Stock-based Compensation Plans and Awards - Stock-based Compensation Expense - Additional Information (Details) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 01, 2014	Aug. 31, 2014	Dec. 31, 2014 USD ($) employee	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jul. 31, 2014
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation included in net loss				$ 7,562	$ 21,815	$ 27,384
Reverse stock split of common stock and treasury stock	0.2	0.2
Stock option exercise price as a percent of trading price of common stock, threshold triggering an adjustment							120.00%
Common Stock
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Reverse stock split of common stock and treasury stock				0.20
Stock options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Capitalized stock-based compensation expense				$ 400	$ 1,000	$ 2,000
Restricted stock units (RSUs)
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of employees affected by modified equity | employee			3
Accelerated compensation cost			$ 3,500