FAIR VALUE MEASUREMENT - The liability component was valued based on the Income Approach (Details) - 2021 Notes [Member] - Fair Value, Inputs, Level 3 [Member] |
6 Months Ended |
---|---|
Jun. 30, 2020
$ / shares
| |
Stock price (USD) | $ 3.79 |
Expected term | 1 year 4 months 17 days |
Risk free rate | 0.16% |
Volatility | 107.87% |
Yield | 12.87% |