diff --git a/src/Language/SystemVerilog/Parser/Parse.y b/src/Language/SystemVerilog/Parser/Parse.y
index 191d8fc..2739265 100644
--- a/src/Language/SystemVerilog/Parser/Parse.y
+++ b/src/Language/SystemVerilog/Parser/Parse.y
@@ -1017,9 +1017,10 @@ Sense :: { Sense }
 
 DelayValue :: { Expr }
   : Number { Number $1 }
+  | Identifier { Ident $1 }
+  | Identifier "::" Identifier { PSIdent $1 $3 }
 -- TODO: Support these other DelayValues?
 -- | real_number
--- | ps_identifier
 -- | time_literal
 -- | 1step
 
diff --git a/test/basic/union.sv b/test/basic/union.sv
index 0ba4339..d5af45d 100644
--- a/test/basic/union.sv
+++ b/test/basic/union.sv
@@ -32,29 +32,31 @@ module wrap;
     C c;
     D d;
 
+    localparam delay = 10;
+
     initial begin
 
         $monitor($time, " %b %b", a.x, a.y);
-        a.x = 5'b01101; #10;
-        a.y = 5'b11101; #10;
+        a.x = 5'b01101; #delay;
+        a.y = 5'b11101; #delay;
 
         $monitor($time, " %b %b", b.x, b.y);
-        b.x = 5'b01101; #10;
-        b.y = 5'b11101; #10;
+        b.x = 5'b01101; #delay;
+        b.y = 5'b11101; #delay;
 
         $monitor($time, " %b %b", c.x, c.y);
-        c.x = 5'b01101; #10;
-        c.y = 5'b11101; #10;
+        c.x = 5'b01101; #delay;
+        c.y = 5'b11101; #delay;
 
         $monitor($time, " %b %b {%b %b} %b {%b %b}", d.x, d.y, d.y.a, d.y.b,
             d.z, d.z.a, d.z.b);
-        d.x = 5'b01101; #10;
-        d.y = '{ a: 3'b110, b: 2'b01 }; #10;
-        d.z = '{ b: 3'b110, a: 2'b01 }; #10;
-        d.y.a = 3'b010; #10;
-        d.y.b = 2'b10; #10;
-        d.z.a = 2'b11; #10;
-        d.z.b = 3'b101; #10;
+        d.x = 5'b01101; #delay;
+        d.y = '{ a: 3'b110, b: 2'b01 }; #delay;
+        d.z = '{ b: 3'b110, a: 2'b01 }; #delay;
+        d.y.a = 3'b010; #delay;
+        d.y.b = 2'b10; #delay;
+        d.z.a = 2'b11; #delay;
+        d.z.b = 3'b101; #delay;
 
     end