Stock-Based Compensation (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense related to employee stock options and employee stock purchases	$ 5,890	$ 4,473	$ 2,950
Cost of Products [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense related to employee stock options and employee stock purchases	164	176	126
Cost of Service [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense related to employee stock options and employee stock purchases	230	218	206
Research and development [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense related to employee stock options and employee stock purchases	1,220	984	514
Selling [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense related to employee stock options and employee stock purchases	1,791	1,366	596
General and administrative [Member]
Stock-based compensation expense for all share-based payment awards
Total stock-based compensation expense related to employee stock options and employee stock purchases	$ 2,485	$ 1,729	$ 1,508