Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2014
Cash, Uninsured Amount	$ 17,600,000
Finite-Lived Intangible Asset, Useful Life
Research and Development Expense	$ 1,300,000	$ 1,300,000	$ 1,400,000
Treasury Stock, Shares, Acquired	0	29,559
Treasury Stock, Value	$ 587,000	$ 587,000
Increase (Decrease) in Income Taxes Receivable	(209,000)	(2,677,000)	436,000
Increase (Decrease) in Accrued Liabilities	$ (361,000)	$ (163,000)	$ (2,243,000)
Common Stock, Shares, Outstanding	7,212,464	7,140,818
Weighted Average Number of Shares Outstanding, Basic	7,190,000	7,102,000	7,028,000
Weighted Average Number of Shares Outstanding, Diluted	7,275,000	7,206,000	7,175,000
Restatement Adjustment [Member]
Increase (Decrease) in Income Taxes Receivable		$ 315,000
Increase (Decrease) in Accrued Liabilities		$ (315,000)
Common Stock, Shares, Outstanding		29,559
Weighted Average Number of Shares Outstanding, Basic		(13,000)
Weighted Average Number of Shares Outstanding, Diluted		(13,000)
Shares, Outstanding		(30,000)
Employee Stock Option [Member]
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 318,000	$ 312,000	$ 320,000
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life		5 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life		14 years
Component Products [Member]
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount				$ 69,000,000
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount				74.00%