Note 16 - Quarterly Financial Data (Unaudited) - Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Net revenue	$ 2,279	$ 2,880	$ 2,206	$ 2,315	$ 1,924	$ 1,924	$ 1,904	$ 1,562
Gross profit	1,071	1,706	1,111	1,236	879	879	765	524	$ 5,124	$ 3,047	$ 1,842
Net loss	$ (1,188)	$ (545)	$ (897)	$ (816)	$ (1,095)	$ (1,127)	$ (1,414)	$ (1,508)	$ (3,446)	$ (5,144)	$ (6,700)
Net loss per share – basic and diluted (in dollars per share)	$ (0.02)	$ (0.01)	$ (0.01)	$ (0.01)	$ (0.02)	$ (0.02)	$ (0.02)	$ (0.02)	$ (0.05)	$ (0.08)	$ (0.12)
Shares used in basic and diluted per share calculation (in shares)	68,075	67,558	67,388	67,388	67,357	67,333	67,331	66,147	67,601	67,042	55,159