EQUITY PLANS (Details) (USD $)	12 Months Ended			1 Months Ended	82 Months Ended	1 Months Ended	12 Months Ended		103 Months Ended	82 Months Ended	103 Months Ended
	Jan. 02, 2015	Dec. 27, 2013	Dec. 28, 2012 plan	Jun. 30, 2006	Jan. 02, 2015	Mar. 31, 2008	Dec. 31, 2010	Dec. 30, 2011	Jan. 02, 2015	Jan. 02, 2015	Jan. 02, 2015	Jun. 30, 2008
Equity plans
Number of share-based compensation plans			2
Compensation expense recognized for stock options issued (in dollars)	$ 258,000	$ 150,000	$ 227,000
Fully-vested options
Stock price at the end of the year (in dollars per share)	$ 14.50				14.50				14.50	14.50	14.50
Unrecognized compensation expense
Weighted-average period over which unrecognized expense is expected to be recognized	6 years 15 days
2006 Plan
Equity plans
Termination period of the plan				10 years
Granted (in shares)					0
Number of shares of common stock reserved for issuance				300,000
Number of shares of common stock reserved for issuance	168,500				168,500				168,500	168,500	168,500
Options
Granted (in shares)					0
Nonvested Options
Granted (in shares)					0
2008 Plan
Equity plans
Termination period of the plan						10 years
Number of shares of common stock reserved for issuance	426,602				426,602	450,000			426,602	426,602	426,602
Shares available for grant under 2008 Plan from 2006 Plan												70,333
Number of additional shares authorized	500,000						350,000
2006 Employee Stock Purchase Plan
Equity plans
Number of shares of common stock reserved for issuance				300,000
Employee Stock Purchase Plan
Shares issuable in any one calendar year	100,000
Purchase price per share as a percentage of fair market value	95.00%
Number of shares available for issuance	81,113				81,113				81,113	81,113	81,113
Stock options
Equity plans
Granted (in shares)	235,000	100,000	202,000
Assumptions
Expected volatility (as a percent)		40.00%	39.00%
Expected volatility, minimum (as a percent)	38.35%
Expected volatility, maximum (as a percent)	40.00%
Expected dividends (as a percent)	0.00%	0.00%	0.00%
Expected term	6 years
Risk-free rate, minimum (as a percent)	1.63%	1.31%	0.65%
Risk-free rate, maximum (as a percent)	1.73%	1.36%	1.09%
Fully-vested options
Intrinsic value of the fully-vested options (in dollars)	5,960,000				5,960,000				5,960,000	5,960,000	5,960,000
Options
Outstanding at the beginning of the period (in shares)	978,000	992,000	912,000
Granted (in shares)	235,000	100,000	202,000
Exercised (in shares)	(198,000)	(9,000)	(5,000)
Forfeited or expired (in shares)	(89,000)	(105,000)	(117,000)
Outstanding at the end of the period (in shares)	926,000	978,000	992,000		926,000			912,000	926,000	926,000	926,000
Vested at the end of the period (in shares)	595,000	796,000	700,000		595,000				595,000	595,000	595,000
Exercisable at the end of the period (in shares)	595,000	796,000	700,000		595,000				595,000	595,000	595,000
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 3.95	$ 3.86	$ 3.94
Granted (in dollars per share)	$ 10.23	$ 3.62	$ 3.30
Exercised (in dollars per share)	$ 2.24	$ 1.65	$ 1.81
Forfeited or expired	$ 2.57
Outstanding at the end of the period (in dollars per share)	$ 5.84	$ 3.95	$ 3.86		5.84			$ 3.94	5.84	5.84	5.84
Vested at the end of the period (in dollars per share)	$ 4.47	$ 4.04	$ 4.09		4.47				4.47	4.47	4.47
Exercisable at the end of the period (in dollars per share)	$ 4.47	$ 4.04	$ 4.09		4.47				4.47	4.47	4.47
Weighted-Average Remaining Contractual Term
Outstanding at the beginning of the period	6 years 5 months 9 days	3 years 4 months 6 days	6 years 11 months 12 days					7 years 5 months 19 days
