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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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.

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- Definition

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.

+ References

No definition available.

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Acquisitions - Summary of Preliminary Allocation of Purchase Price to Fair Value of Assets Acquired and Liabilities Assumed (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 06, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Amortization of intangible assets		$ 402	$ 197	$ 770	$ 582
FeedbackNow [Member]
Business Acquisition [Line Items]
Acquired intangible assets	$ 4,780
Amortization of intangible assets		$ 200		$ 200
FeedbackNow [Member] \| Technology Asset Class [Member]
Business Acquisition [Line Items]
Acquired intangible assets	$ 3,000
Acquired intangible assets, Useful life	6 years 6 months
FeedbackNow [Member] \| Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired intangible assets	$ 1,300
Acquired intangible assets, Useful life	4 years 6 months
FeedbackNow [Member] \| Trade Names [Member]
Business Acquisition [Line Items]
Acquired intangible assets	$ 500
Acquired intangible assets, Useful life	8 years 6 months