3.20.2 html 227 493 1 false 77 0 false 14 false false R1.htm 00090 - Document - Document and Entity Information Sheet http://www.emcore.com/role/DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 00100 - Statement - Consolidated Statements of Operations and Comprehensive Loss Sheet http://www.emcore.com/role/StatementConsolidatedStatementsOfOperationsAndComprehensiveLoss Consolidated Statements of Operations and Comprehensive Loss Statements 2 false false R3.htm 00200 - Statement - Consolidated Balance Sheets Sheet http://www.emcore.com/role/StatementConsolidatedBalanceSheets Consolidated Balance Sheets Statements 3 false false R4.htm 00205 - Statement - Consolidated Balance Sheets (Parenthetical) Sheet http://www.emcore.com/role/StatementConsolidatedBalanceSheetsParenthetical Consolidated Balance Sheets (Parenthetical) Statements 4 false false R5.htm 00300 - Statement - Consolidated Statements of Shareholders' Equity Sheet http://www.emcore.com/role/StatementConsolidatedStatementsOfShareholdersEquity Consolidated Statements of Shareholders' Equity Statements 5 false false R6.htm 00400 - Statement - Consolidated Statements of Cash Flows Sheet http://www.emcore.com/role/StatementConsolidatedStatementsOfCashFlows Consolidated Statements of Cash Flows Statements 6 false false R7.htm 10101 - Disclosure - Description of Business Sheet http://www.emcore.com/role/DisclosureDescriptionOfBusiness Description of Business Notes 7 false false R8.htm 10201 - Disclosure - Summary of Significant Accounting Policies Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 8 false false R9.htm 10301 - Disclosure - Recent Accounting Pronouncements Sheet http://www.emcore.com/role/DisclosureRecentAccountingPronouncements Recent Accounting Pronouncements Notes 9 false false R10.htm 10401 - Disclosure - Acquisition Sheet http://www.emcore.com/role/DisclosureAcquisition Acquisition Notes 10 false false R11.htm 10501 - Disclosure - Cash, Cash Equivalents and Restricted Cash Sheet http://www.emcore.com/role/DisclosureCashCashEquivalentsAndRestrictedCash Cash, Cash Equivalents and Restricted Cash Notes 11 false false R12.htm 10601 - Disclosure - Fair Value Accounting Sheet http://www.emcore.com/role/DisclosureFairValueAccounting Fair Value Accounting Notes 12 false false R13.htm 10701 - Disclosure - Accounts Receivable Sheet http://www.emcore.com/role/DisclosureAccountsReceivable Accounts Receivable Notes 13 false false R14.htm 10801 - Disclosure - Inventory Sheet http://www.emcore.com/role/DisclosureInventory Inventory Notes 14 false false R15.htm 10901 - Disclosure - Property, Plant, and Equipment, net Sheet http://www.emcore.com/role/DisclosurePropertyPlantAndEquipmentNet Property, Plant, and Equipment, net Notes 15 false false R16.htm 11001 - Disclosure - Accrued Expenses and Other Current Liabilities Sheet http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilities Accrued Expenses and Other Current Liabilities Notes 16 false false R17.htm 11101 - Disclosure - Credit Facilities and Debt Sheet http://www.emcore.com/role/DisclosureCreditFacilitiesAndDebt Credit Facilities and Debt Notes 17 false false R18.htm 11201 - Disclosure - Income and Other Taxes Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxes Income and Other Taxes Notes 18 false false R19.htm 11301 - Disclosure - Commitments and Contingencies Sheet http://www.emcore.com/role/DisclosureCommitmentsAndContingencies Commitments and Contingencies Notes 19 false false R20.htm 11401 - Disclosure - Equity Sheet http://www.emcore.com/role/DisclosureEquity Equity Notes 20 false false R21.htm 11501 - Disclosure - Segment Data and Related Information Sheet http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformation Segment Data and Related Information Notes 21 false false R22.htm 11601 - Disclosure - Selected Quarterly Financial Information (unaudited) Sheet http://www.emcore.com/role/DisclosureSelectedQuarterlyFinancialInformationUnaudited Selected Quarterly Financial Information (unaudited) Notes 22 false false R23.htm 11701 - Disclosure - Subsequent Event Sheet http://www.emcore.com/role/DisclosureSubsequentEvent Subsequent Event Notes 23 false false R24.htm 20202 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPolicies 24 false false R25.htm 30203 - Disclosure - Summary of Significant Accounting Policies (Tables) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables Summary of Significant Accounting Policies (Tables) Tables http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPolicies 25 false false R26.htm 30403 - Disclosure - Acquisition (Tables) Sheet http://www.emcore.com/role/DisclosureAcquisitionTables Acquisition (Tables) Tables