Business Acquisition, Additional Percentage Of Voting Interests Acquired

No definition available.

Name:	issi_BusinessAcquisitionAdditionalPercentageOfVotingInterestsAcquired
Namespace Prefix:	issi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionSharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the purchase of noncontrolling interest during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=issi_ChingisTechnologyCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Basis of Presentation Basis of Presentation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended		1 Months Ended	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	May 31, 2013	Sep. 30, 2014	Sep. 14, 2012	Mar. 12, 2015
Business Acquisition [Line Items]
Additional interest acquired	$ 0	$ 199
Chingis Technology Corporation
Business Acquisition [Line Items]
Percentage of interests acquired					94.10%
Percentage of additional voting interests acquired			4.80%	1.10%
Additional interest acquired			$ 1,600	$ 400
Percentage ownership of Chingis	100.00%
ISSI \| Summitview Capital
Business Acquisition [Line Items]
Acquisition price per share of outstanding shares						$ 19.25