Schedule II - Valuation And Qualifying Accounts (Details) - Allowance for sales returns. - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Valuation and Qualifying Accounts | |||
| Balance at beginning of period | $ 10,018 | $ 8,270 | $ 4,334 |
| Additions charged to costs and expenses | 85,429 | 110,033 | 93,768 |
| Deductions | (94,787) | (108,285) | (89,832) |
| Balance at end of period | $ 660 | $ 10,018 | $ 8,270 |