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, 2016	Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ (19,631)	$ (15,411)	[1]	$ (7,554)	[1]	$ (10,008)	[1]	$ (2,638)	[1]	$ (591)	[1]	$ (2,965)	[1]	$ (4,057)	$ (52,604)	$ (10,251)	$ (14,678)
Weighted average shares used to calculate net loss per share, basic															38,994	37,668	36,789
Weighted average shares used to calculate net income (loss) per share, diluted															38,994	37,668	36,789
Basic (in dollars per share)	$ (0.50)	$ (0.39)		$ (0.19)		$ (0.26)		$ (0.07)		$ (0.02)		$ (0.08)		$ (0.11)	$ (1.35)	$ (0.27)	$ (0.40)
Diluted (in dollars per share)	$ (0.50)	$ (0.39)		$ (0.19)		$ (0.26)		$ (0.07)		$ (0.02)		$ (0.08)		$ (0.11)	$ (1.35)	$ (0.27)	$ (0.40)
Restricted stock units
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
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, 2017 For the Year Ended December 31, 2016 FirstQuarter SecondQuarter ThirdQuarter FourthQuarter FirstQuarter SecondQuarter ThirdQuarter FourthQuarter (In thousands, except per share data)Revenues$37,610 $35,093 $28,773 $32,292 $55,146 $61,288 $55,397 $40,561Gross margin8,222 10,008 1,195 1,345 12,784 15,445 14,246 13,613Loss from operations(9,135) (6,695) (13,926) (17,027) (2,450) (932) (2,083) (4,194)Net loss(10,008) (7,554) (15,411) (19,631) (2,965) (591) (2,638) (4,057)Loss per share: Basic$(0.26) $(0.19) $(0.39) $(0.50) $(0.08) $(0.02) $(0.07) $(0.11)Diluted$(0.26) $(0.19) $(0.39) $(0.50) $(0.08) $(0.02) $(0.07) $(0.11)