Revenue Recognition (Details) - Disaggregation of revenue from contracts with customers - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Digital product sales:
Revenue from contracts with customers	$ 2,896,000	$ 4,472,000	$ 6,858,000	$ 11,818,000
Digital Product Sales [Member]
Digital product sales:
Revenue from contracts with customers	2,405,000	3,951,000	5,257,000	10,155,000
Digital Product Lease And Maintenance [Member]
Digital product sales:
Revenue from contracts with customers	491,000	521,000	1,601,000	1,663,000
Catalog And Small Customized Products [Member] | Digital Product Sales [Member]
Digital product sales:
Revenue from contracts with customers	2,405,000	3,951,000	5,257,000	10,155,000
Large Customized Products [Member] | Digital Product Sales [Member]
Digital product sales:
Revenue from contracts with customers
Operating Leases [Member] | Digital Product Lease And Maintenance [Member]
Digital product sales:
Revenue from contracts with customers	240,000	270,000	755,000	900,000
Maintenance Agreements [Member] | Digital Product Lease And Maintenance [Member]
Digital product sales:
Revenue from contracts with customers	$ 251,000	$ 251,000	$ 846,000	$ 763,000