Earnings per share - Summary of Anti-dilutive Shares Excluded from Calculation of Diluted Net Loss per Share (Parenthetical) (Details) - shares	6 Months Ended
	Jun. 30, 2025		Jun. 30, 2024	Dec. 31, 2024		Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share	29,014,362		34,858,928
Common stock outstanding	9,291,697			9,288,868
Common stock issued	9,346,362			9,343,533
Series A Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share	6,669,742		6,704,122
Series A-2 Convertible Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Common stock outstanding	42,019		42,236
Common stock issued	42,019		42,236
Public Warrants [Member] | Warrant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share	575,000
Private Placement Warrants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Warrants Issued	850,119
Outstanding warrants	20,860		20,860	20,860		20,860
Private Placement Warrants [Member] | Warrant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share	20,860
Ladenburg Agreement [Member] | Warrant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share	30,000
PIPE Private Placement Warrants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Warrants Issued	736,337						736,337
Placement Agent Warrants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Warrants Issued	21,091						21,091
Preferred Tranche C Warrants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Outstanding warrants	107,115		107,115	107,115
Common stock issued	17,002,381		17,002,381
Preferred Tranche B Warrants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Outstanding warrants	0	[1]	42,846	42,846	[1]
Common stock issued			6,800,953

[1] On January 1, 2025, 42,846 Preferred Tranche B Warrants expired, unexercised. The Company recognized a gain of $3 thousand in other income in our condensed consolidated statement of operations, representing the fair value of the warrants at expiration. The valuation as of December 31, 2024, was based on a risk-free interest rate of 3.93%, an expected remaining term of 0.23 periods, implied volatility of 75%, and an underlying stock price of $309.37.