Income taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Operating Loss Carryforwards [Line Items]
Provision (benefit) for income taxes	$ 511	$ (13,006)	$ (4,015)
Effective tax rate (in percent)	1.00%	36.00%	12.00%
Change in tax accounting method	$ 0	$ 1,121	$ 0
Increase (decrease) in valuation allowance	12,100	4,700	10,100
Change in valuation allowance - federal	12,270	6,138	6,959
Earnings of foreign subsidiaries that are permanently reinvested and no U.S. income taxes have been provided	5,100
Unrecognized deferred tax liability related to undistributed foreign earnings	0
Unrecognized tax benefits that if recognized would affect the annual effective tax rate	1,600	1,700	5,500
Amount of possible decrease in unrecognized tax benefits within the next 12 months	4,000
Unrecognized tax benefits - interest and penalties expense	91	134	278
Unrecognized tax benefits - interest and penalties accrued	570	493
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	7,800
State and Local Jurisdiction | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credit carryforwards	6,600
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	6,400
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	41,900
Internal Revenue Service (IRS) | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credit carryforwards	3,800
Loss Carryback, Expiration of Statute of Limitations, and Settlement with Taxing Authority
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance	(4,200)
Valuation Allowance, Operating Loss Carryforwards
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance	$ 660
California Franchise Tax Board | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Proceeds from income tax refunds		3,000
Federal Ministry of Finance, Germany | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance		(769)
Tax Year 2015
Operating Loss Carryforwards [Line Items]
Provision (benefit) for income taxes		(4,100)	$ (1,300)
Anticipated tax refund from prior year income taxes		5,400
Proceeds from income tax refunds		$ 4,800