STOCK-BASED COMPENSATION - Expense Related to Employee Stock Options and Nonvested Restricted Common Stock Awards (Details) (USD $)	9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 3,555,454	$ 3,648,904
Cost of product revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	590,467	254,642
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	773,106	258,187
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 2,191,881	$ 3,136,075