Stock-Based Compensation

6 Months Ended

Jun. 30, 2022

Stock-Based Compensation.

Stock-Based Compensation

Note 12—Stock-Based Compensation

Our stock option plans provide for the grant of incentive and non-qualified stock options, restricted stock awards, RSUs, warrants and other stock awards to employees, non-employee directors and consultants.

Stock-based compensation is as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2022		2021		2022		2021
	(In thousands)
Continuing operations
Research and development	$	1,389	$	1,390	$	3,104	$	2,840
Selling, general and administrative		1,793		1,522		3,970		3,132
Total stock-based compensation in continuing operations		3,182		2,912		7,074		5,972
Discontinued operations		(110)		205		(110)		416
Total stock-based compensation	$	3,072	$	3,117	$	6,964	$	6,388

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The following assumptions were applied to all stock option grants:

	Three Months Ended			Six Months Ended
	June 30, 2022			June 30, 2022
Estimated weighted-average fair value	$	1.90		$	2.19
Weighted-average assumptions:
Expected volatility		82	%		82	%
Expected life, in years		5.8			5.8
Risk-free interest rate		2.51	%		2.46	%
Expected dividend yield		—	%		—	%

Stock option activity for all stock plans and related information is as follows:

		Weighted-
		Average			Aggregate
		Exercise		Remaining	Intrinsic
	Options	Price per		Contractual Life	Value
	Outstanding	Share		(In years)	(In thousands)
Balance at December 31, 2021	12,709,887	$	12.61
Granted	125,534		7.29
Exercised	(101,160)		4.10
Forfeited	(367,273)		13.96
Balance at June 30, 2022	12,366,988	$	12.55	5.1	$	46
Vested and expected to vest at June 30, 2022	12,106,495	$	12.53	5.0	$	42
Exercisable at June 30, 2022	9,865,506	$	12.26	4.3	$	—

As of June 30, 2022, there were 2.5 million unvested options outstanding that will vest over a weighted-average period of 2.2 years. The total estimated compensation expense yet to be recognized on outstanding options is $20.0 million.

The Company has 204,500 shares of unvested RSUs outstanding as of June 30, 2022 that vest 50% on December 1, 2022 and 50% on December 1, 2023.