Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on A Recurring Basis (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent receivable	$ 10,100
Total assets	59,762	$ 39,530
Contingent consideration liabilities(1)	16,300
Total liabilities	18,253
Contingent liabilities assumed	12,600
CVRs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchase price	3,700
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent receivable	0
Total assets	49,662	39,530
Contingent consideration liabilities(1)	0
Total liabilities	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent receivable	0
Total assets	0	0
Contingent consideration liabilities(1)	0
Total liabilities	1,953
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent receivable	10,100
Total assets	10,100	0
Contingent consideration liabilities(1)	16,300
Total liabilities	16,300
Level 3 | CVRs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liabilities(1)	3,700
Interest Rate Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	1,953
Interest Rate Swaps | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	0
Interest Rate Swaps | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	1,953
Interest Rate Swaps | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	0
Money market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	49,662	39,530
Money market | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	49,662	39,530
Money market | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	0	0
Money market | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	$ 0	$ 0