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Note 6 - Stockholder's Equity (Details) - Stock Options (USD $)
|
12 Months Ended |
|
Dec. 31, 2013
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
| Stock Options [Abstract] |
|
|
|
|
|
| Stock Options Outstanding |
1,356,446 |
3,813,361 |
|
4,863,239 |
5,835,118 |
| Weighted Average Exercise Price (in Dollars per share) |
$ 15.86 |
$ 15.62 |
|
$ 15.31 |
$ 14.61 |
| Weighted-Average Remaining Contractual Term (Years) |
1 year 332 days |
2 years 204 days |
|
3 years 160 days |
4 years 109 days |
| Aggregate Intrinsic Value (in Dollars) |
$ 25,505,753 |
$ 25,379,573 |
|
$ 8,817,049 |
$ 19,035,591 |
| Options exercisable at December 31, 2013 and expected to vest |
1,353,337 |
|
|
|
|
| Options exercisable at December 31, 2013 and expected to vest (in Dollars per share) |
$ 15.86 |
|
|
|
|
| Options exercisable at December 31, 2013 and expected to vest |
1 year 332 days |
|
|
|
|
| Options exercisable at December 31, 2013 and expected to vest (in Dollars) |
25,437,135 |
|
|
|
|
| Options exercisable at December 31, 2013 |
1,274,757 |
|
|
|
|
| Options exercisable at December 31, 2013 (in Dollars per share) |
$ 15.96 |
|
|
|
|
| Options exercisable at December 31, 2013 |
1 year 277 days |
|
|
|
|
| Options exercisable at December 31, 2013 (in Dollars) |
$ 23,843,458 |
|
|
|
|
| Stock Options Outstanding |
171,484 |
178,484 |
[1] |
152,500 |
|
| Weighted Average Exercise Price (in Dollars per share) |
|
$ 15.63 |
[1] |
$ 13.96 |
|
| Stock Options Outstanding |
(2,445,523) |
(1,151,884) |
|
(685,417) |
|
| Weighted Average Exercise Price (in Dollars per share) |
$ 15.49 |
$ 11.62 |
|
$ 6.85 |
|
| Stock Options Outstanding |
(11,392) |
(76,478) |
|
(438,962) |
|
| Weighted Average Exercise Price (in Dollars per share) |
$ 15.27 |
$ 20.90 |
|
$ 18.66 |
|
|
|
|