SELECTED QUARTERLY FINANCIAL DATA Selected Quarterly Financial Data (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 184,276	$ 187,873	$ 204,838	$ 200,590	$ 222,738	$ 245,081	$ 247,378	$ 218,539	$ 777,577	[1]	$ 933,736	[1]	$ 794,542	[1]
Gross margin	66,925	67,666	77,068	73,208	84,648	92,992	95,467	81,198	284,867		354,305		298,573
Operating income (loss)	1,831	(1,600)	(3,167)	(3,702)	4,792	6,150	6,030	463	(6,638)		17,435		(5,618)
Net income (loss)	$ (343)	$ (2,165)	$ 394	$ (3,221)	$ 3,309	$ 3,382	$ 4,224	$ (6)	$ (5,335)		$ 10,909		$ (4,685)
Net income (loss) - basic (in dollars per share)	$ (0.01)	$ (0.07)	$ 0.01	$ (0.10)	$ 0.10	$ 0.11	$ 0.13	$ 0.00	$ (0.17)		$ 0.35		$ (0.16)
Net income (loss) - diluted (in dollars per share)	$ (0.01)	$ (0.07)	$ 0.01	$ (0.10)	$ 0.10	$ 0.11	$ 0.13	$ 0.00	$ (0.17)		$ 0.34		$ (0.16)
Weighted-average common stock outstanding - basic (in shares)	32,169,000	32,156,000	32,122,000	31,765,000	31,639,000	31,620,000	31,593,000	31,325,000	32,060,000		31,566,000		29,931,000
Weighted-average common stock outstanding - diluted (in shares)	32,169,000	32,156,000	32,486,000	31,765,000	32,118,000	32,085,000	32,039,000	31,325,000	32,060,000		31,989,000		29,931,000
Common stock equivalents and outstanding stock options excluded from the calculation of diluted earnings (loss) per share (in thousands)	2,368,000	2,654,000	1,939,000	2,793,000	1,396,000	1,717,000	2,224,000	2,928,000	2,367,566		1,500,525		2,582,897

[1] Revenue by geographic region disclosed above is net of any inter-segment revenue and, therefore, represents only revenue from external customers according to the location of the operating subsidiary.