CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS | |||
| Unrealized gains (losses) on investments, tax | $ 0 | $ 0 | $ 0 |