Stock Plans and Stock-Based Compensation

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Stock Plans and Stock-Based Compensation

As of March 31, 2026, the Company had three stockholder-approved, stock-based compensation plans: (i) the 2026 Incentive Plan (“2026 Plan”), (ii) the Fifth Amended and Restated 2010 Stock Incentive Plan, as amended (“2010 Plan”), and (iii) the Amended and Restated 2010 Employee Stock Purchase Plan (“ESPP”). New employees are generally issued options as an inducement equity award under Nasdaq Listing Rule 5635(c)(4) outside of the 2010 Plan (“Inducement Awards”).

2026 Stock Incentive Plan

In March 2026, the Company’s stockholders approved the Company’s 2026 Plan under which awards may be made for up to a number of shares of common stock equal to the sum of: (i) 6,407,374 shares of common stock; (ii) such additional number of shares of common stock (up to 3,474,867 shares) as is equal to the number of shares of Common Stock reserved for issuance under the 2010 Stock Incentive Plan (“2010 Plan”) that remain available for grant under the 2010 Plan immediately prior to the date that the 2026 Plan is approved by the Company’s stockholders (the “Effective Date”), or March 17, 2026, and the number of shares of common stock subject to awards granted under the 2010 Plan and the number of shares subject to awards granted under the inducement grant exception under Nasdaq Stock Market Rule 5635(c)(4) (“Inducement Awards”), in each case, that are outstanding as of the Effective Date and which awards expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right, and subject to the terms of the 2026 Plan; and (iii) an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2027 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2036, equal to the lesser of (i) 5% of the sum of (a) the number of outstanding shares of common stock on such date, (b) the number of shares of common stock issuable upon conversion of any outstanding shares of convertible preferred stock of the Company (without giving effect to any restrictions or limitations on conversion) on such date, (c) the number of shares of common stock issuable upon the exercise of pre-funded warrants (without giving effect to any restrictions or limitations on conversion) issued by the Company as of such date, and (d) the number of shares subject to outstanding awards granted under the 2010 Plan, the 2026 Plan or as Inducement Awards as of such date and (ii) an amount determined by the board of directors. Awards in the form of incentive stock options may be granted with respect to a maximum 25,000,000 shares of common stock under the 2026 Plan.

The 2026 Plan permits the granting of incentive and non-qualified stock options and stock awards to employees, officers, directors, and consultants of the Company and its subsidiary at prices determined by the Company’s board of directors. As of March 31, 2026, the Company has not granted options or stock awards under the 2026 Plan. As of March 31, 2026, 7,409,891 shares remained available for grant under the 2026 Plan.

The Fifth Amended and Restated 2010 Stock Incentive Plan, as amended

The 2010 Plan permits the granting of incentive and non-qualified stock options and stock awards to employees, officers, directors, and consultants of the Company and its subsidiary at prices determined by the Company’s board of directors. The Company can issue up to 3,356,600 shares of its common stock pursuant to awards granted under the 2010 Plan. Options vest and become exercisable based on a schedule determined by the board of directors and expire up to ten years from the date of grant. The 2010 Plan uses a “fungible share” concept under which each share of stock subject to awards granted as options and stock appreciation rights (“SARs”) will cause one share per share under the award to be removed from the available share pool, while each share of stock subject to awards granted as restricted stock, restricted stock units, other stock-based awards or performance awards where the price charged for the award is less than 100% of the fair market value of the Company’s common stock will cause 1.3 shares per share under the award to be removed from the available share pool.

Following approval of the 2026 Plan, no additional awards will be made under the 2010 Plan, although all outstanding awards under the 2010 Plan will remain in effect. During the three months ended March 31, 2026, and prior to the approval of the 2026 Plan, no options or stock awards were granted under the 2010 Plan.

Inducement Awards

The Company grants Inducement Awards to certain new employees. These options generally vest as to 25% of the shares underlying the option on the first anniversary of the grant date, and as to an additional 6.25% of the shares underlying the option on each successive quarter thereafter. These options are granted at an exercise price that equals the closing market price of the Company’s common stock on the grant date. During the three months ended March 31, 2026, no Inducement Awards were granted.

Stock Options

A summary of stock option activity under the 2026 Plan, 2010 Plan, and Inducement Awards are summarized as follows:


	Number of Shares	Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value
Outstanding, December 31, 2025	2,429,064	$	16.59	7.80	$	—
Granted	—	—
Exercised	—	—
Canceled/Forfeited	(101,599)	37.64
Outstanding, March 31, 2026	2,327,465	$	15.67	7.40	$	—
Exercisable at March 31, 2026	1,164,823	$	28.71	6.02	$	—
Vested and unvested expected to vest at March 31, 2026	2,327,465	$	15.67	7.40	$	—

The weighted average grant date fair value of the stock options granted during the three months ended March 31, 2025 was $2.67 and was calculated using the following estimated assumptions under the Black-Scholes option pricing model:


									Three Months Ended March 31,
									2025
Expected term (years)									6.0


Risk free interest rate									4.4%
Expected volatility									113%
Expected dividends									None

As of March 31, 2026, there was $3.3 million of unrecognized compensation cost related to unvested employee stock option awards outstanding, which is expected to be recognized as expense over a weighted average period of 2.3 years. There were no employee stock options exercised during each of the three months ended March 31, 2026 and 2025.

Restricted Stock Awards

There were no restricted stock awards outstanding as of March 31, 2026 and no restricted stock awards vested during each of the three months ended March 31, 2026 and 2025.

Restricted Stock Units

The following table presents a summary of RSUs under the 2010 Plan as of March 31, 2026:


	Number of Shares	Weighted Average Grant Date Fair Value
Unvested, December 31, 2025	257,400	$	3.13
Awarded	—	—
Vested	(64,350)	3.13
Forfeited	(44,700)	3.13
Unvested, March 31, 2026	148,350	$	3.13

As of March 31, 2026, there was $0.4 million of unrecognized compensation costs related to RSUs, which are expected to be recognized as expense over a remaining weighted average period of 2.8 years. The fair value of RSUs that vested during the three months ended March 31, 2026 was $0.1 million.

Amended and Restated 2010 Employee Stock Purchase Plan

The Company has reserved 500,000 shares of common stock for issuance under the ESPP. Eligible employees may purchase shares of the Company’s common stock at 85% of the lower closing market price of the common stock at the beginning of the enrollment period or ending date of the purchase period within a two-year enrollment period, as defined. The Company has four six-month purchase periods per each two-year enrollment period. If, within any one of the four purchase periods in an enrollment period, the purchase period ending stock price is lower than the stock price at the beginning of the enrollment period, the two-year enrollment resets at the new lower stock price. No shares were issued under the ESPP during the three months ended March 31, 2026 and 2025. As of March 31, 2026, there were 357,814 shares available for future purchase under the ESPP.

Stock-Based Compensation Expense

For the three months ended March 31, 2026 and 2025, the Company recorded stock-based compensation expense to the following line items in its costs and expenses section of the Condensed Consolidated Statements of Operations and Comprehensive Loss:


	Three Months Ended March 31,
(in thousands)	2026		2025
Research and development	$	229	$	592
General and administrative	346		572
Total stock-based compensation expense	$	575	$	1,164