Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2018

Stockholders' Equity

Schedule of allocation of stock-based compensation expense

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Research and development	$	286	$	309	$	975	$	889
General and administrative		435		658		1,852		1,838
Total	$	721	$	967	$	2,827	$	2,727