Overview and Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Jan. 01, 2019 USD ($)	Dec. 31, 2019 USD ($) Segment Financial_Institution	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Initial offering period		December 2011
Operating segment | Segment		1
Reportable segment | Segment		1
Impairments of short-term investments		$ 0
Expected dividend yield		0.00%	0.00%	0.00%
Number of financial institutions in which cash equivalents and securities held | Financial_Institution		5
Advertising expense		$ 377,200,000	$ 157,700,000	$ 147,200,000
Right-of-use assets		136,972,000
Current operating lease liabilities		15,753,000
Non-current operating lease liabilities		130,301,000
Lease liability recognized		$ 146,054,000
ASU 2016-02 [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Right-of-use assets	$ 9,100,000
Current operating lease liabilities	7,600,000
Non-current operating lease liabilities	12,400,000
Derecognize restructuring plan liability	10,900,000
Lease liability recognized	$ 10,900,000
Operating lease, term		12 months
Lease and non lease component, description		the lessor practical expedient is limited to circumstances in which the nonlease component or components otherwise would be accounted for under the new revenue guidance and both (i) the timing and pattern of transfer are the same for the nonlease component(s) and associated lease component and (ii) the lease component, if accounted for separately, would be classified as an operating lease.
Facebook [Member] | Customer Concentration Risk [Member] | Accounts Receivable [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Entity wide accounts receivables major customer percentage		13.00%	15.00%
Google [Member] | Customer Concentration Risk [Member] | Accounts Receivable [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Entity wide accounts receivables major customer percentage		33.00%	27.00%
Apple [Member] | Customer Concentration Risk [Member] | Accounts Receivable [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Entity wide accounts receivables major customer percentage		34.00%	26.00%
Acquired Intangible Assets [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Impairment of intangible assets		$ 0	$ 0	$ 0
Minimum [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Stipulate payment terms as specific number of days subsequent to end of the month		30 days
Estimated useful lives of intangible assets		12 months
Maximum [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Stipulate payment terms as specific number of days subsequent to end of the month		60 days
Estimated useful lives of intangible assets		84 months
Facebook [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Percentage of transaction fee recognized price		70.00%
Percentage of revenue recognized price		70.00%
Consumable Virtual Items [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Revenue recognition period		1 month