Yes darker colour usually means you're dehydrated. The only other issue would be if you have blood in your urine and if you do you should be seeing a doctor.
I can have darker urine on high bgs but its because I'm dehydrated due to high sugar.
Statin users can get darker/orange urine. Other meds can change your urine colour too. Vit c effervescent can, for me.
Straw coloured urine is 'normal', darker colours as already said probably means you're dehydrated - lighter than straw and being diabetic (and thirsty or drinking lots) usually indicates higher Blood sugar as your kidneys are trying to flush out the excess glucose.