http://www.emcore.com/role/DisclosureAcquisition 26 false false R27.htm 30503 - Disclosure - Cash, Cash Equivalents and Restricted Cash (Tables) Sheet http://www.emcore.com/role/DisclosureCashCashEquivalentsAndRestrictedCashTables Cash, Cash Equivalents and Restricted Cash (Tables) Tables http://www.emcore.com/role/DisclosureCashCashEquivalentsAndRestrictedCash 27 false false R28.htm 30703 - Disclosure - Accounts Receivable (Tables) Sheet http://www.emcore.com/role/DisclosureAccountsReceivableTables Accounts Receivable (Tables) Tables http://www.emcore.com/role/DisclosureAccountsReceivable 28 false false R29.htm 30803 - Disclosure - Inventory (Tables) Sheet http://www.emcore.com/role/DisclosureInventoryTables Inventory (Tables) Tables http://www.emcore.com/role/DisclosureInventory 29 false false R30.htm 30903 - Disclosure - Property, Plant, and Equipment, net (Tables) Sheet http://www.emcore.com/role/DisclosurePropertyPlantAndEquipmentNetTables Property, Plant, and Equipment, net (Tables) Tables http://www.emcore.com/role/DisclosurePropertyPlantAndEquipmentNet 30 false false R31.htm 31003 - Disclosure - Accrued Expenses and Other Current Liabilities (Tables) Sheet http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables Accrued Expenses and Other Current Liabilities (Tables) Tables http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilities 31 false false R32.htm 31203 - Disclosure - Income and Other Taxes (Tables) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables Income and Other Taxes (Tables) Tables http://www.emcore.com/role/DisclosureIncomeAndOtherTaxes 32 false false R33.htm 31303 - Disclosure - Commitments and Contingencies (Tables) Sheet http://www.emcore.com/role/DisclosureCommitmentsAndContingenciesTables Commitments and Contingencies (Tables) Tables http://www.emcore.com/role/DisclosureCommitmentsAndContingencies 33 false false R34.htm 31403 - Disclosure - Equity (Tables) Sheet http://www.emcore.com/role/DisclosureEquityTables Equity (Tables) Tables http://www.emcore.com/role/DisclosureEquity 34 false false R35.htm 31503 - Disclosure - Segment Data and Related Information (Tables) Sheet http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationTables Segment Data and Related Information (Tables) Tables http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformation 35 false false R36.htm 31603 - Disclosure - Selected Quarterly Financial Information (unaudited) (Tables) Sheet http://www.emcore.com/role/DisclosureSelectedQuarterlyFinancialInformationUnauditedTables Selected Quarterly Financial Information (unaudited) (Tables) Tables http://www.emcore.com/role/DisclosureSelectedQuarterlyFinancialInformationUnaudited 36 false false R37.htm 40101 - Disclosure - Description of Business (Business Overview) (Details) Sheet http://www.emcore.com/role/DisclosureDescriptionOfBusinessBusinessOverviewDetails Description of Business (Business Overview) (Details) Details http://www.emcore.com/role/DisclosureDescriptionOfBusiness 37 false false R38.htm 40201 - Disclosure - Summary of Significant Accounting Policies (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesNarrativeDetails Summary of Significant Accounting Policies (Narrative) (Details) Details http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables 38 false false R39.htm 40202 - Disclosure - Summary of Significant Accounting Policies (Property, Plant, and Equipment) (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPropertyPlantAndEquipmentDetails Summary of Significant Accounting Policies (Property, Plant, and Equipment) (Details) Details http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables 39 false false R40.htm 40203 - Disclosure - Summary of Significant Accounting Policies (Performance obligations) (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPerformanceObligationsDetails Summary of Significant Accounting Policies (Performance obligations) (Details) Details http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables 40 false false R41.htm 40204 - Disclosure - Summary of Significant Accounting Policies (Revenue by Product) (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesRevenueByProductDetails Summary of Significant Accounting Policies (Revenue by Product) (Details) Details http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables 41 false false R42.htm 40205 - Disclosure - Summary of Significant Accounting Policies - Adoption of ASC 842 (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesAdoptionOfAsc842Details Summary of Significant Accounting Policies - Adoption of ASC 842 (Details) Details 42 false false R43.htm 40206 - Disclosure - Summary of Significant Accounting Policies - Supplemental