Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 30, 2012	Sep. 28, 2013	Sep. 30, 2012
Net income (loss)	$ 1,386	$ 2,122	$ (7,758)	$ 3,886
Other comprehensive income:
Change in unrealized gain on available-for-sale investments	5		5
Comprehensive income (loss)	1,391	2,122	(7,753)	3,886
Accretion of preferred stock to redemption value and issuance costs		(564)	(1,088)	(1,661)
(Earnings) loss distributable to preferred stockholders		(497)	1,107	(710)
Comprehensive income (loss) attributable to common stockholders	$ 1,391	$ 1,061	$ (7,734)	$ 1,515