Revenue, Gross Profit, Gross Profit Margin and Operating Income (Loss) by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2021	Jul. 03, 2020	Jul. 02, 2021	Jul. 03, 2020
Segment Reporting Information [Line Items]
Revenue	$ 167,523	$ 144,728	$ 330,107	$ 300,196
Gross Profit	$ 72,406	$ 58,702	$ 141,146	$ 123,147
Gross profit margin percentage	43.20%	40.60%	42.80%	41.00%
Operating Income (Loss)	$ 15,992	$ 13,701	$ 27,091	$ 26,951
Operating Segments | Photonics
Segment Reporting Information [Line Items]
Revenue	62,357	47,803	120,851	102,943
Gross Profit	$ 29,593	$ 20,898	$ 57,702	$ 45,559
Gross profit margin percentage	47.50%	43.70%	47.70%	44.30%
Operating Income (Loss)	$ 14,196	$ 6,937	$ 26,591	$ 15,852
Operating Segments | Vision
Segment Reporting Information [Line Items]
Revenue	63,447	64,740	131,083	133,748
Gross Profit	$ 24,443	$ 24,515	$ 51,369	$ 51,090
Gross profit margin percentage	38.50%	37.90%	39.20%	38.20%
Operating Income (Loss)	$ 3,206	$ 4,665	$ 6,572	$ 10,299
Operating Segments | Precision Motion
Segment Reporting Information [Line Items]
Revenue	41,719	32,185	78,173	63,505
Gross Profit	$ 20,874	$ 13,834	$ 36,951	$ 27,742
Gross profit margin percentage	50.00%	43.00%	47.30%	43.70%
Operating Income (Loss)	$ 12,279	$ 6,515	$ 19,724	$ 13,053
Unallocated Corporate and Shared Services
Segment Reporting Information [Line Items]
Gross Profit	(2,504)	(545)	(4,876)	(1,244)
Operating Income (Loss)	$ (13,689)	$ (4,416)	$ (25,796)	$ (12,253)