Revenue Recognition (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue Recognition [line items]
Medicare cap	$ 0	$ 228,000		$ 228,000
Percentage of automatic budget reductions							2.00%
Unbilled Revenue	$ 480,000		$ 480,000
Two Program Projected Measurement Period Liability [Member]
Revenue Recognition [line items]
Medicare cap			247,000
Additional amount owed for Medicare cap					$ 2,300,000	$ 2,300,000	$ 2,300,000
Sequestration [Member]
Revenue Recognition [line items]
Medicare cap			$ 105,000