Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands			1 Months Ended		45 Months Ended
	Jan. 08, 2021	Jul. 04, 2017	Jun. 30, 2020	Apr. 30, 2019	Mar. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Net proceeds from sales to an equity line financing				$ 4,415
Net proceeds from issuance of private placement				23,825
Proceeds from exercise of stock options		$ 552
Proceeds from collaboration agreement		34,910
Cash, cash equivalents and investments					$ 63,351
Accumulated deficit					(226,267)	$ (219,292)
Common Stock [Member]
Class of Stock [Line Items]
Net proceeds from issuance of offerings			$ 10,246		$ 50,009
Common Stock [Member] | Direct Public Offering [Member]
Class of Stock [Line Items]
Proceeds from sales of stock	$ 33,091
Common Stock [Member] | At The Market Offering [Member]
Class of Stock [Line Items]
Net proceeds from issuance of offerings				$ 23,881
Preferred Stock [Member]
Class of Stock [Line Items]
Proceeds from sales of stock		$ 131,211