Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

Summary of Stock-based Compensation Expense

Stock-based compensation expense included in the Company’s condensed consolidated statements of operations and comprehensive loss is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
General and administrative	$	969	$	1,082	$	2,868	$	3,306
Research and development	1,076		980		3,225		2,844
Total stock-based compensation expense	$	2,045	$	2,062	$	6,093	$	6,150

Summary of Stock Option Activity

A summary of the Company’s stock option activity and related information is as follows: 

	Shares	Weighted- Average Exercise Price
Options outstanding at December 31, 2019	5,691,474	$	6.99
Granted	2,028,718	6.09
Exercised	(159,998)	1.54
Canceled	(982,574)	8.83
Options outstanding at September 30, 2020	6,577,620	$	6.57
Exercisable as of September 30, 2020	3,363,541	$	5.32