The Company grants stock-based awards under the Magenta Therapeutics, Inc. 2018 Stock Option and Incentive Plan (the “2018 Plan”). The Company also has outstanding stock options under the Magenta Therapeutics, Inc. 2016 Stock Option and Grant Plan, as amended (the “2016 Plan”), but is no longer granting awards under the 2016 Plan. As of September 30, 2022, 3,000,865 shares of common stock were available for issuance under the 2018 Plan.

During the nine months ended September 30, 2022, the Company granted options to certain employees, directors and consultants with service-based vesting conditions for the purchase of 4,357,798 shares of common stock with a weighted average grant date fair value of $1.51 per share. Stock-based compensation expense is being recognized over the requisite service period of 18 months to four years.

During the nine months ended September 30, 2022, the Company granted 160,558 restricted stock units to certain employees with a weighted average grant date fair value of $2.01 per share. Stock-based compensation expense is being recognized over the requisite service period of 18 months to four years.

Employees may elect to participate in The Magenta Therapeutics, Inc. 2019 Employee Stock Purchase Plan (the “ESPP”). The purchase price of common stock under the ESPP is equal to 85% of the lower of the fair market value of the common stock on the offering date or the exercise date. The six-month offering periods begin in December and June of each year. During the nine months ended September 30, 2022, 49,704 shares of common stock were purchased under the ESPP at a purchase price per share of $0.99. During the nine months ended September 30, 2021, 13,989 shares of common stock were purchased under the ESPP at a purchase price per share of $6.15. As of September 30, 2022, 663,548 shares remained available for issuance under the ESPP.

Stock-based compensation expense was classified in the statements of operations and comprehensive loss as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Research and development expenses	$	315	$	1,335	$	1,304	$	3,276
General and administrative expenses		1,192		2,464		3,953		4,849
	$	1,507	$	3,799	$	5,257	$	8,125

As of September 30, 2022, unrecognized compensation expense related to unvested share-based awards with service-based vesting conditions was $15.5 million, which is expected to be recognized over a weighted average period of 2.4 years. Additionally, the Company had unrecognized compensation cost of $1.7 million related to the unvested performance restricted stock units for which the performance conditions were not considered probable of achievement as of September 30, 2022.