Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Research premium and grant revenue	$ 1,678	$ 1,419
Operating expenses:
Research and development	(12,660)	(13,036)
General and administrative	(4,218)	(3,085)
Total operating expenses	(16,878)	(16,121)
Loss from operations	(15,200)	(14,702)
Other income (expense):
Other income (expense), net	206	998
Interest income	121	88
Interest expense	(1)
Loss before income taxes	(14,874)	(13,616)
Income tax benefit (expense)	(349)	17
Net loss	(15,223)	(13,599)
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on available-for-sale financial assets	(16)	41
Other comprehensive income (loss), net of tax	(16)	41
Comprehensive loss	$ (15,239)	$ (13,558)
Loss per share
Basic (in dollars per share)	$ (5.60)	$ (6.42)
Diluted (in dollars per share)	$ (5.60)	$ (6.42)
Weighted average number of shares:
Basic (in shares)	2,720,423	2,117,895
Diluted (in shares)	2,720,423	2,117,895