STOCK-BASED COMPENSATION - Stock-based Compensation (Details) (USD $)	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 298,000	$ 377,000
Cost of goods sold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	2,000	17,000
Research, development and engineering
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	41,000	75,000
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	255,000	285,000
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expected dividend yield	0.00%	0.00%
Stock-based compensation	247,000	357,000
Unrecognized stock-based compensation, related to stock options	1,400,000
Weighted average recognition period for stock-based compensation	2 years 8 months 15 days
Restricted stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	39,000	15,000
Unrecognized stock-based compensation, related to stock options	400,000
Weighted average recognition period for stock-based compensation	3 years 6 months 13 days
Employee stock purchase plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 12,000	$ 5,000