ACCOUNTS RECEIVABLE - Accounts receivable and related allowance for doubtful accounts (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Receivables [Abstract] | ||
| Accounts receivable | $ 9,748 | $ 9,218 |
| Unbilled accounts receivable | 455 | 637 |
| Allowance for doubtful accounts | (767) | (618) |
| Accounts receivable, net | $ 9,436 | $ 9,237 |