Basic and Diluted Net Income (Loss) Per Share - Earnings (Loss) Per Share Calculation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ (8,211)		$ (4,112)		$ (18,645)		$ (10,669)
Interest on convertible notes, net of tax benefit	0		0	[1]	0		0	[1]
Net income (loss), diluted	$ (8,211)		$ (4,112)		$ (18,645)		$ (10,669)
Weighted average shares used to calculate net income (loss) per share, basic	36,096		28,669		32,980		28,570
Effect of escrow shares	0	[2]	0	[2]	0	[2]	0	[2]
Effect of convertible notes	0	[1]	0	[1]	0	[1]	0	[1]
Weighted average shares used to calculate net income (loss) per share, diluted	36,096		28,669		32,980		28,570
Basic (in dollars per share)	$ (0.23)		$ (0.14)		$ (0.57)		$ (0.37)
Diluted (in dollars per share)	$ (0.23)		$ (0.14)		$ (0.57)		$ (0.37)
Restricted Stock Units (RSUs) [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive equity awards	0	[3],[4]	0	[3],[4]	0	[3],[4]	0	[3],[4]
Stock Options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive equity awards	0	[3]	0	[3]	0	[3]	0	[3]

[1] For each of the three months ended June 30, 2014 and 2013, 2.1 million as-if converted shares associated with the Company's convertible senior notes were excluded from the calculation as their effect would have been anti-dilutive.

[2] (A)For the three months ended June 30, 2014 there were no remaining contingently issuable shares outstanding. For the six months ended June 30, 2013, 30,000 contingently issuable shares were excluded from the calculation as their effect would have been anti-dilutive.

[3] For the three and six months ended June 30, 2014 and 2013, the following equity awards, by type, were excluded from the calculation, as their effect would have been anti-dilutive (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2014 2013 2014 2013Stock options3,042 2,375 3,042 2,375Restricted stock units300 441 300 441Performance based restricted stock units (D)409 2,087 409 2,087Total equity award shares excluded3,751 4,903 3,751 4,903

[4] under the Long-Term Incentive Plan ("LTIP") are presented based on attainment of 100% of the performance goals being met. The LTIP provides for the grants of awards payable in shares of common stock upon the achievement of performance goals set by the Company's Compensation and Development Committee. In addition to the performance conditions, the awards contain market-based multipliers based on the average price of the Company's common stock thirty days prior to the end of each semi-annual performance period. The maximum multiplier for a given semi-annual performance period is 2.75x the original grant and overall achievement is limited to a maximum of 2.5x of the target award over the entire performance period. Based on this formula, the maximum number of shares that could be earned was 0.8 million and 2.0 million for the three months ended June 30, 2014 and 2013