Cash, cash equivalents and short-term and long-term investments.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of customers that are reflected in the stated concentration of risk.

+ References

No definition available.

+ Details

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Namespace Prefix:	gsit_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of principal operations of the entity that are located near geologic fault lines.

+ References

No definition available.

+ Details

Name:	gsit_NumberOfPrincipalOperationsNearFaultLines
Namespace Prefix:	gsit_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of subsidiaries owned by the entity.

+ References

No definition available.

+ Details

Name:	gsit_NumberOfSubsidiaries
Namespace Prefix:	gsit_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

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Balance Type:	debit
Period Type:	duration

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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-Subparagraph (a)
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-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportingUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=gsit_MajorCustomerOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

Name:	srt_MajorCustomersAxis=gsit_MajorCustomerFourMember
Namespace Prefix:
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Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
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1. THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2021 USD ($) subsidiary facility item customer	Mar. 31, 2020 USD ($) customer	Mar. 31, 2019 USD ($) customer
Basis of consolidation and risks and uncertainties
Number of subsidiaries \| subsidiary	4
Number of principal operations near fault lines \| facility	2
Cash, cash equivalents and short-term and long-term investments \| $	$ 59,700
Allowance for doubtful accounts receivable write offs \| $	$ 0	$ 0	$ 0
Number of reporting units \| item	1
Accounts receivable [Member]
Basis of consolidation and risks and uncertainties
Number of customers \| customer	4	3
Accounts receivable [Member] \| Customer One
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	36.00%	33.00%
Accounts receivable [Member] \| Customer Two
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	28.00%	20.00%
Accounts receivable [Member] \| Customer Three
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	15.00%	19.00%
Accounts receivable [Member] \| Customer Four
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	12.00%
Net revenue [Member]
Basis of consolidation and risks and uncertainties
Number of customers \| customer	4	4	4
Net revenue [Member] \| Customer One
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	30.00%	34.00%	31.00%
Net revenue [Member] \| Customer Two
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	22.00%	17.00%	22.00%
Net revenue [Member] \| Customer Three
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	21.00%	15.00%	18.00%
Net revenue [Member] \| Customer Four
Basis of consolidation and risks and uncertainties
Percentage attributable to customers	15.00%	15.00%	15.00%