Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Net of underwriting discounts, commissions and offering expenses	$ 18,916	$ 17,210
Series D Redeemable Convertible Preferred Stock [Member]
Issuance of redeemable convertible preferred stock, net of financing cost			$ 339