Fair Value Measurements - Fair Value Inputs, Liabilities, Quantitative Information (Details) (Contingent Consideration, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration liability	1,886	2,526	$ 6,697
Revenue-based Payments
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration liability	1,610	2,282
Revenue-based Payments | Income Approach Valuation Technique | Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probability of milestone payment	90.00%	90.00%
Revenue-based Payments | Minimum | Income Approach Valuation Technique | Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	1.00%	11.00%
Revenue-based Payments | Maximum | Income Approach Valuation Technique | Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	14.00%	15.00%
Other Payments
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration liability	276	244
Other Payments | Income Approach Valuation Technique | Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	5.00%	5.40%
Probability of milestone payment	100.00%	100.00%