Note 9 - Stockholders' Equity - Summary of Warrants Outstanding (Details)	Mar. 31, 2022 $ / shares shares
Warrants outstanding (in shares)	232,434
First Set of Warrants Expiring September 2024 [Member]
Warrants outstanding (in shares)	5,000
Exercise Price (in dollars per share) | $ / shares	$ 0.30
First Set of Warrants Expiring April 2024 [Member]
Warrants outstanding (in shares)	44,148
Exercise Price (in dollars per share) | $ / shares	$ 1.10
Second Set of Warrants Expiring April 2024 [Member]
Warrants outstanding (in shares)	26,515
Exercise Price (in dollars per share) | $ / shares	$ 1.375
Warrants Expiring March 2025 [Member]
Warrants outstanding (in shares)	29,150
Exercise Price (in dollars per share) | $ / shares	$ 2.50
Warrants Expiring February 2025 [Member]
Warrants outstanding (in shares)	100,532
Exercise Price (in dollars per share) | $ / shares	$ 3.125
Warrants Expiring March 2024 [Member]
Warrants outstanding (in shares)	16,175
Exercise Price (in dollars per share) | $ / shares	$ 3.125
Warrants Expiring December 2026 [Member]
Warrants outstanding (in shares)	10,914
Exercise Price (in dollars per share) | $ / shares	$ 22.99