Fair Value Measurement (Debt Instruments) (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt instruments, fair value	$ 225,657	$ 233,841
Debt instruments, carrying value	140,256	148,932
Convertible Notes
Debt instruments, fair value	91,031	92,338
Debt instruments, carrying value	16,545	16,545
Sensipar Notes
Debt instruments, fair value	47,406	54,097
Debt instruments, carrying value	47,580	54,395
rhPTH 1-84-Secured Debt
Debt instruments, fair value	52,028	50,058
Debt instruments, carrying value	42,790	42,790
Regpara-Secured Debt
Debt instruments, fair value	35,192	37,348
Debt instruments, carrying value	$ 33,341	$ 35,202