Equity Compensation (Activity) (Details) - Stock options - $ / shares
|
|
6 Months Ended |
|
Jan. 01, 2018 |
Jun. 30, 2018 |
Jun. 11, 2013 |
| Shares Subject to Options Outstanding |
|
|
|
| Balance at the beginning of the period (in shares) |
2,069,802
|
2,069,802
|
|
| Exercised (in shares) |
|
(279,012)
|
|
| Expired (in shares) |
|
(2,809)
|
|
| Forfeited (in shares) |
|
(3,587)
|
|
| Balance at the end of the period (in shares) |
|
1,784,394
|
|
| Exercisable options (in shares) |
|
1,649,277
|
|
| Vested and expected to vest at the end of the period (in shares) |
|
1,784,394
|
|
| Weighted Average Exercise Price |
|
|
|
| Balance at the beginning of the period (in dollars per share) |
$ 12.13
|
$ 12.13
|
|
| Exercised (in dollars per share) |
|
11.31
|
|
| Expired (in dollars per share) |
|
5.72
|
|
| Forfeited (in dollars per share) |
|
13.65
|
|
| Balance at the end of the period (in dollars per share) |
|
12.27
|
|
| Exercisable options at the end of the period (in dollars per share) |
|
12.30
|
|
| Vested and expected to vest (in dollars per share) |
|
$ 12.27
|
|
| Weighted-Average Remaining Contractual Life |
|
|
|
| Exercisable options |
|
4 years 8 months 12 days
|
|
| Vested and expected to vest |
|
4 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 |
1,291,644
|
|
|