4. Fair Value Measurement (Debt Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt instruments, fair value	$ 223,825	$ 228,535
Debt instruments, carrying value	266,377	269,419
4.25% Convertible Notes
Debt instruments, fair value	34,801	36,208
Debt instruments, carrying value	66,054	65,194
Exchangeable Notes
Debt instruments, fair value	20,763	21,375
Debt instruments, carrying value	8,468	7,975
Delayed Draw Term Loan
Debt instruments, fair value	29,833	30,300
Debt instruments, carrying value	27,717	27,248
Derivative Liability
Debt instruments, fair value	112	93
Debt instruments, carrying value	112	93
Contingent Consideration
Debt instruments, fair value	1,621	1,358
Debt instruments, carrying value	1,621	1,358
Treximet Secured Notes
Debt instruments, fair value	136,695	139,201
Debt instruments, carrying value	$ 162,405	$ 167,551