Basis of Presentation and Summary of Significant Accounting Policies (Details 4) (USD $)					3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2013 Sales Revenue, Net Revenue Concentration Risk AmerisourceBergen Drug Corporation.	Mar. 31, 2012 Sales Revenue, Net Revenue Concentration Risk AmerisourceBergen Drug Corporation.	Mar. 31, 2013 Sales Revenue, Net Revenue Concentration Risk McKesson Corporation	Mar. 31, 2012 Sales Revenue, Net Revenue Concentration Risk McKesson Corporation	Mar. 31, 2013 Sales Revenue, Net Revenue Concentration Risk Cardinal Health, Inc	Mar. 31, 2012 Sales Revenue, Net Revenue Concentration Risk Cardinal Health, Inc	Mar. 31, 2013 Sales Revenue, Net Revenue Concentration Risk Takeda Pharmaceutical Company Limited (outside the U.S.)	Mar. 31, 2012 Sales Revenue, Net Revenue Concentration Risk Takeda Pharmaceutical Company Limited (outside the U.S.)	Mar. 31, 2013 Sales Revenue, Net Revenue Concentration Risk GPO	Mar. 31, 2012 Sales Revenue, Net Revenue Concentration Risk GPO	Mar. 31, 2013 Sales Revenue, Net Geographical Concentration Risk	Mar. 31, 2012 Sales Revenue, Net Geographical Concentration Risk
Investment Concentration Risk
Cash, cash equivalents and investments	$ 217,100,000
Investment in institutional money market funds	21,500,000
Cash and cash equivalents	33,845,000	46,293,000	37,619,000	63,474,000
Amount invested in a single money market fund collateralized by U.S. treasury and government agency securities	$ 13,500,000
Customers representing 10% or more of revenues
Percentage of revenues from major customer					43.00%	45.00%	22.00%	20.00%	15.00%	15.00%	12.00%	11.00%	30.00%	35.00%
Percentage of revenues From customers outside of the U.S.
Approximate percentage of revenues from customers outside the U.S.															12.00%	11.00%