Segment Data and Related Information (Schedule of Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 23,850	$ 21,745	$ 49,332	$ 45,746
Gross profit	6,427	5,809	13,901	11,617
R&D expense	4,584	4,360	9,226	8,379
Operating loss	(4,981)	(5,507)	(6,434)	(11,311)
Unallocated (income) expense:
Selling, general, and administrative	7,139	6,996	13,026	14,589
Gain on sale of assets	(315)		(1,917)	0
Gain from change in estimate on ARO obligation		(40)	0	(40)
Interest (income) expense, net	(1)	(224)	14	(491)
Foreign exchange gain	156	(304)	9	(318)
Total unallocated expense	6,979	6,428	11,132	13,740
Loss before income tax expense	(5,136)	(4,979)	(6,457)	(10,502)
Operating segments
Segment Reporting Information [Line Items]
Revenue	23,850	21,745	49,332	45,746
Operating loss	1,843	1,449	4,675	3,238
Operating segments \| Aerospace And Defense
Segment Reporting Information [Line Items]
Revenue	13,013	6,872	26,717	11,012
Gross profit	2,844	2,680	7,332	3,902
R&D expense	3,991	1,682	7,942	3,233
Operating loss	(1,147)	998	(610)	669
Operating segments \| Broadband
Segment Reporting Information [Line Items]
Revenue	10,837	14,873	22,615	34,734
Gross profit	3,583	3,129	6,569	7,715
R&D expense	593	2,678	1,284	5,146
Operating loss	$ 2,990	$ 451	$ 5,285	$ 2,569

Asset Retirement Obligation, Gain (Loss) From Revision Of Estimates

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The amount of unallocated income (expense) which was not separately allocated to segments.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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The net amount of operating interest income (expense).

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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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.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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