Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
REVENUES:
Product revenue, net	$ 980	$ 0	$ 980	$ 0
OPERATING EXPENSES:
Cost of sales	105	0	105	0
Research and development	19,652	26,891	39,179	54,374
Selling, general and administrative	50,121	17,193	88,220	30,839
Loss from operations	(68,898)	(44,084)	(126,524)	(85,213)
OTHER (EXPENSE) INCOME:
Other expense, net	(97)	(95)	(17)	(96)
Interest income	557	744	1,164	1,411
NET LOSS	(68,438)	(43,435)	(125,377)	(83,898)
OTHER COMPREHENSIVE LOSS:
Unrealized (loss) gain from available-for-sale securities	(32)	(49)	(69)	183
COMPREHENSIVE LOSS	(68,470)	(43,484)	(125,446)	(83,715)
LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS - BASIC AND DILUTED (Note 10)	$ 68,438	$ 43,435	$ 125,377	$ 83,898
LOSS PER SHARE:
Basic and diluted (in dollars per share)	$ (1.58)	$ (1.01)	$ (2.90)	$ (1.95)
WEIGHTED AVERAGE SHARES:
Basic and diluted (in shares)	43,410,053	43,042,883	43,300,243	43,027,903