Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Raw materials	$ 39,859	$ 36,328
Finished goods	25,585	17,458
Inventories, net	65,444	53,786
Service and sales demonstration inventory, net	$ 39,563	$ 39,614
Service Inventory
Property, Plant and Equipment [Line Items]
Inventory, remaining life	3 years