7. EMPLOYEE BENEFIT PLANS

Employee Stock Purchase Plan

On June 15, 2021, the Company’s stockholders initially approved the 2021 Employee Stock Purchase Plan, which has been amended and restated by the Board of Directors and approved by the Company’s stockholders since then (as amended through the date of this report, the “2021 Purchase Plan”). The most recent amendment, approved by the Company’s Board of Directors on April 23, 2026, and the stockholders on June 16, 2026, increased the number of shares reserved for issuance under such plan by an additional 0.2 million shares, to a total of 1.6 million shares.

The 2021 Purchase Plan commenced on August 1, 2021, and provides for twenty-four-month offering periods with four six-month purchase periods in each offering period. As of June 30, 2026, 0.7 million shares were available for future issuance under the 2021 Purchase Plan.

The Company estimated the fair value of purchase rights granted under the 2021 Purchase Plan during the period using the Black-Scholes-Merton option-pricing model with the following weighted average assumptions, resulting in the following weighted average fair values:

During the six months ended June 30, 2026 and 2025, a total of 117,181 shares and 90,076 shares, respectively, were issued under the 2021 Purchase Plan, at a weighted average purchase price of $18.46 per share and $23.68 per share, respectively. As of June 30, 2026, the estimated unrecognized compensation cost related to the 2021 Purchase Plan was $2.1 million, which is expected to be recognized over a weighted average period of 1.1 years.

Stock Incentive Plan

On November 16, 2011, the Company’s stockholders initially approved the 2011 Stock Incentive Plan, which has been amended and restated by the Board of Directors and approved by the Company’s stockholders a number of times since then (as amended through the date of this report, the “2011 Plan”). The most recent amendment, approved by the Company’s Board of Directors on April 23, 2026, and the stockholders on June 16, 2026, increased the number of shares reserved for issuance under such plan by an additional 0.8 million shares, to a total of 16.7 million shares, and extended the deadline to grant incentive stock options to April 23, 2036. As of June 30, 2026, 4.3 million shares were available for future grant under the 2011 Plan. 

Stock Award Activities

Restricted stock unit (“RSU”)

Nonvested RSU activities were as follows:

The Company withholds common stock to satisfy employee tax withholding obligations in connection with the vesting of RSUs and treats RSUs withheld for tax withholding in a similar manner to common stock repurchases and reports such shares as treasury stock. Shares withheld for taxes related to employees’ tax withholding obligation for shares issued under the equity plans and the respective amounts are reflected in the condensed consolidated statements of stockholders’ equity.

As of June 30, 2026, there was $34.1 million of total unrecognized compensation cost related RSUs which is expected to be recognized over a weighted average period of 2.4 years. Additional information related to RSUs is as follows:

Stock Options

There were no stock options granted during the six months ended June 30, 2026 and 2025. As of June 30, 2026, the outstanding stock options totaled 12,557 shares. Total fair value of shares vested during the three and six months ended June 30, 2026, was immaterial. As of June 30, 2026, there was no remaining unrecognized compensation cost related to unvested stock options.

Stock-Based Compensation

Stock-based compensation is estimated at the grant date based on the award’s fair value and is recognized on a straight-line basis over the vesting periods, generally four years. Stock-based compensation expense before taxes related to the Company’s stock plan and employee stock purchase plan was allocated as follows (in thousands):