Fair Value Measures (Schedule Of Assets And Liabilities Measured At Fair Value) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands |
Jul. 01, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Money market funds included in cash equivalents | $ 78,170 | $ 27,917 |
| Foreign currency contracts included in prepaid expenses and other current assets | 58 | 4 |
| Total financial assets and liabilities | 78,228 | 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 | 78,170 | 27,917 |
| Total financial assets and liabilities | 78,170 | 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 | 58 | 4 |
| Total financial assets and liabilities | $ 58 | $ 4 |