Restructuring and Contract Termination Charges, Net (Narrative) (Details) - USD ($)	3 Months Ended										12 Months Ended
	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Apr. 05, 2020	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Apr. 01, 2018	Jan. 03, 2021	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net	$ (3,062,000)	$ 4,059,000	$ 1,158,000	$ 5,858,000	$ 1,560,000	$ 14,068,000	$ 6,161,000	$ 7,639,000			$ 8,013,000	$ 29,428,000	$ 11,144,000
Accrued restructuring and contract termination costs	4,716,000				11,559,000						4,716,000	11,559,000
Restructuring Reserve1	8,300,000				13,900,000						8,300,000	13,900,000
Restructuring Charges and Changes in Estimates											8,013,000	29,428,000	11,144,000
Accrued restructuring and contract termination costs	8,299,000				13,880,000						8,299,000	13,880,000	6,180,000	$ 13,969,000
Short-term accrued restructuring and other costs [Member]
Restructuring Cost and Reserve [Line Items]
Accrued restructuring and contract termination costs	4,700,000				11,600,000						4,700,000	11,600,000
Accrued expenses and other current liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Accrued restructuring and contract termination costs	2,000,000.0				400,000						2,000,000.0	400,000
Long-term liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Noncurrent					800,000							800,000
Operating lease liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Noncurrent	1,300,000				1,100,000						1,300,000	1,100,000
Operating lease right-of-use assets [Member]
Restructuring Cost and Reserve [Line Items]
Accrued restructuring and contract termination costs	300,000										300,000
Q3 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net									$ 1,764,000
Q1 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net										$ 5,998,000
Q1 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net								7,460,000
Q2 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net							5,590,000
Q3 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net						13,797,000
Q4 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net					2,581,000
Previous restructuring and integration plans [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											219,000	(159,000)	(1,998,000)
Accrued restructuring and contract termination costs	1,102,000				1,365,000						1,102,000	1,365,000	2,671,000	10,921,000
Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											212,000	452,000	4,742,000
Accrued restructuring and contract termination costs	318,000				188,000						318,000	188,000	137,000	3,048,000
Facility Relocation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											4,290,000	827,000	0
Accrued restructuring and contract termination costs	1,998,000				827,000						1,998,000	827,000	0	0
Severance [Member] | Q3 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											0	(77,000)	2,054,000
Accrued restructuring and contract termination costs	24,000				24,000						24,000	24,000	1,415,000	0
Severance [Member] | Q1 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											(255,000)	(1,069,000)	5,998,000
Accrued restructuring and contract termination costs	3,000				258,000						3,000	258,000	1,609,000	0
Severance [Member] | Q1 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											(867,000)	7,483,000	0
Accrued restructuring and contract termination costs	593,000				2,129,000						593,000	2,129,000	0	0
Severance [Member] | Q2 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											(376,000)	5,590,000	0
Accrued restructuring and contract termination costs	272,000				1,889,000						272,000	1,889,000	0	0
Severance [Member] | Q3 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											(2,025,000)	13,797,000	0
Accrued restructuring and contract termination costs	1,507,000				6,311,000						1,507,000	6,311,000	0	0
Severance [Member] | Q4 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges and Changes in Estimates											(386,000)	2,581,000	0
Accrued restructuring and contract termination costs	$ 49,000				889,000						49,000	889,000	0	$ 0
Discovery & Analytical Solutions [Member] | Contract Termination [Member] | 2020 Contract Termination Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net											200,000
Discovery & Analytical Solutions [Member] | Contract Termination [Member] | 2019 Contract Termination Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net												200,000
Discovery & Analytical Solutions [Member] | Contract Termination [Member] | 2018 Contract Termination Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net													$ 5,000,000.0
Discovery & Analytical Solutions [Member] | Severance [Member] | Q3 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net									1,146,000
Discovery & Analytical Solutions [Member] | Severance [Member] | Q1 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net										5,096,000
Discovery & Analytical Solutions [Member] | Severance [Member] | Q1 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net								6,001,000
Change in estimates											(900,000)
Discovery & Analytical Solutions [Member] | Severance [Member] | Q2 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net							4,461,000
Change in estimates											(400,000)
Discovery & Analytical Solutions [Member] | Severance [Member] | Q3 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net						11,156,000
Change in estimates											(1,900,000)
Discovery & Analytical Solutions [Member] | Severance [Member] | Q4 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net					177,000
Change in estimates											(300,000)
Discovery & Analytical Solutions [Member] | Severance [Member] | Previous restructuring and integration plans [Member]
Restructuring Cost and Reserve [Line Items]
Change in estimates											100,000
Diagnostics [Member] | Contract Termination [Member] | 2020 Contract Termination Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net											100,000
Diagnostics [Member] | Contract Termination [Member] | 2019 Contract Termination Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net												$ 200,000
Diagnostics [Member] | Severance [Member] | Q3 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net									$ 618,000
Diagnostics [Member] | Severance [Member] | Q1 2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net										$ 902,000
Diagnostics [Member] | Severance [Member] | Q1 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net								$ 1,459,000
Diagnostics [Member] | Severance [Member] | Q2 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net							$ 1,129,000
Diagnostics [Member] | Severance [Member] | Q3 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net						$ 2,641,000
Change in estimates											(100,000)
Diagnostics [Member] | Severance [Member] | Q4 2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other costs, net					$ 2,404,000
Change in estimates											$ (100,000)