XML 36 R17.htm IDEA: XBRL DOCUMENT v3.24.1
Stockholders’ Equity and Stock-based Compensation
 12 Months Ended
Dec. 31, 2023
Equity [Abstract]  
STOCKHOLDERS’ EQUITY AND STOCK-BASED COMPENSATION STOCKHOLDERS’ EQUITY AND STOCK-BASED COMPENSATION
Preferred Stock
Pursuant to the Amended and Restated Certificate of Incorporation filed on October 14, 2020, as amended, the Company is authorized to issue a total of 10,000,000 shares of undesignated preferred stock, par value $0.001.
Common Stock
Pursuant to the Company’s amended and restated certificate of incorporation filed on October 14, 2020, as amended, the Company is authorized to issue a total of 200,000,000 shares of its common stock, par value $0.001.
Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company's stockholders. Subject to the rights of the Preferred Stock, holders of the Company’s common stock are entitled to receive dividends, as may be declared by the Board of Directors. As of December 31, 2023, no dividends have been declared to date.
2020 Equity Incentive Plan
In October 2020, the Company adopted its 2020 Equity Incentive Plan (the 2020 Plan) which replaced the 2017 Equity Incentive Plan (Prior Plan) upon completion of the IPO. The 2020 Plan provides for the grant of incentive stock options or nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards and other forms of awards to employees, directors, and consultants of the Company. The number of shares of common stock reserved for issuance under the 2020 Plan will automatically increase each year for a period of 10 years, beginning in 2021 and continuing through 2030, in an amount equal to (1) 5.0% of the total numbers of shares of the Company’s common stock outstanding on December 31st of the immediately preceding year, or (2) a lesser number of shares determined by the Board of Directors no later than December 31st of the immediately preceding year. As of December 31, 2023, the maximum number of shares of common stock that may be issued was 20,417,192 shares.
Under the 2020 Plan options shall not have an exercise price less than 100% of the fair market value of the Company’s common stock on the grant date. Vesting periods are determined at the discretion of the Board of Directors. The maximum contractual term is 10 years. Stock options typically vest over four years.
As of December 31, 2023, there were 5,238,438 shares reserved by the Company under the 2020 Plan for the future issuance of equity awards.

Stock Options
Stock option activity under the 2020 Plan as of December 31, 2023 is summarized as follows:
Number of OptionsWeighted-Average Exercise PriceWeighted-Average Remaining Contractual TermAggregate Intrinsic Value
(in thousands)(in years)(in thousands)
Outstanding at December 31, 2022
7,455 $11.83 
Granted3,234 $1.98 
Forfeited (2,151)$9.30 
Exercised(285)$3.23 
Outstanding at December 31, 2023
8,253 $8.92 6.74$19 
Exercisable at December 31, 2023
4,949 $10.66 5.56$13 
Unvested and expected to vest at December 31, 2023
3,303 $6.33 8.65$6 

The aggregate intrinsic values of options outstanding, exercisable, vested and expected to vest were calculated as the difference between the exercise price of the options and the closing price of the Company’s common stock on the Nasdaq Global Select Market on December 31, 2023.
The weighted-average grant-date fair value per share of stock options granted, using the assumptions listed above, was $1.41 and $5.57, during the years ended December 31, 2023 and December 31, 2022, respectively.
The intrinsic value of options exercised for the years ended December 31, 2023 and December 31, 2022 was $29,624 and $2.0 million, respectively, determined as of the applicable date of exercise. There was no future tax benefit related to options exercised, as the Company had accumulated net operating losses as of December 31, 2023.
The Black-Scholes option-pricing model assumptions that the Company used to determine the grant-date fair value of stock options for the years ended December 31, 2023 and December 31, 2022 were as follows, presented on a weighted-average basis:
Year Ended December 31,
20232022
Expected term (in years)5.995.91
Expected volatility79.92%78.21%
Risk-free interest rate3.96%2.28%
Expected dividend—%—%
For the years ended December 31, 2023 and December 31, 2022 total stock-based compensation related to stock options was classified in the Company’s statements of operations and comprehensive loss as follows (in thousands):
Year Ended December 31,
20232022
Research and development expenses$6,243 $8,464 
General and administrative expenses7,948 10,414 
Total stock-based compensation expense
$14,191 $18,878 
As of December 31, 2023, $14.5 million of unrecognized compensation costs related to unvested stock options is expected to be recognized over a weighted average period of 1.67 years.
Early Exercised Options
The Company allows certain of its employees and its consultants to exercise options granted under the Prior Plan prior to vesting. The shares related to early exercised stock options are subject to the Company’s lapsing repurchase right upon termination of employment or service on the Board of Directors at the lesser of the original purchase price or fair market value at the time of repurchase. In order to vest, the holders are required to provide continued service to the Company. The early exercise by an employee or consultant of a stock option is not considered to be a substantive exercise for accounting purposes, and therefore the payment received by the employer for the exercise price is recognized as a liability. For accounting purposes, unvested early exercised shares are not considered issued and outstanding and therefore not reflected as issued and outstanding in the accompanying balance sheets or the accompanying statements of stockholders' equity until the awards vest.
The deposits received are initially recorded in current portion of other liabilities and other noncurrent liabilities for the noncurrent portion. The liabilities are reclassified to common stock and paid-in capital as the repurchase right lapses. During the years ended December 31, 2023 and December 31, 2022, there have been no early exercised options.
