Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
Jun. 25, 2011	Jun. 26, 2010
Net (loss) income	$ (467,000)	$ 13,625,000
Depreciation and amortization	34,000	36,000
Deferred income taxes	(207,000)	(13,569,000)
Share based compensation	54,000	76,000
Change in deferred rent	(8,000)	143,000
Changes in operating assets and liabilities	2,839,000	(96,000)
Net cash provided by operating activities	2,245,000	215,000
Purchases of property and equipment	(36,000)	(76,000)
Net cash used in investing activities	(36,000)	(76,000)
Proceeds from exercise of stock options	4,000	39,000
Principal payments on capital leases	(29,000)	(17,000)
Net cash (used in) provided by financing activities	(25,000)	22,000
Increase in cash and cash-equivalents	2,184,000	161,000
Beginning cash and cash-equivalents	1,408,000	3,074,000
Ending cash and cash-equivalents	3,592,000	3,235,000
Supplementary disclosure of cash flow information:
Cash paid for income taxes	40,000	2,000
Cash paid for interest		$ 1

Name:	giga_SupplementaryDisclosureOfCashFlowInformationAbstract
Namespace Prefix:	giga
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents. Includes cash and cash equivalents associated with the entity's continuing operations. Excludes cash and cash equivalents associated with the disposal group (and discontinued operation).