Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses:
General and administrative	$ 53,798	$ 31,808	$ 19,358
Research and development	222,798	208,472	122,917
Totals	276,596	240,280	142,275
Loss from operations	(276,596)	(240,280)	(142,275)
Other income (expenses):
Interest income	958	971	324
Other income (expense)	(373)	25	(14)
Totals	585	996	310
Net loss	(276,011)	(239,284)	(141,965)
Net loss applicable to common stock	$ (276,011)	$ (239,284)	$ (141,965)
Net loss per common share—basic and diluted	$ (8.29)	$ (7.45)	$ (4.73)
Weighted-average common shares outstanding—basic and diluted	33,295,114	32,126,094	30,010,979