Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued expenses:
Accounts Payable	$ 47,429	$ 11,412
Professional fees	1,835	1,236
Salaries, bonus and related benefits	8,809	6,701
Research and development	7,932	5,007
Research and development - manufacturing	0	518
Research and development - license maintenance fees	4,640	461
Research and development - milestones	850	600
Accrued royalties payable	3,833	2,682
Accrued coupon expense	10,603	12,869
Income taxes payable	0	136
Return reserve	3,240	2,580
Other	1,489	1,187
Total accounts payable and accrued expenses	$ 90,660	$ 45,389