Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating expenses:
Research and development	$ 24,352	$ 22,980
Selling, general and administrative	10,918	8,070
Change in fair value of contingent consideration	3,000	0
Total operating expenses	38,270	31,050
Loss from operations	(38,270)	(31,050)
Other income (expense):
Interest income	3,156	833
Other (expense) income, net	(88)	37
Total other income	3,068	870
Net loss	$ (35,202)	$ (30,180)
Net loss per share, basic and diluted:
Net loss per share, basic and diluted (in dollars per share)	$ (0.83)	$ (0.87)
Weighted average common shares used in the calculation of basic and diluted net loss per common share (shares)	42,236	34,841