Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Summary of Share-based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	384	$	295	$	804	$	606
General and administrative		480		437		862		833
Total	$	864	$	732	$	1,666	$	1,439

Summary of Activity Related to Stock Options

The following table summarizes the activity related to stock options granted under the 2011 Plan and the 2016 Plan during the six months ended June 30, 2024:

				Weighted
	Number of			Average
	Shares			Exercise Price
Options outstanding at December 31, 2023		9,865,770		$	2.83
Granted		3,034,375			1.32
Exercised		(10,000	)		1.24
Forfeited		(122,815	)		2.83
Options outstanding at June 30, 2024		12,767,330			2.47
Options exercisable at December 31, 2023		5,494,746			3.83
Options exercisable at June 30, 2024		6,691,528			3.45

Restricted Stock Units (RSUs)

Summary of Share-based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	118	$	163	$	237	$	332
General and administrative		135		163		273		324
Total	$	253	$	326	$	510	$	656

Summary of the Activity Related to RSUs

The following table summarizes the activity related to RSUs during the six months ended June 30, 2024:

				Weighted Average
	Number of			Grant Date
	Shares			Fair Value
Non-vested RSUs outstanding at December 31, 2023		834,899		$	3.01
Vested		(397,594	)		3.07
Non-vested RSUs outstanding at June 30, 2024		437,305			2.96

2016 Employee Stock Purchase Plan

Summary of Share-based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	2	$	2	$	5	$	5
General and administrative		1		1		1		2
Total	$	3	$	3	$	6	$	7