Financings - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			6 Months Ended
	Mar. 10, 2020	Feb. 05, 2020	Jun. 30, 2021	Jun. 30, 2020
Class of Stock [Line Items]
Sale of stock consideration received on transaction			$ 0	$ 88,661
At The Market Offering [Member]
Class of Stock [Line Items]
Stock issued during period			0	2,814,673
Sale of stock consideration received on transaction				$ 13,000
par value per share				$ 4.77
Underwriting Agreement [Member]
Class of Stock [Line Items]
Stock issued during period		27,826,086
Issuance & sale of common stock in public offering price per share		$ 3.25
Sale of stock consideration received on transaction		$ 84,800
par value per share		$ 3.055
Underwriting Agreement [Member] | Stock Option [Member]
Class of Stock [Line Items]
Stock issued during period	1,284,025
Sale of stock consideration received on transaction	$ 3,900