In March 2020, the Company replaced the 2013 Option Program, or (“2013 Plan”), with its 2020 Stock Option and Grant Plan, or (“2020 Plan”). The 2020 Plan initially allowed the Company to award up to 1,740,325 options and the 304,142 outstanding options granted under the 2013 Plan were transferred to the 2020 Plan. Each vested option will entitle the option holder to purchase a single common share in the Company. Holders of stock options shall be entitled to exercise the vested portion of the stock option during the time period as determined by the Board, provided that a qualified exit, as defined in the 2020 Plan, has occurred. If a qualified exit, as defined in the 2020 Plan, occurs then all of the holders unvested options shall vest immediately. Options that are not exercised during the exercise period will automatically be forfeited. Stock options generally vest over a three-year or four-year period and expire ten years from the grant date. In September 2020, the Company allowed an addition 839,494 options to be awarded under the 2020 Plan.

In October 2020, the Board approved the 2020 Equity Incentive Plan or (“2020 Equity Plan”). The 2020 Equity Plan allowed the Company to award up to 1,625,858 options and the 2,512,427 outstanding options granted under the 2020 Plan were transferred to the 2020 Equity Plan and no further options were available to be issued under the 2020 Plan. The 2020 Equity Plan will cumulatively increase by 5 percent of the number of shares of common stock issued and outstanding on January 1st each year. At March 31, 2021, the Company had 1,925,949 options available for future grant under the 2020 Equity Plan.

The following table sets forth the activity for the Company’s stock options during the periods presented:

	Number of Options			Weighted- average exercise price per share		Weighted- average remaining contractual term (in years)		Aggregate intrinsic value
Outstanding at December 31, 2019		304,142		$	5.58		—		—
Granted		2,235,285			4.67		—		—
Exercised		(1,016	)		1.95		—		—
Outstanding at December 31, 2020		2,538,411		$	4.67		8.8	$	20,009,769
Granted		936,000			12.89		—		—
Outstanding at March 31, 2021		3,474,411		$	6.88		8.9	$	5,392,883
Vested and expected to vest at March 31, 2021		3,170,269		$	7.03		9.4	$	5,185,488
Exercisable at March 31, 2021		800,778		$	3.38		6.7	$	2,227,144

The weighted-average grant date fair value of all stock options granted for the three months ended March 31, 2021 was $9.52. The intrinsic value at March 31, 2021 was based on the closing price of the Company’s common stock on that date of $6.08 per share.

The grant date fair value of stock options vested during the three months ended March 31, 2021 was $0.2 million. Total unrecognized compensation expense related to unvested options granted under the Company’s stock-based compensation plan was $14.4 million at March 31, 2021, which is expected to be recognized over a weighted average period of 3.5 years. The Company recorded stock-based compensation expense related to the issuance of stock as follows (in thousands):

There was no stock-based compensation expense during the three months ended March 31, 2020.

The fair values of the options granted were estimated based on the Black-Scholes model, using the following assumptions:

	Three Months Ended
	March 31,
	2021
Risk-free interest rate		0.5	%
Expected term (in years)		6.1
Expected volatility		90.5	%
Expected dividend yield		—