Note 15 - Commitments and Contingencies - Future Lease Payments (Details) $ in Thousands	Mar. 28, 2020 USD ($)
Operating leases, 2021	$ 488
Finance leases, 2021	11
Total, 2021	499
Operating leases, 2022	503
Finance leases, 2022	20
Total, 2022	523
Operating leases, 2023	515
Finance leases, 2023
Total, 2023	515
Operating leases, 2024	209
Finance leases, 2024
Total, 2024	209
Operating leases, thereafter
Finance leases, thereafter
Total, thereafter
Total future minimum lease payments, operating leases	1,715
Total future minimum lease payments, finance leases	31
Total future minimum lease payments	1,746
Less: imputed interest, operating leases	(174)
Less: imputed interest, finance leases	(11)
Less: imputed interest, total	(185)
Operating leases, present value of lease liabilities	1,541
Finance leases, present value of lease liabilities	20
Total present value of lease liabilities	$ 1,561

Amount of lessee's undiscounted obligation for lease payments for finance and operating lease.

No definition available.

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance and operating lease, due after fourth fiscal year following latest fiscal year.

+ References

No definition available.

+ Details

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Amount of lessee's undiscounted obligation for lease payments for finance and operating lease, due in fourth fiscal year following latest fiscal year.

+ References

No definition available.

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Amount of lessee's undiscounted obligation for lease payments for finance and operating lease, due in next fiscal year following latest fiscal year ended.

+ References

No definition available.

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance and operating lease, due in third fiscal year following latest fiscal year.

+ References

No definition available.

+ Details

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Balance Type:	credit
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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance and operating lease, due in remainder of fiscal year following latest fiscal year ended.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance and operating lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	giga_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease, due after fourth fiscal year following latest fiscal year.

+ References

No definition available.

+ Details

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Namespace Prefix:	giga_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from finance and operating lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	giga_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payments for operating lease, due after year four.

+ References

No definition available.

+ Details

Name:	giga_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour
Namespace Prefix:	giga_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease.

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease.

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Namespace Prefix:	us-gaap_
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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

+ References

+ Details

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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

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