Note 9 - Line of Credit (Details Textual) - USD ($) $ in Thousands		3 Months Ended
	Mar. 08, 2017	Apr. 01, 2017	Dec. 31, 2016
Long-term Line of Credit, Noncurrent		$ 12,725	$ 14,311
Letters of Credit Outstanding, Amount		800	800
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 35,000
Line of Credit, Loan Covenants, Waiver Granted, Amount of Legal Settlement and Office Closure Expenses Excluded	$ 1,300
Debt Instrument, Interest Rate, Effective Percentage		2.40%
Long-term Line of Credit, Noncurrent		$ 12,700	$ 14,300
Line of Credit Facility, Remaining Borrowing Capacity		$ 21,500
Line of Credit Facility, Expiration Date		Dec. 11, 2019
Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 5,000