Line of Credit (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument
Outstanding amount	$ 313,458,000	$ 236,288,000
Line of Credit Agreement
Debt Instrument
Maximum borrowing capacity	$ 50,000,000.0
Borrowing option - percentage of eligible monthly royalty payments	85.00%
Basis for variable rate	5.50%
Debt termination fee	$ 1,000,000.0
Payment of initial commitment fee	150,000
Additional commitment fees payable each of the first and second anniversaries of the closing date	150,000
Outstanding amount	$ 0	$ 0