CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating expenses:
Research and development	$ 41,003	$ 75,579
General and administrative	13,462	7,857
Total operating expenses	54,465	83,436
Loss from operations	(54,465)	(83,436)
Other income (expense):
Non-cash interest expense on liability related to sale of future royalties	(6,813)	0
Change in fair value of warrant liability	0	(1,182)
Loss from equity method investment	(900)	(728)
Other	(17)	(29)
Total other expense, net	(7,730)	(1,939)
Loss before provision for income taxes	(62,195)	(85,375)
Provision for income taxes	109	87
Net loss and comprehensive loss	$ (62,304)	$ (85,462)
Net loss per share - basic and diluted (in dollars per share)	$ (1.41)	$ (2.32)
Weighted average common shares outstanding - basic and diluted (shares)	44,242,070	36,793,090