Granted	9 years 8 months 5 days	2 years 5 months 9 days	9 years 4 months 2 days
Exercised	4 years 8 months 27 days	5 years 8 months 1 day	6 years 8 months 23 days
Outstanding at the end of the period	6 years 5 months 9 days	3 years 4 months 6 days	6 years 11 months 12 days					7 years 5 months 19 days
Vested at the end of the period	4 years 11 months 1 day	7 years 10 months 24 days	6 years 2 months 9 days
Exercisable at the end of the period	4 years 11 months 1 day	7 years 10 months 24 days	6 years 2 months 9 days
Nonvested Options
Nonvested outstanding at the beginning of the period (in shares)	207,000	293,000	341,000
Granted (in shares)	235,000	100,000	202,000
Vested (in shares)	(108,000)	(143,000)	(212,000)
Forfeited (in shares)	(3,000)	(43,000)	(38,000)
Nonvested outstanding at the end of the period (in shares)	331,000	207,000	293,000		331,000			341,000	331,000	331,000	331,000
Nonvested Options, Weighted Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)	$ 3.55	$ 1.28	$ 1.13
Granted (in dollars per share)	$ 4.15	$ 3.62	$ 1.27
Vested (in dollars per share)	$ 3.41	$ 3.17	$ 1.07
Forfeited (in dollars per share)	$ 3.85	$ 3.33	$ 1.10
Nonvested at the end of the period (in dollars per share)	$ 3.37	$ 3.55	$ 1.28		3.37			$ 1.13	3.37	3.37	3.37
Awards granted that were immediately vested (in shares)	0	0	0
Unrecognized compensation expense
Unrecognized compensation expense related to non-vested stock options (in dollars)	422,000				422,000				422,000	422,000	422,000
Stock options | Minimum
Assumptions
Expected term		5 years 9 months	5 years 9 months
Stock options | Maximum
Assumptions
Expected term		6 years	6 years
Stock options | 2008 Plan
Equity plans
Maximum number of shares a participant may be granted in options to purchase during fiscal year	100,000
Incentive stock options | 2006 Plan
Equity plans
Options granted, net of forfeitures, expirations and exercises (in shares)									162,500
Incentive stock options | 2008 Plan
Equity plans
Options granted, net of forfeitures, expirations and exercises (in shares)										646,234
Incentive stock options | 2008 Plan | Maximum
Equity plans
Expiration period from date of grant	10 years
Non-statutory/Nonqualified stock options | 2006 Plan
Equity plans
Options granted, net of forfeitures, expirations and exercises (in shares)											6,000
Non-statutory/Nonqualified stock options | 2006 Plan | Maximum
Equity plans
Expiration period from date of grant						10 years
Non-statutory/Nonqualified stock options | 2008 Plan
Equity plans
Options granted, net of forfeitures, expirations and exercises (in shares)										111,000
Non-statutory/Nonqualified stock options | 2008 Plan | Maximum
Equity plans
Expiration period from date of grant	10 years
Restricted stock
Unrecognized compensation expense
Unrecognized compensation expense related to non-vested restricted stock grants (in dollars)	142,000				142,000				142,000	142,000	142,000
Restricted stock | 2008 Plan
Equity plans
Shares granted										50,000
Assumptions
Vesting period	2 years
Restricted Stock Activity
Intrinsic value of the fully-vested awards (in dollars)	$ 144,000
Restricted Stock
Outstanding at the beginning of period (in shares)	25,000
Granted (in shares)	25,000
Vested (in shares)	(12,500)
Outstanding at the end of period (in shares)	37,500				37,500				37,500	37,500	37,500
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of period (in dollars per share)	$ 2.96
Granted (in dollars per share)	$ 7.13
Vested (in dollars per share)	$ 2.96
Outstanding at the end of period (in dollars per share)	$ 5.74				5.74				5.74	5.74	5.74