Note 10 - Stockholders' Equity (Deficit) - Stock Options Rollforward (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Nonvested shares (in shares)	799,376	835,297
Nonvested, Beginning balance, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 4.25	$ 7.76
Granted, shares (in shares)	581,614	582,353
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 3.17	$ 1.72	$ 7.9
(Vested), shares (in shares)	(674,010)	(618,274)
(Vested), Weighted Average Grant-Date Fair Value (in dollars per share)	$ 4.15	$ 6.61
Nonvested shares (in shares)	706,980	799,376	835,297
Nonvested, Beginning balance, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 3.46	$ 4.25	$ 7.76