Fair Value of Financial Instruments - Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Carrying Amount | MidCap Credit Facility
Financial liabilities:
Total financial liabilities fair value	$ 37,921	$ 39,264
Carrying Amount | Senior Convertible Notes
Financial liabilities:
Total financial liabilities fair value	226,487	225,397
Carrying Amount | Mann Group Convertible Note
Financial liabilities:
Total financial liabilities fair value	8,829	8,829
Carrying Amount | Milestone Rights Liability
Financial liabilities:
Total financial liabilities fair value	3,914	4,838
Carrying Amount | Contingent Milestone Liability
Financial liabilities:
Total financial liabilities fair value	610	610
Carrying Amount | Financing Liability
Financial liabilities:
Total financial liabilities fair value	104,122	104,077
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | MidCap Credit Facility
Financial liabilities:
Total financial liabilities fair value	40,032	41,070
Estimate of Fair Value Measurement | Senior Convertible Notes | Fair Value, Inputs, Level 3
Financial liabilities:
Total financial liabilities fair value	237,293	253,864
Estimate of Fair Value Measurement | Mann Group Convertible Note | Fair Value, Inputs, Level 3
Financial liabilities:
Total financial liabilities fair value	15,857	20,836
Estimate of Fair Value Measurement | Milestone Rights Liability | Fair Value, Inputs, Level 3
Financial liabilities:
Total financial liabilities fair value	11,700	12,600
Estimate of Fair Value Measurement | Contingent Milestone Liability | Fair Value, Inputs, Level 3
Financial liabilities:
Total financial liabilities fair value	610	960
Estimate of Fair Value Measurement | Financing Liability | Fair Value, Inputs, Level 3
Financial liabilities:
Total financial liabilities fair value	$ 99,940	$ 103,239