diff --git a/Cargo.toml b/Cargo.toml
index 429bf25..7d95458 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,7 +29,7 @@ alloc = []
 std = []
 clock = ["time", "std"]
 wasmbind = ["wasm-bindgen", "js-sys"]
-__internal_bench = []
+__internal_bench = ["criterion"]
 
 [dependencies]
 time = { version = "0.1.39", optional = true }
@@ -37,6 +37,8 @@ num-integer = { version = "0.1.36", default-features = false }
 num-traits = { version = "0.2", default-features = false }
 rustc-serialize = { version = "0.3.20", optional = true }
 serde = { version = "1.0.99", default-features = false, optional = true }
+# technically a dev-dependency, but they can't be optional
+criterion = { version = "0.3", optional = true}
 
 [target.'cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))'.dependencies]
 wasm-bindgen = { version = "0.2", optional = true }
@@ -48,7 +50,6 @@ serde_derive = { version = "1", default-features = false }
 bincode = { version = "0.8.0" }
 num-iter = { version = "0.1.35", default-features = false }
 doc-comment = "0.3"
-criterion = "0.3"
 
 [target.'cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))'.dev-dependencies]
 wasm-bindgen-test = "0.2"