Fair Value Measurements - Financial Assets and Liabilities Measured and Recognized at Fair Value on a Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($) $ in Thousands	Sep. 28, 2019	Dec. 29, 2018
Money Market Funds
Assets:
Assets, Fair Value Measurements	$ 12,167	$ 20,708
Earn Out Liability
Liabilities:
Liabilities, Fair Value Measurements	63	334
Level 1 | Money Market Funds
Assets:
Assets, Fair Value Measurements	12,167	20,708
Level 3 | Earn Out Liability
Liabilities:
Liabilities, Fair Value Measurements	$ 63	$ 334