Other (Expense) Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Income and Expenses [Abstract]
Interest income	$ 21,623	$ 13,843	$ 2,864
Interest expense	(18,207)	(13,840)	(134)
Interest expense on nonrecourse liability related to sale of future royalties	(4,500)	(4,271)	(1,434)
Changes in fair value of derivative liabilities	0	0	76
Loss on extinguishment of debt	0	0	(295)
Total	(1,084)	(4,268)	1,077
Amortization of deferred financing costs and debt discount	$ 15,708	$ 11,848	$ 50