Information for Each Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015
Segment Reporting Information [Line Items]
Total segment net revenues	$ 14,918	$ 20,458	$ 28,582	$ 40,343
Operating income (loss)	(3,807)	283	(10,124)	(2,657)
Interest income and other income (expense), net	87	(13)	125	66
Income (loss) before income taxes	(3,720)	270	(9,999)	(2,591)
Thin-film Equipment Segment
Segment Reporting Information [Line Items]
Total segment net revenues	6,088	11,494	11,668	22,122
Photonics
Segment Reporting Information [Line Items]
Total segment net revenues	8,830	8,964	16,914	18,221
Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)	(2,162)	1,281	(7,200)	(539)
Operating Segments | Thin-film Equipment Segment
Segment Reporting Information [Line Items]
Operating income (loss)	(3,674)	6	(9,119)	(3,291)
Operating Segments | Photonics
Segment Reporting Information [Line Items]
Operating income (loss)	1,512	1,275	1,919	2,752
Unallocated Amount to Segment
Segment Reporting Information [Line Items]
Unallocated costs	$ (1,645)	$ (998)	$ (2,924)	$ (2,118)