ACQUISITIONS AND DIVESTITURES - Acquisitions of FEMTOLASERS and V-Gen - General Disclosures (Details) $ in Thousands, € in Millions				12 Months Ended
	Feb. 11, 2015 EUR (€)	Feb. 11, 2015 USD ($)	Sep. 29, 2014 USD ($)	Jan. 02, 2016 USD ($)	Jan. 03, 2015 USD ($)
Acquisition
Net cash used in acquisitions				$ 8,106	$ 34,124
FEMTOLASERS
Acquisition
Purchase price, paid in cash | €	€ 9.1
Net asset adjustment | €	1.9
Purchase price	7.2	$ 8,200
Purchase price deposited at closing into escrow account | €	€ 2.3
Time period for depositing into escrow from the date of closing	30 months	30 months
Repayment of outstanding loan	€ 3.6	$ 4,000
V-Gen
Acquisition
Purchase price, paid in cash			$ 36,400
Purchase price			35,600
Fair value of unearned compensation			800
Initial purchase price			34,000
Net working capital adjustment			2,400
Net cash used in acquisitions			34,100
Selling, general and administrative expense | FEMTOLASERS
Acquisition
Transaction costs incurred		$ 400
Selling, general and administrative expense | V-Gen
Acquisition
Transaction costs incurred			$ 300