Balance sheet information - Intangibles and Other Accrued Expenses (Details) - USD ($)	3 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017
Balance Sheet Related Disclosures [Abstract]
Goodwill	$ 31,300,000		$ 31,300,000
Acquired developed technology	13,875,000		13,875,000
Less accumulated amortization	(10,642,000)		(10,359,000)
Intangible assets, net	3,233,000		3,516,000
Amortization of intangible assets	283,000	$ 260,000
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	6,807,000		10,554,000
Accrued royalties	24,728,000		28,179,000
Customer overpayments and related reserves	6,956,000		5,940,000
Other accrued expenses	6,778,000		6,855,000
Accrued expenses	45,269,000		$ 51,528,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2018	850,000
2019	1,000,000
2020	872,000
2021	$ 509,000