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, 2019	Jun. 30, 2018		Jun. 30, 2017
Income Tax Disclosure [Abstract]
Tax at federal statutory tax rate	$ (6,553)	$ (11,150)		$ (10,044)
State taxes—net of federal benefit	15	32		(1,075)
Non-deductible expenses	110	88		108
Goodwill impairment	537	746		0
Foreign withholding taxes	340	527		1,737
Foreign income taxed at different rates	(66)	(309)		(323)
Stock-based compensation expense	1,002	653		849
Tax exempt income	(94)	(136)		(33)
Change in valuation allowance	5,507	(8,396)		10,039
One-time transition tax	0	44		0
Remeasurement of deferred tax assets and liabilities	0	18,900		0
FIN 48	114	15		(479)
GILTI inclusion	451	0		0
Other	(80)	(2)		62
Total provision for income taxes	$ 1,283	$ 1,012	[1]	$ 841	[1]

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