Estimated Fair Value of Financial Instruments - Fair Value Measurements and Valuation Techniques (Details) - Fair Value, Recurring - Discounted Cash Flow - Level 3	Jun. 30, 2020 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability related to sale of future royalties	$ 288,693,000
Minimum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Future royalty sale, liability, measurement input	16000.00%
Maximum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Future royalty sale, liability, measurement input	26000.00%
Weighted Average | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Future royalty sale, liability, measurement input	19.00%