Equity Incentive Plans and Stock-Based Compensation (Details 4) (USD $)	12 Months Ended
Dec. 31, 2014
Exercise price range $4.13 to $5.39
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 4.13
Exercise price range, high end of range (in dollars per share)	$ 5.39
Options Outstanding
Number Outstanding (in shares)	965,606
Weighted Average Remaining Contractual Life (in years)	7 years 6 months 22 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.39
Options Exercisable
Number Exercisable (in shares)	111,457
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 4.81
Exercise price range $5.46 to $5.46
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 5.46
Exercise price range, high end of range (in dollars per share)	$ 5.46
Options Outstanding
Number Outstanding (in shares)	1,146,916
Weighted Average Remaining Contractual Life (in years)	8 years 0 months 4 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.46
Options Exercisable
Number Exercisable (in shares)	488,272
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 5.46
Exercise Price Range $5.49 to $5.49
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 5.49
Exercise price range, high end of range (in dollars per share)	$ 5.49
Options Outstanding
Number Outstanding (in shares)	35,932
Weighted Average Remaining Contractual Life (in years)	8 years 1 month 28 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.49
Options Exercisable
Number Exercisable (in shares)	14,341
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 5.49
Exercise Price Range $5.63 to $5.63
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 5.63
Exercise price range, high end of range (in dollars per share)	$ 5.63
Options Outstanding
Number Outstanding (in shares)	1,229,750
Weighted Average Remaining Contractual Life (in years)	4 years 3 months 25 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.63
Options Exercisable
Number Exercisable (in shares)	988,752
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 5.63
Exercise Price Range $5.76 to $5.76
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 5.76
Exercise price range, high end of range (in dollars per share)	$ 5.76
Options Outstanding
Number Outstanding (in shares)	1,244,879
Weighted Average Remaining Contractual Life (in years)	7 years 6 months 0 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.76
Options Exercisable
Number Exercisable (in shares)	384,739
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 5.76
Exercise Price Range $6.39 to $8.55
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 6.39
Exercise price range, high end of range (in dollars per share)	$ 8.55
Options Outstanding
Number Outstanding (in shares)	1,298,963
Weighted Average Remaining Contractual Life (in years)	6 years 0 months 29 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.72
Options Exercisable
Number Exercisable (in shares)	972,139
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 7.83
Exercise Price Range $8.73 to $8.73
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 8.73
Exercise price range, high end of range (in dollars per share)	$ 8.73
Options Outstanding
Number Outstanding (in shares)	74,428
Weighted Average Remaining Contractual Life (in years)	8 years 10 months 2 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 8.73
Options Exercisable
Number Exercisable (in shares)	15,982
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 8.73
Exercise Price Range $8.76 to $8.76
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 8.76
Exercise price range, high end of range (in dollars per share)	$ 8.76
Options Outstanding
Number Outstanding (in shares)	1,564,545
Weighted Average Remaining Contractual Life (in years)	9 years 0 months 20 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 8.76
Options Exercisable
Number Exercisable (in shares)	286,198
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 8.76
Exercise Price Range $8.91 to $14.75
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 8.91
Exercise price range, high end of range (in dollars per share)	$ 14.75
Options Outstanding
Number Outstanding (in shares)	1,185,737
Weighted Average Remaining Contractual Life (in years)	6 years 11 months 23 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 12.02
Options Exercisable
Number Exercisable (in shares)	428,013
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 12.64
Exercise Price Range $14.86 to $40.80
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 14.86
Exercise price range, high end of range (in dollars per share)	$ 40.80
Options Outstanding
Number Outstanding (in shares)	2,694,890
Weighted Average Remaining Contractual Life (in years)	1 year 10 months 20 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 22.00
Options Exercisable
Number Exercisable (in shares)	2,616,532
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 22.11
Exercise Price Range $4.13 to $40.80
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 4.13
Exercise price range, high end of range (in dollars per share)	$ 40.80
Options Outstanding
Number Outstanding (in shares)	11,441,646
Weighted Average Remaining Contractual Life (in years)	5 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.73
Options Exercisable
Number Exercisable (in shares)	6,306,425
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 13.41

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

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Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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