Net loss per share attributable to common stockholders - Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss attributable to common stockholders	$ (41,824)	$ (45,563)
Denominator:
Weighted average shares used in computing net loss per share, basic (in shares)	56,444	49,912
Weighted average shares used in computing net loss per share, diluted (in shares)	56,444	49,912
Net loss per share attributable to common stockholders—basic (in usd per share)	$ (0.74)	$ (0.91)
Net loss per share attributable to common stockholders, diluted (in usd per share)	$ (0.74)	$ (0.91)