The Company's 2020 Equity Incentive Plan is described in detail within Note 6 of the Notes to the Consolidated Financial Statements in the 2022 Annual Report on Form 10-K. As of June 30, 2023, there were 2,508,398 options outstanding under the 2020 Plan.

The Company's 2021 Stock Option and Incentive Plan is described in detail within Note 6 of the Notes to the Consolidated Financial Statements in the 2022 Annual Report on Form 10-K. On January 1, 2023, the shares reserved for future grants under the 2021 Plan increased by 1,781,017 pursuant to the 2021 Plan Evergreen Provision. In March of 2023, as part of the Company's annual grant of equity, the Company granted 1,348,380 stock options to employees. As of June 30, 2023, there were 3,252,644 options outstanding under the 2021 Plan.

The Company's 2021 Employee Stock Purchase Plan is described in detail within Note 6 of the Notes to the Consolidated Financial Statements in the 2022 Annual Report on Form 10-K. On January 1, 2023, the shares reserved for future grants under the 2021 ESPP increased by 286,127 pursuant to the 2021 Plan Evergreen Provision. As of June 30, 2023, a total of 572,254 shares of common stock were reserved for issuance under this plan. No stock-based compensation expense was recognized during the three and six months ended June 30, 2023 related to the 2021 ESPP.

The Company recorded stock-based compensation expense of $2.3 million and $4.0 million during the three and six months ended June 30, 2023, respectively, and recorded $1.5 million and $2.5 million during the three and six months ended June 30, 2022, respectively. Stock-based compensation expense was classified as follows in the condensed consolidated statements of operations and comprehensive loss (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Research and development	$	891	$	608	$	1,577	$	1,049
General and administrative		1,366		853		2,414		1,433
Total stock-based compensation	$	2,257	$	1,461	$	3,991	$	2,482

At June 30, 2023, there was approximately $24.8 million unrecognized stock-based compensation expense related to unvested options, which is expected to be recognized over a weighted-average period of 2.78 years. At June 30, 2023, there was approximately $0.1 million unrecognized stock-based compensation expense related to unvested restricted stock, which is expected to be recognized over a weighted-average period of 0.84 years.