Stock-based compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2025	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)		0	0	0	0
Exercised (in shares)		0		0
Aggregate intrinsic value of stock options exercised			$ 100		$ 300
Fair value of stock options vested		$ 300	1,000	$ 1,000	1,700
Total stock-based compensation expense		3,542	4,016	7,592	7,106
Share-based compensation capitalized		100	$ 100	100	$ 100
Unrecognized compensation expense		$ 20,600		$ 20,600
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period (in years)				10 years
Vesting period				48 months
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum shares that may be issued (in shares)		4,333,333		4,333,333
Maximum shares that may be issued, annual increase, period (in years)				10 years
Maximum number of shares that may be issued, annual increase percentage				5.00%
Increase in common stock available for future issuance (in shares)	1,791,393
Shares available for future grants (in shares)		2,224,900		2,224,900
Stock Options - New Employees | 2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period (in years)				10 years
Vesting period				4 years
Stock Options - New Employees | 2011 Plan | Vesting Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year
Vesting percentage				25.00%
Stock Options - New Employees | 2011 Plan | Vesting Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				36 months
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of restricted stock units granted (in dollars per share)		$ 2.66	$ 5.55	$ 2.96	$ 5.86
Grant date fair value of restricted stock units vested		$ 4,200	$ 3,900	$ 7,100	$ 5,800
Restricted stock units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Restricted stock units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Restricted stock units | 2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Vesting percentage				25.00%
RSU, Initial Awards | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
RSU, Annual Awards | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum shares that may be issued (in shares)		2,329,934		2,329,934
Maximum number of shares that may be issued, annual increase percentage				1.00%
Increase in common stock available for future issuance (in shares)	358,279
Annual increase in number of shares that may be issued, term (in years)				10 years
Maximum number of shares that may be issued, annual increase (in shares)				400,000
Maximum percentage of eligible compensation		15.00%		15.00%
Purchase price percentage				85.00%
Common stock shares purchased for issuance under award plan (in shares)		0	0	0	0
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense		$ 0	$ 200	$ 100	$ 300
Unrecognized compensation expense, weighted-average period for recognition				2 years 2 months 12 days