Stock-based compensation - Plans Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 01, 2023	Jun. 30, 2017	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Feb. 28, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares outstanding (in shares)			12,359,185		12,359,185		10,051,283
Weighted-average grant date fair value of options granted (in dollars per share)					$ 4.88	$ 3.95
Intrinsic vale of options exercised					$ 300
Cash received from the exercise of stock options					$ 427	$ 96
Expected dividend yield			0.00%	0.00%	0.00%	0.00%
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized stock compensation cost			$ 33,900		$ 33,900
Weighted-average amortization period of unrecognized stock compensation cost					2 years
Restricted stock units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized stock compensation cost			$ 21,200		$ 21,200
Weighted-average amortization period of unrecognized stock compensation cost					2 years 10 months 24 days
Restricted stock units | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period					4 years
Restricted stock units | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period					1 year
2017 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Cumulative annual increase in number of shares issuable		4.00%
Additional shares authorized (in shares)	4,205,794
Number of options granted in period (in shares)					4,566,682
Number of shares available for future issuance (in shares)			1,718,690		1,718,690
2017 Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expiration period					10 years
2017 Plan | Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period					4 years
Inducement award program
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of options granted in period (in shares)					677,905
Number of shares available for future issuance (in shares)			664,270		664,270
Number of shares authorized (in shares)								2,000,000
Inducement award prior to inducement award program
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares outstanding (in shares)			757,500		757,500
2017 ESPP | Employee stock purchase plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Additional shares authorized (in shares)	450,000
Number of shares available for future issuance (in shares)			454,531		454,531
Purchase of common stock under ESPP (in shares)					291,260	154,235