Description of Business and Basis of Presentation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Schedule of computation of basic and diluted net income (loss) per share
Net income (loss)	$ (9,341)us-gaap_NetIncomeLoss	$ 319us-gaap_NetIncomeLoss
Weighted-average common shares outstanding	29,445	29,047
Effect of potentially dilutive securities:
Weighted-average common shares outstanding, assuming dilution	29,445	29,216
Net income (loss) per share
Basic (in dollars per share)	$ (0.32)us-gaap_EarningsPerShareBasic	$ 0.01us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ (0.32)us-gaap_EarningsPerShareDiluted	$ 0.01us-gaap_EarningsPerShareDiluted
Options to purchase common stock
Effect of potentially dilutive securities:
Effect of potentially dilutive securities	0	76
Restricted stock awards
Effect of potentially dilutive securities:
Effect of potentially dilutive securities	0	53
Restricted stock unit awards
Effect of potentially dilutive securities:
Effect of potentially dilutive securities	0	38
Employee stock purchase plan
Effect of potentially dilutive securities:
Effect of potentially dilutive securities	0	2

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