Pharmaceutical formulations and methods including an immune response modifier compound and an oleic acid component are provided where stability is improved by using oleic acid have low polar impurities such as peroxides. One or more secondary inserts may be disposed in the primary insert and may include a leading surface and a trailing surface. Such sensors may be useful for detecting very small motions, and may be especially useful for motions in which the shape of the user’s thumb results in the same touch area being in contact with the thumb even though the thumb is executing an extension or retraction movement. A partially reflecting mirror is provided on the first side of the window.