Fair Value Measurements - Summary of Reconciliation of Beginning and Ending Balances for Liabilities Measured at Fair Value on Recurring Basis (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Derivative liabilities
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 5,954
Adjustment for partial conversion of April 2020 Notes	(3,426)
Gain (loss) adjustment to fair value	(1,170)
Ending balance	1,358
Warrant liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	51,156
Loan agreement warrants	362
Gain (loss) adjustment to fair value	(30,365)
Settlement for December 2020 Public Offering - Series 1 warrant exercises	(2,841)
Settlement for December 2019 Public Offering warrant exercises	(250)
Ending balance	$ 18,062