Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock-based Compensation Expense

Stock-based compensation expense for the three and nine months ended September 30, 2020 and 2019 was classified in the Company’s condensed consolidated statement of operations and comprehensive loss as follows (in thousands):

	THREE MONTHS ENDED SEPTEMBER 30,				NINE MONTHS ENDED SEPTEMBER 30,
	2020		2019		2020		2019
Research and development	$	345	$	118	$	620	$	272
General and administrative		91		509		93		641
Total stock-based compensation expense	$	436	$	627	$	713	$	913

Summary of Stock Option Activity

Stock option activity under the 2015 Plan is summarized as follows:

	NUMBER OF OPTIONS			WEIGHTED- AVERAGE EXERCISE PRICE		WEIGHTED- AVERAGE REMAINING CONTRACTUAL TERM (IN YEARS)		AGGREGATE INTRINSIC VALUE
Outstanding as of December 31, 2019		2,368,950		$	4.35		8.11	$	10,309
Granted		1,467,424			4.98
Exercised		(251,466	)		3.17				2,442
Cancelled or forfeited		(1,229,054	)		4.52
Outstanding as of September 30, 2020		2,355,854			4.82		8.89	$	11,367
Options exercisable as of December 31, 2019		733,310			3.40		7.41	$	2,275
Options exercisable as of September 30, 2020		365,732			4.04		7.28	$	6,949