Then I agree with the other posters. Take as much off the table as makes you comfortable. If it's doubled, taking half is basically "playing with the house's money".
But, you also risk losing all of your profit.
Though if you got into the stock for a particular reason and feel that it still fits those characteristics, I might just apply a "stop loss limit order". If its very non-liquid, which is sounds like since no options, it could definitly gap below your limit price and never sell and you're left holding the bag.
Sounds like a risky, volatile play to me, I'd probably take some chips off the table!
In general I set stop loss limits when I purchase a stock so I don't have to watch it like a hawk, and get a big surprise next time I check my account. I feel buying securities without the stop loss order is a bit like being on a trapeze without a net
You probably know all this already, especially if you are dabbling in the (most likely) small cap illiquid arena of equities already, but who knows who else is reading?