Stock-Based Compensation and Employee Benefit Plans (Restricted Stock Unit Activity) (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Number of RSUs
Unvested beginning balance (in shares) | shares	3,888,768
RSUs and PRSUs granted (in shares) | shares	2,074,077
RSUs vested (in shares) | shares	(770,664)
RSUs forfeited/expired (in shares) | shares	(1,849,541)
Unvested ending balance (in shares) | shares	3,342,640
Expected to vest after December 31, 2017 (in shares) | shares	2,843,933
Weighted-Average Grant Date Fair Value
Unvested, beginning balance (in dollars per share) | $ / shares	$ 8.46
RSUs and PRSUs granted (in dollars per share) | $ / shares	4.63
RSUs vested (in dollars per share) | $ / shares	8.50
RSUs forfeited/expired (in dollars per share) | $ / shares	7.84
Unvested, ending balance (in dollars per share) | $ / shares	6.18
Expected to vest after December 31, 2017 (in dollars per share) | $ / shares	$ 6.31