NATURE OF BUSINESS (Details)
$ / shares in Units, $ in Thousands
1 Months Ended
Oct. 31, 2016
USD ($)
$ / shares
shares
Jan. 31, 2016
USD ($)
$ / shares
shares
May 31, 2015
USD ($)
$ / shares
shares
Apr. 30, 2015
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Common stock split ratio       0.1449    
Accumulated deficit            
Accumulated deficit | $         $ 223,184 $ 129,008
Initial public offering            
Stock Issued During Period, Shares, New Issues 5,750,000 2,750,000 6,670,000      
Issue price (in dollars per share) | $ / shares $ 16.00 $ 20.00 $ 12.00      
Net proceeds from IPO | $ $ 86,166 $ 51,174 $ 72,029      
Conversion into common stock     12,591,463      
Underwriters over-allotment option            
Stock Issued During Period, Shares, New Issues     870,000