Financing Arrangements (Notes Payable) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Notes Payable, Current and Noncurrent [Abstract]
Net carrying amount	$ 200,567	$ 195,908
Total notes payable	200,567	196,242
2019 convertible senior notes
Notes Payable, Current and Noncurrent [Abstract]
Principal amount outstanding	245,000	245,000
Unamortized discount	(44,433)	(49,092)
Net carrying amount	200,567	195,908
Convertible notes payable, Viking Therapeutics, Inc.
Notes Payable, Current and Noncurrent [Abstract]
Current notes payable	$ 0	$ 334