Summary of Significant Accounting Policies - Advertising and Marketing (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Accounting Policies [Abstract] | |||
| Advertising and marketing costs | $ 6.1 | $ 3.7 | $ 2.2 |