Consider a negative unity feedback system with the forward path transfer function $\dfrac{s^{2}+s+1}{s^{3}+2s^{2}+2s+K},$ where $K$ is a positive real number. The value of $K$ for which the system will have some of its poles on the imaginary axis is ____________.
- $9$
- $8$
- $7$
- $6$