Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Summary of Share-based Compensation Expense

Share-based compensation expense for options granted under the 2011 Plan and the 2016 Plan is reflected in the statements of operations as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Research and development	$	377	$	306
General and administrative		422		413
Total	$	799	$	719

Summary of Activity Related to Stock Options

The following table summarizes the activity related to stock options during the three months ended March 31, 2021:

				Weighted
	Number of			Average
	Shares			Exercise Price
Options outstanding at December 31, 2020		4,248,193		$	3.95
Granted		1,631,156			4.01
Exercised		(62,493	)		0.59
Forfeited		—			—
Options outstanding at March 31, 2021		5,816,856			4.00
Options exercisable at December 31, 2020		2,355,900			4.96
Options exercisable at March 31, 2021		2,708,298			4.76

Restricted Stock Units (RSUs)

Summary of Share-based Compensation Expense

The total share-based compensation expense related to RSUs is reflected in the statements of operations as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Research and development	$	171	$	306
General and administrative		170		413
Total	$	341	$	719

Summary of the Activity Related to RSUs

The following table summarizes the activity related to RSUs during the three months ended March 31, 2021:

				Weighted Average
	Number of			Grant Date
	Shares			Fair Value
Non-vested RSUs outstanding at December 31, 2020		767,271		$	1.78
Granted		965,344			4.01
Vested		(227,754	)		1.72
Non-vested RSUs outstanding at March 31, 2021		1,504,861			3.22

2016 Employee Stock Purchase Plan

Summary of the Activity Related to RSUs

The share-based compensation expense recognized for the 2016 ESPP is reflected in the statements of operations and comprehensive loss as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Research and development	$	8	$	306
General and administrative		6		413
Total	$	14	$	719