Business combinations (Pro Forma Information) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended	3 Months Ended	9 Months Ended
	Dec. 31, 2013	Mar. 31, 2013 Enterasys Networks, Inc.	Mar. 31, 2014 Enterasys Networks, Inc.	Mar. 31, 2013 Enterasys Networks, Inc.
Business Acquisition [Line Items]
Net revenues		$ 137,936	$ 463,600	$ 465,535
Net loss	$ (16,400)	$ (21,166)	$ (63,410)	$ (35,999)
Net loss per share - basic and diluted (USD per share)		$ (0.23)	$ (0.66)	$ (0.38)