Stockholders' Equity - Stock Options Additional Disclosures (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Number of shares	12,984
Options Outstanding, Weighted-Average Remaining Contractual Term	3 years 9 months 16 days
Options Outstanding, Weighted-Average Exercise Price	$ 4.78
Options Exercisable, Number of Shares	9,850
Options Exercisable, Weighted-Average Exercise Price	$ 2.49
Exercise Price Range 0.06
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, maximum	$ 0.06
Number of shares	191
Options Outstanding, Weighted-Average Remaining Contractual Term	0 years 11 months 25 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.06
Options Exercisable, Number of Shares	191
Options Exercisable, Weighted-Average Exercise Price	$ 0.06
Exercise Price Range 0.10 - 0.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, minimum	$ 0.10
Exercise Price, maximum	$ 0.18
Number of shares	1,784
Options Outstanding, Weighted-Average Remaining Contractual Term	1 year 5 months 10 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.10
Options Exercisable, Number of Shares	1,784
Options Exercisable, Weighted-Average Exercise Price	$ 0.10
Exercise Price Range 0.29 - 0.33
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, minimum	$ 0.29
Exercise Price, maximum	$ 0.33
Number of shares	3,509
Options Outstanding, Weighted-Average Remaining Contractual Term	2 years 2 months 46 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.30
Options Exercisable, Number of Shares	3,509
Options Exercisable, Weighted-Average Exercise Price	$ 0.30
Exercise Price Range 1.85
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, maximum	$ 1.85
Number of shares	1,605
Options Outstanding, Weighted-Average Remaining Contractual Term	4 years 0 months 10 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.85
Options Exercisable, Number of Shares	1,605
Options Exercisable, Weighted-Average Exercise Price	$ 1.85
Exercise Price Range 2.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, maximum	$ 2.95
Number of shares	1,195
Options Outstanding, Weighted-Average Remaining Contractual Term	4 years 7 months 18 days
Options Outstanding, Weighted-Average Exercise Price	$ 2.95
Options Exercisable, Number of Shares	1,195
Options Exercisable, Weighted-Average Exercise Price	$ 2.95
Exercise Price Range 10.39
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, maximum	$ 10.39
Number of shares	3,500
Options Outstanding, Weighted-Average Remaining Contractual Term	5 years 6 months 22 days
Options Outstanding, Weighted-Average Exercise Price	$ 10.39
Options Exercisable, Number of Shares	1,458
Options Exercisable, Weighted-Average Exercise Price	$ 10.39
Exercise Price Range 15.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Exercise Price, maximum	$ 15.00
Number of shares	1,200
Options Outstanding, Weighted-Average Remaining Contractual Term	5 years 9 months 20 days
Options Outstanding, Weighted-Average Exercise Price	$ 15.00
Options Exercisable, Number of Shares	108
Options Exercisable, Weighted-Average Exercise Price	$ 15.00