Study to Compare the Awakening Threshold Effects of Belsomra 10 mg and 20 mg to Placebo in Non-elderly Insomniacs

Inclusion Criteria * Meets DSM-5 ( Diagnostic and statistical manual) diagnostic criteria for insomnia disorder * ISI ( Insomnia Severity Index) \> 10 * Age \>18 and \< 65 * Negative audiological screening exam Exclusion Criteria: * BMI \>35 kg/m2 * Have symptoms consistent with the diagnosis of any sleep disorder other than insomnia (e.g., sleep apnea, narcolepsy, periodic leg movements, or restless leg syndrome). * Have a known or suspected diagnosis of Acquired Immune Deficiency Syndrome (AIDS), or have tested seropositive for human immunodeficiency virus (HIV) antibody or antigen previously. * Have any clinically significant abnormal finding in physical examination, neurological assessment, vital signs, elevated body temperature, or clinical laboratory tests, as determined by the Investigator. * Have a known or exaggerated pharmacological sensitivity, hypersensitivity, or intolerance to Belsomra. * Currently taking CYP3A inhibitors. * Positive breathalyzer test for alcohol at Screening, PSG Screening or any Treatment night, or a positive urine drug screen (for amphetamines, barbiturates, benzodiazepines, cocaine, opiates, or cannabinoids) at Screening; * History of hearing difficulty (e.g., use of a hearing aid). * Intends to use any medication including over-the-counter (OTC) medications that would interfere with normal sleep architecture (such as systemic steroids, beta-adrenergic blockers, amphetamines, modafinil, etc.); * Self-reports use of products containing nicotine of greater than 15 cigarettes daily, or cannot avoid products containing nicotine during the normal sleep periods; * Self report consumption of more than five alcoholic beverages on any one day or \> 14 alcoholic beverages weekly over the past week; * Have a history of epilepsy or serious head injury * Average Time in Bed \< 6.5 hrs. * Have used prescribed or OTC medications within 7 days of screening (Day 0) or intend to use any prescription or OTC medication during the study that may interfere with the evaluation of the study drug. This restriction includes taking medications that affect the Central nervous system. Any chronic maintenance therapy should have been maintained at a stable dosing regimen for at least 30 days before screening and subjects must continue this regimen throughout the study. * Have used an investigational drug within 30 days or five half lives (whichever is longer) before screening, or plans to use an investigational drug during the study or have used belsomra or zolpidem