Note 7 - Segment and Geographic Information - Summary of Net Sales to Customers, Attributed to Countries (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 30, 2017	[1],[2]	Sep. 30, 2017	[1]	Jul. 01, 2017	[1]	Apr. 01, 2017	[1]	Dec. 31, 2016	[1]	Sep. 24, 2016	[1]	Jun. 25, 2016	[1]	Mar. 26, 2016	[1]	Dec. 30, 2017	Dec. 31, 2016		Dec. 26, 2015
Net sales	$ 84,090		$ 93,651		$ 93,866		$ 81,097		$ 70,694		$ 69,259		$ 76,353		$ 65,778		$ 352,704	$ 282,084	[1]	$ 269,654
CHINA
Net sales																	82,474	60,291		52,589
Malaysia [Member]
Net sales																	80,102	85,956		60,776
UNITED STATES
Net sales																	38,729	35,204		50,704
Rest of the World [Member]
Net sales																	$ 151,399	$ 100,633		$ 105,585

[1] All quarters presented above were comprised of 13 weeks, except for the fourth quarter ended December 31, 2016 which was comprised of 14 weeks.

[2] The fourth quarter of 2017 includes impact of Tax Act enacted in December 2017.