COMMITMENTS AND CONTINGENCIES - Sublease Income (Details) $ in Thousands	Jun. 30, 2017 USD ($)
Operating Leased Assets [Line Items]
2017 (remaining six months)	$ 166
2018	127
Total future minimum sublease payments	293
New York
Operating Leased Assets [Line Items]
2017 (remaining six months)	84
2018	127
Total future minimum sublease payments	211
Menlo Park
Operating Leased Assets [Line Items]
2017 (remaining six months)	82
2018	0
Total future minimum sublease payments	$ 82