STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Expenses:
Research and development	$ 2,642	$ 4,840	$ 9,032	$ 17,593
General and administrative	1,571	1,529	5,074	4,719
Loss from operations	(4,213)	(6,369)	(14,106)	(22,312)
Interest income	45	36	116	93
Interest expense	(3)	(118)	(159)	(365)
Other income (expense)	1	(13)	(11)	(44)
Net loss	$ (4,170)	$ (6,464)	$ (14,160)	$ (22,628)
Per share information:
Net loss per share of common stock-basic and diluted (in dollars per share)	$ (0.15)	$ (0.33)	$ (0.60)	$ (1.16)
Basic and diluted weighted average shares outstanding (in shares)	28,666,656	19,509,220	23,531,745	19,494,424
Net loss	$ (4,170)	$ (6,464)	$ (14,160)	$ (22,628)
Other comprehensive loss:
Unrealized loss on available-for-sale securities	(18)		(18)
Total comprehensive loss	$ (4,188)	$ (6,464)	$ (14,178)	$ (22,628)