12.         Stock-based Compensation

Shares available for grant

The Company's Amended and Restated 2014 Equity Incentive Plan (the "2014 Plan") expired on  January 31, 2024. Following such expiration and prior to the 2024 Annual Meeting of Stockholders (the "Annual Meeting"), no grants were made under the 2014 Plan. On June 6, 2024, the Company held its Annual Meeting and amended and restated the 2014 Plan (the "Restated 2014 Plan") to extend the term of the 2014 Plan to until April 15, 2034, and to increase the total number of shares of common stock authorized for issuance by 1,000 shares relative to the amount available for issuance at the time the 2014 Plan expired. As of June 30, 2024, the total number of shares authorized for grant under the Restated 2014 Plan was 4,724, of which 1,066 were available for future grants.

Stock Options

The following table summarizes information about the Company’s stock options outstanding as of June 30, 2024, and activity during the six months then ended:

There were no stock options awarded during the three and six months ended June 30, 2024 and 2023, and no unrecognized compensation cost related to unvested stock options as of June 30, 2024.

Restricted Stock Units

The Company issues time-based restricted stock units (“RSUs”) and performance-based restricted stock units ("PSUs") to employees and non-employees. Each RSU and PSU represents the right to receive one share of the Company’s common stock upon vesting and subsequent settlement. PSUs vest upon achievement of performance targets based on the Company's annual operating plan. The fair values of RSUs and PSUs are determined based on the closing price of the Company’s common stock on the date of grant.

Combined RSU and PSU activity for the six months ended June 30, 2024 is summarized below:

As of June 30, 2024, $999 of total unrecognized compensation expense related to unvested RSUs and PSUs was expected to be recognized over a weighted average period of 1.14 years.

Compensation Expense

Stock-based compensation expense is included in the condensed consolidated statements of operations and comprehensive loss in general and administrative, research and development, or sales and marketing expenses, depending on the nature of the services provided. Stock-based compensation expense related to options, RSUs and PSUs was recorded as follows:

401(k) Plan Share Match

During the six months ended June 30, 2024 and 2023, the Company issued 163 and 161 shares of common stock with a fair value of $238 and $249, respectively, to eligible employees’ deferral accounts for the 401(k) Plan matching contribution representing 50% of each eligible employee’s elected deferral (up to the statutory limit) for the year ended December 31, 2023 and 2022.

The expense for the 401(k) Plan share matching was $113 and $219 for the six months ended June 30, 2024 and 2023, respectively.