Fair Value Measurements - Financial Assets and Liabilities Measured and Recognized at Fair Value on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Jun. 28, 2014	Dec. 28, 2013
Earn-Out liability
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Liabilities, Fair Value Measurements	$ 551	$ 624
Level 2 | Earn-Out liability
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Liabilities, 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	551	624
Money market funds
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements	12,245	12,742
Money market funds | Level 1
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements	12,245	12,742
Money market funds | Level 2
Financial assets and liabilities measured and recognized at fair value on a recurring basis
Assets, Fair Value Measurements