Fair Value Measurements - Fair Value Inputs, Liabilities, Quantitative Information (Details) (Contingent Consideration, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration liability	1,842	$ 1,886	$ 2,513	$ 2,526
Revenue-based Payments
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration liability	1,697
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%
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%
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%
Other Payments
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration liability	145
Other Payments | Income Approach Valuation Technique | Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	5.00%
Probability of milestone payment	100.00%