v3.8.0.1
NET LOSS PER SHARE - Antidilutive Securities (Details) - shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Oct. 12, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive securities excluded from computation of earnings per share (in shares) 769,065 4,619,018 4,536,100  
Conversion ratio (in shares) 1     1
Redeemable Convertible Preferred Stock [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Conversion ratio (in shares) 1      
Redeemable Convertible Preferred Stock [Member] | Series A        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive securities excluded from computation of earnings per share (in shares) 0 670,000 670,000  
Redeemable Convertible Preferred Stock [Member] | Series B        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive securities excluded from computation of earnings per share (in shares) 0 2,979,475 2,979,475  
Restricted stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive securities excluded from computation of earnings per share (in shares) 548,005 677,241 593,653  
Stock options        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive securities excluded from computation of earnings per share (in shares) 176,959 248,201 248,871  
Warrants        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive securities excluded from computation of earnings per share (in shares) 44,101 44,101 44,101