Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2019 |
Dec. 31, 2018 |
|
| Commitments And Contingencies [Line Items] | ||
| Letters of credit outstanding | $ 31.3 | $ 31.3 |
| Letters of credit expiration date | Dec. 31, 2030 | |
| Manufacturing | ||
| Commitments And Contingencies [Line Items] | ||
| Purchase commitments for inventory, content licensing, advertising buys and other platform services | $ 52.8 | |
| Loss on purchase obligation for inventory | 0.4 | $ 0.1 |
| Content Providers and Other Vendors | ||
| Commitments And Contingencies [Line Items] | ||
| Purchase commitments for inventory, content licensing, advertising buys and other platform services | $ 75.9 |