As of June 30, 2023, the Company’s stock incentive plans included the 2010 Stock Plan (the “2010 Plan”), the 2020 Equity Incentive Plan (the “2020 Plan”), the 2021 Inducement Equity Incentive Plan, as amended (the “2021 Plan”), and the 2022 Equity Incentive Plan (the “2022 Plan”) (together, the “Plans”).

The 2022 Plan provides for the award of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, other stock-based awards, and cash-based awards to employees, directors, consultants or advisors. Shares of common stock subject to outstanding awards granted under the 2020 Plan and the 2010 Plan that expire, terminate, or are otherwise surrendered, cancelled, forfeited, or repurchased by the Company are available for issuance under the 2022 Plan.

The 2021 Plan provides for the award of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, and other stock-based awards to persons who were not previously an employee or director of the Company or who are commencing employment with the Company following a bona fide period of non-employment, in either case, as an inducement material to such person’s entry into employment with the Company and in accordance with the requirements of the Nasdaq Stock Market Rule 5635(c)(4). Neither consultants nor advisors are eligible to participate in the 2021 Plan.

The 2020 Plan provided for the award of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, and other stock-based awards to employees, directors, consultants or advisors. As of June 15, 2022, the effective date of the 2022 Plan, no further awards will be made under the 2020 Plan. Any options or awards outstanding under the 2020 Plan remain outstanding and effective.

The 2010 Plan provided for the granting of incentive stock options and nonstatutory stock options to employees, directors, consultants or advisors. As of the effective date of the 2020 Plan, no further awards will be made under the 2010 Plan. Any options or awards outstanding under the 2010 Plan remain outstanding and effective.

As of June 30, 2023 and December 31, 2022, there were 3,526,595 and 5,470,240 shares available for grant under the Plans, respectively. The following table presents classification of stock-based compensation expense within the unaudited condensed consolidated statements of operations:


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Cost of sales	$	1,390	$	1,528	$	2,688	$	2,816
Research and development	3,807		2,977		7,322		5,559
Sales and marketing	941		699		1,791		1,223
General and administrative	5,635		5,223		10,852		9,963
Total stock-based compensation	$	11,773	$	10,427	$	22,653	$	19,561

Each restricted stock unit (“RSU”) represents the right to receive one share of the Company’s common stock upon vesting. The fair value of RSUs granted by the Company was calculated based upon the Company’s closing stock price on the date of the grant, and the stock-based compensation expense is recognized over the vesting period. RSUs generally vest over four years with 25% of the grants vesting at the end of the first year and the remaining vesting annually over the following three years.

There were 76,105, 714,980, zero, and 48,700 RSUs granted during the three and six months ended June 30, 2023 and 2022, respectively. The weighted average grant date fair value for each RSU granted during the three and six months ended June 30, 2023 and 2022 was $42.82, $25.37, zero, and $27.76, respectively.

As of June 30, 2023, there was $17,131 of unrecognized compensation cost related to RSUs granted under the Plans, which is expected to be recognized over a weighted average period of 3.26 years. During the three and six months ended June 30, 2023 zero and 12,075 RSUs vested, respectively. The fair value of RSUs vested during the three and six

In February 2023, the Company awarded performance-based restricted stock units ("PRSUs") under the 2022 Plan. Each PRSU represents a contingent right to receive one share of common stock upon the achievement of specified performance goals. The fair value of PRSUs granted by the Company was calculated based upon the Company's closing stock price on the date of the grant, and the stock-based compensation expense is recognized when the grant date is determined and performance conditions are probable of achievement. At the point where performance conditions are considered probable of achievement, the Company records stock-based compensation expense with a cumulative catch-up expense in the period first recognized and on a straight-line basis over the remaining period for which the performance criteria are expected to be completed.

