Fair Value Measurements - Financial Assets and Liabilities Measured and Recognized at Fair Value on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Sep. 27, 2014	Dec. 28, 2013
Money Market Funds
Assets:
Assets, Fair Value Measurements	$ 11,846	$ 12,742
Level 1 | Money Market Funds
Assets:
Assets, Fair Value Measurements	11,846	12,742
Earn Out Liability
Liabilities:
Liabilities, Fair Value Measurements	566	624
Earn Out Liability | Level 3
Liabilities:
Liabilities, Fair Value Measurements	$ 566	$ 624