STOCK-BASED COMPENSATION - Stock-based Compensation (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 377,000	$ 405,000
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	17,000	15,000
Research, Development and Engineering
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	75,000	73,000
Selling, General and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	285,000	317,000
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	357,000	388,000
Unrecognized stock-based compensation, related to stock options	2,500,000
Weighted average recognition period for stock-based compensation	2 years 3 months 20 days
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	15,000	12,000
Unrecognized stock-based compensation, related to stock options	368,000
Weighted average recognition period for stock-based compensation	3 years 10 months 3 days
Employee Stock Purchase Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 5,000	$ 5,000