Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Research premium and grant revenue	$ 1,468	$ 971	$ 4,197	$ 4,175
Operating expenses:
Research and development	(12,668)	(12,058)	(36,371)	(35,037)
General and administrative	(9,525)	(2,992)	(19,313)	(9,445)
Total operating expenses	(22,193)	(15,050)	(55,684)	(44,482)
Loss from operations	(20,725)	(14,079)	(51,487)	(40,307)
Other income (expense):
Other income (expense), net	301	50	391	404
Interest income	69	92	302	234
Interest expense	(42)	(35)	(46)	(35)
Loss before income taxes	(20,397)	(13,972)	(50,840)	(39,704)
Income tax benefit (expense)	(1,872)	(28)	(1,254)	1
Net loss	(22,269)	(14,000)	(52,094)	(39,703)
Other comprehensive income (loss), net of tax
Unrealized gains on available-for-sale securities	69	34	43	67
Other comprehensive income, net of tax	69	34	43	67
Comprehensive loss	$ (22,200)	$ (13,966)	$ (52,051)	$ (39,636)
Loss per share
Basic and Diluted (in dollars per share)	$ (0.79)	$ (0.66)	$ (1.89)	$ (1.87)
Weighted average number of shares:
Basic and Diluted (in shares)	28,147,226	21,276,610	27,517,267	21,236,260