Share-based Compensation Plans - Summary of stock option activity (Details) (USD $)	12 Months Ended
	Dec. 27, 2014
Compensation and Retirement Disclosure [Abstract]
Outstanding at beginning of year	1,346,155
ShareBasedCompensationArrangement	153,500
Exercised	(115,050)
Forfeited	(4,000)
Expired	(53,600)
Outstanding at end of year	1,327,005
Options exercisable at year-end	874,384
Weighted Fair Value, Beginning Balance	$ 1.39
Weighted-Average Exercise Price, Granted	$ 2.87
Weighted-Average Exercise Price, Exercised	$ 0.97
Weighted-Average Exercise Price, Forfeited	$ 1.53
Weighted-Average Exercise Price, Expired	$ 0.70
Weighted Fair Value, Ending Balance	$ 1.63
Weighted-Average Exercise Price, Exercisable at end of Year	$ 1.58
Weighted Remaining Contractural Life (years) Outstanding at end of year	6 years 3 months 12 days
Weighted Remaining Contractural Life (years) Exercisable at end of year	5 years 6 months 5 days
Aggreagate Intrinsic Value, Ending Balance	$ 1,757,317
Aggrtegate Intrinsic value, Exercisable at year-end	$ 874,384