Note 3 - Revenue Recognition - Revenues Disaggregated by Revenue Source (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2021	Sep. 26, 2020	Oct. 02, 2021	Sep. 26, 2020
Revenue	$ 45,471	$ 31,561	$ 138,953	$ 109,246
Engineering Services [Member]
Revenue	16,482	15,087	47,882	43,288
Health Care [Member]
Revenue	19,646	9,015	63,723	41,896
Technology Service [Member]
Revenue	9,343	7,459	27,348	24,062
Time-and-materials Contract [Member] | Engineering Services [Member]
Revenue	11,624	10,369	33,922	33,980
Time-and-materials Contract [Member] | Health Care [Member]
Revenue	19,324	8,844	62,985	41,498
Time-and-materials Contract [Member] | Technology Service [Member]
Revenue	9,109	7,347	26,770	23,683
Fixed-price Contract [Member] | Engineering Services [Member]
Revenue	4,858	4,660	13,893	9,163
Permanent Placement Services [Member] | Engineering Services [Member]
Revenue	0	58	67	145
Permanent Placement Services [Member] | Health Care [Member]
Revenue	322	171	738	398
Permanent Placement Services [Member] | Technology Service [Member]
Revenue	$ 234	$ 112	$ 578	$ 379