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Term Loan - Additional Information (Detail) - Silicon Valley Bank [Member] - Term Loans [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 18, 2019	Aug. 31, 2018
Debt Instrument [Line Items]
Loan agreement, description			Contemporaneously with executing the Loan Agreement, the Company drew down $5.0 million.
Interest expense	$ 0.0	$ 0.1	$ 0.0	$ 0.4
Warrants to Purchase Common Stock [Member]
Debt Instrument [Line Items]
Warrants issued in connection with loan			1,839
Excercise price of warrants or rights	$ 74.80		$ 74.80
Warrant expiration date						Aug. 21, 2028
Tranche One [Member]
Debt Instrument [Line Items]
Aggregate principal amount of loans					$ 5.0
Amount borrowed	$ 5.0		$ 5.0