BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Line Items]
Estimated period of amortization for the cost of inventory evaluation tools	5 years
Amortization expense	$ 400,000	$ 1,500,000	$ 1,000,000
Depreciation expense	2,200,000	2,200,000	2,700,000
Impairment charge related to property and equipment	0	0	200,000
General length of product warranty	12 months
Stock-based compensation expense	1,526,000	1,433,000	1,565,000
Net foreign currency transaction gain	300,000		400,000
Net foreign currency transaction loss		(600,000)
Cumulative translation adjustment	$ 18,200,000	$ 20,800,000
Minimum
Accounting Policies [Line Items]
Estimated useful lives of assets	3 years
Maximum
Accounting Policies [Line Items]
Estimated useful lives of assets	7 years
Customer concentration risk | Accounts receivable
Accounting Policies [Line Items]
Number of major customers	1	2
Net accounts receivable, major customer D | Customer concentration risk | Accounts receivable
Accounting Policies [Line Items]
Percentage of net accounts receivable	74.00%	61.00%
Net accounts receivable, major customer E | Customer concentration risk | Accounts receivable
Accounting Policies [Line Items]
Percentage of net accounts receivable		23.00%
Equipment sales
Accounting Policies [Line Items]
Percent revenue recognized upon shipment	90.00%
Percent cost recognized upon shipment	100.00%
Percent revenue recognized upon customer acceptance	10.00%
Installation services
Accounting Policies [Line Items]
Percentage of total invoice amount typically assigned to the installation element in customer agreements	10.00%