Balance Sheet Components (Schedule of Available-for-Sale Short-Term Investments) (Details) - USD ($) $ in Thousands |
Jul. 01, 2018 |
Dec. 31, 2017 |
---|---|---|
Available-for-sale Securities, Amortized Cost Basis [Abstract] | ||
Cost | $ 125,894 | $ 124,978 |
Unrealized Gains | 0 | 0 |
Unrealized Losses | (115) | (146) |
Estimated Fair Value | 125,779 | 124,832 |
U.S. treasuries | ||
Available-for-sale Securities, Amortized Cost Basis [Abstract] | ||
Cost | 125,740 | 124,816 |
Unrealized Gains | 0 | 0 |
Unrealized Losses | (115) | (146) |
Estimated Fair Value | 125,625 | 124,670 |
Certificates of deposit | ||
Available-for-sale Securities, Amortized Cost Basis [Abstract] | ||
Cost | 154 | 162 |
Unrealized Gains | 0 | 0 |
Unrealized Losses | 0 | 0 |
Estimated Fair Value | $ 154 | $ 162 |