Description of Business and Summary of Significant Accounting Policies (AntiDilutive) (Details) - shares shares in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Anti-dilutive weighted-average common stock equivalents excluded from the calculation of diluted net income per share | |||
| Total (in shares) | 665 | 2,345 | 4,918 |
| Options | Common Stock | |||
| Anti-dilutive weighted-average common stock equivalents excluded from the calculation of diluted net income per share | |||
| Total (in shares) | 660 | 2,328 | 4,756 |
| Restricted stock units | |||
| Anti-dilutive weighted-average common stock equivalents excluded from the calculation of diluted net income per share | |||
| Total (in shares) | 5 | 17 | 162 |