Schedule II - Valuation and Qualifying Accounts: (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 230,000	$ 217,000
Charged to expenses	55,000	67,000
Written off	(159,000)	(54,000)
Balance at end of year	126,000	230,000
Inventory Valuation Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	645,000	738,000
Charged to expenses	179,000	(92,000)
Written off	(1,000)	(1,000)
Balance at end of year	$ 823,000	$ 645,000