4. Fair Value Measurement (Debt Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt instruments, fair value	$ 230,249	$ 228,535
Debt instruments, carrying value	268,553	269,419
4.25% Convertible Notes
Debt instruments, fair value	37,473	36,208
Debt instruments, carrying value	66,928	65,194
Exchangeable Notes
Debt instruments, fair value	21,207	21,375
Debt instruments, carrying value	9,016	7,975
Delayed Draw Term Loan
Debt instruments, fair value	30,601	30,300
Debt instruments, carrying value	28,183	27,248
Derivative Liability
Debt instruments, fair value	72	93
Debt instruments, carrying value	72	93
Contingent Consideration
Debt instruments, fair value	1,501	1,358
Debt instruments, carrying value	1,501	1,358
Treximet Secured Notes
Debt instruments, fair value	139,395	139,201
Debt instruments, carrying value	$ 162,853	$ 167,551