Acquisition - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	3 Months Ended
Jun. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Goodwill	$ 69	$ 69
Systron Donner Inertial, Inc.
Business Acquisition [Line Items]
Purchase price	24,978
Cash acquired	541
Inventories	8,522
Accounts receivable	4,291
Other assets	355
Net liabilities assumed	(4,853)
Goodwill	69
Developed technology \| Systron Donner Inertial, Inc.
Business Acquisition [Line Items]
Intangible assets	$ 250
Intangible assets useful life (years)	7 years
Land and building \| Systron Donner Inertial, Inc.
Business Acquisition [Line Items]
Property, plant and equipment	$ 12,890
Property and equipment \| Systron Donner Inertial, Inc.
Business Acquisition [Line Items]
Property, plant and equipment	$ 2,913

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of other assets expected to be realized or consumed before one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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The amount of inventory recognized as of the acquisition date.

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Amount of liabilities assumed at the acquisition date.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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