Stockholders' equity - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Nov. 14, 2023	Sep. 30, 2026 USD ($) $ / shares shares	Sep. 30, 2025 USD ($) shares	Sep. 30, 2026 USD ($) $ / shares shares	Sep. 30, 2025 USD ($) shares	Feb. 11, 2026 $ / shares	Dec. 31, 2025 $ / shares shares
Class of Warrant or Right [Line Items]
Conversion ratio	0.1
2025 2-Year Warrants
Class of Warrant or Right [Line Items]
Number of warrants exercised (in shares)		6,779,910		6,779,910
Warrants, exercise price (in dollars per share) | $ / shares		$ 6.000		$ 6.000			$ 6.000
Proceeds from warrant exercises | $				$ 40.7
2025 3-Year Warrants
Class of Warrant or Right [Line Items]
Number of warrants exercised (in shares)		664,356		664,356
Warrants, exercise price (in dollars per share) | $ / shares		$ 4.200		$ 4.200			4.200
Proceeds from warrant exercises | $				$ 2.8
Class of warrant or right, warrants exercised (in shares)		1,873
Private Placement Offering Warrants
Class of Warrant or Right [Line Items]
Number of warrants exercised (in shares)		10,008,240		10,008,240
Warrants, exercise price (in dollars per share) | $ / shares		$ 1.0680		$ 1.0680			$ 1.068
Number of securities called by warrants (in shares)		1,000,824		1,000,824
Number of securities called by each warrant (in shares)		0.1		0.1			0.1
Share price, ten day average (in dollars per share) | $ / shares						$ 45.41
Common stock issued (in shares)				765,440
New At-The-Market Offering
Class of Warrant or Right [Line Items]
Number of shares issued (in shares)		0	871,236	1,476,538	979,308
Proceeds from issuance of equity | $		$ 0.0	$ 5.2	$ 35.8	$ 5.5
Shares available for issuance under the plan | $		$ 55.3		$ 55.3