The Company has stock-based compensation plans under which it grants stock options, restricted stock units ("RSUs"), and performance restricted stock units ("PRSUs") to officers, directors and third parties. Total stock-based compensation for the periods presented is as follows (in thousands):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2025		2024		2025		2024
Cost of sales	$	553	$	554	$	3,596	$	1,037
Research and development		4,159		5,614		7,803		9,929
Sales, general and administrative		10,912		10,792		26,543		23,316
Total	$	15,624	$	16,960	$	37,942	$	34,282

As of June 30, 2025, there was $75.1 million of unrecognized compensation expense for RSUs and PRSUs to be recognized over a weighted average period of 1.83 years.

The Company issued approximately 385,769 and 3,915,180 shares of common stock, before net share settlement, upon vesting of RSUs and PRSUs during the three and six months ended June 30, 2025, respectively. The Company issued approximately 309,000 and 3,473,000 shares of common stock, before net share settlement, upon vesting of RSUs and PRSUs during the three and six months ended June 30, 2024, respectively.

Employees are eligible to participate in the Employee Stock Purchase Plan ("ESPP") approved by its shareholders. During the three and six months ended June 30, 2025, there were approximately 319,220 shares issued under the ESPP. During the three and six months ended June 30, 2024, there were approximately 251,000 shares issued under the ESPP.

The Company estimates the fair value of shares issued to employees under the ESPP using the Black-Scholes option-pricing model. The assumptions used to estimate the fair value of stock options granted and stock purchase rights under the ESPP are as follows:


	Three and Six Months Ended
	June 30,
	2025		2024
Risk-free interest rate	4.30% - 4.44%		5.40% - 5.41%
Expected dividend yield		—		—
Expected term (years)		0.50		0.50
Volatility	54.74% - 91.91%		54.47% - 58.41%

In connection with debt financing entered into with Squadron Medical Finance Solutions, LLC ("Squadron Medical") in 2018, and amended in 2019 and 2020, the Company issued common stock warrants to Squadron Medical and a participant lender (the “Squadron Medical Warrants”). The Squadron Medical Warrants expire in May 2027 and are exercisable by cash or cashless exercise. No Squadron Medical Warrants have been exercised as of June 30, 2025.

The Company issued warrants to its Chairman and Chief Executive Officer (the “Executive Warrants”). The Executive Warrants had a five-year term and are exercisable by cash or cashless exercise. In October 2022, the term was extended to seven years and in May 2024, the term was extended to nine years. No Executive Warrants have been exercised as of June 30, 2025.

Pursuant to an order entered by the Delaware Chancery Court on September 27, 2024, the Company issued 1,133,160 common stock warrants, to L-5 Healthcare Partners, LLC, a stockholder of the Company (the "L-5 Healthcare Warrants"), at a purchase price of $1.98 per each share represented by the warrant, for a total purchase price of approximately $2.2 million. The L-5 Healthcare Warrants expire in August 2026 and are exercisable by cashless exercise. All L-5 Healthcare Warrants have been exercised as of June 30, 2025.

A summary of all outstanding warrants for common stock as of June 30, 2025, is as follows (in thousands, except for strike price data):


	Number of Warrants		Strike Price		Expiration
2018 Squadron Medical Warrants		845	$	3.15	May 2027
2019 Squadron Medical Warrants		4,839	$	2.17	May 2027
2020 Squadron Medical Warrants		1,076	$	4.88	May 2027
Executive Warrants		1,327	$	5.00	December 2026
Other1		90	$	12.15	Various through June 2026
Total		8,177

(1)

Weighted-average strike price.

All outstanding warrants were deemed to qualify for equity classification under authoritative accounting guidance.

On March 31, 2025, the Compensation Committee of the Board of Directors of the Company adopted a salary conversion plan (the “Plan”) under which the cash payment of base salaries for certain Company executive officers was reduced by 10% to 50% and, in exchange, the Company's executive officers were granted RSUs. The RSUs granted under the Plan will vest in two equal installments on August 5, 2025 and December 5, 2025, subject to the respective executive officer's continued employment with the Company on each vesting date.