DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and Equipment (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2016 | |
| Minimum | |
| Property and Equipment [Line Items] | |
| Estimated useful lives | 2 years |
| Maximum | |
| Property and Equipment [Line Items] | |
| Estimated useful lives | 7 years |
| Leasehold improvements | Minimum | |
| Property and Equipment [Line Items] | |
| Estimated useful lives | 2 years |
| Leasehold improvements | Maximum | |
| Property and Equipment [Line Items] | |
| Estimated useful lives | 7 years |