STOCK BASED COMPENSATION - Narrative (Details) - USD ($) $ in Thousands |
1 Months Ended | 12 Months Ended | |
|---|---|---|---|
May 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Stock-based compensation | |||
| Employee Stock Purchase Plan, Purchase Price Percentage | 85.00% | ||
| Employee Stock Purchase Plan, Compensation Expense | $ 457 | ||
| Stock options | |||
| Stock-based compensation | |||
| Shares of common stock authorized for issuance outstanding (in shares) | 2,326,801 | 1,452,149 | |
| Vesting period | 4 years | ||
| Contractual life | 10 years | ||
| Stock options | Minimum | |||
| Stock-based compensation | |||
| Period following termination date vested options are exercisable | 1 month | ||
| Stock options | Maximum | |||
| Stock-based compensation | |||
| Period following termination date vested options are exercisable | 3 months | ||
| 2014 Stock Incentive Plan | |||
| Stock-based compensation | |||
| Shares of common stock authorized for issuance (in shares) | 2,700,000 | 1,021,509 | |
| Increase in number of authorized shares on the first day of each fiscal year, as a percentage of outstanding common stock (as a percent) | 4.00% |