Quarterly report pursuant to Section 13 or 15(d)

Note 5 - Capital Stock, Stock Plans and Stock-based Compensation - Company's Stock Option Plans (Details)

v3.5.0.2
Note 5 - Capital Stock, Stock Plans and Stock-based Compensation - Company's Stock Option Plans (Details) - USD ($)
 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Options outstanding, shares (in shares) 218,200 239,023
Options outstanding, weighted average exercise price (in dollars per share) $ 7.65 $ 7.81
Options granted, shares (in shares) 62,000 12,000
Options granted, weighted average exercise price (in dollars per share) $ 4.09 $ 4.19
Forfeited/expired (in shares) (33,000) (29,400)
Forfeited/expired (in dollars per share) $ 8.14 $ 8.13
Options outstanding, shares (in shares) [1] 247,200 218,200
Options outstanding, weighted average exercise price (in dollars per share) [1] $ 6.69 $ 7.65
Options outstanding, weighted average remaining contractual term [1] 4 years 219 days 5 years 36 days
Options outstanding, aggregate intrinsic value [1],[2] $ 126,267 $ 25,464
Options exercisable, shares (in shares) [1] 181,867 169,533
Options exercisable, weighted average exercise price (in dollars per share) [1] $ 7.61 $ 8.47
Options exercisable, weighted average remaining contractual term [1] 4 years 4 years 292 days
Options exercisable, aggregate intrinsic value [1],[2] $ 69,516 $ 25,464
Options exercisable and expected to be vested, shares (in shares) 239,750 212,333
Options exercisable and expected to be vested, weighted average exercise price (in dollars per share) $ 6.78 $ 7.72
Options exercisable and expected to be vested, weighted average remaining contractual term 4 years 219 days 5 years 36 days
Options exercisable and expected to be vested, aggregate intrinsic value [2] $ 118,542 $ 25,464
Exercised, shares (in shares)   (3,423)
Exercised, weighted average exercise price (in dollars per share)   $ 2.79
Exercised, aggregate intrinsic value [2]   $ 4,298
Forfeited/expired, shares (in shares) (33,000) (29,400)
Forfeited/expired, weighted average exercise price (in dollars per share) $ 8.14 $ 8.13
[1] Options with exercise prices ranging from $2.79 to $14.75
[2] The intrinsic value of a stock option is the amount by which the market value of the underlying stock exceeds the exercise price of the option.