Note 7 - Income Taxes (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Cumulative Three Year Pre-tax Income (Loss)	$ (17,600)
Deferred Tax Assets, Valuation Allowance	44,731	$ 42,289
Income Tax Credits and Adjustments	200	400	$ 500
Undistributed Earnings of Foreign Subsidiaries	49,000
Increase (Decrease) of Net Income Due to Impact of Tax Holidays	$ 1,000	$ 800
Increase (Decrease) of Earning Per Share Due To Impact Of Tax Holidays	$ 0.04	$ 0.03
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 5,200	$ 5,600
Decrease in Unrecognized Tax Benefits is Reasonably Possible	800
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 1,200	1,400
Unrecognized Tax Benefits, Interest Expense, Net of Accrued Interest Reversed		$ 100
Minimum [Member]
Collection Term Range	4 years
Maximum [Member]
Collection Term Range	10 years
SINGAPORE
Foreign Earnings Repatriated	$ 17,400
Domestic Tax Authority [Member]
Operating Loss Carryforwards	31,000
Tax Credit Carryforward, Amount	8,200
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	22,200
Tax Credit Carryforward, Amount	13,600
Foreign Tax Authority [Member]
Operating Loss Carryforwards	$ 200