Note 11 - Share-based Compensation - Restricted Stock Units Activity (Details)	6 Months Ended
	Jul. 01, 2017 $ / shares shares
Time-based Restricted Stock Units [Member] | The 2007 and 2014 Plan [Member]
Outstanding non-vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 7.33
Outstanding non-vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 7.39
Outstanding non-vested (in shares) | shares	197,734
Granted (in shares) | shares	15,000
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 4.97
Vested (in shares) | shares	25,000
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 5.41
Forfeited or expired (in shares) | shares	0
Forfeited or expired, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Outstanding non-vested (in shares) | shares	187,734
Performance-based Restricted Stock Units [Member] | The 2014 Plan [Member]
Outstanding non-vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 5.36
Outstanding non-vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 5.11
Outstanding non-vested (in shares) | shares	200,000
Granted (in shares) | shares	200,000
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 4.85
Vested (in shares) | shares	0
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Forfeited or expired (in shares) | shares	0
Forfeited or expired, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Outstanding non-vested (in shares) | shares	400,000