COMMITMENTS AND CONTINGENCIES - LEASES (Details) - Cambridge Lease $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
|
Sep. 17, 2012
USD ($)
ft²
|
Dec. 31, 2016
USD ($)
|
Dec. 31, 2015
USD ($)
|
|
| Commitments | |||
| Lease space (in square feet) | ft² | 26,150 | ||
| Term of commercial lease | 6 years 3 months | ||
| Term of lease extension option | 5 years | ||
| Standby letter of credit | $ 311 | ||
| Deferred rent liability | $ 276 | $ 391 | |
| Leasehold improvements, net | $ 143 | $ 185 | |