Deferred Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Deferred commissions
As of beginning of period			$ 14,718
Additions			1,396
Expense recognized			(5,517)
As of end of period	$ 10,597		10,597
Deferred professional service costs
As of beginning of period			6,711
Additions			983
Expense recognized			(2,417)
As of end of period	5,277		5,277
Total deferred commissions and professional service costs
As of beginning of period			21,429
Additions			2,379
Expense recognized			(7,934)
As of end of period	15,874		15,874
Impairment charges	$ 200	$ 200	$ 1,500	$ 800