Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Per 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	Dec. 31, 2009
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)	$ (6,518)	$ (5,857)	$ (6,696)	$ (16,703)	$ (3,665)	$ (6,603)	$ (13,666)	$ (4,795)	$ (35,774)	$ (28,730)	$ 10,653	$ 10,653
Weighted average shares - basic									59,811	56,592	48,902
Basic net income (loss) per share (usd per share)	$ (0.10)	$ (0.10)	$ (0.11)	$ (0.29)	$ (0.06)	$ (0.12)	$ (0.24)	$ (0.09)	$ (0.60)	$ (0.51)	$ 0.22
Weighted average shares - diluted									59,811	56,592	50,544
Diluted net income (loss) per share (usd per share)	$ (0.10)	$ (0.10)	$ (0.11)	$ (0.29)	$ (0.06)	$ (0.12)	$ (0.24)	$ (0.09)	$ (0.60)	$ (0.51)	$ 0.21
Securities excluded from calculations of net loss per share because impact would have been anti-dilutive	3,595				3,767				0
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculations of net loss per share because impact would have been anti-dilutive	2,698				3,127				0
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculations of net loss per share because impact would have been anti-dilutive	405				640				0
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculations of net loss per share because impact would have been anti-dilutive	492				0				0