Stockholders' Equity - Stock Options Additional Disclosures (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Number of Shares | shares	8,443
Options Outstanding, Weighted Average Remaining Contractual Term	3 years 7 months 25 days
Options Outstanding, Weighted Average Exercise Price	$ 7.10
Options Exercisable, Number of Shares | shares	6,250
Options Exercisable, Weighted Average Exercise Price	$ 5.19
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 | shares	446
Options Outstanding, Weighted Average Remaining Contractual Term	6 months 25 days
Options Outstanding, Weighted Average Exercise Price	$ 0.11
Options Exercisable, Number of Shares | shares	446
Options Exercisable, Weighted Average Exercise Price	$ 0.11
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 | shares	1,182
Options Outstanding, Weighted Average Remaining Contractual Term	1 year 5 months 20 days
Options Outstanding, Weighted Average Exercise Price	$ 0.32
Options Exercisable, Number of Shares | shares	1,182
Options Exercisable, Weighted Average Exercise Price	$ 0.32
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 | shares	968
Options Outstanding, Weighted Average Remaining Contractual Term	3 years 10 days
Options Outstanding, Weighted Average Exercise Price	$ 1.85
Options Exercisable, Number of Shares | shares	968
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 | shares	1,147
Options Outstanding, Weighted Average Remaining Contractual Term	3 years 7 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 2.95
Options Exercisable, Number of Shares | shares	1,147
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 | shares	3,500
Options Outstanding, Weighted Average Remaining Contractual Term	4 years 6 months 22 days
Options Outstanding, Weighted Average Exercise Price	$ 10.39
Options Exercisable, Number of Shares | shares	2,334
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 | shares	1,200
Options Outstanding, Weighted Average Remaining Contractual Term	4 years 9 months 20 days
Options Outstanding, Weighted Average Exercise Price	$ 15.00
Options Exercisable, Number of Shares | shares	173
Options Exercisable, Weighted Average Exercise Price	$ 15.00