v3.23.1
Income taxes - Schedule of effective income tax rate reconciliation (Details)
12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Income Tax Disclosure [Abstract]      
Tax expense computed at the federal statutory rate 21.00% 21.00% 21.00%
Change in valuation allowance (13.00%) (33.00%) (25.00%)
Research and development credit benefit 4.00% 3.00% 1.00%
Business combination (4.00%) (2.00%) 0.00%
Stock-based compensation (1.00%) 12.00% 3.00%
Change in fair value of contingent consideration and holdbacks (1.00%) 0.00% 0.00%
Gain on deconsolidation of variable interest entity (1.00%) 0.00% 0.00%
Total income tax expense 5.00% 1.00% 0.00%