In March 2023, the Company awarded to certain executive officers PRSUs for a maximum of 62,693 shares (based on 150% achievement of the applicable performance conditions outlined in the awards), with a target award of 41,795 PRSUs (based on 100% achievement of the applicable performance conditions), and a threshold award of 20,898 PRSUs (based on 50% achievement of the applicable performance conditions). All PRSUs were considered granted under ASC 718, Compensation—Stock Compensation ("Topic 718"). The PRSUs granted in March 2023 are scheduled to vest, if at all, upon the certification by the Company's compensation committee of the achievement of the applicable performance conditions following the filing of the Company's Annual Report on Form 10-K for the fiscal year ending December 31, 2025.

In August 2022, the Company awarded 90,000 PRSUs to an executive officer of which 30,150 PRSUs were considered granted under Topic 718 at the time the PRSUs were awarded. In March 2023, of the 90,000 PRSUs awarded in August 2022, an additional 45,000 PRSUs were considered granted under Topic 718. Of the 45,000 PRSUs that were considered granted in March 2023, 18,000 PRSUs are scheduled to vest, if at all, upon the certification by the Company's compensation committee of the achievement of the applicable performance conditions following the filing of the Company's Annual Report on Form 10-K for the fiscal year ending December 31, 2023 and 27,000 PRSUs are scheduled to vest, if at all, upon the certification by the Company's compensation committee of the achievement of the applicable performance conditions following the filing of the Company's Annual Report on Form 10-K for the fiscal year ending December 31, 2025.

No conditions were determined to be probable under any of the Company's PRSUs as of June 30, 2023 and no expense was recorded during the three and six months ended June 30, 2023. The weighted average grant date fair value for each PRSU granted during the six months ended June 30, 2023 was $22.48. No PRSUs vested during the three and six months ended June 30, 2023.

Stock options must be granted at an exercise price not less than 100% of the fair market value per share at the grant date. The board of directors or compensation committee determines the exercise price of the Company’s stock options based on the closing price of the common stock as reported on the Nasdaq Global Select Market on the date of the grant. The maximum contractual term of options granted under the Plans is typically 10 years, options generally vest over four years with 25% of the shares underlying the option vesting at the end of the first year and the remaining vesting monthly over the following three years. In February 2023, we granted to our chief executive officer a premium priced option to purchase 65,525 shares of common stock with an exercise price equal to 110% of the closing price of our common stock on the date of grant.

During the three and six months ended June 30, 2023 and 2022, 340,229, 526,430, 54,661, and 192,546 options under the Plans were exercised for total proceeds of $4,698, $5,565, $396, and $1,304, respectively.

The fair value of each option award is determined on the date of grant using the Black Scholes Merton option-pricing model. The calculation of fair value includes several assumptions that require management’s judgment. The expected terms of options granted to employees during 2023 and 2022 were calculated using an average of historical exercises. Estimated volatility for the six months ended June 30, 2023 and 2022 incorporates a calculated volatility derived from the historical closing prices of shares of common stock of similar entities whose share prices were publicly available

for the expected term of the option. The risk-free interest rate is based on the U.S. Treasury constant maturities in effect at the time of grant for the expected term of the option. The Company accounts for forfeitures as they occur; as such, the Company does not estimate forfeitures at the time of grant.


	Six Months Ended June 30,
	2023		2022
Valuation assumptions
Expected dividend yield	—	%	—	%
Expected volatility	67	%	56	%
Expected term (years)	4.97		4.75
Risk-free interest rate	3.77	%	1.90	%

The weighted average grant date fair value per share of options granted during the three and six months ended June 30, 2023 and 2022 was $22.20, $15.20, $13.67, and $13.54, respectively. The intrinsic value of options exercised during the three and six months ended June 30, 2023 and 2022 was $8,102, $11,305, $977, and $4,286, respectively.

As of June 30, 2023, there was $82,562 of unrecognized compensation cost related to unvested stock options granted under the Plans, which is expected to be recognized over a weighted average period of 2.37 years. The fair value of shares vested during the three and six months ended June 30, 2023 and 2022 was $10,842, $27,867, $10,159, and $29,704, respectively.