Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income	$ 804,000	$ 797,000	$ 1,354,000	$ 1,304,000
Other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	43,000	18,000	(35,000)	(78,000)
Comprehensive income	$ 847,000	$ 815,000	$ 1,319,000	$ 1,226,000