Note 19 - Subsequent Events (Details Textual)	Apr. 23, 2020 USD ($)
Subsequent Event [Member]
Proceeds from Paycheck Protection Program Under CARES Act	$ 786,200

The cash inflow received from loan funding under the Paycheck Protection Program which was established under the Coronavirus Aid, Relief and Economic Security (CARES) Act in March 2020.

No definition available.

Name:	giga_ProceedsFromPaycheckProtectionProgramUnderCaresAct
Namespace Prefix:	giga_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration