Yes, you can complete the Scientist career without ever joining your Sim at work. All you need for promotion is two breakthroughs at each level.
I don't recommend skipping the laboratory entirely. Scientists have some great inventions and the lab is the only place to use the Invention Constructor without cheats. It's also a good place to obtain crystals and metals, by asking your coworkers for them and ordering them to do scientific tasks. It's a shame that gardening doesn't really work there any longer but the rest of the career makes up for it, in my opinion.