Condensed Consolidated Statements Of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Consolidated Statements Of Operations And Comprehensive Loss [Abstract]
Revenue
Operating expenses:
General and administrative	3,772	642	4,992	1,170
Research and development	2,282	1,453	4,133	2,443
Amortization of intangible assets	167	166	333	332
Total operating expenses	6,221	2,261	9,458	3,945
Other income:
Interest income	41	3	80	3
Total other income	41	3	80	3
Net loss	(6,180)	(2,258)	(9,378)	(3,942)
Other comprehensive loss:
Unrealized gain on available-for-sale securities, net of tax	3		1
Comprehensive loss	$ (6,177)	$ (2,258)	$ (9,377)	$ (3,942)
Net loss per share:
Basic and diluted net loss per share	$ (0.43)	$ (0.23)	$ (0.67)	$ (0.45)
Weighted average shares used to compute net loss per common share - basic and diluted	14,233	9,791	14,019	8,678