Share-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Compensation Expenses

Total share-based compensation expense included in the condensed consolidated statements of operations and comprehensive loss is as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Research and development	$	376	$	204	$	957	$	907
General and administrative	314		266		1,487		996
	$	690	$	470	$	2,444	$	1,903

Summary of Stock Option Activity

Stock option activity for the nine months ended September 30, 2019 is as follows:

	Shares Subject to Outstanding Options		Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Options outstanding as of December 31, 2018	1,671,666		$	5.42
Options granted	658,030		2.36
Options forfeited	(384,695	)	7.26
Options exercised	(12,999	)	0.76
Options outstanding as of September 30, 2019	1,932,002		$	4.05	8.24	$	211