Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

16. Stock-Based Compensation

Equity incentive plans. In February 2011, the Company’s stockholders approved the Gevo, Inc. 2010 Stock Incentive Plan (as amended and restated to date, the “2010 Plan”) and the Employee Stock Purchase Plan.

The 2010 Plan provides for the grant of non-qualified stock options, incentive stock options, stock appreciation rights, restricted stock awards, restricted stock units and other equity awards to employees and directors of the Company. In May 2023, upon approval of the shareholders at the 2023 Annual Meeting of Stockholders, the 2010 Plan was amended and restated, which increased the number of shares of common stock reserved for issuance under the 2010 Plan to 37,980,074 shares. At December 31, 2023, 13,613,130 shares were available for future issuance under the 2010 Plan.

Stock-based compensation expense. The Company records stock-based compensation expense during the requisite service period for share-based payment awards granted to employees and non-employees.

The following table sets forth the Company’s stock-based compensation expense for the periods indicated (in thousands):

	Year Ended December 31,
	2023		2022
Equity Classified Awards
Cost of production	$	59	$	(25)
General and administrative		15,204		14,342
Other		1,824		2,618
Total equity classified awards		17,087		16,935
Total stock-based compensation	$	17,087	$	16,935

Stock option award activity. Stock option activity under the Company’s stock incentive plans and changes during the year ended December 31, 2023, were as follows:

				Weighted-
				Average
		Weighted-		Remaining
		Average		Contractual		Aggregate
	Number of	Exercise		Term		Intrinsic
	Options	Price (1)		(years)		Value
Options outstanding at December 31, 2022	5,945,321	$	4.65		9.1	$	—
Granted	3,368,717	$	1.69			$	—
Canceled or forfeited	(1,204,915)	$	4.06			$	—
Exercised	—	$	—			$	—
Options outstanding at December 31, 2023	8,109,123	$	3.51		8.8	$	—
Options vested and expected to vest at December 31, 2023	3,046,060	$	4.80		8.0	$	—

(1) Exercise price of options outstanding range from $1.15 to $876 as of December 31, 2023. The higher end of the range is due to the impact of several reverse stock splits during the years 2015 to 2018.

During the year ended December 31, 2023, 3.0 million stock options vested. As of December 31, 2023, the total unrecognized compensation expense, net of actual forfeitures, relating to stock options was $8.6 million, which is expected to be recognized over the remaining weighted-average period of approximately 1.9 years.

The following table sets forth the weighted average Black-Scholes option pricing model assumptions (no dividends were expected) and resulting grant date fair value for the stock options granted during the years ended December 31, 2023, and 2022:

	Year Ended December 31,
	2023			2022
Risk-free interest rate		4.30	%		2.90	%
Expected volatility factor		153	%		134	%
Expected option life (years)		6.0			6.0
Weighted-average fair value	$	1.41		$	2.18

There is a maximum contractual term of ten years for the share options. The Company settles stock option exercises with newly issued common shares. No tax benefits were realized by the Company in connection with these exercises as the Company maintains net operating loss carryforwards and has established a valuation allowance against the entire tax benefit.

Restricted Stock. The Company periodically grants restricted stock awards to employees and directors. The vesting period for restricted stock awards granted may be based upon a service period or based upon the attainment of performance objectives. The Company recognizes stock-based compensation over the vesting period, generally two to three years, for awards that vest based upon a service period.

Non-vested restricted stock awards at December 31, 2023, and changes during the year ended December 31, 2023, were as follows:

		Weighted-
		Average
	Number of	Grant-Date
	Shares	Fair Value
Outstanding at December 31, 2022	5,254,457	$	3.94
Granted	4,208,021	$	1.49
Vested and issued	(2,415,824)	$	4.08
Canceled or forfeited	(887,313)	$	3.39
Non-vested at December 31, 2023	6,159,341	$	2.30

The total fair value of restricted stock that vested during the years ended December 31, 2023, and 2022, was $9.8 million and $10.2 million, respectively. As of December 31, 2023, the total unrecognized compensation expense, net of actual forfeitures, relating to restricted stock awards was $10.3 million, which is expected to be recognized over the remaining weighted-average period of approximately 1.8 years. As of December 31, 2023, there are no unvested liability-classified restricted stock awards.