit, Current   $ 1,600,000us-gaap_LinesOfCreditCurrent
/ us-gaap_CreditFacilityAxis
= giga_NewAmendedCreditFacilityMember
$ 1,200,000us-gaap_LinesOfCreditCurrent
/ us-gaap_CreditFacilityAxis
= giga_NewAmendedCreditFacilityMember
Minimum [Member]      
Note 13 - Line of Credit (Details) [Line Items]      
Debt Instrument, Basis Spread on Variable Rate 2.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
   
Maximum [Member]      
Note 13 - Line of Credit (Details) [Line Items]      
Debt Instrument, Basis Spread on Variable Rate 6.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_RangeAxis
= us-gaap_MaximumMember