Note 7 - Share-based Compensation - Stock Option Activity (Details) - $ / shares
|
3 Months Ended |
12 Months Ended |
Mar. 31, 2020 |
Dec. 31, 2019 |
| Share-based Payment Arrangement, Option [Member] |
|
|
| Outstanding at beginning of period (in shares) |
1,570,455
|
|
| Outstanding at beginning of period (in dollars per share) |
$ 1.96
|
|
| Granted (in shares) |
0
|
0
|
| Granted, weighted average exercise price (in dollars per share) |
|
|
| Exercised (in shares) |
(251,180)
|
|
| Exercised, weighted average exercise price (in dollars per share) |
$ 1.84
|
|
| Forfeited (in shares) |
|
|
| Forfeited, weighted average exercise price (in dollars per share) |
|
|
| Expired (in shares) |
|
|
| Expired, weighted average exercise price (in dollars per share) |
|
|
| Outstanding (in shares) |
1,319,275
|
1,570,455
|
| Outstanding at beginning of year, weighted average exercise price (in dollars per share) |
$ 1.98
|
$ 1.96
|
| Service vesting-based stock options exercisable at March 31, 2020 (in shares) |
1,263,377
|
|
| Service vesting-based stock options exercisable at March 31, 2020 (in dollars per share) |
$ 1.96
|
|
| Performance Shares [Member] |
|
|
| Outstanding at beginning of period (in shares) |
737,497
|
|
| Outstanding at beginning of period (in dollars per share) |
$ 1.64
|
|
| Granted (in shares) |
|
|
| Granted, weighted average exercise price (in dollars per share) |
|
|
| Exercised (in shares) |
(17,113)
|
|
| Exercised, weighted average exercise price (in dollars per share) |
$ 1.64
|
|
| Outstanding (in shares) |
720,384
|
737,497
|
| Outstanding at beginning of year, weighted average exercise price (in dollars per share) |
$ 1.64
|
$ 1.64
|
| Service vesting-based stock options exercisable at March 31, 2020 (in shares) |
720,384
|
|
| Service vesting-based stock options exercisable at March 31, 2020 (in dollars per share) |
$ 1.64
|
|