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Goodwill And Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 03, 2017	Jul. 01, 2015
Goodwill and Intangible Assets Disclosure [Line Items]
Accumulated Impairment		$ 255	$ 3,444
Amortization of intangible assets	$ 0	766	$ 2,964
Goodwill	0	17,489
Goodwill impairment	$ 17,489	$ 15,715
Shannon Systems
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill					$ 33,204
Bigtera
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill				$ 625

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- Definition

Goodwill and Intangible Assets Disclosure [Line Items]

+ References

No definition available.

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

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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.

+ References

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

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