Note 5 - Fair Value Measurements - Fair Value Measurements (Details) - USD ($) $ in Thousands		Dec. 31, 2024	Jun. 30, 2024
Total		$ 0	$ 0
US Treasury Bill Securities [Member]
Investments, fair value	[1]	0	0
US Treasury Notes Securities [Member]
Investments, fair value	[1]	0	0
Money Market Funds [Member]
Cash and cash equivalents, fair value	[2]	0	0
Fair Value, Inputs, Level 2 [Member]
Total		13,830	33,487
Fair Value, Inputs, Level 2 [Member] | US Treasury Bill Securities [Member]
Investments, fair value	[1]	0	0
Fair Value, Inputs, Level 2 [Member] | US Treasury Notes Securities [Member]
Investments, fair value	[1]	0	0
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Cash and cash equivalents, fair value	[2]	13,830	33,487
Fair Value, Inputs, Level 3 [Member]
Total		127,141	126,091
Fair Value, Inputs, Level 3 [Member] | US Treasury Bill Securities [Member]
Investments, fair value	[1]	82,049	91,319
Fair Value, Inputs, Level 3 [Member] | US Treasury Notes Securities [Member]
Investments, fair value	[1]	45,092	34,772
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Cash and cash equivalents, fair value	[2]	0	0
Fair Value, Inputs, Level 1 [Member]
Total		140,971	159,578
Fair Value, Inputs, Level 1 [Member] | US Treasury Bill Securities [Member]
Investments, fair value	[1]	82,049	91,319
Fair Value, Inputs, Level 1 [Member] | US Treasury Notes Securities [Member]
Investments, fair value	[1]	45,092	34,772
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Cash and cash equivalents, fair value	[2]	$ 13,830	$ 33,487

[1] We have current and non-current debt securities (U.S. Treasury bills and notes) intended to enhance returns on our cash as well as to fund future obligations.

[2] Our corporate money market funds are readily convertible into cash and the net asset value of each fund on the last day of the quarter is used to determine its fair value.