Revenues - Narrative (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 Recognition [Abstract]
Fees to GPOs	$ 2,300	$ 2,800	$ 6,900	$ 7,600
Short-term deferred revenues, net	101,641		101,641		$ 90,894
Deferred cost of sales	24,200		24,200		13,100
Deferred revenues recognized	13,200		77,500
Short-term deferred revenues, gross					104,000
Long-term deferred revenues	$ 5,163		$ 5,163		$ 7,083