Liability Related to the Revenue Interest Purchase Agreement - Summary (Details) - USD ($)		1 Months Ended		12 Months Ended
	Jun. 26, 2019	Mar. 31, 2020	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Liability Related to the Revenue Interest Purchase Agreement
Proceeds from revenue interest liability, net of issuance costs				$ 25,000,000	$ 124,424,000	$ 0
Revenue Interest Purchase Agreement (RIPA)
Liability Related to the Revenue Interest Purchase Agreement
Revenue interest liability				176,604,000	132,544,000
Revenue interest payments				500,000
Interest expense recognized				19,560,000	$ 8,100,000
Revenue Interest Purchase Agreement (RIPA) | Oberland
Liability Related to the Revenue Interest Purchase Agreement
Proceeds from revenue interest liability	$ 125,000,000.0
Total amount of subsequent installment, subject to RIPA terms and conditions	75,000,000.0
Amount of subsequent installment, subject to regulatory approval	25,000,000.0
Amount of subsequent installment, subject to achievement of Sales Threshold	50,000,000.0
Milestone amount for worldwide sales to receive the Third Payment	$ 100,000,000.0
Trailing number of months sales must be at or above milestone amount	6 months
Revenue interest rate which will take effect if annual net sales equals or exceeds the Sales Threshold by December 31, 2021	2.50%
Initial revenue interest rate	7.50%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	$ 350,000,000.0
Percentage of invested capital received by December 31, 2024, to qualify for second reduced revenue interest rate	100.00%
Revenue interest rate if annual net sales equal or exceed the Sales Threshold and if the Purchasers receive 100% of their invested capital by December 31, 2024	0.40%
Percentage of increase in royalty rate upon drawdown of third payment	33.33%
Percentage of revenue interests payment on which agreement terminates	195.00%
Percentage of revenue interests payment on which agreement terminates, if prior to the anniversary of the closing date, if put option is exercised	120.00%
Percentage of revenue interests payment on which agreement terminates, prior to the third anniversary of the closing date, if put option is exercised	175.00%
Percentage of revenue interests payment on which agreement terminates, after the third anniversary of the closing date, if put option is exercised	195.00%
Revenue interest payments			$ 600,000
Repayment amount expected to pay in next twelve months				$ 5,400,000
Proceeds from revenue interest liability, net of issuance costs		$ 25,000,000.0
Effective annual imputed interest rate (as a percent)	10.60%
Revenue Interest Purchase Agreement (RIPA) | Oberland | Net Sales Less Than $250 Million
Liability Related to the Revenue Interest Purchase Agreement
Initial revenue interest rate	7.50%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	$ 250,000,000
Hypothetical sales generated	100,000,000
Hypothetical repayment obligation	$ 7,500,000
Revenue Interest Purchase Agreement (RIPA) | Oberland | Net Sales Greater Than $250 Million But Less Than $350 Million
Liability Related to the Revenue Interest Purchase Agreement
Revenue interest rate which will take effect if annual net sales equals or exceeds the Sales Threshold by December 31, 2021	2.50%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	$ 250,000,000
Hypothetical sales generated	100,000,000
Hypothetical repayment obligation	2,500,000
Revenue Interest Purchase Agreement (RIPA) | Oberland | Net Sales Greater Than $350 Million
Liability Related to the Revenue Interest Purchase Agreement
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	350,000,000
Hypothetical sales generated	100,000,000
Hypothetical repayment obligation	$ 2,500,000