cash information (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesSupplementalCashInformationDetails Summary of Significant Accounting Policies - Supplemental cash information (Details) Details 43 false false R44.htm 40207 - Disclosure - Summary of Significant Accounting Policies (Leases) (Details) Sheet http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesLeasesDetails Summary of Significant Accounting Policies (Leases) (Details) Details http://www.emcore.com/role/DisclosureSummaryOfSignificantAccountingPoliciesTables 44 false false R45.htm 40401 - Disclosure - Acquisition (Details) Sheet http://www.emcore.com/role/DisclosureAcquisitionDetails Acquisition (Details) Details http://www.emcore.com/role/DisclosureAcquisitionTables 45 false false R46.htm 40402 - Disclosure - Acquisition - Assets Acquired and Liabilities Assumed (Details) Sheet http://www.emcore.com/role/DisclosureAcquisitionAssetsAcquiredAndLiabilitiesAssumedDetails Acquisition - Assets Acquired and Liabilities Assumed (Details) Details 46 false false R47.htm 40403 - Disclosure - Acquisition - Pro Forma Information (Details) Sheet http://www.emcore.com/role/DisclosureAcquisitionProFormaInformationDetails Acquisition - Pro Forma Information (Details) Details 47 false false R48.htm 40501 - Disclosure - Cash, Cash Equivalents and Restricted Cash (Details) Sheet http://www.emcore.com/role/DisclosureCashCashEquivalentsAndRestrictedCashDetails Cash, Cash Equivalents and Restricted Cash (Details) Details http://www.emcore.com/role/DisclosureCashCashEquivalentsAndRestrictedCashTables 48 false false R49.htm 40701 - Disclosure - Accounts Receivable (Schedule of Components of Accounts Receivable) (Details) Sheet http://www.emcore.com/role/DisclosureAccountsReceivableScheduleOfComponentsOfAccountsReceivableDetails Accounts Receivable (Schedule of Components of Accounts Receivable) (Details) Details http://www.emcore.com/role/DisclosureAccountsReceivableTables 49 false false R50.htm 40702 - Disclosure - Accounts Receivable (Allowance for Doubtful Accounts Rollforward) (Details) Sheet http://www.emcore.com/role/DisclosureAccountsReceivableAllowanceForDoubtfulAccountsRollforwardDetails Accounts Receivable (Allowance for Doubtful Accounts Rollforward) (Details) Details http://www.emcore.com/role/DisclosureAccountsReceivableTables 50 false false R51.htm 40801 - Disclosure - Inventory (Schedule of Components of Inventory) (Details) Sheet http://www.emcore.com/role/DisclosureInventoryScheduleOfComponentsOfInventoryDetails Inventory (Schedule of Components of Inventory) (Details) Details http://www.emcore.com/role/DisclosureInventoryTables 51 false false R52.htm 40901 - Disclosure - Property, Plant, and Equipment, net (Schedule of Property, Plant, and Equipment) (Details) Sheet http://www.emcore.com/role/DisclosurePropertyPlantAndEquipmentNetScheduleOfPropertyPlantAndEquipmentDetails Property, Plant, and Equipment, net (Schedule of Property, Plant, and Equipment) (Details) Details http://www.emcore.com/role/DisclosurePropertyPlantAndEquipmentNetTables 52 false false R53.htm 40902 - Disclosure - Property plant and equipment - Narrative (Details) Sheet http://www.emcore.com/role/DisclosurePropertyPlantAndEquipmentNarrativeDetails Property plant and equipment - Narrative (Details) Details 53 false false R54.htm 41001 - Disclosure - Accrued Expenses and Other Current Liabilities (Schedule of Accrued Liabilities) (Details) Sheet http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedLiabilitiesDetails Accrued Expenses and Other Current Liabilities (Schedule of Accrued Liabilities) (Details) Details http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables 54 false false R55.htm 41002 - Disclosure - Accrued Expenses and Other Current Liabilities (Schedule of Product Warranty Accruals) (Details) Sheet http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfProductWarrantyAccrualsDetails Accrued Expenses and Other Current Liabilities (Schedule of Product Warranty Accruals) (Details) Details http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables 55 false false R56.htm 41003 - Disclosure - Accrued Expenses and Other Current Liabilities (Severance and Restructuring Accruals) (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesSeveranceAndRestructuringAccrualsNarrativeDetails Accrued Expenses and Other Current Liabilities (Severance and Restructuring Accruals) (Narrative) (Details) Details http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables 56 false false R57.htm 41004 - Disclosure - Accrued Expenses and Other Current Liabilities (Schedule of Restructuring and Related Costs) (Details) Sheet http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfRestructuringAndRelatedCostsDetails Accrued Expenses and Other Current Liabilities (Schedule of Restructuring and Related Costs) (Details) Details http://www.emcore.