Equity Incentive Plans and Stock-Based Compensation (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2013
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)	1,087,176
Weighted Average Remaining Contractual Life (in years)	8 years 7 months 2 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.45
Options Exercisable
Number Exercisable (in shares)	93,470
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 4.80
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)	1,306,654
Weighted Average Remaining Contractual Life (in years)	9 years 0 months 4 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.46
Options Exercisable
Number Exercisable (in shares)	240,292
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)	36,918
Weighted Average Remaining Contractual Life (in years)	9 years 1 month 21 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.49
Options Exercisable
Number Exercisable (in shares)	5,734
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)	1,511,307
Weighted Average Remaining Contractual Life (in years)	5 years 3 months 22 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.63
Options Exercisable
Number Exercisable (in shares)	724,285
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)	1,246,839
Weighted Average Remaining Contractual Life (in years)	8 years 6 months 0 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 5.76
Options Exercisable
Number Exercisable (in shares)	219,246
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 5.76
Exercise Price Range $6.39 to $7.79
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)	$ 7.79
Options Outstanding
Number Outstanding (in shares)	1,138,049
Weighted Average Remaining Contractual Life (in years)	7 years 4 months 2 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.27
Options Exercisable
Number Exercisable (in shares)	531,824
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 7.27
Exercise Price Range $8.11 to $13.30
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 8.11
Exercise price range, high end of range (in dollars per share)	$ 13.30
Options Outstanding
Number Outstanding (in shares)	1,177,647
Weighted Average Remaining Contractual Life (in years)	5 years 8 months 27 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.21
Options Exercisable
Number Exercisable (in shares)	784,077
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.15
Exercise Price Range $13.31 to $18.69
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 13.31
Exercise price range, high end of range (in dollars per share)	$ 18.69
Options Outstanding
Number Outstanding (in shares)	1,250,463
Weighted Average Remaining Contractual Life (in years)	2 years 9 months 30 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 16.92
Options Exercisable
Number Exercisable (in shares)	1,138,570
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 17.15
Exercise Price Range $19.13 to $21.51
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 19.13
Exercise price range, high end of range (in dollars per share)	$ 21.51
Options Outstanding
Number Outstanding (in shares)	1,318,182
Weighted Average Remaining Contractual Life (in years)	2 years 6 months 15 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 20.15
Options Exercisable
Number Exercisable (in shares)	1,237,247
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 20.10
Exercise Price Range $21.95 to $40.80
Exercise price range
Exercise price range, low end of range (in dollars per share)	$ 21.95
Exercise price range, high end of range (in dollars per share)	$ 40.80
Options Outstanding
Number Outstanding (in shares)	1,303,911
Weighted Average Remaining Contractual Life (in years)	1 year 11 months 27 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 26.12
Options Exercisable
Number Exercisable (in shares)	1,267,988
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 26.21
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)	11,377,146
Weighted Average Remaining Contractual Life (in years)	5 years 8 months 12 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.32
Options Exercisable
Number Exercisable (in shares)	6,242,733
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.35