Business Segments and Significant Customers: (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 29, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 24, 2011	Jun. 25, 2011	Mar. 26, 2011	Dec. 29, 2012	Dec. 31, 2011
Business segments and significant customers
Total net revenue	$ 43,542,000	$ 46,601,000	$ 48,016,000	$ 47,020,000	$ 44,464,000	$ 37,518,000	$ 43,609,000	$ 36,641,000	$ 185,179,427	$ 162,232,418
Sales of distributed products									2,600,000
Total net revenue | Customer concentration risk | Costco
Business segments and significant customers
Total net revenue									$ 64,600,000	$ 49,300,000
Concentration risk (as a percent)									35.00%	30.00%