Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Company's Stock Option Plans (Details)

v3.4.0.3
Note 4 - Company's Stock Option Plans (Details) - USD ($)
 3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2015
Dec. 31, 2014
Options outstanding, shares (in shares) 218,200 [1] 222,766 [1] 218,200 239,023
Options outstanding, weighted average exercise price (in dollars per share) $ 7.65 [1] $ 7.89 [1] $ 7.65 $ 7.81
Options outstanding, weighted average remaining contractual term [1] 4 years 219 days 5 years    
Options outstanding, aggregate intrinsic value [1],[2] $ 13,980 $ 22,616    
Options exercisable, shares (in shares) [1] 181,533 167,766    
Options exercisable, weighted average exercise price (in dollars per share) [1] $ 8.18 $ 8.84    
Options exercisable, weighted average remaining contractual term [1] 4 years 219 days 4 years 328 days    
Options exercisable, aggregate intrinsic value [1],[2] $ 13,980 $ 22,616    
Options exercisable and expected to be vested, shares (in shares) 212,333 213,966    
Options exercisable and expected to be vested, weighted average exercise price (in dollars per share) $ 7.72 $ 8.01    
Options exercisable and expected to be vested, weighted average remaining contractual term 4 years 219 days 5 years    
Options exercisable and expected to be vested, aggregate intrinsic value [2] $ 13,980 $ 22,616    
Exercised, shares (in shares)   (1,257)    
Exercised, weighted average exercise price (in dollars per share)   $ 2.79    
Exercised, aggregate intrinsic value [2]   $ 2,043    
Forfeited/expired, shares (in shares)   (15,000)    
Forfeited/expired, weighted average exercise price (in dollars per share)   $ 7.10    
[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.