Balance Sheet Components - Schedule of Allowance for Sales Incentives (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Movement in Valuation Allowances and Reserves [Roll Forward] | ||
| Beginning balance | $ (17,739) | |
| Ending balance | (21,897) | $ (17,739) |
| Allowance for Sales Incentives | ||
| Movement in Valuation Allowances and Reserves [Roll Forward] | ||
| Beginning balance | (10,442) | (8,503) |
| Charged to revenue | (50,958) | (44,264) |
| Utilization of sales return/incentive reserve | 47,650 | 42,325 |
| Ending balance | $ (13,750) | $ (10,442) |