Discontinued Operations - Schedule of Details on Income Statement Caption on TSA Billing (Detail) (Aurora [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total TSA billing to Aurora	$ 48	$ 977
Product cost of revenue [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total TSA billing to Aurora	41	577
Research and development expense [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total TSA billing to Aurora	0	21
Selling, general and administrative expenses [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total TSA billing to Aurora	$ 7	$ 379