Concentrations: (Details)	12 Months Ended
Sep. 30, 2015 USD ($) customer item	Sep. 30, 2014 USD ($) customer item	Sep. 30, 2013 USD ($) customer
Concentration of Credit Risk
Number of Banks \| item	2
Provision for loss on unbilled receivables	$ 1,237,841	$ 3,680,679
Net sales \| Major Customers
Concentrations
Number of major customers \| customer	5	5	5
Number of major annual customers \| customer	2	3	2
Concentration of risk (as a percent)	57.00%	59.00%	64.00%
Accounts receivable and unbilled receivables	$ 3,500,000	$ 7,900,000	$ 5,900,000
Net sales \| Major Customers \| Pilatus
Concentrations
Concentration of risk (as a percent)	20.00%	17.00%
Net sales \| Major Customers \| Eclipse
Concentrations
Concentration of risk (as a percent)	15.00%	14.00%	24.00%
Net sales \| Major Customers \| Fed Ex
Concentrations
Concentration of risk (as a percent)		12.00%
Net sales \| Major Customers \| AAI
Concentrations
Concentration of risk (as a percent)			14.00%
Net sales \| Major Customers \| Government contractors and Agencies
Concentrations
Concentration of risk (as a percent)	20.00%	39.00%	28.00%
Net sales \| Major Products \| Air data systems and components
Concentrations
Concentration of risk (as a percent)	2.00%	12.00%	12.00%
Net sales \| Major Products \| FPDS
Concentrations
Concentration of risk (as a percent)	98.00%	88.00%	88.00%
Inventory \| Supplier Concentration Risk
Concentrations
Concentration of risk (as a percent)	43.00%	15.00%
Number of major suppliers \| item	1	1
Delta
Concentration of Credit Risk
Provision for loss on unbilled receivables	$ 1,300,000	$ 3,700,000

No definition available.

Name:	issc_ConcentrationOfCreditRiskAbstract
Namespace Prefix:	issc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of banks for maintenance of cash balances.

+ References

No definition available.

+ Details

Name:	issc_NumberOfBanks
Namespace Prefix:	issc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of major customers of the entity on an annual basis.

+ References

No definition available.

+ Details

Name:	issc_NumberOfMajorAnnualCustomers
Namespace Prefix:	issc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of major customers of the entity.

+ References

No definition available.

+ Details

Name:	issc_NumberOfMajorCustomers
Namespace Prefix:	issc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of major suppliers of the entity.

+ References

No definition available.

+ Details

Name:	issc_NumberOfMajorSuppliers
Namespace Prefix:	issc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense related to write-down of unbilled receivables to the amount expected to be collected.

+ References

No definition available.

+ Details

Name:	issc_ProvisionForLossOnUnbilledReceivables
Namespace Prefix:	issc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ConcentrationRiskLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13537-108611

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3,4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 4
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 3
-Subparagraph a
-Article 5

+ Details

Name:	us-gaap_ReceivablesNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=issc_PilatusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=issc_EclipseAerospaceIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=issc_FedExCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=issc_AmericanAirlinesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=issc_GovernmentContractorsAndAgenciesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_ProductConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=issc_AirDataSystemsAndComponentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=issc_FlatPanelDisplaySystemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_SupplierConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=issc_DeltaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: