Financial Instruments Measured at Fair Value (Tables)

3 Months Ended

Mar. 28, 2015

Fair Value Disclosures [Abstract]

Short-Term Investments by Security Type

Investments that we have classified as short-term, by security type, are as follows (in thousands):

	March 28, 2015
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Municipal securities	$	110	$	—	$	—	$	110
Bank certificates of deposit		1,000		—		—		1,000
	$	1,110	$	—	$	—	$	1,110
	December 27, 2014
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Municipal securities	$	155	$	—	$	—	$	155
Bank certificates of deposit		1,000		—		—		1,000
	$	1,155	$	—	$	—	$	1,155

Effective Maturities of Short-Term Investments

Effective maturities of short-term investments are as follows (in thousands):

	March 28, 2015				December 27, 2014
	Amortized		Estimated		Amortized		Estimated
	Cost		Fair Value		Cost		Fair Value
Due in one year or less	$	1,110	$	1,110	$	1,155	$	1,155

Assets Measured at Fair Value on Recurring Basis

The following table summarizes, by major security type, our assets that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands):

	Fair value measurements at March 28, 2015 using:
							Total estimated
	Level 1		Level 2		Level 3		fair value
Cash	$	59,145	$	—	$	—	$	59,145
Municipal securities		—		110		—		110
Money market funds		—		9,464		—		9,464
Bank certificates of deposit		—		1,000		—		1,000
	$	59,145	$	10,574	$	—	$	69,719
	Fair value measurements at December 27, 2014 using:
							Total estimated
	Level 1		Level 2		Level 3		fair value
Cash	$	66,467	$	—	$	—	$	66,467
Municipal securities		—		155		—		155
Money market funds		—		4,418		—		4,418
Bank certificates of deposit		—		1,000		—		1,000
	$	66,467	$	5,573	$	—	$	72,040