Share-Based Compensation Plans

3 Months Ended

Mar. 31, 2025

Share-Based Payment Arrangement, Noncash Expense [Abstract]

Note J – Share-based Compensation Plans

We primarily use the Black-Scholes option pricing model to value stock options granted to employees and non-employees, including stock options granted to members of our Board of Directors. However, the fair value of stock option market-based awards is

calculated based on a Monte Carlo simulation as of the date of issuance. All stock options have 10-year terms and generally vest ratably over a 3 or 4-year period.

A summary of option activity for the three months ended March 31, 2025 is presented below:


	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2024		5,242,916		$	28.76
Granted		90,134			3.04
Exercised		—			—
Forfeited		(40,423	)		20.82
Expired		(99,463	)		76.90
Outstanding at March 31, 2025		5,193,164		$	27.42		7.93	$	—
Vested or expected to vest at March 31, 2025		5,193,164		$	27.42		7.93	$	—
Exercisable at March 31, 2025		2,711,308		$	46.08		6.61	$	—

The weighted average grant-date fair values of stock options granted during the three months ended March 31, 2025 and 2024 were $2.61 and $8.82, respectively.

As of March 31, 2025, there was approximately $10.9 million of total unrecognized share-based compensation expense related to these stock options and stock options granted under subsidiary plans which, if all milestones are achieved, will be recognized over a weighted average period of 1.3 years.

Certain employees and consultants have been granted non-vested stock. The fair value of non-vested market-based awards is calculated based on a Monte Carlo simulation as of the date of issuance. The fair value of other non-vested stock is calculated based on the closing sale price of our common stock on the date of issuance.

A summary of non-vested stock activity for the three months ended March 31, 2025 is presented below:


	Non-vested Shares			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2024		42,222		$	17.30
Granted		77,551			2.69
Vested		(69,325	)		3.63
Forfeited		(6,333	)		21.25
Outstanding at March 31, 2025		44,115		$	12.52

As of March 31, 2025, there was approximately $1.0 million of unrecognized share-based compensation expense related to these non-vested shares and non-vested shares granted under subsidiary plans which will be recognized over a period of 3.0 years.

During the three months ended March 31, 2025, 18,365 shares were issued under the 2019 Employee Stock Purchase Plan and 17,268 shares were issued as a result of the vesting of non-vested stock.

The impact on our results of operations from share-based compensation for the three months ended March 31, 2025 and 2024, was as follows (in thousands):


	Three Months Ended March 31,
	2025		2024
Research and development	$	826	$	1,314
General and administrative		2,507		2,882
Total share-based compensation expense	$	3,333	$	4,196