Summary of business and significant accounting policies - Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred rent related to tenant improvement lease incentives and graduated rent payments	$ 5,500	$ 7,500
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	2,644	4,869	$ 841
Facility Closing
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 2,644	$ 2,743	$ 224