Stock-based Compensation

3 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

5. Stock-based Compensation

The Company recognized stock-based compensation as follows:

	Three Months Ended March 31,
	2023		2022
	(In thousands)
Research and development	$	5,655	$	6,626
General and administrative		5,320		5,313
Total stock-based compensation	$	10,975	$	11,939

2019 Equity Incentive Plan and 2022 Inducement Plan

On January 1, 2023, the Company added 4,144,785 shares to the shares reserved for issuance under the 2019 Equity Incentive Plan (2019 Plan). As of March 31, 2023, the Company had reserved 24,195,457 shares of common stock for issuance under the 2019 Plan, of which 10,247,399 shares were available for issuance of future awards. On January 1, 2022, the Company adopted the 2022 Inducement Plan (Inducement Plan) for the grant of equity-based awards to individuals who were not previously employees or non-employee directors of the Company. As of March 31, 2023, 1,402,807 shares were available for issuance of future awards under the Inducement Plan.

Option activity is shown below:

	Number of Options			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(In years)		(In thousands)
Outstanding as of December 31, 2022		13,713,272		$	14.62
Granted		66,918			9.15
Exercised		(132,192	)		8.16
Forfeited		(985,811	)		12.85
Outstanding as of March 31, 2023		12,662,187		$	14.80	$	7.7	$	—
Exercisable as of March 31, 2023		7,169,954		$	14.94	$	7.0	$	—
Vested and expected to vest as of March 31,    2023		12,662,187		$	14.80	$	7.7	$	—

The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying stock options and the fair value of the Company’s common stock for stock options that were in-the-money. As of March 31, 2023, total unrecognized stock-based compensation related to unvested stock options was $52.8 million, which the Company expects to recognize over a remaining weighted-average period of 2.5 years.

Restricted Stock Activity

Activity for the RSUs is shown below. In May 2021 and January 2022, the Company issued RSUs with market conditions to certain executives, which are also included in the table below. The RSUs with market conditions are earned based on stock price performance and continued service by the employee.

	Number of Shares			Weighted Average Grant Date Fair Value per Share
Unvested restricted stock units as of December 31, 2022		3,044,618		$	11.68
Granted		467,432			7.73
Vested		(323,868	)		12.36
Forfeited		(64,927	)		12.77
Unvested restricted stock units as of    March 31, 2023		3,123,255		$	10.81

As of March 31, 2023, total unrecognized stock-based compensation related to unvested restricted stock units was $29.2 million, which the Company expects to recognize over a remaining weighted-average period of 2.4 years.

2019 Employee Stock Purchase Plan

The 2019 Employee Stock Purchase Plan (2019 ESPP) enables eligible employees of the Company to purchase shares of common stock at a discount. On January 1, 2023, 591,397 shares were added to the shares reserved for issuance under the 2019 ESPP pursuant to the annual automatic increase. As of March 31, 2023, the Company has reserved for issuance 3,373,816 shares of common stock pursuant to the 2019 ESPP. Each offering period is approximately six months long. 2019 ESPP participants will purchase shares of common stock at a price per share equal to 85% of the lesser of (1) the fair market value per share of the common stock on the first trading day of the offering period or (2) the fair market value of the common stock on the purchase date.