Stock Option Plan

9 Months Ended

Sep. 30, 2026

Stock Option Plan [Abstract]

Stock Option Plan

12. Stock Option Plan

Equity Incentive Plan

In 2010, the Company adopted the 2010 Equity Compensation Plan (the “2010 Plan”). There have been no issuances under the 2010 Plan since the adoption of the 2016 Equity Incentive Plan (the “2016 Plan”). The 2010 Plan expired in 2025, and all options available for issuance under the 2010 Plan upon expiration were moved to the 2016 Plan. Accordingly, no shares are available for future issuance under the 2010 Plan as of September 30, 2026.

In 2016, the Company’s Board of Directors adopted the 2016 Plan under which incentive stock options (“ISOs”), nonqualified stock options (“NSOs”), stock appreciation rights (“SARs”), restricted stock, and restricted stock units (“RSUs”) may be granted to employees, directors, and consultants.

In connection with the Merger, the Company adopted the 2026 Equity Incentive Plan (the “2026 EIP”) effective on April 9, 2026. Pursuant to the Merger Agreement, the 2016 Plan was terminated effective as of the closing of the Merger, and no further awards may be granted thereunder. All outstanding Legacy Ionetix stock options were assumed by the Company under the 2026 EIP and converted into options to purchase shares of the Company’s common stock, with the number of underlying shares and exercise price adjusted based on the Conversion Ratio. The converted options otherwise continued to be subject to substantially the same terms and conditions applicable to such options immediately prior to the Merger. The 2026 EIP provides for the issuance of incentive awards of ISOs, NSOs, SARs, RSUs and Stock Bonus Awards (“SBAs”). ISOs may be granted only to employees. The maximum aggregate number of shares of common stock that may be issued under the 2026 EIP is 11,935,631 shares.

Stock option

Stock option activity during the nine months ended September 30, 2026 is as follows:

		Number of options				Weighted average exercise price				Weighted average remaining contractual life (years)				Aggregate intrinsic value
Balance as of December 31, 2025			14,162,648			$	0.31				6.41			$	2,541
Retroactive application of reverse recapitalization			(7,061,496	)
Balance as of December 31, 2025, adjusted			7,101,152				0.62				6.41				2,541
Options granted			646,357				2.55
Options exercised			(465,019	)			0.31								1,151
Options cancelled			(540,179	)			0.55
Balance as of September 30, 2026			6,742,311			$	0.83				6.48			$	14,610
Vested and expected to vest at September 30, 2026			6,742,311			$	0.83				6.48			$	14,610
Exercisable at September 30, 2026			4,617,129			$	0.57				5.41			$	11,215

The options granted during the three months ended September 30, 2026 and 2025 had a weighted-average grant-date fair value per share of $2.08 and $0.61, respectively, and the options granted during the nine months ended September 30, 2026 and 2025 had a weighted-average grant-date fair value per share of $2.03 and $0.60, respectively. The total fair value of options vested was $90 and $94 during the three months ended September 30, 2026 and 2025, respectively, and $398 and $367 during the nine months ended September 30, 2026 and 2025, respectively.

Fair Value Inputs

The fair value of stock options granted was estimated using the following weighted-average assumptions:

		Nine Months Ended September 30,
		2026				2025
Expected term (in years)			6.1				5.7
Expected volatility			70.0	%			65.4	%
Risk-free rate			4.2	%			4.1	%
Dividend yield			—				—

Stock-Based Compensation

The Company’s total stock-based compensation for the three and nine months ended September 30, 2026 and 2025 is as follows:

		Three Months Ended September 30,								Nine Months Ended September 30,
		2026				2025				2026				2025
Cost of revenue		$	17			$	6			$	51			$	9
Research and development			13				13				37				37
Selling, general and administrative			149				81				367				343
Total stock-based compensation		$	179			$	100			$	455			$	389

As of September 30, 2026, the unrecognized stock-based compensation related to outstanding unvested options was $1.9 million and is expected to be recognized over a weighted average period of 2.7 years.