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

Summary Of Significant Accounting Policies (Schedule Of Assets And Liabilities Measured At Fair Value) (Details)

Summary Of Significant Accounting Policies (Schedule Of Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Jan. 02, 2016
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
Total financial assets and liabilities	27,921
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds included in cash equivalents	27,917	$ 14,460
Foreign currency contracts included in prepaid expenses and other current assets		33
Total financial assets and liabilities		14,493
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets and liabilities	27,917
Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds included in cash equivalents	27,917	14,460
Total financial assets and liabilities		14,460
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
Total financial assets and liabilities	$ 4
Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [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		33
Total financial assets and liabilities		$ 33