Note 2 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares |
6 Months Ended | |
---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
|
Outstanding stock options weighted-average exercise price, January 1 (in dollars per share) | $ 23.67 | $ 25.03 |
Outstanding stock options, January 1 (in shares) | 29,324 | 31,949 |
Exercised stock options (in shares) | (7,949) | |
Exercised stock options weighted-average exercise price (in dollars per share) | $ 29.87 | |
Outstanding stock options, March 31 (in shares) | 21,375 | 31,949 |
Outstanding stock options weighted-average exercise price, March 31 (in dollars per share) | $ 26.91 | $ 25.03 |
Exercisable stock options weighted-average exercise price, March 31 (in dollars per share) | $ 26.91 | $ 25.03 |
Exercisable stock options, March 31 (in shares) | 21,375 | 31,949 |