Note 6 - Stockholders' Equity - Summary of Activity for Stock Options and Restricted Stock (Details)	9 Months Ended
	Sep. 30, 2023 shares
Equity awards outstanding, beginning of year (in shares)	5,135,685
Granted (in shares)	0
Exercised or vested (in shares)	(246,156)
Expired or Forfeited (in shares)	(192,500)
Equity awards outstanding, end of period (in shares)	4,697,029
Restricted Stock [Member]
Equity awards outstanding, beginning of year (in shares)	8,732,286
Granted (in shares)	3,570,237
Exercised or vested (in shares)	(2,209,888)
Expired or Forfeited (in shares)	(138,059)
Equity awards outstanding, end of period (in shares)	9,954,576