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables 57 false false R58.htm 41101 - Disclosure - Credit Facilities and Debt (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureCreditFacilitiesAndDebtNarrativeDetails Credit Facilities and Debt (Narrative) (Details) Details http://www.emcore.com/role/DisclosureCreditFacilitiesAndDebt 58 false false R59.htm 41201 - Disclosure - Income and Other Taxes (Continuing Operations before Income Taxes) (Details) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesContinuingOperationsBeforeIncomeTaxesDetails Income and Other Taxes (Continuing Operations before Income Taxes) (Details) Details http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables 59 false false R60.htm 41202 - Disclosure - Income and Other Taxes (Income Tax (Benefit) Expense) (Details) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesIncomeTaxBenefitExpenseDetails Income and Other Taxes (Income Tax (Benefit) Expense) (Details) Details http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables 60 false false R61.htm 41203 - Disclosure - Income and Other Taxes (Provision for Income Taxes) (Details) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesProvisionForIncomeTaxesDetails Income and Other Taxes (Provision for Income Taxes) (Details) Details http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables 61 false false R62.htm 41204 - Disclosure - Income and Other Taxes (Deferred Tax Assets) (Details) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesDeferredTaxAssetsDetails Income and Other Taxes (Deferred Tax Assets) (Details) Details http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables 62 false false R63.htm 41205 - Disclosure - Income and Other Taxes (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesNarrativeDetails Income and Other Taxes (Narrative) (Details) Details http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables 63 false false R64.htm 41206 - Disclosure - Income and Other Taxes (Unrecognized Gross Tax Benefit) (Details) Sheet http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesUnrecognizedGrossTaxBenefitDetails Income and Other Taxes (Unrecognized Gross Tax Benefit) (Details) Details http://www.emcore.com/role/DisclosureIncomeAndOtherTaxesTables 64 false false R65.htm 41301 - Disclosure - Commitments and Contingencies (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureCommitmentsAndContingenciesNarrativeDetails Commitments and Contingencies (Narrative) (Details) Details http://www.emcore.com/role/DisclosureCommitmentsAndContingenciesTables 65 false false R66.htm 41302 - Disclosure - Commitments and Contingencies (ARO Rollforward) (Details) Sheet http://www.emcore.com/role/DisclosureCommitmentsAndContingenciesAroRollforwardDetails Commitments and Contingencies (ARO Rollforward) (Details) Details http://www.emcore.com/role/DisclosureCommitmentsAndContingenciesTables 66 false false R67.htm 41303 - Disclosure - Commitments and Contingencies - Phoenix Navigation Components, LLC Legal Proceeding (Details) Sheet http://www.emcore.com/role/DisclosureCommitmentsAndContingenciesPhoenixNavigationComponentsLlcLegalProceedingDetails Commitments and Contingencies - Phoenix Navigation Components, LLC Legal Proceeding (Details) Details 67 false false R68.htm 41401 - Disclosure - Equity (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureEquityNarrativeDetails Equity (Narrative) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 68 false false R69.htm 41402 - Disclosure - Equity (Schedule of Stock Options Activity) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfStockOptionsActivityDetails Equity (Schedule of Stock Options Activity) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 69 false false R70.htm 41403 - Disclosure - Equity (Schedule of Restricted Stock Activity) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfRestrictedStockActivityDetails Equity (Schedule of Restricted Stock Activity) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 70 false false R71.htm 41404 - Disclosure - Equity (Restricted Stock Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureEquityRestrictedStockNarrativeDetails Equity (Restricted Stock Narrative) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 71 false false R72.htm 41405 - Disclosure - Equity (Schedule of Performance Stock Activity) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfPerformanceStockActivityDetails Equity (Schedule of Performance Stock Activity) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 