Stock-based compensation - Narrative (Details) $ in Millions			1 Months Ended		12 Months Ended
	Jan. 01, 2021 shares	Dec. 28, 2015 shares	Jul. 31, 2023 shares	Sep. 30, 2020 period shares	Dec. 31, 2023 USD ($) shares	Jan. 01, 2024 shares	Feb. 28, 2023 shares	Jan. 31, 2023 shares	Dec. 31, 2022 shares	Feb. 28, 2022 shares	Jan. 31, 2022 shares	Jan. 01, 2022 shares	Oct. 31, 2020 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized					150,000,000				150,000,000				150,000,000
Common stock, shares outstanding					60,467,188				48,966,216
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs | $					$ 3.1
Expected to be recognized over a weighted average period					1 year 2 months 12 days
Stock-based compensation, shares authorized for issuance										563,500	563,500
Share-based compensation, number of common stock issuable per RSU vested					1
Time-Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs | $					$ 3.5
Expected to be recognized over a weighted average period					3 years 2 months 12 days
Stock-based compensation, shares authorized for issuance							824,600	824,600
Share-based compensation, number of common stock issuable per RSU vested					1
Employee Stock Option | Share-Based Payment Arrangement, Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, shares authorized for issuance			351,000
Stock-based compensation, options vesting description			four years
Options outstanding (in shares)					351,000
Employee Stock Option | Share-Based Payment Arrangement, Employee | Share-Based Payment Arrangement, Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, options vesting description			one year
Employee Stock Option | Share-Based Payment Arrangement, Employee | Share-Based Payment Arrangement, Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, options vesting description			P3M
2015 Incentive Stock Option and Grant Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance		2,525,327
Cliff vesting period		1 year
Contractual life of options from the date of grant		10 years
Common stock shares available for issuance					3,358,336
2015 Incentive Stock Option and Grant Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period		5 years
2015 Incentive Stock Option and Grant Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period		8 years
2020 Stock Option and Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance				6,567,144
Common stock shares available for issuance					3,358,336
Percentage of outstanding shares of common stock	5.00%
Unrecognized compensation costs | $					$ 51.6
Expected to be recognized over a weighted average period					2 years 1 month 6 days
Options outstanding (in shares)					9,475,009				6,993,052
2020 Stock Option and Incentive Plan | Subsequent event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized						3,023,359
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance					1,673,129
Percentage of outstanding shares of common stock	1.00%
Common stock, shares authorized												604,671
Maximum authorized payroll deduction percentage of eligible compensation for eligible employees				15.00%
Number of annual offering periods (or more) | period				1
Shares issued under employee stock purchase plan (in shares)					133,784
Common stock, shares outstanding	656,714