Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 215,846		$ 215,846		$ 168,655
Less accumulated depreciation and amortization		(93,423)		(93,423)		(67,189)
Total property and equipment, net		122,423		122,423		101,466
Depreciation and amortization expense		12,100	$ 7,700	32,800	$ 20,800
Servers—network infrastructure
Property, Plant and Equipment [Line Items]
Gross property and equipment		114,564		114,564		84,979
Buildings
Property, Plant and Equipment [Line Items]
Gross property and equipment		0		0		13,035
Buildings | ASC 842
Property, Plant and Equipment [Line Items]
Change in property and equipment for adoption of new ASU	$ (13,000)
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property and equipment		13,525		13,525		8,692
Capitalized internal-use software
Property, Plant and Equipment [Line Items]
Gross property and equipment		48,047		48,047		31,171
Depreciation and amortization expense				8,700	$ 4,600
Office and computer equipment
Property, Plant and Equipment [Line Items]
Gross property and equipment		18,870		18,870		13,528
Office furniture
Property, Plant and Equipment [Line Items]
Gross property and equipment		6,736		6,736		6,124
Software
Property, Plant and Equipment [Line Items]
Gross property and equipment		2,203		2,203		1,025
Depreciation and amortization expense		3,400	$ 1,800
Leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property and equipment		11,472		11,472		9,870
Leasehold improvements | ASC 842
Property, Plant and Equipment [Line Items]
Change in property and equipment for adoption of new ASU	$ 1,600
Asset retirement obligation
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 429		$ 429		$ 231