Share-based compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Weighted-Average Grant-Date Fair Value
Total share-based compensation expense	$ 3,998	$ 4,722
Cost of Sales
Weighted-Average Grant-Date Fair Value
Total share-based compensation expense	601	560
Selling, General and Administrative Expenses
Weighted-Average Grant-Date Fair Value
Total share-based compensation expense	2,798	3,101
Research and Development Expense.
Weighted-Average Grant-Date Fair Value
Total share-based compensation expense	$ 599	$ 1,061
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)	39
Vested (in shares)	(4)
Forfeited (in shares)	(53)
Outstanding at the end of the period (in shares)	1,219
Weighted-Average Grant-Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 34.27
Grants (in dollars per share)	$ 31.56
Vested/released (in dollars per share)	$ 32.88
Forfeitures (in dollars per share)	$ 35.99
Outstanding at the end of the period (in dollars per share)	$ 34.11
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)	10
Exercised (in shares)	(10)
Expired or forfeited (in shares)	(62)
Outstanding at the end of the period (in shares)	2,329
Weighted Average Exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 31.65
Grants (in dollars per share)	$ 30.49
Exercised (in dollars per share)	$ 28.77
Expired or forfeited (in dollars per share)	$ 36.03
Outstanding at the end of the period (in dollars per share)	$ 31.54