Income taxes - Difference Between Provision for Income Taxes and Amount Computed Using Statutory Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Tax at federal statutory tax rate	$ 85	$ (5,098)	$ (11,150)
State taxes—net of federal benefit	40	15	32
Non-deductible expenses	157	110	88
Goodwill impairment	0	537	746
Foreign withholding taxes	486	340	527
Foreign income taxed at different rates	(289)	(66)	(309)
Stock-based compensation expense	(87)	1,002	653
Tax exempt income	(73)	(94)	(136)
Change in valuation allowance	239	4,068	(8,396)
One-time transition tax	0	0	44
Remeasurement of deferred tax assets and liabilities	0	0	18,900
FIN 48	0	114	15
GILTI inclusion	778	451	0
Other	0	(3)	(2)
Total provision for income taxes	$ 1,336	$ 1,376	$ 1,012