Information for Each Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Segment Reporting Information [Line Items]
Total segment net revenues	$ 19,115	$ 16,834	$ 49,081	$ 65,941
Unallocated costs	(1,751)	(1,429)	(4,436)	(4,417)
Gain (loss) on divestitures			(208)	2,207
Loss from operations	(2,982)	(11,010)	(18,997)	(18,642)
Interest income and other, net	220	(8)	392	411
Loss before income taxes	(2,762)	(11,018)	(18,605)	(18,231)
Operating Segments
Segment Reporting Information [Line Items]
Loss from operations	(1,231)	(9,581)	(14,353)	(16,432)
Equipment
Segment Reporting Information [Line Items]
Total segment net revenues	11,760	7,401	26,293	43,179
Equipment | Operating Segments
Segment Reporting Information [Line Items]
Loss from operations	(1,423)	(10,298)	(14,607)	(15,493)
Intevac Photonics
Segment Reporting Information [Line Items]
Total segment net revenues	7,355	9,433	22,788	22,762
Intevac Photonics | Operating Segments
Segment Reporting Information [Line Items]
Loss from operations	$ 192	$ 717	$ 254	$ (939)