Dunno if Id make that distinction, or how useful that distinction is.
For me, electronica is roughly 93-98, first & second wave of UK London techno/WARP offshoots which still had some tenuous relationship with dancefloor/chill out scenes.
IDM is 97/98 on and typifies a more avant/experimental tendency, especially with rhythm & timbre, which quickly turned to pastiche crunchy/glitchy drum sounds ala Richard Devine, Push Button Objects & Funkstorung.
This is arbitrary and there's a ton of crossover and grey areas. Kinda like the nebulous Jungle>>Drum & bass problem.