USANA Health Sciences, Inc. Annual report pursuant to Section 13 and 15(d)

Segment Information (Consolidated Net Sales And Long Lived Assets) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 271,298	$ 260,598	$ 256,016	$ 272,990	$ 299,023	$ 296,767	$ 301,460	$ 291,998	$ 1,060,902	$ 1,189,248	$ 1,047,265
Long-lived assets	184,565				158,780				184,565	158,780
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									471,165	586,518	482,965
Long-lived assets	90,886				89,509				90,886	89,509
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									105,111	116,299	$ 121,056
Long-lived assets	$ 54,809				$ 49,195				$ 54,809	$ 49,195