Note 8 - Stockholders' Equity - Schedule of Warrant Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Outstanding (in shares)	2,393	86
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 2.40	$ 5.14
Outstanding, Aggregate Fair Market Value	$ 3,747	$ 3,747	$ 194
Outstanding, Weighted Average Remaining Contractual Term (Year)	3 years 7 months 6 days	4 years 7 months 17 days	4 years 8 months 26 days
Issued (in shares)		2,307
Issued (in dollars per share)		$ 2.30
Issued		$ 3,553
Issued (Year)		4 years 7 months 17 days
Outstanding (in shares)	2,393	2,393	86
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 2.40	$ 2.40	$ 5.14
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 2.40	$ 2.40	$ 5.14
Class Of Warrant Or Right, Outstanding (in shares)	2,393	2,393	86
Class of Warrant or Rights, Warrants Issued March 26, 2020 [Member]
Outstanding (in shares)	25
Outstanding (in shares)	25	25
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.25
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 6.25
Class Of Warrant Or Right, Expiration Date	Mar. 25, 2025
Class Of Warrant Or Right, Outstanding (in shares)	25	25
Class of Warrant or Rights, Warrants Issued March 30, 2020 [Member]
Outstanding (in shares)	61
Outstanding (in shares)	61	61
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.6875
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 4.6875
Class Of Warrant Or Right, Expiration Date	Mar. 27, 2025
Class Of Warrant Or Right, Outstanding (in shares)	61	61
Class of Warrant or Rights, Warrants Issued October 23, 2020 [Member]
Outstanding (in shares)	470
Outstanding (in shares)	470	470
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 2.88
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 2.88
Class Of Warrant Or Right, Expiration Date	Oct. 21, 2025
Class Of Warrant Or Right, Outstanding (in shares)	470	470
Class of Warrant or Rights, Warrants Issued October 28, 2020 [Member]
Outstanding (in shares)	173
Outstanding (in shares)	173	173
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 2.6875
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 2.6875
Class Of Warrant Or Right, Expiration Date	Oct. 28, 2025
Class Of Warrant Or Right, Outstanding (in shares)	173	173
Class of Warrant or Rights, Warrants Issued February 16, 2021 [Member]
Outstanding (in shares)	171
Outstanding (in shares)	171	171
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.06
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 4.06
Class Of Warrant Or Right, Expiration Date	Feb. 11, 2026
Class Of Warrant Or Right, Outstanding (in shares)	171	171
Class of Warrant or Rights, Warrants Issued April 12, 2021 [Member]
Outstanding (in shares)	1,493
Outstanding (in shares)	1,493	1,493
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 1.875
Class Of Warrant Or Right, Exercise Price (in dollars per share)	$ 1.875
Class Of Warrant Or Right, Expiration Date	Apr. 07, 2026
Class Of Warrant Or Right, Outstanding (in shares)	1,493	1,493