COMMITMENTS AND CONTINGENCIES - Sublease Income (Details) $ in Thousands	Mar. 31, 2017 USD ($)
Operating Leased Assets [Line Items]
2017 (remaining nine months)	$ 254
2018	127
Total future minimum sublease payments	381
New York
Operating Leased Assets [Line Items]
2017 (remaining nine months)	124
2018	127
Total future minimum sublease payments	251
Menlo Park
Operating Leased Assets [Line Items]
2017 (remaining nine months)	130
2018	0
Total future minimum sublease payments	$ 130