STOCK-BASED COMPENSATION - Stock-based Compensation (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 334,000	$ 371,000	$ 1,057,000	$ 1,128,000
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	16,000	17,000	42,000	49,000
Research, Development and Engineering
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	53,000	68,000	198,000	215,000
Selling, General and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	265,000	286,000	817,000	864,000
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	293,000	365,000	959,000	1,091,000
Unrecognized stock-based compensation, related to stock options	1,600,000		1,600,000
Weighted average recognition period for stock-based compensation			2 years
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	36,000	1,000	83,000	22,000
Unrecognized stock-based compensation, related to stock options	400,000		400,000
Weighted average recognition period for stock-based compensation			3 years 4 months 19 days
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	$ 15,000