Note 8 - Shareholders' Equity - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 02, 2017 USD ($) $ / shares shares
Options outstanding (in shares) | shares	2,323,581
Options outstanding - weighted average exercise price (in dollars per share) | $ / shares	$ 6.22
Granted (in shares) | shares	65,000
Granted - weighted average exercise price (in dollars per share) | $ / shares	$ 5.31
Exercised (in shares) | shares	(180,334)
Exercised - weighted average exercise price (in dollars per share) | $ / shares	$ 4.11
Forfeited or expired (in shares) | shares	(113,166)
Forfeited or expired - weighted average exercise price (in dollars per share) | $ / shares	$ 11.55
Options outstanding (in shares) | shares	2,095,081
Options outstanding - weighted average exercise price (in dollars per share) | $ / shares	$ 6.08
Options outstanding - weighted average remaining contractual term (Year)	3 years 40 days
Options outstanding - aggregate intrinsic value | $	$ 1,502
Vested and Expected to Vest (in shares) | shares	1,984,765
Options vested and expected to vest - weighted average exercise price (in dollars per share) | $ / shares	$ 6.15
Options vested and expected to vest - weighted average remaining contractual term (Year)	3 years
Options vested and expected to vest - aggregate intrinsic value | $	$ 1,403
Options exercisable (in shares) | shares	1,265,548
Exercisable - weighted average exercise price (in dollars per share) | $ / shares	$ 5.07
Exercisable - weighted average remaining contractual term (Year)	2 years 29 days
Exercisable - aggregate intrinsic value | $	$ 1,035