For the three months ended March 31, 2025 and 2024, the Company recorded stock-based compensation expense as follows (in thousands):


	For the Three Months Ended March 31,
	2025		2024
Research and development	$	425	$	509
Selling, general and administrative		5,425		7,739
Total stock-based compensation	$	5,850	$	8,248

As of March 31, 2025, there were outstanding stock options to purchase 12,577,619 shares of common stock, of which stock options to purchase 7,079,684 shares of common stock were exercisable.

During the three months ended March 31, 2025 and 2024, the Company granted seven-year term options to purchase an aggregate of 510,956 and 793,495 shares, respectively, of the Company’s common stock to employees. The Company recorded stock-based compensation related to stock options totaling $4.8 million and $5.4 million, respectively, during the three months ended March 31, 2025 and 2024.

During the three months ended March 31, 2025 and 2024, options to purchase 975,155 shares and 664,432 shares, respectively, of the Company’s common stock were exercised, with proceeds of $4.8 million and $1.5 million, respectively, to the Company.

As of March 31, 2025, there was approximately $42.2 million of unrecognized compensation expense related to non-vested stock option awards granted under the 2018 Stock Incentive Plan. The cost is expected to be recognized over a weighted average period of approximately 2.6 years.

The Company granted 3,439 and 35,693 restricted stock units during the three months ended March 31, 2025 and 2024, respectively. During the three months ended March 31, 2025 and 2024, the Company recorded non-cash stock-based compensation expense related to restricted stock units totaling $1.1 million and $2.9 million, respectively.

As of March 31, 2025, there was approximately $8.3 million of unrecognized compensation expense related to non-vested restricted stock units granted under the 2018 Stock Incentive Plan. The cost is expected to be recognized over a weighted average period of approximately 2.7 years.