Description of Business	6 Months Ended
Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	NOTE 1. Description of Business Business Overview EMCORE Corporation (referred to herein, together with its subsidiaries, as the “Company,” “we,” “our,” or “EMCORE”) was established in 1984 as a New Jersey corporation. The Company became publicly traded in 1997 and is listed on the Nasdaq stock exchange under the ticker symbol EMKR. EMCORE pioneered the linear fiber optic transmission technology that enabled the world’s first delivery of Cable TV (“CATV”) directly on fiber, and today is a leading provider of advanced Mixed-Signal Optics products that enable communications systems and service providers to meet growing demand for increased bandwidth and connectivity. The Mixed-Signal Optics technology at the heart of our broadband communications products is shared with our fiber optic gyros and inertial sensors to provide the aerospace and defense markets with state-of-the-art navigation systems technology. With the acquisition of Systron Donner Inertial, Inc. (“SDI”), a navigation systems provider with a scalable, chip-based platform for higher volume gyro applications utilizing Quartz MEMS technology, in June 2019, EMCORE further expanded its portfolio of gyros and inertial sensors with SDI’s quartz MEMS gyro and accelerometer technology. EMCORE has fully vertically-integrated manufacturing capability through our indium phosphide compound semiconductor wafer fabrication facility at our headquarters in Alhambra, CA, and through our quartz processing and sensor manufacturing facility in Concord, CA. These facilities support EMCORE’s vertically-integrated manufacturing strategy for quartz and fiber optic gyro products, for navigation systems, and for our chip, laser, transmitter, and receiver products for broadband applications. Interim Financial Statements The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim information, and with the instructions to Form 10‑Q and Rule 10‑01 of Regulation S-X promulgated by the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and notes required by U.S. GAAP for annual financial statements. In our opinion, the interim financial statements reflect all normal adjustments that are necessary to provide a fair presentation of the financial results for the interim periods presented. Operating results for interim periods are not necessarily indicative of results that may be expected for an entire fiscal year. The condensed consolidated balance sheet as of September 30, 2019 has been derived from the audited consolidated financial statements as of such date. For a more complete understanding of our business, financial position, operating results, cash flows, risk factors and other matters, please refer to our Annual Report on Form 10‑K for the fiscal year ended September 30, 2019.

NOTE 1. Description of Business

Business Overview

EMCORE Corporation (referred to herein, together with its subsidiaries, as the “Company,” “we,” “our,” or “EMCORE”) was established in 1984 as a New Jersey corporation. The Company became publicly traded in 1997 and is listed on the Nasdaq stock exchange under the ticker symbol EMKR. EMCORE pioneered the linear fiber optic transmission technology that enabled the world’s first delivery of Cable TV (“CATV”) directly on fiber, and today is a leading provider of advanced Mixed-Signal Optics products that enable communications systems and service providers to meet growing demand for increased bandwidth and connectivity. The Mixed-Signal Optics technology at the heart of our broadband communications products is shared with our fiber optic gyros and inertial sensors to provide the aerospace and defense markets with state-of-the-art navigation systems technology. With the acquisition of Systron Donner Inertial, Inc. (“SDI”), a navigation systems provider with a scalable, chip-based platform for higher volume gyro applications utilizing Quartz MEMS technology, in June 2019, EMCORE further expanded its portfolio of gyros and inertial sensors with SDI’s quartz MEMS gyro and accelerometer technology. EMCORE has fully vertically-integrated manufacturing capability through our indium phosphide compound semiconductor wafer fabrication facility at our headquarters in Alhambra, CA, and through our quartz processing and sensor manufacturing facility in Concord, CA. These facilities support EMCORE’s vertically-integrated manufacturing strategy for quartz and fiber optic gyro products, for navigation systems, and for our chip, laser, transmitter, and receiver products for broadband applications.

Interim Financial Statements

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim information, and with the instructions to Form 10‑Q and Rule 10‑01 of Regulation S-X promulgated by the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and notes required by U.S. GAAP for annual financial statements. In our opinion, the interim financial statements reflect all normal adjustments that are necessary to provide a fair presentation of the financial results for the interim periods presented. Operating results for interim periods are not necessarily indicative of results that may be expected for an entire fiscal year. The condensed consolidated balance sheet as of September 30, 2019 has been derived from the audited consolidated financial statements as of such date. For a more complete understanding of our business, financial position, operating results, cash flows, risk factors and other matters, please refer to our Annual Report on Form 10‑K for the fiscal year ended September 30, 2019.