Takeda Termination and Transition Agreement (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Takeda Termination And Transition Agreement Narrative Details
Shares of Common Stock issued	0	6.1	0
Value of Common Stock issued		$ 54,900,000
Future milestone payment in cash or common stock		30,000,000
Milestone payment trigger amount on worldwide net sales		750,000,000
Assets acquired:
Revestive raw materials		16,600,000
PTH raw materials		17,100,000
Revestive product rights		20,700,000
Estimated useful life of agreement		12 years
Revestive products rights amortization expense	1,800,000	1,400,000
Estimated annual amortization for each of the next five years	$ 1,800,000