Description of Business and Summary of Significant Accounting Policies - Reclassification (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Reclassification [Line Items]
Prepaid expenses and other current assets	$ 13,964	$ 15,813	$ 15,322	$ 12,482	$ 9,252	$ 7,842	$ 9,033	$ 7,655
Current assets	278,107	274,753	291,516	301,554	121,724	125,920	117,105	111,248
Contract acquisition costs	$ 31,965	25,993	19,995	16,808	13,361	10,880	7,852	5,539
As previously reported
Reclassification [Line Items]
Prepaid expenses and other current assets		41,806	35,317	29,290	22,613	18,722	16,885	13,194
Current assets		300,746	311,511	318,362	135,085	136,800	124,957	116,787
Contract acquisition costs		0	0	0	0	0	0	0
Adjustment
Reclassification [Line Items]
Prepaid expenses and other current assets		(25,993)	(19,995)	(16,808)	(13,361)	(10,880)	(7,852)	(5,539)
Current assets		(25,993)	(19,995)	(16,808)	(13,361)	(10,880)	(7,852)	(5,539)
Contract acquisition costs		$ 25,993	$ 19,995	$ 16,808	$ 13,361	$ 10,880	$ 7,852	$ 5,539