Equity Compensation (Activity) (Details) - Stock options - $ / shares
|
6 Months Ended |
|
Jun. 30, 2016 |
Jun. 11, 2013 |
| Shares Subject to Options Outstanding |
|
|
| Balance at the beginning of the period (in shares) |
4,572,672
|
|
| Granted (in shares) |
50,000
|
|
| Exercised (in shares) |
(163,071)
|
|
| Expired (in shares) |
(49,001)
|
|
| Forfeited (in shares) |
(42,701)
|
|
| Balance at the end of the period (in shares) |
4,367,899
|
|
| Exercisable options (in shares) |
3,317,629
|
|
| Vested and expected to vest at the end of the period (in shares) |
3,316,345
|
|
| Weighted Average Grant Date Fair Value |
|
|
| Granted (in dollars per share) |
$ 4.63
|
|
| Weighted Average Exercise Price |
|
|
| Balance at the beginning of the period (in dollars per share) |
10.72
|
|
| Granted (in dollars per share) |
8.16
|
|
| Exercised (in dollars per share) |
4.36
|
|
| Expired (in dollars per share) |
13.38
|
|
| Forfeited (in dollars per share) |
16.02
|
|
| Balance at the end of the period (in dollars per share) |
10.85
|
|
| Exercisable options at the end of the period (in dollars per share) |
9.54
|
|
| Vested and expected to vest (in dollars per share) |
$ 10.79
|
|
| Weighted-Average Remaining Contractual Life |
|
|
| Exercisable options |
5 years 2 months 12 days
|
|
| Vested and expected to vest |
5 years 9 months 18 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%
|
| Increase in number of shares authorized for issuance |
0
|
|