Income Taxes - Rate reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Rate reconciliation
Federal tax benefit at statutory rate	(21.00%)	(21.00%)	(21.00%)
State rate, net of federal benefit	(2.00%)	3.10%	3.10%
Permanent differences	(0.90%)	(0.70%)	(0.60%)
Research and development	0.00%	0.40%	0.00%
Change in valuation allowance	(15.00%)	(23.40%)	(23.40%)
Stock compensation true-up	(3.10%)	0.00%	0.00%
Other	0.40%	(0.40%)	(0.10%)
Total tax provision	0.40%	0.00%	0.00%