Revenue Contract Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Movement in Deferred Revenue [Roll Forward]
Contract with Customer, Liability	$ (4,282)	$ (7,066)
Contract with Customer, Liability	(7,692)	(7,874)
Equipment revenue [Member]
Movement in Deferred Revenue [Roll Forward]
Deferred Revenue, Additions	(6,869)	(4,086)
Increase (Decrease) in Deferred Revenue	3,619	3,136
Software revenue [Member]
Movement in Deferred Revenue [Roll Forward]
Deferred Revenue, Additions	(3,115)	(5,507)
Increase (Decrease) in Deferred Revenue	$ 2,955	$ 5,649