Shareholder Equity (Tables)

3 Months Ended

Mar. 31, 2019

Summary of Stock-Based Compensation Expense

Stock-based compensation expense by award type was as follows (in thousands):



	Three Months Ended March 31,
	2019		2018
Stock options	$	325	$	375
Restricted stock	—		23
Employee stock purchase plan	1		3
	$	326	$	401

The Company allocated stock-based compensation expense as follows in the condensed consolidated statements of operations and comprehensive loss (in thousands):



	Three Months Ended March 31,
	2019		2018
Research and development expense	$	52	$	165
General and administrative expense	274		236
	$	326	$	401

Summary of Stock Option Activity and Related Information

A summary of the stock option activity is presented below:



	Shares		Weighted-Average Exercise Price
Outstanding at December 31, 2018	3,941,947		$	2.12
Granted	2,110,115		0.85
Exercised	—		—
Cancelled or forfeited	(363,500	)	2.44
Outstanding at March 31, 2019	5,688,562		$	1.62
Exercisable at March 31, 2019	1,076,840		$	3.13