Revenue Recognition (Details) - Disaggregation of revenue from contracts with customers - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Digital product sales:
Revenue from contracts with customers	$ 3,599	$ 4,535
Digital Product Sales [Member]
Digital product sales:
Revenue from contracts with customers	3,091	3,948
Digital Product Lease And Maintenance [Member]
Digital product sales:
Revenue from contracts with customers	508	587
Catalog And Small Customized Products [Member] | Digital Product Sales [Member]
Digital product sales:
Revenue from contracts with customers	3,091	2,948
Large Customized Products [Member] | Digital Product Sales [Member]
Digital product sales:
Revenue from contracts with customers		1,000
Operating Leases [Member] | Digital Product Lease And Maintenance [Member]
Digital product sales:
Revenue from contracts with customers	292	327
Maintenance Agreements [Member] | Digital Product Lease And Maintenance [Member]
Digital product sales:
Revenue from contracts with customers	$ 216	$ 260