Basic and Diluted Net IncomePer Share Earnings (Loss) Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended														12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014	Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ (1,440)	$ (2,066)	[1]	$ (4,119)	[1]	$ (7,053)	[1]	$ (4,467)	$ (4,469)	[1]	$ (8,211)	[1]	$ (10,434)	[1]	$ (14,678)	$ (27,581)	$ (49,404)
Weighted average shares used to calculate net loss per share, basic															36,789	34,699	28,805
Effect of convertible notes (in shares)															0	0	0
Weighted average shares used to calculate net income (loss) per share, diluted															36,789	34,699	28,805
Basic (in dollars per share)	$ (0.04)	$ (0.06)		$ (0.11)		$ (0.19)		$ (0.12)	$ (0.12)		$ (0.23)		$ (0.35)		$ (0.40)	$ (0.79)	$ (1.72)
Diluted (in dollars per share)	$ (0.04)	$ (0.06)		$ (0.11)		$ (0.19)		$ (0.12)	$ (0.12)		$ (0.23)		$ (0.35)		$ (0.40)	$ (0.79)	$ (1.72)
Restricted Stock Units (RSUs) [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive equity awards (in shares)															0	0	0
Employee Stock Option [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive equity awards (in shares)															0	0	0

[1] For the Year Ended December 31, 2015 For the Year Ended December 31, 2014 FirstQuarter SecondQuarter ThirdQuarter FourthQuarter FirstQuarter SecondQuarter ThirdQuarter FourthQuarter (In thousands, except per share data)Revenues$48,687 $47,049 $44,780 $44,077 $43,799 $49,964 $50,805 $48,174Gross margin12,626 12,601 13,007 13,918 11,148 12,007 14,697 13,950Loss from operations(6,993) (3,533) (2,016) (1,523) (9,464) (7,429) (4,103) (4,304)Net loss(7,053) (4,119) (2,066) (1,440) (10,434) (8,211) (4,469) (4,467)Loss per share: Basic$(0.19) $(0.11) $(0.06) $(0.04) $(0.35) $(0.23) $(0.12) $(0.12)Diluted$(0.19) $(0.11) $(0.06) $(0.04) $(0.35) $(0.23) $(0.12) $(0.12)