SELECTED QUARTERLY FINANCIAL DATE (UNAUDITED) (Tables)

12 Months Ended

Dec. 31, 2019

Condensed Financial Information Disclosure [Abstract]

Selected Quarterly Financial Information

Net loss per share for all periods presented has been retroactively adjusted to reflect the 1-for-3.98 reverse stock split effected on June 15, 2018.

	2019
(in thousands, except per share data)	Q1		Q2		Q3		Q4
Operating expenses	$	37,775	$	37,837	$	45,096	$	58,116
Net loss	(37,897)		(36,626)		(44,119)		(58,171)
Net loss per share, basic and diluted	$	(0.90)	$	(0.75)	$	(0.89)	$	(1.17)

	2018
(in thousands, except per share data)	Q1		Q2		Q3		Q4
Operating expenses	$	20,098	$	25,279	$	29,408	$	28,810
Net loss	(20,504)		(25,362)		(29,098)		(27,844)
Net loss per share, basic and diluted	$	(9.00)	$	(10.89)	$	(0.71)	$	(0.66)