Equity and Stock Based Compensation Plans (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	$ 2,702	$ 1,482	$ 5,912	$ 4,535
Cost of products [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	55	50	153	128
Cost of service [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	74	62	204	195
Research and development [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	412	289	1,092	952
Selling [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	476	451	1,418	1,374
General and administrative [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	789	630	2,149	1,886
Restructuring [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense	$ 896	$ 0	$ 896	$ 0