Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating expenses:
Research and development	$ 5,936	$ 5,813	$ 19,190	$ 16,360
General and administrative	2,347	2,388	7,695	5,966
Total operating expenses	8,283	8,201	26,885	22,326
Loss from operations	(8,283)	(8,201)	(26,885)	(22,326)
Other (expense) income:
Interest expense	(199)	(282)	(662)	(709)
Interest and investment income	50		183
Other income, net	13	(2)	82	11
Total other expense, net	(136)	(284)	(397)	(698)
Net loss	$ (8,419)	$ (8,485)	$ (27,282)	$ (23,024)
Net loss per share - basic and diluted (in dollars per share)	$ (0.54)	$ (0.55)	$ (1.77)	$ (4.11)
Weighted-average common shares outstanding used in net loss per share - basic and diluted (in shares)	15,512,608	15,297,794	15,407,747	5,596,412