Warrants - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Warrants and Rights Note Disclosure [Abstract]
Number of warrants exercised	0
Purchase of common stock warrants exercised (in shares)	35,000	3,000	307,000
Number of warrants exercised on cashless basis (in shares)	0		34,000,000
Proceeds from warrant exercises	$ 100	$ 4	$ 343
Shares issued (in shares)			24,000,000