Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balance at Jan. 03, 2010	$ 21,259	$ 35	$ 177,862	$ 1,130	$ (157,768)
Balance (in shares) at Jan. 03, 2010		35,042
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans and employee stock purchase plans, shares		1,471
Common stock issued under stock plans and employee stock purchase plans, value	3,229	2	3,227
Private stock Offering, net issuance costs and warrants, value	18		18
Issuance of common stock from exercise of warrants, shares		1,293
Issuance of common stocks warrants, value	2,780	1	2,779
Change in unrealized gain on available-for-sale securities	(514)			(514)
Stock-based compensation	2,418		2,418
Net income (loss)	123				123
Balance at Jan. 02, 2011	29,313	38	186,304	616	(157,645)
Balance (in shares) at Jan. 02, 2011		37,806
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans and employee stock purchase plans, shares		830
Common stock issued under stock plans and employee stock purchase plans, value	2,046	1	2,045
Change in unrealized gain on available-for-sale securities	(503)			(503)
Stock-based compensation	1,676		1,676
Net income (loss)	(7,594)				(7,594)
Balance at Jan. 01, 2012	24,938	39	190,025	113	(165,239)
Balance (in shares) at Jan. 01, 2012		38,636
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans and employee stock purchase plans, shares		748
Common stock issued under stock plans and employee stock purchase plans, value	1,148	1	1,147
Private stock Offering, net of issuance costs and warrants, shares		5,122
Private stock Offering, net issuance costs and warrants, value	9,345	5	9,340
Issuance of common stock from exercise of warrants, shares		0
Issuance of common stocks warrants, value	2,236	0	2,236
Change in unrealized gain on available-for-sale securities	(124)			(124)
Stock-based compensation	2,049		2,049
Net income (loss)	(12,314)				(12,314)
Balance at Dec. 30, 2012	$ 27,278	$ 45	$ 204,797	$ (11)	$ (177,553)
Balance (in shares) at Dec. 30, 2012		44,506