STOCK OPTIONS STOCK OPTIONS - FAIR VALUE ASSUMPTIONS (Details) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Option value (in dollars per share) | $ 1.87 | $ 2.21 | |
| Risk-free rate (as a percent) | 0.60% | ||
| Expected dividend yield (as a percent) | 0.00% | 0.00% | 0.00% |
| Expected volatility - low (as a percent) | 49.50% | 53.00% | 53.00% |
| Expected volatility - high (as a percent) | 50.30% | 54.00% | 54.00% |
| Expected term (in years) | 6 years | ||
| Minimum | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Option value (in dollars per share) | $ 0.80 | $ 0.90 | $ 3.50 |
| Risk-free rate (as a percent) | 1.50% | 0.20% | |
| Expected term (in years) | 4 years | 4 years | |
| Maximum | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Option value (in dollars per share) | $ 0.91 | $ 1.84 | $ 4.30 |
| Risk-free rate (as a percent) | 1.80% | 1.60% | |
| Expected term (in years) | 10 years | 10 years | |