Equity Compensation (Range) (Details) - Stock options
|
12 Months Ended |
|
Dec. 31, 2017
$ / shares
shares
|
|---|
| Options Outstanding |
|
| Number of Underlying Shares | shares |
2,069,802
|
| Options Exercisable |
|
| Number of Underlying Shares | shares |
1,786,261
|
| 4.78-7.28 |
|
| Equity compensation |
|
| Range of Exercise Price, low end of range (in dollars per share) |
$ 4.78
|
| Range of Exercise Price, high end of range (in dollars per share) |
7.28
|
| Options Outstanding |
|
| Weighted Average Exercise Price (in dollars per share) |
$ 6.01
|
| Number of Underlying Shares | shares |
703,312
|
| Weighted-Average Remaining Contractual Life |
3 years 6 months
|
| Options Exercisable |
|
| Number of Underlying Shares | shares |
693,299
|
| Weighted-Average Remaining Contractual Life |
3 years 4 months 24 days
|
| 7.49-11.29 |
|
| Equity compensation |
|
| Range of Exercise Price, low end of range (in dollars per share) |
$ 7.49
|
| Range of Exercise Price, high end of range (in dollars per share) |
11.29
|
| Options Outstanding |
|
| Weighted Average Exercise Price (in dollars per share) |
$ 10.01
|
| Number of Underlying Shares | shares |
434,929
|
| Weighted-Average Remaining Contractual Life |
5 years 6 months
|
| Options Exercisable |
|
| Number of Underlying Shares | shares |
338,311
|
| Weighted-Average Remaining Contractual Life |
5 years 1 month 6 days
|
| 11.72-17.66 |
|
| Equity compensation |
|
| Range of Exercise Price, low end of range (in dollars per share) |
$ 11.72
|
| Range of Exercise Price, high end of range (in dollars per share) |
17.66
|
| Options Outstanding |
|
| Weighted Average Exercise Price (in dollars per share) |
$ 14.700
|
| Number of Underlying Shares | shares |
483,862
|
| Weighted-Average Remaining Contractual Life |
6 years 10 months 24 days
|
| Options Exercisable |
|
| Number of Underlying Shares | shares |
335,285
|
| Weighted-Average Remaining Contractual Life |
6 years 10 months 24 days
|
| 19.56-22.92 |
|
| Equity compensation |
|
| Range of Exercise Price, low end of range (in dollars per share) |
$ 19.56
|
| Range of Exercise Price, high end of range (in dollars per share) |
22.92
|
| Options Outstanding |
|
| Weighted Average Exercise Price (in dollars per share) |
$ 21.02
|
| Number of Underlying Shares | shares |
447,699
|
| Weighted-Average Remaining Contractual Life |
6 years 1 month 6 days
|
| Options Exercisable |
|
| Number of Underlying Shares | shares |
419,366
|
| Weighted-Average Remaining Contractual Life |
6 years 1 month 6 days
|