Shares of common stock reserved for issuance under the Company’s equity incentive plans were as follows:


	September 30, 2025
Outstanding stock awards		13,873,027
Reserved for future award grants		4,559,667
Reserved for future ESPP		306,323
Total common stock reserved for stock awards		18,739,017

A summary of the Company’s service-based stock option activity (excluding performance-based stock option activity, which is presented separately below) for the nine months ended September 30, 2025 is as follows:


	Outstanding Service-Based Options
(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Balance—December 31, 2024		8,607,718		$	5.07		7.64	$	21,949
Options granted		4,617,500			4.11
Options exercised		(118,511	)		2.32
Options forfeited or expired		(304,948	)		6.54
Balance—September 30, 2025		12,801,759		$	4.71		7.85	$	37,105
Options vested and exercisable as of September 30, 2025		6,602,404		$	5.79		6.68	$	18,792

The weighted-average grant date fair value of options granted was $4.47 and $3.55 per share for the three months ended September 30, 2025 and 2024 and $3.01 and $1.49 per share for the nine months ended September 30, 2025 and 2024, respectively. As of September 30, 2025, the unrecognized stock-based compensation cost of unvested options was $14.8 million, which is expected to be recognized over a weighted-average period of 2.2 years.

The Company estimated the fair value of service-based stock options using the Black-Scholes option-pricing model. Fair value of stock options is recognized as compensation expense on a straight-line basis over the requisite service periods of the awards. Fair value of stock options was estimated using the following range of assumptions:


	Three Months Ended September 30,		Nine Months Ended September 30,
	2025	2024	2025	2024
Expected term (in years)	6.02 - 6.08	5.77 - 6.08	5.50 - 6.08	5.50 - 6.08
Volatility	89.54 - 90.15%	82.57 - 83.59%	83.72 - 90.15%	72.61 - 83.59%
Risk-free interest rate	3.70 - 4.16%	3.48 - 4.15%	3.70 - 4.50%	3.48 - 4.65%
Dividend yield	–%	–%	–%	–%

During 2024, the Company granted performance-based stock options ("PSOs") to the executive leadership team. Vesting of the PSOs is based upon attainment of certain Medicare reimbursement coverages by the end of 2025 and subject to continuous service by the executives. Fair value was estimated using the Black-Scholes option-pricing model. Total grant-date fair value of the PSOs was $0.3 million. As of September 30, 2025, the unrecognized stock-based compensation cost of unvested PSOs was immaterial.

A summary of the Company's performance-based stock option activity for the nine months ended September 30, 2025 is as follows:


	Outstanding Performance-Based Options
(in thousands, except share and per share data)	Number of Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Balance—December 31, 2024		271,500	$	1.61		9.20	$	1,133
Balance—September 30, 2025		271,500	$	1.61		8.45	$	1,334
Options vested and exercisable as of September 30, 2025		—		—		—		—

A summary of the Company’s RSU activity for the nine months ended September 30, 2025 is as follows:


	Unvested Service-Based Restricted Stock Units
(in thousands, except share and per share data)	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Fair Value
Balance—December 31, 2024		433,484		$	6.34	$	2,506
RSUs vested		(197,819	)		9.46		1,023
RSUs forfeited		(10,897	)		5.88
Balance—September 30, 2025		224,768		$	3.61	$	1,465

As of September 30, 2025, the unrecognized stock-based compensation cost of unvested RSUs was $0.5 million, which is expected to be recognized over a weighted-average period of 1.0 year.

In March 2025, the Company granted performance-based RSUs ("PSUs") to the executive leadership team. A percentage of the number of RSUs will vest based upon achieving the Company's operational target as of the end of 2026, and subject to continuous service by the executives throughout March 2028. Fifty percent of the aggregate number of achieved PSUs (if any) will vest upon certification in March 2027, with the remaining fifty percent vesting in March 2028. The total grant-date fair value of the PSUs was $2.1 million. As of September 30, 2025, the Company no longer considered the achievement of the operational target to be probable. Accordingly, the Company reversed previously recognized stock-based compensation expense and no stock-based compensation cost was recognized for the nine months ended September 30, 2025.

A summary of the Company's PSUs activity for the nine months ended September 30, 2025 is as follows:


	Unvested Performance-Based Restricted Stock Units
(in thousands, except share and per share data)	Number of Shares		Weighted- Average Grant Date Fair Value		Aggregate Fair Value
Balance—December 31, 2024		—	$	—	$	—
PSUs granted		575,000		3.63
Balance—September 30, 2025		575,000	$	3.63	$	3,749

During the nine months ended September 30, 2025 and 2024, 193,738 and 391,415 shares of common stock were purchased under the Employee Stock Purchase Plan ("ESPP"), respectively. The fair value of stock purchase rights granted under the ESPP was estimated using the following range of assumptions:


	Three and Nine Months Ended September 30,
	2025	2024
Expected term (in years)	0.5	0.5
Volatility	92.85%	61.35%
Risk-free interest rate	4.22%	5.43%
Dividend yield	–%	–%
Fair value	1.59	0.51

The following is a summary of stock-based compensation expense by award type (in thousands):


	Three Months Ended September 30,					Nine Months Ended September 30,
	2025			2024		2025		2024
Service-based stock options	$	1,956		$	1,267	$	5,066	$	3,719
Performance-based stock options		35			36		105		77
Service-based RSUs		202			1,324		1,463		4,056
Performance-based RSUs		(259	)		—		—		—
ESPP		148			50		497		165
Total stock-based compensation expense	$	2,082		$	2,677	$	7,131	$	8,017

The following is a summary of stock-based compensation expense by function (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2025		2024		2025		2024
Cost of revenue	$	156	$	156	$	537	$	463
Research and development		698		1,006		2,512		2,999
Selling, general and administrative		1,228		1,515		4,082		4,555
Total stock-based compensation expense	$	2,082	$	2,677	$	7,131	$	8,017