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, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 159,503	$ 163,587	$ 171,360	$ 165,678	$ 184,276	$ 187,873	$ 204,838	$ 200,590	$ 660,128	[1]	$ 777,577	[1]	$ 933,736	[1]
Gross margin	56,895	55,796	60,504	56,677	66,925	67,666	77,068	73,208	229,872		284,867		354,305
Operating income (loss)	(7,653)	(5,140)	(5,424)	(8,542)	1,831	(1,600)	(3,167)	(3,702)	(26,759)		(6,638)		17,435
Net income (loss)	$ (11,296)	$ (5,047)	$ (5,811)	$ (8,241)	$ (343)	$ (2,165)	$ 394	$ (3,221)	$ (30,395)		$ (5,335)		$ 10,909
Net income (loss) - basic (in dollars per share)	$ (0.35)	$ (0.15)	$ (0.18)	$ (0.25)	$ (0.01)	$ (0.07)	$ 0.01	$ (0.10)	$ (0.94)		$ (0.17)		$ 0.35
Net income (loss) - diluted (in dollars per share)	$ (0.35)	$ (0.15)	$ (0.18)	$ (0.25)	$ (0.01)	$ (0.07)	$ 0.01	$ (0.10)	$ (0.94)		$ (0.17)		$ 0.34
Weighted-average common stock outstanding - basic (in shares)	32,600,000	32,600,000	32,717,000	32,344,000	32,169,000	32,156,000	32,122,000	31,765,000	32,493,000		32,060,000		31,566,000
Weighted-average common stock outstanding - diluted (in shares)	32,600,000	32,600,000	32,717,000	32,344,000	32,169,000	32,156,000	32,486,000	31,765,000	32,493,000		32,060,000		31,989,000
Common stock equivalents and outstanding stock options excluded from the calculation of diluted earnings (loss) per share (in thousands)	1,914,000	2,191,000	1,972,000	1,725,000	2,368,000	2,654,000	1,939,000	2,793,000	1,914,021		2,367,566		1,500,525

[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.