Fair Value Measurement (Details 3) (USD $)	9 Months Ended				9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 2% Senior Convertible Notes Due 2017	Mar. 26, 2007 2% Senior Convertible Notes Due 2017	Sep. 30, 2013 Contingent consideration Regulatory approvals contingency factor, probability adjusted contingent payments	Sep. 30, 2013 Contingent consideration Regulatory approvals contingency factor, expected approval dates	Sep. 30, 2013 Contingent consideration Attainment of future revenue targets contingency factor
Fair Value Inputs, Liabilities, Quantitative Information
Fair value discount rate (as a percent)					13.00%	20.30%	16.00%
Principal balance outstanding			$ 205,000,000
Carrying value of debt	168,467,000	161,793,000	168,500,000
Fair value of debt			440,600,000	148,100,000
Stated interest rate on debt (as a percent)			2.00%	2.00%
Amount of transfers into or out of level 1	0
Amount of transfers into or out of level 2	$ 0