Long-term Debt - Schedule of Interest Expense Related to Notes (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Amortization of Issuance Costs		$ 5,084	$ 0
Convertible Debt
Debt Instrument [Line Items]
Contractual Interest Expense	$ 1,218	3,656
Amortization of Issuance Costs	1,744	4,656
Total interest expense	2,962	8,312
Convertible Senior Notes due 2025 | Convertible Debt
Debt Instrument [Line Items]
Contractual Interest Expense	1,218	3,656
Amortization of Issuance Costs	744	2,224
Total interest expense	1,962	5,880
Convertible Senior Notes due 2027 | Convertible Debt
Debt Instrument [Line Items]
Contractual Interest Expense	0	0
Amortization of Issuance Costs	1,000	2,432
Total interest expense	1,000	2,432
Secured Notes Due Twenty Twenty Eight
Debt Instrument [Line Items]
Contractual Interest Expense	7,656	9,017
Amortization of Issuance Costs	363	428
Total interest expense	$ 8,019	$ 9,445