Overview of the Business and Basis of Presentation - Financial assets and liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Common Stock [Member]
Assets, Fair value	$ 4,871	$ 4,489
Preferred Stock [Member]
Assets, Fair value	2,883	2,883
Available-for-sale Securities [Member]
Assets, Fair value	14,784	21,429
Cash and Cash Equivalents [Member]
Assets, Fair value	18,285	9,336
Equity Securities [Member]
Assets, Fair value	7,754	7,372
Corporate Debt Securities [Member]
Assets, Fair value	14,784	21,429
Cash [Member]
Assets, Fair value	14,234	4,473
Money Market Funds [Member]
Assets, Fair value	4,051	4,863
Fair Value, Inputs, Level 1 [Member] | Common Stock [Member]
Assets, Fair value	4,871	4,489
Fair Value, Inputs, Level 1 [Member] | Preferred Stock [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 1 [Member] | Available-for-sale Securities [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Assets, Fair value	18,285	9,336
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets, Fair value	4,871	4,489
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 1 [Member] | Cash [Member]
Assets, Fair value	14,234	4,473
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets, Fair value	4,051	4,863
Fair Value, Inputs, Level 2 [Member] | Common Stock [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Preferred Stock [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member]
Assets, Fair value	14,784	21,429
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Assets, Fair value	14,784	21,429
Fair Value, Inputs, Level 2 [Member] | Cash [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Common Stock [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Preferred Stock [Member]
Assets, Fair value	2,883	2,883
Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Assets, Fair value	2,883	2,883
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Cash [Member]
Assets, Fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Assets, Fair value	$ 0	$ 0