Available credit line for letter of credit under the line of credit facilities.

No definition available.

Name:	ixys_AvailableCreditLineForLetterOfCredit
Namespace Prefix:	ixys_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt covenant the company must maintain to stay compliant per the agreement.

+ References

No definition available.

+ Details

Name:	ixys_LineOfCreditLeverageRatio
Namespace Prefix:	ixys_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the security deposit matures, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	ixys_SecurityDepositMaturityDate
Namespace Prefix:	ixys_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the credit facility first became available, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInitiationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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

- Definition

The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease.

+ References

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=ixys_April2015IkbDeutscheIndustriebankLoanPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=ixys_BankOfWestAmendedAndRestatedCreditAgreementDecember2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=ixys_BankOfWestAmendedAndRestatedCreditAgreementNovember202015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 8 - Borrowing Arrangements (Details Textual)		1 Months Ended		6 Months Ended	8 Months Ended	18 Months Ended
Note 8 - Borrowing Arrangements (Details Textual)	Nov. 20, 2015 USD ($)	Dec. 31, 2016	Apr. 30, 2015 USD ($)	Sep. 30, 2017 USD ($)	Nov. 30, 2016	Sep. 30, 2017 USD ($)	Sep. 30, 2017 EUR (€)	Sep. 30, 2017 EUR (€)	Mar. 31, 2017 USD ($)	Mar. 31, 2017 EUR (€)	Apr. 30, 2015 EUR (€)
April 2015 IKB Deutsche Industriebank Loan Payable [Member]
Debt Instrument, Face Amount			$ 7,200,000								€ 6,500,000
Debt Instrument, Interest Rate, Stated Percentage			1.75%								1.75%
Debt Instrument, Periodic Payment, Principal						$ 274,000	€ 232,000
Security Deposit \| €										€ 1,000,000
Long-term Debt, Gross				$ 4,900,000		$ 4,900,000		€ 4,200,000	$ 5,000,000	€ 4,600,000
Debt Instrument, Maturity Date			Mar. 31, 2022
Security Deposit, Maturity Date			Dec. 29, 2017
Bank of West Amended and Restated Credit Agreement December, 2016 [Member]
Line of Credit Facility, Expiration Date		Nov. 20, 2019
Bank of West Amended and Restated Credit Agreement December, 2016 [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility, Interest Rate at Period End				3.01%		3.01%		3.01%
Line of Credit, Leverage Ratio		2.5
Bank of West Amended and Restated Credit Agreement December, 2016 [Member] \| Minimum [Member] \| Revolving Credit Facility [Member]
Debt Instrument, Basis Spread on Variable Rate				0.75%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.25%
Bank of West Amended and Restated Credit Agreement December, 2016 [Member] \| Maximum [Member] \| Revolving Credit Facility [Member]
Debt Instrument, Basis Spread on Variable Rate				2.50%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.625%
Bank of West Amended and Restated Credit Agreement November 20, 2015 [Member]
Line of Credit Facility, Initiation Date	Nov. 20, 2015
Bank of West Amended and Restated Credit Agreement November 20, 2015 [Member] \| Revolving Credit Facility [Member]
Line of Credit, Leverage Ratio					2
Debt Issuance Costs, Net				$ 324,000		$ 324,000			399,000
Long-term Line of Credit				72,700,000		72,700,000			$ 72,600,000
Available Credit Line for Letter of Credit				$ 10,000,000		$ 10,000,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 125,000,000