Fair Value Measurement (Details) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2013	Dec. 29, 2012
Earn-out liability
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Liabilities, Fair Value Measurements	$ 624	$ 652
Money market funds
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements	12,742	10,839
Level 1 | Earn-out liability
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Liabilities, Fair Value Measurements
Level 1 | Money market funds
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements	12,742	10,839
Level 2 | Earn-out liability
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Liabilities, Fair Value Measurements
Level 2 | Money market funds
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements
Level 3 | Earn-out liability
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Liabilities, Fair Value Measurements	624	652
Level 3 | Money market funds
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements