Employee Stock and Benefit Plans (Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 06, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Options
Options Outstanding, Number of Shares [Roll Forward]
Number of shares, beginning balance		6,076,000	5,861,000	5,517,000
Number of shares, Options granted at common stock price		2,339,000	993,000	1,230,000
Number of shares, options canceled as part of stock option exchange				(1,961,000)
Number of shares, Options granted as part of stock option exchange				1,961,000
Number of shares, Options exercised		0	(21,000)	(90,000)
Number of shares, Options cancelled		(1,087,000)	(757,000)	(796,000)
Number of shares, ending balance		7,328,000	6,076,000	5,861,000	5,517,000
Number of shares, Exercisable		4,078,000
Number of shares, Vested and expected to vest		6,260,000
Options Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, beginning balance (in dollars per share)		$ 5.47	$ 5.73	$ 7.58
Weighted average exercise price, Options granted at common stock price (in dollars per share)		3.17	4.29	4.50
Share-based Compensation Arrangement by Share-based Payment Award, Options, Canceled in Period, Weighted Average Exercise Price, Stock Option Exchange				8.11
Share-based Compensation Arrangement by Share-based Payment Award, Options, Granted in Period, Weighted Average Exercise Price, Stock Option Exchange				4.73
Weighted average exercise price, Options exercised (in dollars per share)		0.00	3.51	3.69
Weighted average exercise price, Options canceled (in dollars per share)		6.68	6.00	8.81
Weighted average exercise price, ending balance (in dollars per share)		4.56	5.47	5.73	$ 7.58
Weighted average exercise price, exercisable (in dollars per share)		5.35
Weighted average exercise price, vested and expected to vest (in dollars per share)		4.73
Weighted Average Fair Value Grant
Weighted average fair value grant, Options granted at common stock prrice (in dollars per share)		$ 1.01	$ 1.51	$ 1.51
Options, Additional Information
Weighted average remaining contractual life, outstanding		5 years
Weighted average remaining contractual life, exercisable		4 years 2 months 9 days
Weighted average remaining contractual life, vested and expected to vest		4 years 9 months 21 days
Intrinsic value, options exercised		$ 0	$ 0	$ 0
Market Based Stock Options
Options Outstanding, Number of Shares [Roll Forward]
Number of shares, Options granted at common stock price				400,000	200,000
Stock Option Exchange Program | Stock Options
Options Outstanding, Number of Shares [Roll Forward]
Number of shares, Options granted at common stock price		2,000,000
Options Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, Options granted at common stock price (in dollars per share)	$ 4.73
Weighted Average Fair Value Grant
Weighted average fair value grant, Options granted at common stock prrice (in dollars per share)				$ 0.74