v3.20.2

Segment and Geographic Information - Concentration Risk (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) segment	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Information
Number of reportable segments (in segments) | segment			2
Revenue	$ 201,073	$ 153,798	$ 559,239	$ 411,493
Accounts receivable, net	95,756		95,756		$ 33,655
Graduate Program Segment
Segment Information
Revenue	122,036	103,393	356,178	308,970
University client A | Customer concentration risk | Sales Revenue, Net | Graduate Program Segment
Segment Information
Revenue	$ 19,300	$ 20,500	$ 55,500	$ 64,300
Percentage of concentration of credit risk	10.00%	13.00%	10.00%	16.00%
University client A | Credit concentration risk | Accounts receivable, net | Graduate Program Segment
Segment Information
Percentage of concentration of credit risk			12.00%		18.00%
Accounts receivable, net	$ 11,100		$ 11,100		$ 6,100
University client B | Credit concentration risk | Accounts receivable, net | Graduate Program Segment
Segment Information
Percentage of concentration of credit risk			11.00%		15.00%
Accounts receivable, net	$ 11,000		$ 11,000		$ 4,900

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