Stockholders' Equity - Exercise Price (Details)	6 Months Ended
	Jul. 01, 2017 USD ($) $ / shares shares
Shareholders' Equity
Options Outstanding (in shares) | shares	553,915
Weighted Average Remaining Contractual Life	3 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 5.10
Options Exercisable (in shares) | shares	520,815
Weighted Average Exercise Price (in dollars per share)	$ 4.86
Stock Options
Intrinsic value
Intrinsic value related to options outstanding | $	$ 473,948
Intrinsic value related to vested options outstanding | $	$ 500,000
Closing stock price (in dollars per share)	$ 4.31
Stock Options | Exercise Price Range From Dollars 1.70 to Dollars 1.86
Shareholders' Equity
Exercise price, low end of range (in dollars per share)	1.70
Exercise price, high end of range (in dollars per share)	$ 1.86
Options Outstanding (in shares) | shares	138,600
Weighted Average Remaining Contractual Life	1 year 3 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 1.75
Options Exercisable (in shares) | shares	138,600
Weighted Average Exercise Price (in dollars per share)	$ 1.75
Stock Options | Exercise Price Range From Dollars 2.4 to Dollars 4.16
Shareholders' Equity
Exercise price, low end of range (in dollars per share)	2.40
Exercise price, high end of range (in dollars per share)	$ 4.16
Options Outstanding (in shares) | shares	156,450
Weighted Average Remaining Contractual Life	3 years 1 month 6 days
Weighted Average Exercise Price (in dollars per share)	$ 3.55
Options Exercisable (in shares) | shares	156,450
Weighted Average Exercise Price (in dollars per share)	$ 3.55
Stock Options | Exercise Price Range From Dollars 4.28 to Dollars 7.21
Shareholders' Equity
Exercise price, low end of range (in dollars per share)	4.28
Exercise price, high end of range (in dollars per share)	$ 7.21
Options Outstanding (in shares) | shares	213,400
Weighted Average Remaining Contractual Life	5 years 4 months 24 days
Weighted Average Exercise Price (in dollars per share)	$ 6.88
Options Exercisable (in shares) | shares	191,300
Weighted Average Exercise Price (in dollars per share)	$ 6.84
Stock Options | Exercise Price Range From Dollars 7.61 to Dollars 13.21
Shareholders' Equity
Exercise price, low end of range (in dollars per share)	7.61
Exercise price, high end of range (in dollars per share)	$ 13.21
Options Outstanding (in shares) | shares	45,465
Weighted Average Remaining Contractual Life	6 years 3 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 12.36
Options Exercisable (in shares) | shares	34,465
Weighted Average Exercise Price (in dollars per share)	$ 12.37