NET LOSS PER SHARE - Antidilutive Shares (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Aug. 11, 2016
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Earnings Per Share (in shares)	3,165,387	3,685,125	3,682,019
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Earnings Per Share (in shares)	46,247	79,457	414,001
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Earnings Per Share (in shares)	265,684	218,505	79,940
Convertible Debt Securities [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Earnings Per Share (in shares)	2,863,935	2,768,657	0
Convertible Notes Payable [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt issued				$ 50,000,000