2. All females must have a negative serum human chorionic gonadotropin (hCG) pregnancy test result at Screening and Baseline. Females of child-bearing potential must agree to use a medically acceptable method of contraception (e.g., abstinence, an intrauterine device (IUD), a double-barrier method such as condom + spermicide or condom + diaphragm with spermicide, a contraceptive implant, an oral contraceptive or have a vasectomized partner) throughout the entire study period and for 30 days after study drug discontinuation. The only subjects who will be exempt from this requirement are postmenopausal women (defined as greater than age 50 and at least 12 months of amenorrhea) or subjects who have been sterilized surgically or who are otherwise proven sterile (e.g., bilateral tubal ligation with surgery at least 6 months prior to dosing, hysterectomy, or bilateral oophorectomy with surgery at least 2 months prior to dosing). All women who are of reproductive potential and who are using hormonal contraceptives must have been on a stable dose of the same hormonal contraceptive product for at least 12 weeks prior to dosing and must continue to use the same contraceptive during the study and for 30 days after study drug discontinuation.