Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Research and development expenses		$ 4,739		$ 11,100
General and administrative expenses	$ 1,184	5,929	$ 3,119	9,612
Gain on sale of assets		(1,410)	(2,139)	(1,410)
Total operating expenses	1,184	9,258	980	19,302
Loss from operations	(1,184)	(9,258)	(980)	(19,302)
Other income and expenses:
Interest income	3	207	48	572
Interest expense		(1,049)		(1,527)
Other income, net	18	670	18	369
Total other income and expenses	21	(172)	66	(586)
Net loss	(1,163)	(9,430)	(914)	(19,888)
Other comprehensive income:
Unrealized gain on marketable securities				9
Other comprehensive income				9
Comprehensive loss	$ (1,163)	$ (9,430)	$ (914)	$ (19,879)
Net loss per common share - basic and diluted	$ (0.09)	$ (0.71)	$ (0.07)	$ (1.49)
Weighted-average common shares used to compute basic and diluted net loss per common share	13,380	13,344	13,380	13,343