Property and Equipment, Net (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Property and Equipment [Line Items] | |||
| Total property and equipment | $ 105,366 | $ 65,380 | |
| Accumulated depreciation and amortization expenses | (31,738) | (14,458) | |
| Total property and equipment, net | 73,628 | 50,922 | |
| Depreciation expense | 17,300 | 9,200 | $ 2,600 |
| Capitalized computer software, amortization | 12,400 | 4,900 | 1,400 |
| Computer hardware | |||
| Property and Equipment [Line Items] | |||
| Total property and equipment | 10,421 | 5,667 | |
| Furniture and equipment | |||
| Property and Equipment [Line Items] | |||
| Total property and equipment | 3,187 | 2,448 | |
| Internal-use software development costs | |||
| Property and Equipment [Line Items] | |||
| Total property and equipment | 81,640 | 48,557 | |
| Total property and equipment, net | 62,800 | 42,100 | |
| Capitalized computer software additions | 33,100 | 27,100 | $ 15,000 |
| Leasehold improvements | |||
| Property and Equipment [Line Items] | |||
| Total property and equipment | $ 10,118 | $ 8,708 | |