SCHEDULE II - Valuation and Qualifying Accounts (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Allowance for Uncollectible Accounts
Changes in valuation and qualifying accounts
Balance at Beginning of Year	$ 137,000	$ 138,000
Additions Charged to Costs and Expenses	225,000	52,000
Deductions	(42,000)	(53,000)
Balance at End of Year	320,000	137,000
Inventory Reserves
Changes in valuation and qualifying accounts
Balance at Beginning of Year	732,000	1,100,000
Additions Charged to Costs and Expenses	457,000	524,000
Deductions	(439,000)	(892,000)
Balance at End of Year	$ 750,000	$ 732,000