Revenue, Gross Profit, Gross Profit Margin and Operating Income (Loss) by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2021	Oct. 02, 2020	Oct. 01, 2021	Oct. 02, 2020
Segment Reporting Information [Line Items]
Revenue	$ 177,726	$ 142,929	$ 507,833	$ 443,125
Gross Profit	$ 76,298	$ 59,105	$ 217,444	$ 182,252
Gross profit margin percentage	42.90%	41.40%	42.80%	41.10%
Operating Income (Loss)	$ 15,275	$ 11,866	$ 42,366	$ 38,817
Operating Segments | Photonics
Segment Reporting Information [Line Items]
Revenue	55,263	46,394	176,113	149,337
Gross Profit	$ 25,311	$ 20,166	$ 83,014	$ 65,725
Gross profit margin percentage	45.80%	43.50%	47.10%	44.00%
Operating Income (Loss)	$ 9,294	$ 7,026	$ 35,885	$ 22,878
Operating Segments | Vision
Segment Reporting Information [Line Items]
Revenue	65,346	64,299	196,429	198,047
Gross Profit	$ 24,763	$ 24,586	$ 76,132	$ 75,676
Gross profit margin percentage	37.90%	38.20%	38.80%	38.20%
Operating Income (Loss)	$ 5,606	$ 3,799	$ 12,178	$ 14,098
Operating Segments | Precision Motion
Segment Reporting Information [Line Items]
Revenue	57,117	32,236	135,291	95,741
Gross Profit	$ 27,743	$ 15,011	$ 64,694	$ 42,753
Gross profit margin percentage	48.60%	46.60%	47.80%	44.70%
Operating Income (Loss)	$ 14,957	$ 7,675	$ 34,681	$ 20,728
Unallocated Corporate and Shared Services
Segment Reporting Information [Line Items]
Gross Profit	(1,519)	(658)	(6,396)	(1,902)
Operating Income (Loss)	$ (14,582)	$ (6,634)	$ (40,378)	$ (18,887)