PREPAID EXPENSES AND OTHER ASSETS - Summary of other noncurrent assets (Details 1) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Other Assets, Noncurrent Disclosure [Abstract] | ||
| Deferred activation fees | $ 360 | $ 293 |
| Deposits | 114 | 116 |
| Total other noncurrent assets | $ 474 | $ 409 |