Acquisitions - Summary of Intangible Assets Subject to Amortization Acquired (Detail) - Headway $ in Millions	Apr. 04, 2017 USD ($)
Existing Technology
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value, Intangible Asset	$ 1.0
Weighted average life (in years), Intangible Assets	2 years
Publisher Relationships
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value, Intangible Asset	$ 5.0
Weighted average life (in years), Intangible Assets	3 years
Advertiser Relationships
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value, Intangible Asset	$ 4.8
Weighted average life (in years), Intangible Assets	5 years
MediaMath Agreement
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value, Intangible Asset	$ 2.1
Weighted average life (in years), Intangible Assets	9 years
Non-Compete Agreements
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value, Intangible Asset	$ 1.1
Weighted average life (in years), Intangible Assets	4 years
Trade Name
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value, Intangible Asset	$ 1.9
Weighted average life (in years), Intangible Assets	5 years

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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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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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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