We issue RSAs and RSUs to participants in our equity plans in the form of time-based RSAs and RSUs and performance-based RSAs and RSUs.

Compensation cost related to RSA and RSU grants was $2.4 million and $1.8 million for the three months ended September 30, 2023 and September 24, 2022, respectively, and $6.7 million and $5.1 million for the nine months ended September 30, 2023 and September 24, 2022, respectively, and

was included in selling, general and administrative expenses in the Condensed Consolidated Statements of Operations.

The following table summarizes our RSA and RSU activity for the nine months ended September 30, 2023:


	Shares	Weighted Average Fair Value
Balance at December 31, 2022	238,922	$	92.07
Granted	109,688	$	96.01
Vested	(70,550)	$	80.24
Canceled	(17,692)	$	83.49
Balance at September 30, 2023	260,368	$	97.51

For the nine months ended September 30, 2023, we granted 29,399 performance-based RSUs with a grant date fair value of $113.15 per share. For the nine months ended September 24, 2022, we granted 23,995 performance-based RSUs with a grant date fair value of $111.31 per share.

As of September 30, 2023, there was $16.0 million of unrecognized compensation cost related to unvested RSA and RSU grants that is expected to be recognized over a weighted average period of 2.2 years.

We grant stock options to participants in our equity plans. Compensation cost related to stock option grants was $0.5 million and $0.5 million for the three months ended September 30, 2023 and September 24, 2022, respectively, and $1.5 million and $1.3 million for the nine months ended September 30, 2023 and September 24, 2022, respectively, and was included as selling, general and administrative expenses in the Condensed Consolidated Statements of Operations.

The following table summarizes our stock option activity for the nine months ended September 30, 2023:


	Shares	Weighted Average Price		Weighted Average Remaining Term (years)	Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2022	268,119	$	84.03
Granted	79,404	$	91.13
Canceled	(6,510)	$	93.48
Exercised	(24,297)	$	72.33
Balance at September 30, 2023	316,716	$	86.51	5.6	$	982
Exercisable at September 30, 2023	136,117	$	80.50	4.6	$	704

As of September 30, 2023, there was $4.6 million of unrecognized compensation cost related to unvested stock options that is expected to be recognized over a weighted average period of 2.8 years.

During the nine months ended September 30, 2023, we issued 14,975 shares under the ESPP. During the three and nine months ended September 24, 2022, we issued 8,712 shares and 13,327 shares, respectively, under the ESPP.