6. STOCK-BASED COMPENSATION - Stock option activity (Details) |
3 Months Ended |
|---|---|
|
Mar. 31, 2018
USD ($)
shares
| |
| Option price per share | $ | $ 1,044 |
| Number | shares | 3,075 |
| Stock Option 1 | |
| Option price per share | $ | $ 1,680 |
| Number | shares | 1,725 |
| Stock Option 2 | |
| Option price per share | $ | $ 400 |
| Number | shares | 500 |
| Stock Option 3 | |
| Option price per share | $ | $ 134 |
| Number | shares | 850 |