Note 1 - Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 26, 2015

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 26,			September 27,			September 26,			September 27,
	2015			2014			2015			2014
Cost of sales	$	100		$	85		$	413		$	350
Research and development		256			453			841			1,364
Selling, general and administrative		1,281			1,047			3,827			2,919
Total share-based compensation		1,637			1,585			5,081			4,633
Income tax benefit		(70	)		(60	)		(181	)		(157	)
Total share-based compensation, net	$	1,567		$	1,525		$	4,900		$	4,476

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 26,		September 27,		September 26,		September 27,
	2015		2014		2015		2014
Weighted average common shares		26,175		25,481		25,995		25,309
Effect of dilutive stock options		621		693		684		389
		26,796		26,174		26,679		25,698

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 26,		September 27,		September 26,		September 27,
	2015		2014		2015		2014
Customers individually accounting for more than 10% of net sales		two		two		one		two
Percentage of net sales		29%		26%		17%		27%