Share-based compensation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Weighted Average Grant Date Fair Value
Total	$ 4,388	$ 3,998
Cost of Sales
Weighted Average Grant Date Fair Value
Total	546	601
Selling, General and Administrative Expense
Weighted Average Grant Date Fair Value
Total	2,743	2,798
Research and Development Expense
Weighted Average Grant Date Fair Value
Total	$ 1,099	$ 599
Stock options
Stock option awards, Shares
Outstanding at the beginning of the period (in shares)	2,064
Exercised (in shares)	(13)
Expired or forfeited (in shares)	(32)
Outstanding at the end of the period (in shares)	2,019
Weighted Average Exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 32.91
Exercised (in dollars per share)	12.00
Expired or forfeited (in dollars per share)	35.43
Outstanding at the end of the period (in dollars per share)	$ 33.00
Restricted Stock Awards
Restricted stock awards including restricted stock units, Shares
Outstanding at the beginning of the period (in shares)	1,398
Granted (in shares)	49
Released (in shares)	(7)
Forfeited (in shares)	(13)
Outstanding at the end of the period (in shares)	1,427
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 31.97
Granted (in dollars per share)	19.54
Released (in dollars per share)	31.19
Forfeited (in dollars per share)	32.36
Outstanding at the end of the period (in dollars per share)	$ 31.55
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