Stockholders' Equity - Stock Option Activity Under Equity-Based Plans (Details) |
3 Months Ended |
|---|---|
|
Mar. 31, 2018
shares
| |
| Number of Shares | |
| Balance (in shares) | 1,296,863 |
| Exercised (in shares) | (206,430) |
| Forfeited (in shares) | (4,167) |
| Balance (in shares) | 1,086,266 |
| Exercisable (in shares) | 1,011,038 |