Net loss per share attributable to common stockholders - Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net loss attributable to common stockholders	$ (57,395)	$ (60,517)	$ (158,375)	$ (166,748)
Denominator:
Weighted average shares used in computing net loss per share, basic (in shares)	57,041	56,287	56,753	53,005
Weighted average shares used in computing net loss per share, diluted (in shares)	57,041	56,287	56,753	53,005
Net loss per share attributable to common stockholders—basic (in usd per share)	$ (1.01)	$ (1.08)	$ (2.79)	$ (3.15)
Net loss per share attributable to common stockholders, diluted (in usd per share)	$ (1.01)	$ (1.08)	$ (2.79)	$ (3.15)