Description of Business (Policies)	6 Months Ended
Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interim Financial Statements	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 adjustments, which are all normal recurring 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, 2020 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, 2020.
Significant Accounting Policies and Estimates	Significant Accounting Policies and Estimates Our significant accounting policies are detailed in “Note 2 - Summary of Significant Accounting Policies” of our Annual Report on Form 10-K for the year ended September 30, 2020. There have been no significant changes to our accounting policies during the six months ended March 31, 2021. The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities, as of the date of the financial statements, and the reported amounts of revenue and expenses during the reported period. If these estimates differ significantly from actual results, the impact to the condensed consolidated financial statements may be material. There have been no material changes in our critical accounting policies and estimates from those disclosed in our Annual Report on Form 10-K for the fiscal year ended September 30, 2020. Please refer to Part II, Item 7 of our Annual Report on Form 10-K for the fiscal year ended September 30, 2020 for a discussion of our critical accounting policies and estimates.
Disaggregation of Revenue and Revenue Recognition	Disaggregation of Revenue - Revenue is classified based on the product line of business. For additional information on the disaggregated revenues by geographical region, see "Note 13 – Segment Data and Related Information" in the notes to the condensed consolidated financial statements.
New Accounting Updates Recently Adopted and Recent Accounting Standards or Updates Not Yet Effective	New Accounting Updates Recently Adopted •In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which changes the way entities measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net earnings. The new standard is effective for annual periods beginning after December 15, 2019, including interim periods within those annual periods. The new standard was effective for our fiscal year beginning October 1, 2020. We adopted the new standard on October 1, 2020, and it did not have a material impact on the condensed consolidated financial statements. (b)Recent Accounting Standards or Updates Not Yet Effective •In March 2020, the FASB issued ASU 2019-12 Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The new standard is effective for annual periods beginning after December 15, 2020, including interim periods within those annual periods. The new standard will be effective for our fiscal year beginning October 1, 2021 and early adoption is permitted. The Company is currently evaluating the new guidance to determine the impact it may have on the condensed consolidated financial statements and related disclosures.
Fair Value of Financial Instruments	Accounting Standards Codification Topic 820 (“ASC 820”), Fair Value Measurement, establishes a valuation hierarchy for disclosure of the inputs to valuation techniques used to measure fair value. This standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value: •Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities. •Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly, through market corroboration, for substantially the full term of the financial instrument. •Level 3 inputs are unobservable inputs based on our own assumptions used to measure assets or liabilities at fair value. Classification of an asset or liability within this hierarchy is determined based on the lowest level input that is significant to the fair value measurement. Valuation techniques used to measure fair value under ASC 820 must maximize the use of observable inputs and minimize the use of unobservable inputs.
Cash and Cash Equivalents	Cash consists primarily of bank deposits or highly liquid short-term investments with a maturity of three months or less at the time of purchase.
Restricted Cash	Restricted cash represents temporarily restricted deposits held as compensating balances against short-term borrowing arrangements.
Legal Costs	Professional legal fees are expensed when incurred. We accrue for contingent losses when such losses are probable and reasonably estimable.
Segment Reporting	The reportable segments reported below are the Company’s segments for which separate financial information is available and upon which operating results are evaluated by the chief operating decision maker to assess performance and to allocate resources. The Company has determined that it has two reportable segments: (i) Aerospace and Defense and (ii) Broadband. The Company’s Chief Executive Officer is the chief operating decision maker and he assesses the performance of the operating segments and allocates resources based on segment profits. We do not allocate sales and marketing, general and administrative expenses, or interest expense and interest income to our segments, because management does not include the information in its measurement of the performance of the operating segments. Also, a measure of segment assets and liabilities, has not been provided to the Company's chief operating decision maker and therefore is not shown below.

Description of Business (Policies)

6 Months Ended

Mar. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

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 adjustments, which are all normal recurring 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, 2020 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, 2020.

Significant Accounting Policies and Estimates

Our significant accounting policies are detailed in “Note 2 - Summary of Significant Accounting Policies” of our Annual Report on Form 10-K for the year ended September 30, 2020. There have been no significant changes to our accounting policies during the six months ended March 31, 2021. The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities, as of the date of the financial statements, and the reported amounts of revenue and expenses during the reported period. If these estimates differ significantly from actual results, the impact to the condensed consolidated financial statements may be material. There have been no material changes in our critical accounting policies and estimates from those disclosed in our Annual Report on Form 10-K for the fiscal year ended September 30, 2020. Please refer to Part II, Item 7 of our Annual Report on Form 10-K for the fiscal year ended September 30, 2020 for a discussion of our critical accounting policies and estimates.

Disaggregation of Revenue and Revenue Recognition

Disaggregation of Revenue - Revenue is classified based on the product line of business. For additional information on the disaggregated revenues by geographical region, see "Note 13 – Segment Data and Related Information" in the notes to the condensed consolidated financial statements.

New Accounting Updates Recently Adopted and Recent Accounting Standards or Updates Not Yet Effective

New Accounting Updates Recently Adopted

•In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which changes the way entities measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net earnings. The new standard is effective for annual periods beginning after December 15, 2019, including interim periods within those annual periods. The new standard was effective for our fiscal year beginning October 1, 2020. We adopted the new standard on October 1, 2020, and it did not have a material impact on the condensed consolidated financial statements.

(b)Recent Accounting Standards or Updates Not Yet Effective

•In March 2020, the FASB issued ASU 2019-12 Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The new standard is effective for annual periods beginning after December 15, 2020, including interim periods within those annual periods. The new standard will be effective for our fiscal year beginning October 1, 2021 and early adoption is permitted. The Company is currently evaluating the new guidance to determine the impact it may have on the condensed consolidated financial statements and related disclosures.

Fair Value of Financial Instruments

Accounting Standards Codification Topic 820 (“ASC 820”), Fair Value Measurement, establishes a valuation hierarchy for disclosure of the inputs to valuation techniques used to measure fair value. This standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value:

•Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

•Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly, through market corroboration, for substantially the full term of the financial instrument.

•Level 3 inputs are unobservable inputs based on our own assumptions used to measure assets or liabilities at fair value.

Classification of an asset or liability within this hierarchy is determined based on the lowest level input that is significant to the fair value measurement.

Valuation techniques used to measure fair value under ASC 820 must maximize the use of observable inputs and minimize the use of unobservable inputs.

Cash and Cash Equivalents

Cash consists primarily of bank deposits or highly liquid short-term investments with a maturity of three months or less at the time of purchase.

Restricted Cash

Restricted cash represents temporarily restricted deposits held as compensating balances against short-term borrowing arrangements.

Legal Costs

Professional legal fees are expensed when incurred. We accrue for contingent losses when such losses are probable and reasonably estimable.

Segment Reporting

The reportable segments reported below are the Company’s segments for which separate financial information is available and upon which operating results are evaluated by the chief operating decision maker to assess performance and to allocate resources. The Company has determined that it has two reportable segments: (i) Aerospace and Defense and (ii) Broadband.

The Company’s Chief Executive Officer is the chief operating decision maker and he assesses the performance of the operating segments and allocates resources based on segment profits. We do not allocate sales and marketing, general and administrative expenses, or interest expense and interest income to our segments, because management does not include the information in its measurement of the performance of the operating segments. Also, a measure of segment assets and liabilities, has not been provided to the Company's chief operating decision maker and therefore is not shown below.