Short-Term Investments - Summary of Short-Term Investments (Detail) - USD ($) $ in Thousands	Apr. 01, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	$ 19,241	$ 26,656
Gross Unrealized Gains	6	0
Gross Unrealized Losses	(9)	(52)
Total short-term investments, Estimated Fair Value	19,238	26,604
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	18,141	25,557
Gross Unrealized Gains	6	0
Gross Unrealized Losses	(9)	(52)
Total short-term investments, Estimated Fair Value	18,138	25,505
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	1,100	1,099
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total short-term investments, Estimated Fair Value	$ 1,100	$ 1,099