Stock-Based Incentive Compensation Plans

3 Months Ended

Mar. 31, 2025

Share-Based Payment Arrangement [Abstract]

Stock-Based Incentive Compensation Plans

Stock Options

The table below summarizes the stock option activity for the three months ended March 31, 2025:


	Number of Shares	Weighted- Average Exercise Price		Weighted-Average Contractual Remaining Life (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2024	1,041,131	$	10.98

Exercised	(20,045)	$	5.11
Canceled and forfeited	—	$	—
Outstanding as of March 31, 2025	1,021,086	$	11.10	2.61	$	5,745
Options vested and exercisable, March 31, 2025	1,021,086	$	11.10	2.61	$	5,745
Options vested and expected to vest, March 31, 2025	1,021,086	$	11.10	2.61	$	5,745

As of March 31, 2025, there is no unrecognized compensation cost related to stock options.

There were no stock options granted during the three months ended March 31, 2025 and 2024.

Restricted Stock Units (“RSUs”)

RSUs are share awards that entitle the holder to receive freely tradable shares of the Company’s common stock upon vesting. RSUs generally vest over one to four years based upon continued services and are settled at vesting in shares of the Company's common stock. Certain RSUs vest based upon continued services and the achievement of financial milestones. The grant date fair value of the RSUs is equal to the closing price of the Company’s common stock on the grant date.

The Company granted performance-based restricted stock unit awards subject to market and service vesting conditions to certain executive officers under SI-BONE's 2018 Equity Incentive Plan (“PSUs”). The shares subject to PSUs vest over a three-year performance period. The actual number of PSUs that will vest in each measurement period will be determined by the Compensation Committee based on the Company’s total shareholder return (“TSR”) relative to the TSR of the Median Peer Companies (as defined in the award agreement). The grant date fair value of each stock award with a market condition was determined using the Monte Carlo valuation model. The table below summarizes the assumptions used to estimate the grant date fair value of the PSUs granted:


	Three Months Ended March 31,
						2025				2024
Expected volatility of common stock				49.0%	to	57.0%		47.0%	to	59.0%
Expected volatility of peer companies						30.0%	to	126.0%		29.0%	to	97.0%
Correlation coefficient of peer companies				0.05	to	1.00		(0.01)	to	1.00
Risk-free interest rate						4.1%	to	4.2%		4.1%	to	4.7%
Dividend yield	—%	to	1.0%	0.6%	to	4.7%

The table below summarizes RSU and PSU activity for the three months ended March 31, 2025:


	RSUs		PSUs
	Number of Shares	Weighted Average Grant Date Fair Value	Number of Shares	Weighted Average Grant Date Fair Value
Outstanding as of December 31, 2024	1,884,640	$18.47	610,541	$16.47
Granted	1,128,922	16.79	337,110	15.89
Vested	(252,923)	20.20	(120,155)	15.75
Canceled and forfeited	(51,377)	18.76	(42,039)	19.50
Outstanding as of March 31, 2025	2,709,262	17.61	785,457	16.17

Employee Stock Purchase Plan

The Company’s 2018 Employee Stock Purchase Plan (the “ESPP”) allows eligible employees to purchase shares of the Company's common stock through payroll deductions at the price equal to 85% of the lesser of the fair market value of the stock as of the first date or the ending date of each six month offering period. The offering period generally commences in May and November. On March 26, 2020, the Company's Compensation Committee approved the amendment of the terms of future offerings under the ESPP which, among other things, increased the maximum number of shares that may be purchased on any single purchase date, provided for automatic enrollment in a new offering.

The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model, which is being amortized over the requisite service period. The Company did not issue any shares under ESPP for the three months ended March 31, 2025 and 2024. As of March 31, 2025 and December 31, 2024, total accumulated ESPP related employee payroll deductions amounted to $1.3 million and $0.3 million, respectively, which were included within accrued compensation and related expenses in the condensed consolidated balance sheets.

Stock-Based Compensation

The table below presents the detail of stock-based compensation expense amounts included in the condensed consolidated statements of operations:


	Three Months Ended March 31,
	2025		2024
	(in thousands)
Cost of goods sold	$	160	$	235
Sales and marketing	2,623		3,221
Research and development	834		820
General and administrative	3,046		2,754
	$	6,663	$	7,030

Warrants

The table below summarizes common stock warrants activity for the three months ended March 31, 2025:


Date		Outstanding Balance at December 31, 2024	Price per Share		Warrants Issued	Warrant Exercised	Warrant Expired	Outstanding Balance at March 31, 2025
Issuance	Expiration
3/1/2017	3/1/2027	1,388	$	5.94	—	—	—	1,388
10/20/2015	10/20/2025	41,650	$	16.47	—	—	—	41,650
11/9/2015	11/9/2025	25,709	$	16.47	—	—	—	25,709
12/22/2016	12/22/2026	9,712	$	10.03	—	—	—	9,712
		78,459			—	—	—	78,459