Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Number of shares
Outstanding as at beginning of period (in shares)		5,768,028
Granted (in shares)		3,132,140
Exercised (in shares)	(135,525)	(108,459)
Forfeited (in shares)		(461,761)
Outstanding as at end of period (in shares)		8,329,948	5,768,028
Options vested and exercisable as at end of period (in shares)		2,913,655
Options expected to vest as at end of period (in shares)		5,416,293
Weighted Average Exercise Price
Outstanding as at beginning of period (in dollars per share)		$ 15.99
Granted (in dollars per share)		6.57
Exercised (in dollars per share)		2.71
Forfeited (in dollars per share)		22.32
Outstanding at end of period (in dollars per share)		12.23	$ 15.99
Options vested and exercisable as at end of period (in dollars per share)		14.20
Options expected to vest as at end of period (in dollars per share)		$ 11.17
Weighted Average Remaining Contractual Life
Weighted Average Remaining Contractual Life of outstanding options (in years)		8 years 5 months 23 days	8 years 9 months 25 days
Weighted Average Remaining Contractual Life of vested and exercisable options (in years)		7 years 10 months 9 days
Weighted Average Remaining Contractual Life of expected to vest options (in years)		8 years 9 months 21 days
Intrinsic Value of outstanding options		$ 353	$ 11,365
Intrinsic Value of vested and exercisable options		271
Intrinsic Value of expected to vest options		$ 82
Unvested early exercised stock options		25,629		25,629
Number of shares vested		109,896