A detonator assembly is provided. The detonator assembly comprises a deflagration to detonation transition body, a first thermally stable secondary explosive contained by the body, and a bulkhead coupled to the deflagration to detonation transition body. The bulkhead contains pressure within the body associated with firing the detonator assembly at least until a transition from a deflagration operation mode of the detonator assembly to a detonation operation mode of the detonator assembly has occurred. A second thermally stable secondary explosive may alternatively be included in the deflagration to detonation transition body, either separated from the first thermally stable secondary explosive or mixed with the first thermally stable secondary explosive. The detonator assembly comprises effectively no primary explosive.