At December 31, 2023 and December 31, 2022, there was $0.2 million and $0.9 million recorded in “current portion of other liabilities”, respectively, related to shares held by employees and nonemployees that were subject to repurchase.
At December 31, 2023 and December 31, 2022, there was zero and $0.2 million recorded in “other noncurrent liabilities”, respectively, related to shares held by employees and nonemployees that were subject to repurchase.
Restricted Stock
Restricted stock units and awards as of December 31, 2023 are summarized as follows:
Number of Restricted StockWeighted-Average Grant Date Fair ValueWeighted-Average Remaining Vesting Life
(in thousands)(in years)
Outstanding at December 31, 2022
2,298 $9.18 
Granted - restricted stock units1,634 $1.98 
Vested and converted to shares(1,268)$10.56 
Forfeited(1,007)$4.67 
Unvested outstanding at December 31, 2023
1,657 $3.76 1.92
Restricted Stock Units
Pursuant to the 2020 Plan, the RSUs granted have a three-year vest period and in order to vest, the holder is required to provide service to the Company.
For the years ended December 31, 2023 and December 31, 2022 total stock-based compensation related to RSUs was classified in the Company’s statements of operations and comprehensive loss as follows (in thousands):
Year Ended December 31,
20232022
Research and development expenses$5,371 $5,665 
General and administrative expenses4,710 5,339 
Total stock-based compensation expense
$10,081 $11,004 
As of December 31, 2023, there was $3.3 million of unrecognized stock-based compensation related to RSUs, which is expected to be recognized over a weighted average period of 1.69 years.
For the year ended December 31, 2023 and December 31, 2022, 1,234,192 RSUs and 295,053 RSUs have vested, respectively.
Restricted Stock Awards (RSAs)
For the years ended December 31, 2023 and December 31, 2022 total stock-based compensation related to RSAs was classified in the Company’s statements of operations and comprehensive loss as follows (in thousands):
Year Ended December 31,
20232022
Research and development expenses$— $— 
General and administrative expenses142 142 
Total stock-based compensation expense
$142 $142 
As of December 31, 2023, there was $0.1 million of unrecognized stock-based compensation related to RSAs, which is expected to be recognized over a weighted average period of 0.58 years.
The total grant date fair value for RSAs vested during the years ended December 31, 2023 and December 31, 2022 was $0.1 million and $0.1 million, respectively.
2020 Employee Stock Purchase Plan
In October 2020, the Company adopted its 2020 Employee Stock Purchase Plan (ESPP), which initially reserved 688,000 shares of the Company’s common stock for employee purchase under terms and provisions established by the Board of Directors. The number of shares of our common stock reserved for issuance under the ESPP automatically increases in 2021 and continuing through 2030, by the lesser of (i) 1.0% of the total number of shares of common stock outstanding on December 31st of the immediately preceding year, and (ii) 1,376,000 shares, except before the date of any increase, the Board of Directors may determine that such increase will be less than the amount set forth in clauses (i) and (ii). Effective January 1, 2023 and 2022, the number of shares authorized under the ESPP for employee purchases increased by 569,674 and 565,798 shares, respectively. The ESPP is intended to qualify as an ‘employee stock purchase plan’ under Section 423 of the Internal Revenue Code. Under the current offering adopted pursuant the ESPP, each offering period shall not exceed 27 months, with shorter duration purchase periods within each offering. Employees are eligible to participate if they are employed by the Company for at least 20 hours per week and more than five months of the year. As of December 31, 2023, 1,601,194 shares of common stock were available and reserved for future issuance under the ESPP.
Under the ESPP, employees may purchase common stock through payroll deductions at a price equal to 85% of the lower of the fair market value of common stock on the first trading day of each offering period or on the purchase date. The initial offering period commenced on October 8, 2020, the date of the underwriting agreement related to the Company’s IPO. A new offering (Subsequent Offering) automatically began in 2021, and a new offering will begin every six months thereafter over the term of the ESPP. Each Subsequent Offering will be approximately 24 months long and will consist of four purchase periods (with the purchase dates occurring on June 30 and December 31 each year during the term of the Subsequent Offering). Contributions under the ESPP are limited to a maximum of 15% of an employee’s eligible compensation.
The fair values of the rights granted under the ESPP were calculated using the following assumptions:
Year Ended December 31,
20232022
Expected term (in years)
0.50 - 2.00
0.49 - 2.00
Expected volatility
70.74% - 82.61%
56.55% - 87.15%
Risk-free interest rate
4.40% - 5.53%
0.22% - 2.84%
Dividend yield—%—%
For the years ended December 31, 2023 and December 31, 2022 total stock-based compensation related to ESPP was classified in the Company’s statements of operations and comprehensive loss as follows (in thousands):
Year Ended December 31,
20232022
Research and development expenses$399 $845 
General and administrative expenses169 276 
Total stock-based compensation expense
$568 $1,121 
Stock-Based Compensation Summary
Total stock-based compensation expense was classified in the Company’s statements of operations and comprehensive loss for the years ended December 31, 2023 and December 31, 2022 as follows for stock options, RSUs, RSAs and ESPP (in thousands):
Year Ended December 31,
20232022
Research and development expenses$12,013 $14,974 
General and administrative expenses12,969 16,171 
Total stock-based compensation expense
$24,982 $31,145