NET LOSS PER COMMON SHARE - Computation of Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Net loss per common share | |||||||||||
| Net loss | $ (27,559) | $ (26,444) | $ (24,520) | $ (15,653) | $ (9,525) | $ (9,362) | $ (4,674) | $ (3,694) | $ (94,176) | $ (27,255) | $ (17,917) |
| Extinguishment of preferred stock | 31,806 | ||||||||||
| Accretion of prior preferred stock | (23,327) | (3,300) | |||||||||
| Loss attributable to common shareholders — basic and diluted | $ (94,176) | $ (20,021) | $ (21,217) | ||||||||
| Weighted-average number of common shares used in net loss per share-basic and diluted (in shares) | 27,100,231 | 23,460,340 | 23,417,378 | 23,130,153 | 24,262,945 | 13,542,282 | 933,997 | ||||
| (Loss) earnings per share - basic | $ (0.46) | $ (0.46) | $ (0.45) | $ 0.34 | $ (3.88) | $ (1.48) | $ (22.72) | ||||
| Series D convertible redeemable preferred stock | |||||||||||
| Net loss per common share | |||||||||||
| Accretion of prior preferred stock | $ (1,245) | ||||||||||