GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Summary of Net Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 43,334	$ 42,029	$ 101,588	$ 85,227
Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	99.98%	100.00%	100.00%	100.00%
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 3,006	$ 6,392	$ 11,574	$ 10,575
United States | Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	7.00%	15.00%	11.00%	12.00%
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 26,742	$ 23,863	$ 60,740	$ 34,122
South Korea | Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	62.00%	57.00%	60.00%	40.00%
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 5,115	$ 2,268	$ 8,715	$ 15,349
China | Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	12.00%	5.00%	9.00%	18.00%
Taiwan
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 2,518	$ 5,498	$ 8,038	$ 16,320
Taiwan | Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	6.00%	13.00%	8.00%	19.00%
Other Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 4,866	$ 1,589	$ 10,230	$ 3,870
Other Asia | Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	11.00%	4.00%	10.00%	5.00%
Europe and others
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, amount	$ 1,087	$ 2,419	$ 2,291	$ 4,991
Europe and others | Geographic Concentration Risk | Net Sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, percentage	2.00%	6.00%	2.00%	6.00%