Consolidated Statements of Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 2,633,000	$ 3,168,000
Other comprehensive loss:
Change in unrealized loss on marketable securities, net of tax	(254,000)	(56,000)
Comprehensive income	$ 2,379,000	$ 3,112,000