Share-based compensation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Weighted Average Grant Date Fair Value
Total share-based compensation expense	$ 4,921	$ 5,091	$ 8,919	$ 9,813
Cost of Sales
Weighted Average Grant Date Fair Value
Total share-based compensation expense	713	620	1,314	1,180
Selling, General and Administrative Expenses
Weighted Average Grant Date Fair Value
Total share-based compensation expense	3,112	3,324	5,910	6,425
Research and Development Expense.
Weighted Average Grant Date Fair Value
Total share-based compensation expense	$ 1,096	$ 1,147	$ 1,695	$ 2,208
Restricted Stock Awards
Restricted stock awards including restricted stock units, Shares
Outstanding at the beginning of the period (in shares)			1,237
Granted (in shares)			597
Vested (in shares)			(125)
Forfeited (in shares)			(59)
Outstanding at the end of the period (in shares)	1,650		1,650
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)			$ 34.27
Grants (in dollars per share)			31.32
Vested/released (in dollars per share)			40.70
Forfeitures (in dollars per share)			35.92
Outstanding at the end of the period (in dollars per share)	$ 32.66		$ 32.66
Restricted Stock Awards | Minimum
Weighted Average Grant Date Fair Value
Expiration term			1 year
Restricted Stock Awards | Maximum
Weighted Average Grant Date Fair Value
Expiration term			5 years
Stock options
Stock option awards, Shares
Outstanding at the beginning of the period (in shares)			2,391
Granted (in shares)			17
Exercised (in shares)			(74)
Expired or forfeited (in shares)			(119)
Outstanding at the end of the period (in shares)	2,215		2,215
Weighted Average Exercise price
Outstanding at the beginning of the period (in dollars per share)			$ 31.65
Grants (in dollars per share)			30.22
Exercised (in dollars per share)			19.07
Expired or forfeited (in dollars per share)			38.62
Outstanding at the end of the period (in dollars per share)	$ 31.69		$ 31.69