Share-Based Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2021

A summary of option activity for the nine months ended September 30, 2021 is presented below:

	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2020		28,966,901		$	3.70
Granted		8,447,864			3.52
Exercised		(2,414,403	)		3.39
Forfeited		(1,343,995	)		3.22
Expired		(846,601	)		5.18
Outstanding at September 30, 2021		32,809,766		$	3.65		7.54	$	54,322,145
Vested or expected to vest at September 30, 2021		32,809,766		$	3.65		7.54	$	54,322,145
Exercisable at September 30, 2021		14,386,054		$	3.89		5.99	$	21,107,993

Summary of Non-vested Stock Activity

A summary of non-vested stock activity for the nine months ended September 30, 2021 is presented below:

	Non-vested Shares			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		886,816		$	2.14
Granted		1,960,701			3.24
Vested		(1,771,967	)		3.13
Forfeited		(30,000	)		3.23
Outstanding at September 30, 2021		1,045,550		$	2.38

Schedule of Share-Based Compensation Expense

The impact on our results of operations from share-based compensation for the three and nine months ended September 30, 2021 and 2020, was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	1,185	$	902	$	3,349	$	2,944
General and administrative		3,591		1,718		10,790		4,537
Total share-based compensation expense	$	4,776	$	2,620	$	14,139	$	7,481