Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses:
Research and development	$ 10,756	$ 11,981
General and administrative	13,026	4,692
Total operating expenses	23,782	16,673
Loss from operations	(23,782)	(16,673)
Other income (expense):
Interest income	557	336
Interest expense	(632)	(276)
Other income (expense), net	(22)	(202)
Total other income (expense)	(97)	(142)
Net loss	$ (23,879)	$ (16,815)
Net loss per share basic and diluted	$ (0.75)	$ (0.78)
Weighted average common shares outstanding, basic and diluted	31,704	21,570
Other comprehensive (loss) income:
Unrealized gains from available-for-sale securities, net of tax of $0	$ 9	$ (89)
Total other comprehensive (loss) income	9	(89)
Comprehensive loss	$ (23,870)	$ (16,904)