Intangible Assets (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 27, 2020	Jun. 28, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019	May 26, 2020	Dec. 31, 2019
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	$ 73,675,000			$ 73,675,000			$ 93,474,000
Accumulated Amortization	57,193,000			57,193,000			53,984,000
Net Carrying Value	16,482,000			16,482,000			39,490,000
Intangible asset impairment charges	0	$ 19,571,000	$ 0	19,571,000	$ 0
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	16,482,000			16,482,000			39,490,000
Distribution networks
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	38,060,000			38,060,000			38,060,000
Accumulated Amortization	38,060,000			38,060,000			38,060,000
Net Carrying Value	0			0			0
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	0			0			0
Completed technologies
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	21,917,000			21,917,000			31,987,000
Accumulated Amortization	11,678,000			11,678,000			9,160,000
Net Carrying Value	10,239,000			10,239,000			22,827,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	10,239,000			10,239,000			22,827,000
Completed technologies | Sualab [Member]
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Intangible asset impairment charges		10,070,000
Customer relationships
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	10,578,000			10,578,000			14,407,000
Accumulated Amortization	6,980,000			6,980,000			6,402,000
Net Carrying Value	3,598,000			3,598,000			8,005,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	3,598,000			3,598,000			8,005,000
Customer relationships | Sualab [Member]
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Intangible asset impairment charges		3,382,000
Customer relationships | EnShape GmbH [Member]
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Accumulated Amortization						$ 228,000
Intangible asset impairment charges		219,000
Intangible assets acquired		0				$ 447,000
In-process technologies
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	2,300,000			2,300,000			8,200,000
Accumulated Amortization	0			0			0
Net Carrying Value	2,300,000			2,300,000			8,200,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	2,300,000			2,300,000			8,200,000
In-process technologies | Sualab [Member]
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Intangible asset impairment charges		$ 5,900,000
Non-compete agreements
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	710,000			710,000			710,000
Accumulated Amortization	422,000			422,000			350,000
Net Carrying Value	288,000			288,000			360,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	288,000			288,000			360,000
Trademarks
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Gross Carrying Value	110,000			110,000			110,000
Accumulated Amortization	53,000			53,000			12,000
Net Carrying Value	57,000			57,000			98,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Carrying Value	57,000			57,000			$ 98,000
Indefinite-lived intangible asset excluding in-process technologies
Distribution Rights, Developed Technology Rights, Customer Contracts And Relationships, Other Intangible Assets, And Trademarks
Net Carrying Value	14,182,000			14,182,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of fiscal 2020	831,000			831,000
2021	3,272,000			3,272,000
2022	2,902,000			2,902,000
2023	2,211,000			2,211,000
2024	1,697,000			1,697,000
2025	1,374,000			1,374,000
Thereafter	1,895,000			1,895,000
Net Carrying Value	$ 14,182,000			$ 14,182,000