Note 7 - Stockholder's Equity - Outstanding Warrants (Details) - $ / shares	Jun. 30, 2022	Jan. 14, 2022	Dec. 31, 2021
Total outstanding and exercisable (in shares)	43,936,895		26,456,895
Underlying shares of common stock (in shares)	1,006,285		132,265
Series 1 February 2018 Warrants [Member]
Total outstanding and exercisable (in shares)			8,979,000
Underlying shares of common stock (in shares)			44,895
Exercise price per share (in dollars per share)			$ 400.00
Series 2 February 2018 Warrants [Member]
Total outstanding and exercisable (in shares)			8,709,500
Underlying shares of common stock (in shares)			43,548
Exercise price per share (in dollars per share)			$ 400.00
November 2018 Warrants [Member]
Total outstanding and exercisable (in shares)			8,768,395
Underlying shares of common stock (in shares)			43,842
Exercise price per share (in dollars per share)			$ 80.00
Placement agent warrants issued in the January 2022 financing [Member]
Total outstanding and exercisable (in shares)	1,330,000
Underlying shares of common stock (in shares)	66,500	66,500
Exercise price per share (in dollars per share)	$ 10.00	$ 10.00
Warrants Issued in the January 2022 Financing [Member]
Total outstanding and exercisable (in shares)	16,150,000
Underlying shares of common stock (in shares)	807,500
Exercise price per share (in dollars per share)	$ 9.60