Note 2 - Investments (Details Textual)	3 Months Ended			6 Months Ended	9 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares		Mar. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2023 USD ($) $ / shares shares		Mar. 31, 2022 USD ($)	Mar. 31, 2023 $ / shares	Dec. 31, 2022 $ / shares	Sep. 30, 2021	Jan. 31, 2021 USD ($) $ / shares
Statement [Line Items]
Investment Owned, Fair Value	$ 20,800,000				$ 20,800,000
Investment Owned, Cost	$ 27,600,000				$ 27,600,000
Value of Fair Value Investments to Company Assets, Percent	37.40%				37.40%
Equity Securities without Readily Determinable Fair Value, Amount	$ 2,827,000		$ 4,208,000	$ 3,992,000	$ 2,827,000		$ 4,208,000
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss, Total	1,000,000.0			1,000,000.0	1,000,000.0
Equity Securities, FV-NI, Total	13,184,000			14,300,000	13,184,000
Debt Securities, Available-for-Sale, Total	7,649,000	[1]		10,625,000	7,649,000	[1]
OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax	80,000		(141,000)		(939,000)		(428,000)
Investment Income, Net	1,155,000		(3,495,000)		(189,000)		(1,950,000)
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	245,000	[2]		133,000	245,000	[2]
Debt Securities, Available-for-Sale, Periodic Principal Payments					750,000
Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Cumulative Amount	2,500,000				2,500,000
Equity Securities without Readily Determinable Fair Value, Downward Price Adjustment, Cumulative Amount	3,300,000				3,300,000
Income (Loss) from Equity Method Investments	0		(173,000)		0		(206,000)
Realized Gain (Loss) on Principal Payment Proceeds	394,000		524,000		1,300,000		1,700,000
Equity Securities Without Readily Determinable Fair Values, Unrealized Gain (Loss)	0		187,000		1,800,000		187,000
U S Global Investors Funds [Member]
Statement [Line Items]
Investment Owned, Fair Value	12,400,000			12,800,000	12,400,000
HIVE Blockchain Technologies Ltd. [Member] | Convertible Securities [Member]
Statement [Line Items]
Investment Owned, Balance, Principal Amount											$ 15,000,000.0
HIVE Blockchain Technologies Ltd. [Member] | Warrants and Convertible Debentures [Member] | Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities and Equity Securities [Member]
Statement [Line Items]
Investment Owned, Fair Value	7,900,000			11,100,000	7,900,000
HIVE Blockchain Technologies Ltd. [Member] | Unsecured Convertible Debentures [Member]
Statement [Line Items]
Debt Securities, Available-for-Sale, Total	7,600,000			10,600,000	$ 7,600,000
OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax	$ 6,900,000
HIVE Blockchain Technologies Ltd. [Member] | Unsecured Convertible Debentures [Member] | Convertible Debt Securities [Member]
Statement [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.00%				8.00%
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares	$ 11.70				$ 11.70						$ 2.34
Investment Income, Net	$ 394,000		$ 524,000		$ 1,300,000		1,700,000
HIVE Blockchain Technologies Ltd. [Member] | Common Shares Purchase Warrants [Member]
Statement [Line Items]
Investment, Common Share Purchase Warrants (in shares) | shares	5,000,000				5,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares								$ 3.00	$ 15.00
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares	5				5
Equity Securities, FV-NI, Total	$ 222,000			515,000	$ 222,000
HIVE Blockchain Technologies Ltd. [Member] | Common Shares Purchase Warrants [Member] | Estimate of Fair Value Measurement [Member]
Statement [Line Items]
Equity Securities, FV-NI, Total	5,900,000				5,900,000
Debt Securities, Available-for-Sale, Total	16,000,000.0				16,000,000.0
HIVE Blockchain Technologies Ltd. [Member] | Convertible Securities [Member]
Statement [Line Items]
Investment Owned, Balance, Principal Amount	8,300,000				8,300,000
Thunderbird Entertainment Group [Member]
Statement [Line Items]
Equity Securities, FV-NI, Realized Gain							$ 1,900,000
The Sonar Company [Member]
Statement [Line Items]
Equity Securities without Readily Determinable Fair Value, Amount	362,000				362,000
Other Investments and Securities, at Cost	$ 175,000				$ 175,000
Investment Owned, Direct Percentage	2.80%				2.80%
Galileo New Economy Fund L P [Member]
Statement [Line Items]
Equity Method Investment, Ownership Percentage										22.00%
Income (Loss) from Equity Method Investments	$ 173,000				$ 206,000
Galileo New Economy Fund L P [Member] | Cash [Member]
Statement [Line Items]
Proceeds from Equity Method Investment, Distribution, Return of Capital				85,000
Galileo New Economy Fund L P [Member] | Common Shares [Member]
Statement [Line Items]
Proceeds from Equity Method Investment, Distribution, Return of Capital				$ 228,000

[1] Principal payments of $750,000 are due quarterly with a final maturity date in January 2026.

[2] Held-to-maturity debt investments are carried at amortized cost, and the fair value is classified as Level 2 according to the fair value hierarchy.