Note 14 - Stock-based Compensation - Schedule of Unvested Performance Restricted Stock Options (Details) - Performance-based Restriced Stock Units [Member] - $ / shares	12 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Balance, number of restricted stock units (in shares)	757,501	890,000
Balance, weighted average grant date fair value (in dollars per share)	$ 1.15	$ 1.15
Forfeited, number of unvested PRSUs (in shares)		(132,499)
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)		$ 1.15
Granted, number of restricted stock units (in shares)	492,950	0
Granted, weighted average grant date fair value (in dollars per share)	$ 2.48
Balance, number of restricted stock units (in shares)	1,250,451	757,501
Balance, weighted average grant date fair value (in dollars per share)	$ 1.67	$ 1.15