SHARE-BASED COMPENSATION

3 Months Ended

Mar. 31, 2025

Share-Based Payment Arrangement [Abstract]

Equity Incentive Plans

The Company has grants outstanding under its 2008 Equity Incentive Plan (the “2008 Plan”), its amended and restated 2016 Equity Incentive Plan (the “2016 Plan”), and the Viridian 2020 Equity Incentive Plan (the “2020 Plan” and collectively with the 2008 Plan and the 2016 Plan, the “Equity Incentive Plans”). Additionally, beginning in July 2021, the Company granted stock options and RSUs outside of its Equity Incentive Plans to certain employees to induce them to accept employment with the Company (the “Inducement Awards”). The terms and conditions of the Inducement Awards are substantially similar to those awards granted under the Company’s Equity Incentive Plans.

In June 2022, the Company’s stockholders approved the amendment and restatement of the 2016 Plan to, among other things, transfer the then remaining number of shares available for issuance under the 2020 Plan into the 2016 Plan so that the Company operates from a single equity plan going forward. In June 2023, the Company’s stockholders approved a further amendment and

restatement of the 2016 Plan to, among other things, increase the number of shares reserved for issuance thereunder by 2,000,000 shares. In June 2024, the Company’s stockholders approved a further amendment and restatement of the 2016 Plan to, among other things, increase the number of shares reserved for issuance thereunder by 2,000,000 shares. The 2016 Plan will terminate on April 19, 2034.

As of March 31, 2025, the Company had the following balances by plan:


	Restricted Stock Units Outstanding	Stock Options Outstanding	Shares Available for Issuance
Inducement Awards	—	7,158,917	—
2020 Plan	—	54,076	—
2016 Plan	1,128,506	6,911,066	2,258,071
2008 Plan	—	24	—
Total	1,128,506	14,124,083	2,258,071

Restricted Stock Units

RSUs granted under the Equity Incentive Plans and the Inducement Awards generally vest annually over a 4-year period and are settled in shares of the Company’s common stock.

A summary of RSU activity is as follows:


	RSUs	Weighted-Average Grant Date Fair Value
Nonvested, December 31, 2024	314,075	$15.51
Granted	841,178	$14.45
Vested	(8,315)	$33.83
Forfeited	(18,432)	$16.06
Nonvested, March 31, 2025	1,128,506	$14.57

Stock Options

Options granted under the Equity Incentive Plans and the Inducement Awards have an exercise price equal to the market value of the common stock at the date of grant and expire 10 years from the date of grant. Options generally vest 25% on the first anniversary of the vesting commencement date and 75% ratably in equal monthly installments over the remaining 36 months or in equal monthly or quarterly amounts over periods of up to 48 months.

A summary of common stock option activity is as follows:


	Number of Options	Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2024	11,348,519	$18.11	7.85	$	37,138
Granted	4,258,077	$15.24
Exercised	(185,426)	$12.39
Forfeited or expired	(1,297,087)	$23.63
Outstanding as of March 31, 2025	14,124,083	$16.81	8.69	$	2,285
Vested and expected to vest as of March 31, 2025	14,124,083	$16.81	8.69	$	2,285
Exercisable as of March 31, 2025	3,456,329	$19.83	6.87	$	673
Vested as of March 31, 2025	3,456,329	$19.83	6.87	$	673

Fair Value Assumptions

The Company uses the Black-Scholes option pricing model to estimate the fair value of stock options granted under its equity compensation plans. The Black-Scholes model requires inputs for risk-free interest rate, dividend yield, volatility, and expected terms of the options. Because the Company has a limited history of stock purchase and sale activity, expected volatility is based on a blend of historical data from public companies that are similar to the Company in size and nature of operations, as well as the Company’s own volatility. The Company will continue to use similar entity volatility information until its historical volatility is relevant to measure expected volatility for option grants. The Company accounts for forfeitures as they occur. The risk-free rate for periods within the contractual life of each option is based on the U.S. Treasury yield curve in effect at the time of the grant for a period commensurate with the expected term of the grant. The expected term (without regard to forfeitures) for options granted represents the period of time that options granted are expected to be outstanding and is derived from the contractual terms of the options granted, and actual and expected option-exercise behaviors. The fair value of the underlying common stock is based on the closing price of the common stock on The Nasdaq Capital Market at the date of grant.

The weighted-average grant-date fair value of options granted during the three months ended March 31, 2025 and 2024 was $10.53 and $14.43, respectively. The fair value was determined by the Black-Scholes option pricing model using the following weighted-average assumptions:


	Three Months Ended March 31,
	2025	2024
Expected term, in years	4.96	5.11
Expected volatility	85.2%	89.5%
Risk-free interest rate	4.0%	4.1%
Expected dividend yield	—%	—%
Weighted average exercise price	$15.24	$20.05

Employee Stock Purchase Plan

The 2016 Employee Stock Purchase Plan (“ESPP”) allows qualified employees to purchase shares of common stock at a price equal to 85% of the lower of: (i) the closing price at the beginning of the offering period or (ii) the closing price at the end of the offering period. As of March 31, 2025, the Company had 51,915 shares available for issuance, and 143,532 cumulative shares had been issued under the ESPP.

Share-Based Compensation Expense

Share-based compensation related to all equity awards issued pursuant to the Equity Incentive Plans, the Inducement Awards, and for estimated shares to be issued under the ESPP for the purchase periods active during each respective period is included in the condensed consolidated statements of operations and comprehensive loss as follows:


	Three Months Ended March 31,
		2025		2024
		(in thousands)
Research and development		$	5,748	$	6,678
General and administrative		4,472		6,010
Total share-based compensation expense		$	10,220	$	12,688

During the three months ended March 31, 2025 and 2024, the Company recorded $1.6 million and $3.5 million, respectively, of incremental share-based compensation related to the acceleration of vesting for former executive officers.

As of March 31, 2025, the Company had $113.8 million of total unrecognized share-based compensation costs related to stock options, which the Company expects to recognize over a weighted-average remaining period of 3.18 years. As of March 31, 2025, the Company had $15.6 million of total unrecognized share-based compensation costs related to unvested RSUs, which the Company expects to recognize over a weighted-average remaining period of 3.57 years.