Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Balance Sheets [Abstract]
Trade receivables, allowance for doubtful accounts	$ 8	$ 8
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	3,395,521	3,395,521
Common stock, shares outstanding	3,395,521	3,395,521