Muslim scholars hold different opinions regarding the purity of the smooth surfaces with wiping. Some of them view that it will be pure and that opinion was adopted by Shaykh Ibn Taymiyyah . According to that opinion, when you wipe the commode with dry tissue, this is enough to purify it.

Other scholars view that it cannot be purified with that and this is the opinion of the majority of scholars. According to them, the commode will not be purified by just wiping it with a dry tissue, rather water should be poured on the place affected by urine drops. So, if that impure place touches a wet or moist thing, that thing becomes impure according to many scholars. But, if you wish to follow those who adopt the first opinion which states that the purification has been done, then there is no blame on you. 

However, what you should do is to pour water on the place you know that urine drops affected or wash the parts of your body that touched it while it is wet to be on the safe side and be certain of purification. That is if you are certain that urine has already affected that place and that your body has already touched it while it was wet. But if you only have doubt about that, then do not pay any attention to that doubt because caring about such doubts may cause Waswasah (obsessive whispers). Moreover, the basic principle is that things are pure until they are certainty proven otherwise.