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Term Loan - Additional Information (Detail) - Silicon Valley Bank [Member] - Term Loans [Member] - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2018
Debt Instrument [Line Items]
Loan agreement, description		Contemporaneously with executing the Loan Agreement, the Company drew down the first $5.0 million tranche.
Interest expense		$ 0.0	$ 0.9	$ 0.2
Prepayment Fee [Member]
Debt Instrument [Line Items]
Payment of fees	$ 0.1
Final Payment Fee [Member]
Debt Instrument [Line Items]
Payment of fees	0.3
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
Warrant expiration date					Aug. 21, 2028
Tranche One [Member]
Debt Instrument [Line Items]
Aggregate principal amount of loans	$ 5.0