Income taxes - Additional Information (Details) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
	Dec. 31, 2014	Jan. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Operating Loss Carryforwards [Line Items]
Provision (benefit) for income taxes			$ (13,006)	$ (4,015)	$ 1,093
Effective tax rate (in percent)			36.00%	12.00%	16.00%
Change in tax accounting method			$ 1,121	$ 0	$ 0
Increase (decrease) in valuation allowance			4,700	10,100	699
Change in valuation allowance - federal			6,138	6,959	0
Earnings of foreign subsidiaries that are permanently reinvested and no U.S. income taxes have been provided			4,100
Unrecognized deferred tax liability related to undistributed foreign earnings			560
Unrecognized tax benefits that if recognized would affect the annual effective tax rate			1,700	5,500	4,800
Amount of possible decrease in unrecognized tax benefits within the next 12 months			1,300
Unrecognized tax benefits - interest and penalties expense			134	278	$ 159
Unrecognized tax benefits - interest and penalties accrued			493	603
Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Extension Period	1 year
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards			10,900
State and Local Jurisdiction | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credit carryforwards			5,600
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards			8,500
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards			7,500
Internal Revenue Service (IRS) | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credit carryforwards			3,100
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			913
Federal Ministry of Finance, Germany | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance			(800)
Tax Year 2015
Operating Loss Carryforwards [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions			5,400	$ 1,300
Tax Year 2009 and 2010 | California Franchise Tax Board | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Proceeds from Income Tax Refunds		$ 3,000	$ 3,000