Spire Global, Inc. Quarterly report [Sections 13 or 15(d)]

Stock-Based Compensation - Schedule of the Stock Based Compensation Expense based on Roles and Responsibilities of the Employees (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2,768	$ 3,830	$ 9,774	$ 14,957
Location, Statement of Income, Balance [Axis]: us-gaap:CostOfRevenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	126	62	380	254
Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,655	2,802	5,821	10,107
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	710	747	2,566	2,409
Location, Statement of Income, Balance [Axis]: us-gaap:SellingAndMarketingExpense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 277	$ 219	$ 1,007	$ 2,187