Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating expenses:
Research and development expenses	$ 6,361	$ 13,106
General and administrative expenses	3,683	4,270
Total operating expenses	10,044	17,376
Loss from operations	(10,044)	(17,376)
Other income and expenses:
Interest income	365	275
Interest expense	(478)
Other (expense) income, net	(301)	(681)
Total other income and expenses	(414)	(406)
Net loss	$ (10,458)	$ (17,782)
Net loss per common share - basic and diluted	$ (0.78)	$ (1.33)
Weighted-average common shares used to compute basic and diluted net loss per common share	13,343	13,343
Comprehensive loss:
Net loss	$ (10,458)	$ (17,782)
Unrealized gain (loss) on marketable securities	9	(12)
Comprehensive loss	$ (10,449)	$ (17,794)