Note 7 - Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2024

Notes Tables

Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]

	June 30,			December 31,
	2024			2023
Stock price	$	3.50		$	12.00
Risk-free interest rate		4.52	%		3.84	%
Expected dividend yield		—			—
Expected term in years		3.3			3.8
Expected volatility		160	%		148	%

Schedule of Unvested Restricted Stock Units Roll Forward [Table Text Block]

	Number of			Weighted
	Units and			Average Grant
	Awards			Date Fair Value
	(in thousands)
Unvested balance at December 31, 2023		1,311		$	196.21
Granted		—			—
Forfeited		—			—
Vested		(283	)		85.50
Unvested balance at March 31, 2024		1,028		$	226.69
Unvested balance at June 30, 2024		1,028		$	226.69

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

					Weighted
					Average
	Number		Weighted		Remaining		Aggregate
	of Options		Average		Contractual		Intrinsic Value
	(in thousands)		Exercise Price		Term (years)		(in thousands)
Outstanding at December 31, 2023		22,474	$	85.50		9.5	$	—
Granted		—	$	—			$	—
Exercised		—	$	—			$	—
Cancelled/forfeited		—	$	—			$	—
Expired		—	$	—			$	—
Outstanding at Balance at June 30, 2024		22,474	$	85.50		9.0	$	—
Expected to vest		16,304	$	85.50		9.0	$	—
Exercisable		6,170	$	85.50		9.0	$	—

Share-Based Payment Arrangement, Cost by Plan [Table Text Block]

	For the three months ended				For the six months ended
	June 30,		June 30,		June 30,		June 30,
	2024		2023		2024		2023
Research and development	$	45	$	6	$	90	$	6
General and administrative		147		21		293		32
Total stock-based compensation expense	$	192	$	27	$	383	$	38

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

				Weighted
				Average		Aggregate
				Exercise		Intrinsic Value
	Warrants			Price		(in thousands)
Outstanding, December 31, 2023		524,601		$	32.42	$	—
Granted		441,076			6.20
Exercised		(220,538	)		22.55
Outstanding, March 31, 2024		745,139		$	29.50	$	—
Granted		1,420,741			6.25
Exercised		(689,680	)		6.20
Outstanding, June 30, 2024		1,476,200		$	8.64	$	—

Warrant [Member]

Notes Tables

Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]

	January 2023			New Series A			New Series B
	Warrants			Warrants			Warrants
Stock price	$	14.25		$	14.25		$	14.25
Risk-free interest rate		4.40	%		4.02	%		4.40	%
Expected dividend yield		—			—			—
Expected term in years		2.1			5.0			1.5
Expected volatility		185	%		138	%		187	%

	October 2022			Series C			Series D			Placement Agent
	Warrants			Warrants			Warrants			Warrants
Stock price	$	4.76		$	4.76		$	4.76		$	4.76
Risk-free interest rate		5	%		4.64	%		4.96	%		4.64	%
Expected dividend yield		—			—			—			—
Expected term in years		3.4			5.0			1.5			5.0
Expected volatility		160	%		141	%		132	%		141	%