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Schedules of Concentration of Risk Based on Accounts Receivable (Detail) - Customer Concentration Risk - Accounts Receivable	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Concentration Risk [Line Items]
Concentration risk, percentage	31.00%	37.00%
Advertiser A
Concentration Risk [Line Items]
Concentration risk, percentage	18.00%	10.00%
Advertiser B
Concentration Risk [Line Items]
Concentration risk, percentage	32.00%	41.00%

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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.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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