Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2022

Schedule of components and classification of stock-based compensation expense

The components and classification of stock-based compensation expense, excluding the Company’s matching contributions to the Plug Power Inc. 401(k) Savings & Retirement Plan and quarterly Board compensation, were as follows (in thousands):

	Year ended December 31,
	2022		2021		2020
Cost of sales	$	7,259	$	1,965	$	324
Research and development		6,369		5,983		1,624
Selling, general and administrative		156,127		64,443		12,444
	$	169,755	$	72,391	$	14,392

Nonvested Restricted Stock Shares Activity

A summary of restricted stock award activity for the year ended December 31, 2022 is as follows (in thousands except share amounts):

		Weighted		Aggregate
		Average Grant Date		Intrinsic
	Shares	Fair Value		Value
Unvested restricted stock at December 31, 2021	4,851,873	$	21.59	$	136,968
Granted	4,289,682		20.28		—
Vested	(2,628,397)		(13.96)		—
Forfeited	(236,782)		23.84		—
Unvested restricted stock at December 31, 2022	6,276,376	$	21.56	$	77,639

Service Stock Options Awards

Assumptions made for the purpose of estimating fair value

	December 31,	December 31,	December 31,
	2022	2021	2020
Expected term of options (years)	5	3-5	6
Risk free interest rate	1.26% - 4.34%	0.61% - 1.23%	0.37% - 1.37%
Volatility	73.38% - 85.97%	72.46% - 76.60%	64.19% - 68.18%

Schedule of Share-based Compensation, Stock Options, Activity

					Weighted
			Weighted		Average
			Average		Remaining		Aggregate
			Exercise		Contractual		Intrinsic
	Shares		Price		Terms		Value
Options outstanding at December 31, 2021	$	9,786,909	$	11.65		7.70	$	172,412
Options exercisable at December 31, 2021		4,724,624		4.37		6.50		112,715
Options unvested at December 31, 2021		5,062,285		18.44		8.80		59,697
Granted		3,261,724		20.25		—		—
Exercised		(757,424)		2.96		—		—
Forfeited		(212,940)		24.25		—		—
Options outstanding at December 31, 2022	$	12,078,269	$	14.34		7.57	$	42,835
Options exercisable at December 31, 2022		6,661,969		8.41		6.40		42,182
Options unvested at December 31, 2022	$	5,416,300	$	21.63		9.01	$	653

Performance Stock Option Awards

Assumptions made for the purpose of estimating fair value

	December 31,		December 31,
	2022		2021
Remaining VWAP performance period (years)		3		3
Risk- free interest rate		3.10%		1.12%
Expected volatility		75.00%		70.00%
Closing stock price on grant date	$	26.38	$	26.92

Schedule of Share-based Compensation, Stock Options, Activity

The following table reflects the Performance Stock Option activity for the year ended December 31, 2022. Solely for the purposes of this table, the number of shares is based on participants earning the maximum number of shares underlying the Performance Stock Options (i.e., 200% of the target number of shares).

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
		Exercise		Contractual	Intrinsic
	Shares	Price		Terms	Value
Options outstanding at December 31, 2021	14,020,000	$	26.92	6.70	$	18,336
Options exercisable at December 31, 2021	—		—	—		—
Options unvested at December 31, 2021	14,020,000		26.92	6.70		18,336
Granted	1,500,000		26.38	6.64		—
Exercised	—		—	—		—
Forfeited	—		—	—		—
Options outstanding at December 31, 2022	15,520,000	$	26.87	5.81	$	—
Options exercisable at December 31, 2022	1,391,000		26.92	5.73		—
Options unvested at December 31, 2022	14,129,000	$	26.86	5.82	$	—