Stock-based compensation expense, net of forfeitures of $0.7 million and $0.1 million, was $4.4 million and $3.1 million for the three months ended March 31, 2024 and 2023, respectively.

At March 31, 2024, the aggregate unrecognized compensation expense related to unvested equity awards was $35.5 million, which is expected to be recognized as compensation expense in fiscal years 2024 through 2027.

A summary of stock option activity for the three months ended March 31, 2024 is below:


(in thousands, except for weighted average exercise price)	Options outstanding	Weighted average exercise price
Outstanding at January 1, 2024	920	$	13.04

Exercised	(107)	10.29
Canceled/forfeited	(11)	9.94
Outstanding at March 31, 2024	802	$	13.46

A summary of unvested restricted stock units activity for the three months ended March 31, 2024 is below:


(in thousands, except for weighted average award value)	Restricted Stock Unit Awards	Weighted average award value
Outstanding at January 1, 2024	839	$	35.83
Granted	429	48.81
Vested	(329)	32.88
Canceled/forfeited	(110)	34.88
Outstanding at March 31, 2024	829	$	44.38

A total of 330,000 shares of Company common stock are available for purchase under the Company's 2021 Employee Stock Purchase Plan ("ESPP"), subject to adjustment as provided for in the ESPP. As of March 31, 2024, no shares of common stock were purchased.