Note 6 - Series D Redeemable Convertible Preferred Stock (Details Textual)	6 Months Ended
	Jun. 30, 2022 $ / shares shares	Dec. 31, 2021 shares
Preferred Stock, Shares Outstanding, Ending Balance (in shares)	0	0
Series D Convertible Preferred Stock [Member]
Registration Delay Payment, Number Used to be Multiplied by the Number of Days	0.0005
Preferred Stock, Shares Outstanding, Ending Balance (in shares)	907,144	907,144
Conversion of Series D Convertible Preferred Stock into Common Stock [Member]
Preferred Stock, Convertible, Conversion Price | $ / shares	$ 0.25
Conversion of Stock, Shares Issued (in shares)	3,628,576