Generally speaking, there is no concern here even if you keep losing money on your Corporation. The issue is how are you supporting these losses, are you and your partner lending more money to the C corporation and properly recording these loans, are these loans ever going to be repaid etc..?
Now, a more important question for you would be why have you not converted from the C to S corporation status, had you done that, you could have at least been able to deduct these losses on your personal tax return, as it seems that you might have sufficient basis to make these deductions.
Another question arises, non-tax related, why are you still in business? If losses are accumulating and there are no signs of profitability why bother continuing this business. Now, this company could be a small development stage company and you could be developing a block buster product, and revenue and profits could be explosive, in that case you have to continue and remain a C corporation.