Revenue Recognition Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Contract Assets and Liabilities [Abstract]
Contract with Customer, Liability, Revenue Recognized	$ 125	$ 231
Contract with Customer, Asset, Net, Current	65	65	$ 65
Contract with Customer, Asset, Net, Noncurrent	1,498	1,498	999
Contract with Customer, Asset, Net	1,563	1,563	1,064
Customer Contract Liability Discounts	(1,892)	(1,892)	(1,656)
Customer Contract Liability Rights of Return	(857)	(857)	(325)
Contract with Customer, Liability, Current	$ (2,749)	$ (2,749)	$ (1,981)