NET LOSS PER COMMON SHARE (Tables)

12 Months Ended

Dec. 31, 2016

NET LOSS PER COMMON SHARE.

Schedule of computations of basic and diluted net loss per share

	Years ended December 31,
		2016		2015	2014
Net loss	$	(94,176)	$	(27,255)	$	(17,917)
Extinguishment of preferred stock - see Note 12		—		31,806		—
Accretion and dividends of prior preferred stock - See Note 12		—		(23,327)		(3,300)
Accretion and dividends of Series D preferred stock		—		(1,245)		—
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		24,262,945		13,542,282		933,997
Loss per share - basic and diluted	$	(3.88)	$	(1.48)	$	(22.72)

Schedule of potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding

	Years ended December 31,
	2016	2015	2014
Outstanding stock options	2,326,801	1,452,149	281,029
Warrants	2,445	2,445	18,809
Redeemable convertible preferred stock	—	—	6,552,820
Unvested restricted stock	82,512	75,718	15,387
Restricted stock units	41,741	—	—