Equity Compensation (Activity) (Details) - Stock options - $ / shares
|
3 Months Ended |
|
Mar. 31, 2016 |
Jun. 11, 2013 |
| Shares Subject to Options Outstanding |
|
|
| Balance at the beginning of the period (in shares) |
4,572,672
|
|
| Exercised (in shares) |
(25,248)
|
|
| Expired (in shares) |
(31,064)
|
|
| Forfeited (in shares) |
(18,496)
|
|
| Balance at the end of the period (in shares) |
4,497,864
|
|
| Exercisable options (in shares) |
3,301,042
|
|
| Vested and expected to vest at the end of the period (in shares) |
4,412,280
|
|
| Weighted Average Exercise Price |
|
|
| Balance at the beginning of the period (in dollars per share) |
$ 10.72
|
|
| Exercised (in dollars per share) |
4.59
|
|
| Expired (in dollars per share) |
13.20
|
|
| Forfeited (in dollars per share) |
14.97
|
|
| Balance at the end of the period (in dollars per share) |
10.72
|
|
| Exercisable options at the end of the period (in dollars per share) |
9.09
|
|
| Vested and expected to vest (in dollars per share) |
$ 10.64
|
|
| Weighted-Average Remaining Contractual Life |
|
|
| Exercisable options |
5 years 2 months 12 days
|
|
| Vested and expected to vest |
5 years 10 months 24 days
|
|
| 2013 Plan |
|
|
| Stock options |
|
|
| Potential annual increase in shares authorized for issuance as a percentage of shares outstanding as of the preceding December 31 |
|
5.00%
|