Revenue Recognition (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accumulated deficit	$ (557,002)		$ (557,002)		$ (544,010)
Revenue	16,554	$ 17,691	50,461	$ 48,491
Long-term accounts receivable	500		500		300
Deferred revenue	$ 2,300		$ 2,300		$ 2,100