Company: ATRA
Filing Date: 2025-03-07
Form Type: 10-K
Source: 0000950170-25-035507
Chunk: 236

Company: Atara Biotherapeutics, Inc.
Filing Date: 2025-03-07
Form: 10-K
Item: Item 1B
Chunk 236
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 The estimated fair value of stock options that vested in the years ended December 31, 2024 and 2023 was $9.0 million and $17.0 million, respectively. Employee Stock Purchase PlanIn May 2014, we adopted the 2014 Employee Stock Purchase Plan (“2014 ESPP”), which became effective on October 15, 2014 upon the pricing of our IPO. Following stockholder approval, in June 2024, we amended the 2014 ESPP to increase the number of shares of our common stock available for issuance under the 2014 ESPP by 40,000 shares. The 2014 ESPP permits eligible employees to purchase common stock at a discount through payroll deductions during defined offering periods. Eligible employees can purchase shares of the Company’s common stock at 85% of the lower of the fair market value of the common stock at (i) the beginning of the offering period or (ii) at the end of the purchase period. We recorded $0.2 million and $0.7 million of expense related to the 2014 ESPP in the years ended December 31, 2024 and 2023, respectively. A total of 25,897 and 35,850 shares were purchased under the ESPP during the years ended December 31, 2024 and 2023, respectively. As of December 31, 2024, there was $0.1 million of unrecognized stock-based compensation expense related to the ESPP that is expected to be recognized by the end of second quarter of 2025. As of December 31, 2024, there were 23,731 shares authorized under the 2014 ESPP.Reserved SharesThe following shares of common stock were reserved for future issuance under our equity incentive plans as of December 31, 2024:

        Total Shares Reserved

        2014 Equity Incentive Plan

        554,974

        2018 Inducement Plan

        170,873

        2024 Equity Incentive Plan

        392,571

        2014 Employee Stock Purchase Plan

        23,731

        Total reserved shares of common stock

        1,142,149

      Stock-based Compensation ExpenseThe following is a summary of stock-based compensation expense for the periods presented: 

        Year Ended December 31,

        2024

        2023

        (in thousands)

        Research and development