USANA Health Sciences, Inc. Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measures (Schedule Of Assets And Liabilities Measured At Fair Value) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds included in cash equivalents	$ 74,584	$ 27,917
Foreign currency contracts included in prepaid expenses and other current assets		4
Foreign currency contracts included in other current liabilities	(37)
Total financial assets and liabilities	74,547	27,921
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds included in cash equivalents	74,584	27,917
Total financial assets and liabilities	74,584	27,917
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts included in prepaid expenses and other current assets		4
Foreign currency contracts included in other current liabilities	(37)
Total financial assets and liabilities	$ (37)	$ 4