72 false false R73.htm 41406 - Disclosure - Equity (Performance Stock Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureEquityPerformanceStockNarrativeDetails Equity (Performance Stock Narrative) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 73 false false R74.htm 41407 - Disclosure - Equity (Schedule of Stock-based Compensation Expense - by Award Type) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfStockBasedCompensationExpenseByAwardTypeDetails Equity (Schedule of Stock-based Compensation Expense - by Award Type) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 74 false false R75.htm 41408 - Disclosure - Equity (Schedule of Stock-based Compensation Expense - by Expense Category) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfStockBasedCompensationExpenseByExpenseCategoryDetails Equity (Schedule of Stock-based Compensation Expense - by Expense Category) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 75 false false R76.htm 41409 - Disclosure - Equity (Capital Stock) (Details) Sheet http://www.emcore.com/role/DisclosureEquityCapitalStockDetails Equity (Capital Stock) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 76 false false R77.htm 41410 - Disclosure - Equity (401k) (Details) Sheet http://www.emcore.com/role/DisclosureEquity401kDetails Equity (401k) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 77 false false R78.htm 41411 - Disclosure - Equity (Schedule of Earnings per Share) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfEarningsPerShareDetails Equity (Schedule of Earnings per Share) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 78 false false R79.htm 41412 - Disclosure - Equity (Employee Stock Purchase Plan) (Details) Sheet http://www.emcore.com/role/DisclosureEquityEmployeeStockPurchasePlanDetails Equity (Employee Stock Purchase Plan) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 79 false false R80.htm 41413 - Disclosure - Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) Sheet http://www.emcore.com/role/DisclosureEquityScheduleOfCommonStockReservedForFutureIssuancesDetails Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) Details http://www.emcore.com/role/DisclosureEquityTables 80 false false R81.htm 41501 - Disclosure - Segment Data and Related Information (Schedule of Reportable Segment (Details) Sheet http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationScheduleOfReportableSegmentDetails Segment Data and Related Information (Schedule of Reportable Segment (Details) Details http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationTables 81 false false R82.htm 41502 - Disclosure - Segment Data and Related Information (Schedule of Revenue by Geographic Region) (Details) Sheet http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationScheduleOfRevenueByGeographicRegionDetails Segment Data and Related Information (Schedule of Revenue by Geographic Region) (Details) Details http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationTables 82 false false R83.htm 41503 - Disclosure - Segment Data and Related Information (Narrative) (Details) Sheet http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationNarrativeDetails Segment Data and Related Information (Narrative) (Details) Details http://www.emcore.com/role/DisclosureSegmentDataAndRelatedInformationTables 83 false false R84.htm 41601 - Disclosure - Selected Quarterly Financial Information (unaudited) (Summary of Selected Quarter Financial Information) (Details) Sheet http://www.emcore.com/role/DisclosureSelectedQuarterlyFinancialInformationUnauditedSummaryOfSelectedQuarterFinancialInformationDetails Selected Quarterly Financial Information (unaudited) (Summary of Selected Quarter Financial Information) (Details) Details http://www.emcore.com/role/DisclosureSelectedQuarterlyFinancialInformationUnauditedTables 84 false false R85.htm 41701 - Disclosure - Subsequent Event (Details) Sheet http://www.emcore.com/role/DisclosureSubsequentEventDetails Subsequent Event (Details) Details http://www.emcore.com/role/DisclosureSubsequentEvent 85 false false All Reports Book All Reports tmb-20200930x10k.htm tmb-20200930.xsd tmb-20200930_cal.xml tmb-20200930_def.xml tmb-20200930_lab.xml tmb-20200930_pre.xml tmb-20200930xex21d1.htm tmb-20200930xex23d1.htm tmb-20200930xex31d1.htm tmb-20200930xex31d2.htm tmb-20200930xex32d1.htm tmb-20200930xex32d2.htm tmb-20200930xex4d2.htm tmb-20200930x10k002.jpg tmb-20200930x10k003.jpg tmb-20200930x10k004.jpg tmb-20200930x10k005.jpg tmb-20200930x10k006.jpg tmb-20200930x10k007.jpg http://xbrl.sec.gov/dei/2019-01-31 http://fasb.org/us-gaap/2019-01-31 http://fasb.org/srt/2019-01-31 http://xbrl.sec.gov/exch/2019-01-31 true true