Fair Value Measurements - Investments (Details) - USD ($) $ in Thousands	3 Months Ended
Jun. 27, 2015	Mar. 28, 2015	Mar. 29, 2014
Schedule of Available-for-sale Securities
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	$ 27,500
Available for sale Securities Current
Schedule of Available-for-sale Securities
Cost	27,516	$ 22,962
Available-for-sale Securities, Gross Unrealized Gain	1	2
Available-for-sale Securities, Gross Unrealized Loss	0	0
Available-for-sale Securities	27,517	22,964
Available for sale Securities Current \| Commercial Paper
Schedule of Available-for-sale Securities
Cost	21,664	15,537
Available-for-sale Securities, Gross Unrealized Gain	0	0
Available-for-sale Securities, Gross Unrealized Loss	0	0
Available-for-sale Securities	21,664	15,537
Available for sale Securities Current \| Government agencies
Schedule of Available-for-sale Securities
Cost		2,702
Available-for-sale Securities, Gross Unrealized Gain			$ 0
Available-for-sale Securities, Gross Unrealized Loss			0
Available-for-sale Securities		2,702
Available for sale Securities Current \| Corporate Bonds
Schedule of Available-for-sale Securities
Cost		853
Available-for-sale Securities, Gross Unrealized Gain		0
Available-for-sale Securities, Gross Unrealized Loss			0
Available-for-sale Securities		853
Available for sale Securities Current \| Municipal Bonds
Schedule of Available-for-sale Securities
Cost	5,852	3,870
Available-for-sale Securities, Gross Unrealized Gain	1	2
Available-for-sale Securities, Gross Unrealized Loss	0		$ 0
Available-for-sale Securities	$ 5,853	$ 3,872

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-SubTopic 10

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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