diff --git a/src/traditional_de/estimate_delay.jl b/src/traditional_de/estimate_delay.jl
index 4c1b2aa..40efcb0 100644
--- a/src/traditional_de/estimate_delay.jl
+++ b/src/traditional_de/estimate_delay.jl
@@ -51,11 +51,9 @@ function estimate_delay(x::AbstractVector, method::String,
         return mincrossing(c, τs)
     elseif method=="exp_decay"
         c = autocor(x, τs; demean=true)
-        if any(x -> x ≤ 0, c)
-            error("The correlation function has elements that are ≤ 0. "*
-            "We can't fit an exponential to it. Please choose another method.")
-        end
-        τ = exponential_decay_fit(τs, c)
+        idx = length(c)
+        idx = findfirst(<(0), c)
+        τ = exponential_decay_fit(τs[:idx], c[:idx])
         return round(Int,τ)
     elseif method=="exp_extrema"
         c = autocor(x, τs; demean=true)