Unaudited Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Jan. 01, 2023	13,202
Balance at Jan. 01, 2023	$ 13	$ 317,174	$ (305,292)	$ 11,895
Issuance of common stock from private placement, net of stock issuance cost (in shares)	450
Issuance of common stock from private placement, net of stock issuance cost	$ 1	2,292	0	2,293
Common stock issued under stock plans and employee stock purchase plans (in shares)	34
Common stock issued under stock plans and employee stock purchase plans	$ 0	0	0	0
Stock-based compensation	0	715	0	715
Net income (loss)	$ 0	0	(1,228)	(1,228)
Balance (in shares) at Apr. 02, 2023	13,686
Balance at Apr. 02, 2023	$ 14	320,181	(306,520)	13,675
Balance (in shares) at Jan. 01, 2023	13,202
Balance at Jan. 01, 2023	$ 13	317,174	(305,292)	11,895
Net income (loss)				(3,497)
Balance (in shares) at Jul. 02, 2023	13,725
Balance at Jul. 02, 2023	$ 14	320,950	(308,789)	12,175
Balance (in shares) at Apr. 02, 2023	13,686
Balance at Apr. 02, 2023	$ 14	320,181	(306,520)	13,675
Common stock issued under stock plans and employee stock purchase plans (in shares)	39
Common stock issued under stock plans and employee stock purchase plans	$ 0	122	0	122
Stock-based compensation	0	647	0	647
Net income (loss)	$ 0	0	(2,269)	(2,269)
Balance (in shares) at Jul. 02, 2023	13,725
Balance at Jul. 02, 2023	$ 14	320,950	(308,789)	12,175
Balance (in shares) at Dec. 31, 2023	14,118
Balance at Dec. 31, 2023	$ 14	322,436	(305,555)	16,895
Issuance of common stock from private placement, net of stock issuance cost (in shares)	223
Issuance of common stock from private placement, net of stock issuance cost	$ 0	3,535	0	3,535
Common stock issued under stock plans and employee stock purchase plans (in shares)	81
Common stock issued under stock plans and employee stock purchase plans	$ 0	0	0	0
Stock-based compensation	0	1,709	0	1,709
Net income (loss)	$ 0	0	108	108
Balance (in shares) at Mar. 31, 2024	14,422
Balance at Mar. 31, 2024	$ 14	327,680	(305,447)	22,247
Balance (in shares) at Dec. 31, 2023	14,118
Balance at Dec. 31, 2023	$ 14	322,436	(305,555)	16,895
Net income (loss)				(1,442)
Balance (in shares) at Jun. 30, 2024	14,458
Balance at Jun. 30, 2024	$ 14	328,788	(306,997)	21,805
Balance (in shares) at Mar. 31, 2024	14,422
Balance at Mar. 31, 2024	$ 14	327,680	(305,447)	22,247
Common stock issued under stock plans and employee stock purchase plans (in shares)	36
Common stock issued under stock plans and employee stock purchase plans	$ 0	188	0	188
Stock-based compensation	0	920	0	920
Net income (loss)	$ 0	0	(1,550)	(1,550)
Balance (in shares) at Jun. 30, 2024	14,458
Balance at Jun. 30, 2024	$ 14	$ 328,788	$ (306,997)	$ 21,805