Financial instruments and fair value measurement Available-for-Sale Investments - Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Jun. 30, 2015
Available-for-Sale Investments - Contractual Maturity [Abstract]
Less than one year, Amortized Cost	$ 25,405	$ 13,561
Less than one year, Fair Value	25,391	13,555
One to three years, Amortized Cost	153,513	188,539
One to three years, Fair Value	153,948	188,057
Above three years, Amortized Cost	42,944	15,673
Above three years, Fair Value	$ 42,865	$ 15,587