STOCK-BASED COMPENSATION - Stock-based Compensation (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012	Oct. 02, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 371,000	$ 472,000	$ 1,128,000	$ 1,875,000
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	17,000	13,000	49,000	69,000
Research, Development and Engineering
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	68,000	62,000	215,000	303,000
Selling, General and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	286,000	397,000	864,000	1,503,000
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	365,000	443,000	1,091,000	1,763,000
Unrecognized stock-based compensation, related to stock options	2,800,000		2,800,000
Weighted average recognition period for stock-based compensation			2 years 8 months 12 days
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	1,000	24,000	22,000	92,000
Employee Stock Purchase Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 5,000	$ 5,000	$ 15,000	$ 20,000