Notes Payable - Schedule of Notes Payable (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Convertible Notes Payable [Abstract]
Notes, par value	$ 575,000
Less: debt discount, net of amortization	(160,223)
Convertible senior notes, net	414,777		0
Equity	$ 152,061	[1]

[1] Included in the consolidated balance sheets within additional paid-in capital.