Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended
	Aug. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Class Of Stock [Line Items]
Capital stock authorized for issuance		150,000,000
Common stock, shares authorized		145,000,000	145,000,000
Common stock, par value		$ 0.001	$ 0.001
Preferred stock, shares authorized		5,000,000
Preferred stock, par value		$ 0.001
Common stock, shares outstanding		104,326,672	102,376,000
ATM Agreement
Class Of Stock [Line Items]
Shares issued to institutional investors		0
ATM Agreement | Maximum
Class Of Stock [Line Items]
Common stock shares value reserved for future issuance	$ 250,000,000
Percentage of commission to sales agent	3.00%
2004 Equity Incentive Plan, 2013 Equity Incentive Plan, 2021 Equity Incentive Plan and Inducement Grants
Class Of Stock [Line Items]
Common Stock, Share reserve for issuance		15,228,479