Balance sheet information - Goodwill Impairment (Details) $ in Thousands	12 Months Ended
	Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)		Jun. 30, 2017 USD ($)	[1]
Goodwill [Line Items]
Number of reporting segments | segment	3
Goodwill impairment	$ 2,556	$ 2,666	[1]	$ 0
Advertising Segment
Goodwill [Line Items]
Goodwill impairment	$ 2,556
Mobile Navigation
Goodwill [Line Items]
Goodwill impairment		$ 2,700

[1] See Note 1 for a summary of adjustments.