Fair Value of Financial Instruments - Summary of Conclusions Reached Regarding Fair Value Measurements (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Balance at January 1	$ 2,871	$ 2,601
Net Change in fair value included in earnings	1,648	363
Balance at March 31,	4,519	2,964
Significant Unobservable Inputs (Level 3) [Member] | Warrant Liability, Related Party [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Balance at January 1	2,871	2,601
Net Change in fair value included in earnings	1,648	363
Balance at March 31,	4,519	$ 2,964
Fair Value, Measurements, Recurring [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Total	4,519		$ 2,871
Fair Value, Measurements, Recurring [Member] | Warrant Liability, Related Party [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Total	4,519		2,871
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Total	4,519		2,871
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Warrant Liability, Related Party [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Total	$ 4,519		$ 2,871