Stock-based compensation (Schedule of stock option activity) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2025 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of options, Outstanding, beginning of year | shares	1,185,000
Number of options, Granted | shares	825,000
Number of options, exercised | shares	(145,000)
Number of options, Forfeited | shares	(7,500)
Number of options, Outstanding, end of year | shares	1,857,500	1,185,000
Number of options, Exercisable, end of year | shares	1,132,500
Number of options, Unvested | shares	725,000
Weighted- average exercise price beginning of year | $ / shares	$ 1.47
Weighted average exercise price, Granted | $ / shares	2.99
Weighted average exercise price, exercised | $ / shares	1.11
Weighted average exercise price, Forfeited | $ / shares	2.76
Weighted-average exercise price end of year | $ / shares	2.17	$ 1.47
Stock options Exercisable, Weighted-average exercise price end of year | $ / shares	1.61
Stock options Unvested, Weighted average exercise price | $ / shares	$ 3.04
Stock options, Granted, Weighted average remaining contractual life (years)	4 years 9 months 21 days
Stock options, Outstanding, Weighted average remaining contractual life (years)	4 years 21 days	4 years 2 months 4 days
Stock options, Exercisable, Weighted average remaining contractual life (years)	3 years 6 months 25 days
Unvested, Weighted average remaining contractual life (years)	4 years 2 months 4 days
Stock options, Outstanding, Aggregate intrinsic value | $	$ 0.15	$ 1.18
Stock options, Exercisable, Aggregate intrinsic value | $	0.71
Stock options, Unvested, Aggregate intrinsic value | $	$ 0