STOCK-BASED COMPENSATION - Equity Incentive Plan (Details) - USD ($) $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
Jan. 01, 2016 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Payments Related to Tax Withholding for Share-based Compensation | $ 1,121 | $ 3,158 | $ 316 | |
| 2014 Equity Incentive Plan | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Increase to shares of common stock reserved for issuance | 2,450,865 | 2,450,865 | ||
| Shares reserved for issuance under share-based compensation plan | 5,116,753 | 5,017,525 | ||
| Maximum annual increase of common stock reserved for issuance under share-based compensation plan | 4,000,000 | |||
| Maximum annual increase of common stock reserved for issuance under share-based compensation plan, as a percent of total shares outstanding | 5.00% | |||