Note 2 - Basis of Presentation and Summary of Significant Accounting Policies (Details Textual)	6 Months Ended
	Nov. 30, 2022 shares
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants (in shares)	6,209,000
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities (in shares)	23,981,704
Restricted Stock Units (RSUs) [Member]
Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements (in shares)	16,884,493
Share-Based Payment Arrangement, Option [Member]
Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements (in shares)	4,674,512