Net Loss Per Common Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic income per share
Net income	$ 691,000	$ 711,000	$ 270,000	$ 1,569,000
Basic income (loss) per share (in dollars per share)			$ 0.05	$ 0.31
Weighted average shares outstanding (in shares)	5,080,000	5,045,000	5,076,000	5,026,000
Diluted income per share
Dilutive effect of stock options (in shares)	24,000	50,000	25,000	39,000
Total weighted average shares outstanding (in shares)	5,104,000	5,095,000	5,101,000	5,065,000
Diluted income (loss) per share (in dollars per share)	$ 0.14	$ 0.14	$ 0.05	$ 0.31