INCOME TAXES - Additional information (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| INCOME TAXES | |||
| Income before income taxes | $ (286,697) | $ (338,918) | $ (239,552) |
| State income tax expense | $ 63 | $ 252 | $ 377 |
| Federal statutory rates | 21.00% | 21.00% | 21.00% |
| Valuation allowance | $ 235,174 | $ 174,863 | |
| Increase in valuation allowance | 60,300 | 86,200 | |
| Federal net operating loss ("NOL") carryforwards | 870,200 | ||
| State net operating loss ("NOL") carryforwards | $ 585,900 | ||
| Percentage of taxable income utilize | 80.00% | ||
| Federal NOLs generated | $ 166,900 | $ 236,100 | |
| NOL Carry over period | 20 years | ||
| Federal research tax credit carryforwards | $ 11,000 | ||
| State research tax credit carryforwards | 9,400 | ||
| Impact on effective tax rate | $ 5,500 | ||