Summary of Significant Accounting Policies (Details 4) (USD $)					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Sales Revenue, Net Revenue Concentration Risk AmerisourceBergen Drug Corporation.	Dec. 31, 2012 Sales Revenue, Net Revenue Concentration Risk AmerisourceBergen Drug Corporation.	Dec. 31, 2011 Sales Revenue, Net Revenue Concentration Risk AmerisourceBergen Drug Corporation.	Dec. 31, 2013 Sales Revenue, Net Revenue Concentration Risk McKesson Corporation	Dec. 31, 2012 Sales Revenue, Net Revenue Concentration Risk McKesson Corporation	Dec. 31, 2011 Sales Revenue, Net Revenue Concentration Risk McKesson Corporation	Dec. 31, 2013 Sales Revenue, Net Revenue Concentration Risk Cardinal Health, Inc	Dec. 31, 2012 Sales Revenue, Net Revenue Concentration Risk Cardinal Health, Inc	Dec. 31, 2011 Sales Revenue, Net Revenue Concentration Risk Cardinal Health, Inc	Dec. 31, 2013 Sales Revenue, Net Revenue Concentration Risk Takeda Pharmaceutical Company Limited (outside the U.S.)	Dec. 31, 2012 Sales Revenue, Net Revenue Concentration Risk Takeda Pharmaceutical Company Limited (outside the U.S.)	Dec. 31, 2011 Sales Revenue, Net Revenue Concentration Risk Takeda Pharmaceutical Company Limited (outside the U.S.)	Dec. 31, 2013 Sales Revenue, Net Revenue Concentration Risk GPO	Dec. 31, 2012 Sales Revenue, Net Revenue Concentration Risk GPO	Dec. 31, 2011 Sales Revenue, Net Revenue Concentration Risk GPO	Dec. 31, 2013 Sales Revenue, Net Geographical Concentration Risk	Dec. 31, 2012 Sales Revenue, Net Geographical Concentration Risk	Dec. 31, 2011 Sales Revenue, Net Geographical Concentration Risk
Investment Concentration Risk
Cash, cash equivalents and investments	$ 213,800,000
Investment in institutional money market funds	18,800,000
Cash and cash equivalents	26,986,000	46,293,000	63,474,000	112,646,000
Amount invested in a single money market fund collateralized by U.S. treasury and government agency securities	$ 12,200,000
Customers representing 10% or more of revenues
Percentage of revenues from major customer					41.00%	34.00%	41.00%	24.00%	17.00%	21.00%	16.00%	12.00%	13.00%	11.00%	31.00%	13.00%	30.00%	32.00%	35.00%
Percentage of revenues From customers outside of the U.S.
Approximate percentage of revenues from customers outside the U.S.																				11.00%	32.00%	14.00%