Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating expenses:
Research and development expenses	$ 4,739	$ 13,678	$ 11,100	$ 26,784
General and administrative expenses	5,929	3,513	9,612	7,783
Gain on sale of assets	(1,410)		(1,410)
Total operating expenses	9,258	17,191	19,302	34,567
Loss from operations	(9,258)	(17,191)	(19,302)	(34,567)
Other income and expenses:
Interest income	207	282	572	557
Interest expense	(1,049)		(1,527)
Other (expense) income, net	670	(860)	369	(1,541)
Total other income and expenses	(172)	(578)	(586)	(984)
Net loss	$ (9,430)	$ (17,769)	$ (19,888)	$ (35,551)
Net loss per common share - basic and diluted	$ (0.71)	$ (1.33)	$ (1.49)	$ (2.66)
Weighted-average common shares used to compute basic and diluted net loss per common share	13,344	13,343	13,343	13,343
Comprehensive loss:
Net loss	$ (9,430)	$ (17,769)	$ (19,888)	$ (35,551)
Unrealized gain (loss) on marketable securities		11	9	(1)
Comprehensive loss	$ (9,430)	$ (17,758)	$ (19,879)	$ (35,552)