Summary of business and significant accounting policies - Deferred Costs (Details) $ in Thousands	9 Months Ended
	Mar. 31, 2020 USD ($)
Contract with Customer Asset [Roll Forward]
Balance, June 30, 2019	$ 79,802
Content licensing costs incurred	97,826
Customized software development costs incurred	2,950
Less: cost of revenue recognized	(97,880)
Balance, March 31, 2020	82,698
Content
Contract with Customer Asset [Roll Forward]
Balance, June 30, 2019	71,466
Content licensing costs incurred	97,826
Customized software development costs incurred	0
Less: cost of revenue recognized	(92,903)
Balance, March 31, 2020	76,389
Development
Contract with Customer Asset [Roll Forward]
Balance, June 30, 2019	8,336
Content licensing costs incurred	0
Customized software development costs incurred	2,950
Less: cost of revenue recognized	(4,977)
Balance, March 31, 2020	$ 6,309