Note 6 - Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

						Weighted-
						average
				Weighted-		contractual
	Number of			average		term		Aggregate
	shares			exercise price		(in years)		intrinsic value
Outstanding at January 1, 2021		2,526,166			6.99		8.10	$	115,472,832
Granted		—		$	—
Exercised		(52,694	)		4.10
Forfeited		(5,935	)		4.10
Expired		—			—
Outstanding at December 31, 2021		2,467,537		$	7.06		6.99	$	29,503,551
Granted		2,975,000			7.00
Exercised		(142,409	)		4.10
Forfeited		(164,443	)		7.84
Expired		—			—
Outstanding at December 31, 2022		5,135,685		$	7.10		5.09	$	25,064,799
Granted		—			—
Exercised		(246,156	)		6.08
Forfeited		(192,500	)		11.30
Expired		—			—
Outstanding at December 31, 2023		4,697,029		$	6.98		4.10	$	47,607,209
Exercisable at December 31, 2023		2,133,273		$	6.60		4.72	$	22,518,984

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended
	December 31, 2023		December 31, 2022			December 31, 2021
Volatility		N/A		88.37 - 89.67	%		N/A
Expected term (in years)		N/A		3.13 - 4.0			N/A
Risk-free rate		N/A		2.99 - 3.35	%		N/A
Expected dividend yield		N/A		—	%		N/A

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

				Weighted-average
				grant date fair
	Number of shares			value
Outstanding at January 1, 2021		10,785,034			13.38
Granted		2,738,974			39.49
Vested		(1,302,737	)		18.14
Forfeited		(189,231	)		21.80
Outstanding at December 31, 2021		12,032,040			18.67
Granted		5,179,201			12.75
Vested		(6,291,999	)		11.28
Forfeited		(2,186,956	)		22.44
Outstanding at December 31, 2022		8,732,286			16.12
Granted		3,620,237			13.77
Vested		(2,500,263	)		11.98
Forfeited		(213,192	)		12.14
Outstanding at December 31, 2023		9,639,068		$	17.05