Note 8 - Stock-based Compensation - Restricted Stock Activity (Details) - Restricted Stock Units (RSUs) [Member]	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Beginning balance, unvested restricted stock units, shares (in shares) | shares	767,048
Beginning balance, unvested restricted stock units, weighted average grant date fair value (in dollars per share) | $ / shares	$ 1.32
Granted, unvested restricted stock units, shares (in shares) | shares	100,000
Granted, unvested restricted stock units, weighted average grant date fair value (in dollars per share) | $ / shares	$ 1.25
Ending balance, unvested restricted stock units, shares (in shares) | shares	867,048
Ending balance, unvested restricted stock units, weighted average grant date fair value (in dollars per share) | $ / shares	$ 1.31