Fair Value of Financial Instruments - Fair Value of Financial Instruments (Parenthetical) (Detail) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
MidCap Credit Facility
Fair Value Of Financial Instruments [Line Items]
Note payable, percentage of hypothetical yield	12.5	12
Note payable, percentage of interest rate increases (decreases)	2.00%	2.00%
MidCap Credit Facility | Minimum
Fair Value Of Financial Instruments [Line Items]
Financial liabilities fair value	$ 39.4	$ 40.0
MidCap Credit Facility | Maximum
Fair Value Of Financial Instruments [Line Items]
Financial liabilities fair value	$ 40.7	$ 42.4
Mann Group Convertible Note
Fair Value Of Financial Instruments [Line Items]
Note payable, percentage of hypothetical yield	13.5	13
Note payable, percentage of interest rate increases (decreases)	2.00%	2.00%
Mann Group Convertible Note | Volatility
Fair Value Of Financial Instruments [Line Items]
Note payable, percentage of volatility	60.9	77.8
Mann Group Convertible Note | Minimum
Fair Value Of Financial Instruments [Line Items]
Financial liabilities fair value	$ 15.6	$ 20.5
Mann Group Convertible Note | Maximum
Fair Value Of Financial Instruments [Line Items]
Financial liabilities fair value	$ 16.1	$ 21.2
Senior Convertible Notes
Fair Value Of Financial Instruments [Line Items]
Note payable, percentage of hypothetical yield	11	13
Note payable, percentage of interest rate increases (decreases)	2.00%	2.00%
Senior Convertible Notes | Volatility
Fair Value Of Financial Instruments [Line Items]
Note payable, percentage of volatility	61.8	75.8
Senior Convertible Notes | Minimum
Fair Value Of Financial Instruments [Line Items]
Financial liabilities fair value	$ 229.4	$ 245.0
Senior Convertible Notes | Maximum
Fair Value Of Financial Instruments [Line Items]
Financial liabilities fair value	$ 245.7	$ 263.4
Financing Liability
Fair Value Of Financial Instruments [Line Items]
Note payable, percentage of hypothetical yield	10.5	10