Financings - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Mar. 10, 2020	Feb. 05, 2020	Mar. 31, 2020	Mar. 31, 2019
Class of Stock [Line Items]
Sale of stock consideration received on transaction			$ 88,661
At The Market Offering [Member]
Class of Stock [Line Items]
Stock issued during period			2,814,673	0
Sale of stock consideration received on transaction			$ 13,000
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] | Maximum
Class of Stock [Line Items]
Stock issued during period		4,173,912
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