Business Combination - Schedule of Allocation of Purchase Consideration to Tangible and Intangible Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Assets acquired
Goodwill	$ 73,058	$ 74,116
Boston-based Dataxu, Inc, Demand-Side Platform (DSP)
Assets acquired
Current assets	50,829
Restricted cash	1,303
Property and equipment, net	4,503
Goodwill	71,676
Operating lease right-of-use assets	24,658
Other long-term assets	235
Total assets acquired	223,404
Liabilities assumed
Current liabilities	(51,428)
Operating lease liabilities	(24,658)
Total liabilities assumed	(76,086)
Total purchase consideration	147,318
Boston-based Dataxu, Inc, Demand-Side Platform (DSP) | Developed Technology
Assets acquired
Intangible assets	$ 56,400
Liabilities assumed
Estimated Useful Lives (in years)	6 years
Boston-based Dataxu, Inc, Demand-Side Platform (DSP) | Customer Relationships
Assets acquired
Intangible assets	$ 13,400
Liabilities assumed
Estimated Useful Lives (in years)	4 years
Boston-based Dataxu, Inc, Demand-Side Platform (DSP) | Tradename
Assets acquired
Intangible assets	$ 400
Liabilities assumed
Estimated Useful Lives (in years)	6 months