Debt Instrument, Closing Fee Percentage

No definition available.

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Period Type:	duration

- Definition

Debt Instrument, Covenant, Fixed Charge Coverage Ratio

+ References

No definition available.

+ Details

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Namespace Prefix:	emkr_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Revolving Commitments, Excess Availability Term

+ References

No definition available.

+ Details

Name:	emkr_DebtInstrumentCovenantRevolvingCommitmentsExcessAvailabilityTerm
Namespace Prefix:	emkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument, Covenant, Revolving Commitments, Excess Availability Term Percentage

+ References

No definition available.

+ Details

Name:	emkr_DebtInstrumentCovenantRevolvingCommitmentsExcessAvailabilityTermPercentage
Namespace Prefix:	emkr_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Available Credit Facilities

+ References

No definition available.

+ Details

Name:	emkr_NumberOfAvailableCreditFacilities
Namespace Prefix:	emkr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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

- 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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
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

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

- Details

Name:	us-gaap_DebtInstrumentAxis=emkr_NewABLCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Credit Agreement - Narrative (Details)	Aug. 09, 2022 USD ($) creditFacility	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)
Line of Credit Facility [Line Items]
Standby letters of credit, total amount outstanding		$ 4,616,000	$ 5,042,000
New ABL Credit Agreement
Line of Credit Facility [Line Items]
Excess availability term	$ 5,000,000
Excess availability term, percentage	0.15
Fixed charge coverage ratio (not less than)	1.10
Secured Debt \| New ABL Credit Agreement
Line of Credit Facility [Line Items]
Principal amount	$ 6,000,000
Debt instrument, closing fee percentage	0.0150
Secured Debt \| New ABL Credit Agreement \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	5.50%
Revolving Credit Facility \| New ABL Credit Agreement
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 40,000,000
Debt instrument, closing fee percentage	0.010
Unused capacity fee percentage	0.50%
Long-term line of credit		5,500,000	9,600,000
Standby letters of credit, total amount outstanding		6,600,000	$ 5,900,000
Line of credit facility, remaining borrowing capacity		$ 13,600,000
Revolving Credit Facility \| New ABL Credit Agreement \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.75%
Revolving Credit Facility \| Secured Debt
Line of Credit Facility [Line Items]
Number of credit facilities \| creditFacility	2