Fair value of financial instruments - Additional Information (Details) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018	Jan. 31, 2020	Aug. 31, 2019	Aug. 16, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on non-marketable equity securities	$ 0	$ 1,300,000	$ 0
Non-marketable equity investments	6,670,000	458,000
Marketable equity securities	0	1,349,000
Income related to proportionate share of equity investment	876,000	0	$ 0
Non-marketable equity investments accounted for under the equity method	20,027,000	0
Warrant to purchase non-marketable equity investment units	713,000	0
Non-marketable debt investments	5,917,000	0
Unrealized gain		1,100,000
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	0	$ 0
Grab Holdings Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment				$ 6,200,000
Series B Preferred Stock Units And Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment	4,000,000.0
Preferred Units
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment	3,600,000			$ 3,600,000
Ads Business | Discontinued Operations, Disposed of by Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Member interest value					$ 15,600,000	$ 15,600,000
Warrant
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	448,000
Fair value adjustment of warrants	265,000
Convertible Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable debt investments	$ 5,900,000
Convertible Debt Securities 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible notes receivable, interest rate	6.50%
Convertible Debt Securities 1 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable debt investments	$ 1,500,000
Convertible Debt Securities 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible notes receivable, interest rate	6.00%
Convertible Debt Securities 2 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable debt investments	$ 4,000,000.0
Convertible Debt Securities 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible notes receivable, interest rate	6.00%
Convertible Debt Securities 3 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable debt investments	$ 417,000
Maximum loan amount	$ 710,000