Acquisition - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 13,418	$ 11,051
3M's Drive-Thru Communications Systems
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	2,367
Property, plant and equipment – net	735
Total assets	8,412
Warranty liability	1,412
Cash consideration	7,000
3M's Drive-Thru Communications Systems \| Trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	510
3M's Drive-Thru Communications Systems \| Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	1,200
3M's Drive-Thru Communications Systems \| Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	$ 3,600

Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Assets Acquired Including Goodwill

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- Definition

Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Current And Noncurrent Liabilities, Warranty Liability

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- Definition

Amount of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit, 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 property, plant, and equipment recognized as of the acquisition date.

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Amount recognized for assets, including goodwill, 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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